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A hypothesis: The role of a high-risk male in the etiology of cervical carcinoma
A hypothesis: The role of a high-risk etiology of cervical carcinoma A correlation
of epidemiology
ALBERT
PH.D.(SYD.),
SINGER,
Shejjeld,
England
BEVAN
L.
Sydney,
Australia,
MALCOLM Sydney,
REID, and
M.D., Birmingham,
COPPLESON,
and molecular
D.PHIL.(OXON),
male in the
biology
M.R.C.0.G
B.V.Sc.
England M.D.,
F.R.C.O.G.
Australia
Certain impressive epidemiological evidence appearing in the last few years leads to the conclusion that some males are more pane to have a spouse with squamous cancer of the cervix than others. Advances in knourledge in otherjelds, especially at the molecular biological level, enable speculation on reasons for this curious con&sion. These readily testable theories, together with an outline of thr ezlidence on which they re.ct,form the substance of this hypothesis.
cervix known as metaplasia. During this process columnar epithelium of the cervical canal is replaced quite physiologically by stratified squamous epitheliurn.
THE PUBLICATION of no fewer than 40 papers since the report of Rigoni-Stern’ in Verona in 1842 dealing with women and girls at special risk of developing squamous cancer of the cervix attests to the preoccupation of epidemiologists with the female. A reasonable degree of certainty now surrounds the characteristics of those women at high risk,‘, ’ especially their early age of first coitus and a cluster of epidemiological variables which are dependent on this key factor, such as early marriage, low socioeconomic class, number of coital partners, and nonmembership in a religious 4, 5 Evidence of this kind led us6-* to propose group. that a carcinogen is present in the male sperm and that it acts on a target cell which we regard as the stem cell of an important phase of epithelial transition on the From
The high-riek male-e
Epidemiological opinion is equally firm that the disease can be properly regarded as venereal.‘. ‘. “’ It is not surprising then that the possible complicity of the male as carcinogen donor has recently come under attention so that, as in the case of the female, a specific group of males is increasingly being regarded as at higher risk.“-” Suspicions as to the existence of such a group derives from evidence of various direct and indirect sources. Indeed, two broad categories of epidemiological clues can be recognized in the male: (1) the association of cervical cancer with genital cancer at other sites or with venereal disease, or with the evidence of sexual promiscuity; and (2) those from traditional demographic studies correlating cervical cancer or positive cervical cytology with the occupational group of the husband. In the first category, Martinez” observed a higher incidence than expected of cervical cancer in the wives of husbands with penile cancer. Feminella” in New York studied 101 wives of men with prostate cancer.
the Department
of Obstetrics and Gynaecoloa, and the Jessop Ho.@al for Women (Dr. Singer); Queen Elizabeth Research Znstitute for Mothers and Infants, University of Sydney, and the Department of Obstetrics and Gynaecology, University of Birmingham, Birmingham Maternity Hospital (Dr. Reid); and the Department of Obstetrics and Gynaecologv, King George V Hospital (Dr. Coppleson).
University of Sheffield,
Received for publication Accepted December
October
ev#dence
7, 1975.
16, 1975.
Reprint requests: Dr. Albert Singer, Department of Obstetrics and Gynecology, Jessop Hospital for Women, University of Shefjeld, SheSJieM S? 7RE, England. 110
Volume Number
126 1
Three developed invasive cervical disease and two possessed an abnormal cervical smear. This incidence is higher than would normally be expected in such a population. Blythe-Smith and .Jenkins17 mapped the high frequency of premalignant and malignant lesions within a housing estate in Atlanta of indigent Negro women. They were able to indicate a cohabitation relationship between some of the affected women with soecific males. The sexual behavior of Jewish husbands has been the subject of some enquiry in the literature because their wives belong to a well-studied group of women considered to be at low risk for the development of cervical neoplasia.‘. ’ It is suggested’8s ” that the increasingly liberal sexual behavior of the Jewish male may be responsible for the development of cervical carcinoma in many -Jewish women in whom Martinlg could find “no accepted behavioral factor of etiological significance.” He also found that 80 percent of husbands of Jewish women with this neoplasm had a history of’ venereal disease. Pridan and Lilienfeld” also showed that 80 percent of Jewish males whose wives had this malignancy had more than nine sexual partners compared with 44 percent in a matched control group. The increasing frequency of venereal infections in Jewish males has been suggested by Ravich” to be associated with a slight but noticeable rise in their rate of prostate cancer.“” Studies in Israel23 have shown a difference in the rate of this cancer between occidental and oriental Jews. This community difference mirrors a similar relationship in the distribution of cervical cancer between European (Rumanian) and oriental (Yeminite) Jewish women residing in Israel.‘4 It is believed that liberal sexual behavior is commoner among the former. Before leaving the topic of these Israeli figures, it is relevant to mention again the report of‘ Lilienfeld and Pridan*’ concerning the over twofold higher incidence of widows among women with cervical cancer. This curious fact has again been observed in an Australian study,‘” where the incidence of widows was even higher. We could well ask what caused the death of the spouse in these cases. Tradirional demographic studies have evaluated more precisely an opinion widely shared by practicing gynecologists for many years emphasizing the importance of the contribution of a low socioeconomic environment to the origin of squamous cancer of the cervix.26-~2n As long ago as 1908, Theilhaber and Greischer’” in Munich showed a sixfold increase in the risk of developing the disease among the wives of “day laborers, unskilled workers, agricultural laborers, paupers, factory hands, and lower officials” as compared with the wives of “physicians, lawyers, heads of
Role of high-risk
male in cervical
111
carcinoma
Table I. Standardized mortality ratios fi~r cw\ id carcinoma by husbands’ occupations in mat-r14 women.
Occupations
of husbands
Fishermen. seamen, deck and engine-room ratings, barge and boatmen Laborers Crane and hoist operators Transport and long-distance lorry drivers Lodginghouse and hotel keepers Textile
workers
Miners and quarrymen Gas, coke, and chemical workers Gardeners and groundsmen, service, sport, and recreation workers Clerical workers Civil engineers Administrators, managers, and senior government officials Teachers Scientists Clergymen
1 80 I50 140
13) 150 133 120 I I:,
08
67
40-64 60 40
.50
-. -
30 17 12
firms, persons of independent means, and high officials.” More recently in Britain, Wakefield and associates”’ on the basis of positive cytology and Beral’ on the basis of standardized mortaiity rates have shown an almost linear correlation between incidence and husband’s occupation based on the classification of the Registrar General. There was an over threefold difference of incidence between the wives of manual laborers compared with those of men in professional occupations (Table I).
Derivation of the mokm& It seems justified to speak of the existence of a group in the male population at high risk”-‘” in the same wa? although with less documentation, as epidemiologists have delimited a female counterpart.“.“ A multidisciplined attack at the biological and molecular level on the latter problem has allowed a more precise definition of the tissue at risk and possibly of the stem celi of the neoplasm itself.“” 31 It has thus gone some way toward an understanding of why such a group of women is so predisposed. In the more recent course of this research a general theory of neopfasia has been constructed,33 some elements of which enable a hypothesis to be proposed on the rcaasom for the exist-
112 Singer, Reid, and Coppleson
02)
Fig. 1. Arrangement of surface filaments of the normal [A) and cancerous (B) cell as theoretically predicted.” It is proposed that histones of sperm origin (H in (C)) in the environment of the differentiating metaplastic cell rapidly evoke the appearance of excessive DNA-containing filaments at its surface and these specifically determine its neoplastic destiny. Different males may have qualitative or quantitative differences in their gamete histones (H, h) of more or less efficacy in the proposed reaction. ence of males more prone to produce cervical cancer in their sexual partner.
an associated
Role of cell surface DNA The evidence for such a theory is documented elsewhere,33 but its essentials can be summarized as follows: 1. The majority of the DNA of the eukaryote cell possesses a base sequence fitting it for the combined function of cytoskeleton and environmental sensor. The minor portion of the cellular DNA has a base sequence which is more suitable as a code for the synthesis of amino acids by the familiar transcriptiontranslation mechanism. 2. At any given time a very small fraction of the total cellular DNA, probably less than 1 percent, exists throughout the cytoplasm and also on the surface of the cell in the form of a deoxyribonucleoprotein network. 3. The reservoir for this surface network is the nucleus from which its component filaments are drawn to this site during cellular differentiation by the familiar process of ameboid movement. This ameboid activity by the differentiating cell represents a piecemeal
exposure of the genome to the cellular ambient t.nvironment whereby a small but specific fraction of the DNA available in the reservoir is selected. Integration of this fraction with the environment both retains it outside the nucleus as a superficial network and pry grams it for the activation of the protein-synthesizing component of the cellular DNA. This network with which the protein-synthesizing-function DNA is proposedly colinear is thus a type of’ selective switch. ~l‘he coincidence of proportionate amounts of these tl\ o functional types of DNA, namely, switchgear and protein-synthetic, results respectively in the production of both the mucoid coat (glycocalyx) and the cytoplasmic coat of the differentiated cell. Earlv in the differentiation process, DNA not so utilized retreats to the nucleus where it is insulated from further activation IJ\ the cytoplasmic and mucoid coats. 4. Carcinogens in the cell environment cause the projection by a variety of mechanisms of disproportionately increased amounts of sensory or switchgrar type DNA toward the cell surface followed by its subsequent retention in this site (Fig. 1, .d and B). Two end results are thereby made possible: (1) an increased potential for activation of that DNA fraction concerned with protein synthesis and (2) alteration in the surface properties of the cell contingent on an increased content of surface DNA.
Induced modification of surface DNA by histone For several reasons we have incriminated basic proteins of the sperm head as those substances in the environment of the stem cell of the metaplastic process which are capable of evoking an excessive amount of the DNA of the metaplastic cell to the cell surface.‘” The idea was based on the avidity shown by molecular DNA in vitro under the electron microscope to aggregate and become densely concentrated on films of polystyrene containing histone as contrasted with the behavior of these molecules on films containing other proteins. 3’ Proceeding from such studies to the use of’ histones in cell cultures it was found that a few minutes’ contact with low doses (50 to 100 pg per milliliter) of histone but not with other proteins (e.g., albumin. globulin, gelatin) resulted in the enlargement of the nucleus with the production of an extensive mucoid coat which resulted in cell aggregation (Fig. 1, L’).“’ Such a mucoid coat was shown in previous studies to contain a DNA skeleton derived in turn from the cell nucleus.“6 Hamster kidney cells exposed to low doses of histones behave in the same way with nuclear enlargcment. Cells so treated show tumorigenic and invasive properties.“‘, ”
Volume Number
126 1
Role of high-risk
male in cervical carcinoma
Fig. 2A. Photomicrograph of human melanoma cell from tissue culture rotary shadowed and viewed under the light microscope. The surface coat growing in vitro is extensively covered w-ith microfilaments. Intervening smooth areas of the cell surface are more extensive in normal cellz. ( x 1,000.)
Fig.
2B. Photomicrograph
of human
colonic
cancer
cell. See legend
of Fig. 2A.
113
114
Singer,
Reid,
and Coppleson
Based on a similar argument, the polyamines spermine and spermidine of seminal plasma may be expected to show the same sort of activity as the basic proteins of the sperm head. These basic substances which reach high concentrations in human semen have a similar avidity for DNA.‘”
Comment Correlation of epidemiological findings indicating the existence of variation among different males with the proposed importance of histones in causing the initial cellular events associated with neoplasia poses the question of the existence of a variation in the content of these basic proteins among the sperm of different males. Histones exist in close association with DNA when the latter is in a condensed state, such as in heterochromatin, and, indeed, vary in linear fashion as the heterochromatin content of the nucleus varies.” Not surprisingly, some of the richest sources of very basic proteins are found in association with the condensed DNA of the sperm head.“’ It seems reasonable then to attempt a correlation between quantitative or qualitative variations in sperm histones and those diverse behavioral and sociological attributes of the individual which have been uncovered by epidemiological and other evidence such as occupation group, premature widowhood, and perhaps sexual promiscuity. Methods are available for the extraction of histones from the sperm head4’ and for their further characterization on polyacrylamide gels by electrophoresis”” which are adaptable to human sperm.“” It is thus possible to compare both the types and quantities of the sperm histones of partners of known cases of precancerous and cancerous women with a control
series. Similar quantitative studies are possible in seeking differences in the basic polyamine content of different semen samples. At the cellular level it should be possible to add sperm basic proteins to cultures of normal differentiating cells and examine their subsequent fate on reinjection into the host in the same way as Latner and co-workers3* have done. Hamster kidney cells so treated were shown to produce a tumor upon reinjection which actively invaded host tissues. Evidence of an equally indirect type is afforded by morphological study of the surface coat of histone-treated cells. On theoretical grounds potentially neoplastic cells should be covered by a coat with an increased content of surface filaments (Fig. 1, B), a prediction which has been realized in some recent studies both of ours (Fig. 2)” and of some American groups.‘6 Variations in the sperm head content of DNA have recently been reported between different strains of mice using cytophotometric means.” It is possible that some of this variation is reflected in variations in histone content with which the DNA is associated and this too may be resolvable with cytochemical techniques of the type used for showing quantitative strain difference in histones in plant cells” and in the human cervix uteri.“’ We wish to thank Prof. Martin Vessey and Prof. Sir Richard Doll of Oxford for the constructive and critical comments on the manuscript; Mr. Robert Markham and Mr. Peter Blackwell of Sydney and the editor of Pathologyfor kind permission to reproduce Fig. 2, anti for their assistance in many of the studies on which this hypothesis is based.
REFERENCE6 1. Rigoni-Stern, D.: Fatti staristici relativi alle mallartie cancrose the servirono di base alle poche case dette dal Dott. G. Servire, Prog. Pathol. Terap. Ser. 2: 507, 1842. 2. Rotkin, I.: A comparison review of key epidemiological studies in cervical cancer related to current searches for transmissible agents, Cancer Res. 35: 1353, 1973. 3. Kessler, I.: Perspectives on the epidemiology of cervical cancer with special reference to the herpes virus hypothesis. Cancer Res. 34: 1091, 1974. 4. Conpleson, M.: Carcinoma of the cervix: Epidemiology ani*aetiology, Br. J. Hosp. Med. 2: 961, 1969. 5. Wvnder. E. L.. Cornfield. T., Schroff, P., and Doraiswami, K./R.: Study oienvironn&& factors in carcinoma of the cervix, AM. J. OBSTET. GYNECOL. 68: 1016, 1954. 6. Reid, B. L.: Cancer of the cervix uteri: Review of causal factors with an hypothesis for its origin, Med. J. Aust. 1: 375, 1965. 7. Coppleson, M., and Reid, B.: Preclinical Carcinoma of the Cervix, Oxford, 1967, Pergamon Press, p. 254. 8. Reid, B. L., and Coppleson, M.: In McDonald, R. M.,
editor: Oxford,
Scientific Basis of Obstetrics 1971, J. & A. Churchill, Ltd,
and Gynaecotogy, p. 415.
9. Beral, V.: Cancer of the cervix: A sexually transmitted disease,
Lancet
2: 1037,
1974.
10. Boyd, J. T., and Doll, R.: A study of the aetiology of carcinoma of the cervix uteri, Br. J. Cancer 18: 419, 1964. 11. Singer, A.: The male factor in cervical cancer, Oxford Med. Sch. Gaz. 25: 18, 1973. 12. Singer, A.: Carcinoma of the cervix and herpes virus, Br. Med. J. 3: 290, 1972. 13. Singer, A.: Cancer of the cervix: A sexually transmitted infection? Lancet 2: 41, 1974. 14. Singer, A.: Multifactorial Aspects of the Cause and Nature of Cervical Precancer. London. 1975, Edgar-GentilIi Prize Essay, Royal College of Ob&et&ians and Gynaecologists. 15. Martinez, L.: Relationship of squamous cell carcinoma of the cervix uteri to squamous cell carcinoma of the penis, Cancer 24: 777, 1969. 16. Feminella, J.: An apparent increase in genital carcinomas
Volume Number
17.
18. 19. 20.
21. 22.
23. 24.
25. 26.
27.
28. 29.
30.
31.
32.
33
126 1
amongst wives of men with prostatic cancer: An epidemiological study, Bull. Clin. Med. 20: 6 3, 1973. Btythe-Smith, D., and Jenkins, R.: Cervical cancer in a housing project: Report of a cluster of cases, AM. J. OBSTET.GYNECOL. 104:603, 1969. Martin, C.: Marital and coital factors in cervical cancer, Am. J. Pub. Health 27: 803, 1967. Martin, C.: Marital and Coital Factors in Cervical Cancer, Ann Arbor, Mich., 1967, University Microfilm. Pridan, H., and Lilienfeld, A. M.: Carcinoma of the cervix in Jewish women in Israel 1960-1967: An epidemiological survey, Isr. J. Med. SC;. 7: 1465, 1971. Ravich, A.: Viral carcinogenesis in venereally susceptible organs, Cancer 27: 1493. 197 1. Kaplan, G.. and O’Conor. V.: The incidence of carcinoma of the prostate in Jews and Gentiles, J. A. M. A. 196: 804, 1966. Kook, N., and Kook, H.: Carcinoma of the prostate in Israel: Preliminary report, Br. J. Ural. 34: 322, 1962. Steinitz, R., and Costin. C.: Cancer in Israel, Fact and figures, 1960-1966, Jerusalem, 1970, Ministry of Health and Israel Cancer Association. Singer, A.. Heitner, C., Coppleson, M., Smith, P., and Reid, B. L.: Unpublished. Aitken-Swan, J., and Baird, D.: Cancer of the uterine cervix in Aberdeenshire: Epidemiological aspects, Br. J. Cancer 20: 642, 1966. Dorn, H. F., and Cutler. S. J.: Morbidity From Cancer in the United States, Washington D.C., 1959, USPHS Publication No. 590, U.S. Govt. Printing Office. Wynder, E. L.: Epidemiology of carcinoma in situ of the cervix, Obstet. Gvnecol. Survey 24: 697, 1969. Theilhaber and Greischer, 191’0: quoted by Kennaway, E. L.: The racial and social incidence of cancer of the uterus, Br. J. Cancer 2: 177, 1948. Wakefield, J., Yule, R.. Smith, A., and Adelstein, A. M.: Abnormal cytological smears, carcinoma of the cervix uteri.and husbands’occupation, Br. Med. J. 2: 142, 1973. Coppleson, M., and Reid, B. L.: The origin and nature of premalignant lesions of the cervix uteri, in Taymor, M. L.. and Green, T. H., editors: Progress in Gynaecology, New York, 1975, Grune % Stratton, Inc. Reid, B. L., and Coppleson, M.: The natural history of cervical carcinoma, in Jordan, J., and Singer, A., editors: The Cervix, London, 1976. W. 8. Saunders Company. Reid, B. I,.: Integration of the living cell with its environment: Speculation on the function of the DNA content of surface mucoids. Biosvstems 5: 207, 1974.
Role of high-risk
34.
35.
36.
37.
38.
39.
40. 41. 42.
43.
44. 45.
46. 47.
48.
male in cervical
carctnoma
115
Reid, B. L.. and Blackwell, P. XI.: The behaviour of DNA molecules on polvstyrene films. .4ust. J. Med. I‘echnol. 4: 168. 1973. Reid, B. L., and BlackweIl, P. M.: Histone and polyaminoacid DNA interactions at molecubr and cellular levels, Proc. Eighth Int. Congr. Electron tlic-roscopv. Canberra 2: 270, r974. ’ Reid. B. L.. and Blackwell, P. M.: Nuclear extensions of cultured cells: A possible mechanism of cellular differentiation, in Ledoux, ‘L., editor: Informative hfolecules in Biological Systems, Amsterdam, 195 1. Norrlr Holland Publishing Co., p. 285. Latner, A. L., and Longstaff. E.: ‘Transformation ot mammalian cells bv crude histones, Br. J, (;anr:et- 25: 280, 1971. Lamer, A. L., Longstaff-, E., and Turner, A. G.. Enhanced malignant behaviour of cells treated v+ith crude rat histone. Br. J. Cancer 27: 218, 1973. Tabor, H.: The protective effect of spermme and other polyamines against heat denaturation of deosvribonucleic acid. Biochemistrv 1: 497. 1962. Himes, M.: An analysis of heterochromatin in maize root tips, J. Cell Biol. 35: 175. 1967. Bloch, D. P.: A catalog of sperm histones, (;enetics 61: suppl. 93, 1969. Coelingh, J. P., Rozijn, T. H., and Montonrt, C. R.: lsotation and partial characterisation of a basic protein from bovine sperm heads, Biochem. Biophvs. Acta 188: 353. 1969. Pan+, S., and Chalkley, R.: High resolution acrvlamide gel electrophoresis of histones. Arch. Biochrm. Biophys. 130:337, 1969. Reid, B. L.: Unpublished. Markham, R.. Blackwell, P. Xf., and L’sher, G.: A shadow-casting technique for the examination of the surface topography of cultured cells. Pathology 7: 45. 1975. Kalata, G. B.: MicroviIli: A major difference between normal and cancer cells, Science 188: Hl!). 1975. Moore, G. P. M., and Beatty, R. A.: The DNA content of spermatozoa from different strains of mice. J. Reprod. Fez-m. 38: 473, 1974. Hertzog, R. E.: Zur Bestimmung von Arginin im Zellkern des menslichen Portio Epithels. .4rch C;vn,rekol. 217: 437, 1974.
of epidemiology
ALBERT
PH.D.(SYD.),
SINGER,
Shejjeld,
England
BEVAN
L.
Sydney,
Australia,
MALCOLM Sydney,
REID, and
M.D., Birmingham,
COPPLESON,
and molecular
D.PHIL.(OXON),
male in the
biology
M.R.C.0.G
B.V.Sc.
England M.D.,
F.R.C.O.G.
Australia
Certain impressive epidemiological evidence appearing in the last few years leads to the conclusion that some males are more pane to have a spouse with squamous cancer of the cervix than others. Advances in knourledge in otherjelds, especially at the molecular biological level, enable speculation on reasons for this curious con&sion. These readily testable theories, together with an outline of thr ezlidence on which they re.ct,form the substance of this hypothesis.
cervix known as metaplasia. During this process columnar epithelium of the cervical canal is replaced quite physiologically by stratified squamous epitheliurn.
THE PUBLICATION of no fewer than 40 papers since the report of Rigoni-Stern’ in Verona in 1842 dealing with women and girls at special risk of developing squamous cancer of the cervix attests to the preoccupation of epidemiologists with the female. A reasonable degree of certainty now surrounds the characteristics of those women at high risk,‘, ’ especially their early age of first coitus and a cluster of epidemiological variables which are dependent on this key factor, such as early marriage, low socioeconomic class, number of coital partners, and nonmembership in a religious 4, 5 Evidence of this kind led us6-* to propose group. that a carcinogen is present in the male sperm and that it acts on a target cell which we regard as the stem cell of an important phase of epithelial transition on the From
The high-riek male-e
Epidemiological opinion is equally firm that the disease can be properly regarded as venereal.‘. ‘. “’ It is not surprising then that the possible complicity of the male as carcinogen donor has recently come under attention so that, as in the case of the female, a specific group of males is increasingly being regarded as at higher risk.“-” Suspicions as to the existence of such a group derives from evidence of various direct and indirect sources. Indeed, two broad categories of epidemiological clues can be recognized in the male: (1) the association of cervical cancer with genital cancer at other sites or with venereal disease, or with the evidence of sexual promiscuity; and (2) those from traditional demographic studies correlating cervical cancer or positive cervical cytology with the occupational group of the husband. In the first category, Martinez” observed a higher incidence than expected of cervical cancer in the wives of husbands with penile cancer. Feminella” in New York studied 101 wives of men with prostate cancer.
the Department
of Obstetrics and Gynaecoloa, and the Jessop Ho.@al for Women (Dr. Singer); Queen Elizabeth Research Znstitute for Mothers and Infants, University of Sydney, and the Department of Obstetrics and Gynaecology, University of Birmingham, Birmingham Maternity Hospital (Dr. Reid); and the Department of Obstetrics and Gynaecologv, King George V Hospital (Dr. Coppleson).
University of Sheffield,
Received for publication Accepted December
October
ev#dence
7, 1975.
16, 1975.
Reprint requests: Dr. Albert Singer, Department of Obstetrics and Gynecology, Jessop Hospital for Women, University of Shefjeld, SheSJieM S? 7RE, England. 110
Volume Number
126 1
Three developed invasive cervical disease and two possessed an abnormal cervical smear. This incidence is higher than would normally be expected in such a population. Blythe-Smith and .Jenkins17 mapped the high frequency of premalignant and malignant lesions within a housing estate in Atlanta of indigent Negro women. They were able to indicate a cohabitation relationship between some of the affected women with soecific males. The sexual behavior of Jewish husbands has been the subject of some enquiry in the literature because their wives belong to a well-studied group of women considered to be at low risk for the development of cervical neoplasia.‘. ’ It is suggested’8s ” that the increasingly liberal sexual behavior of the Jewish male may be responsible for the development of cervical carcinoma in many -Jewish women in whom Martinlg could find “no accepted behavioral factor of etiological significance.” He also found that 80 percent of husbands of Jewish women with this neoplasm had a history of’ venereal disease. Pridan and Lilienfeld” also showed that 80 percent of Jewish males whose wives had this malignancy had more than nine sexual partners compared with 44 percent in a matched control group. The increasing frequency of venereal infections in Jewish males has been suggested by Ravich” to be associated with a slight but noticeable rise in their rate of prostate cancer.“” Studies in Israel23 have shown a difference in the rate of this cancer between occidental and oriental Jews. This community difference mirrors a similar relationship in the distribution of cervical cancer between European (Rumanian) and oriental (Yeminite) Jewish women residing in Israel.‘4 It is believed that liberal sexual behavior is commoner among the former. Before leaving the topic of these Israeli figures, it is relevant to mention again the report of‘ Lilienfeld and Pridan*’ concerning the over twofold higher incidence of widows among women with cervical cancer. This curious fact has again been observed in an Australian study,‘” where the incidence of widows was even higher. We could well ask what caused the death of the spouse in these cases. Tradirional demographic studies have evaluated more precisely an opinion widely shared by practicing gynecologists for many years emphasizing the importance of the contribution of a low socioeconomic environment to the origin of squamous cancer of the cervix.26-~2n As long ago as 1908, Theilhaber and Greischer’” in Munich showed a sixfold increase in the risk of developing the disease among the wives of “day laborers, unskilled workers, agricultural laborers, paupers, factory hands, and lower officials” as compared with the wives of “physicians, lawyers, heads of
Role of high-risk
male in cervical
111
carcinoma
Table I. Standardized mortality ratios fi~r cw\ id carcinoma by husbands’ occupations in mat-r14 women.
Occupations
of husbands
Fishermen. seamen, deck and engine-room ratings, barge and boatmen Laborers Crane and hoist operators Transport and long-distance lorry drivers Lodginghouse and hotel keepers Textile
workers
Miners and quarrymen Gas, coke, and chemical workers Gardeners and groundsmen, service, sport, and recreation workers Clerical workers Civil engineers Administrators, managers, and senior government officials Teachers Scientists Clergymen
1 80 I50 140
13) 150 133 120 I I:,
08
67
40-64 60 40
.50
-. -
30 17 12
firms, persons of independent means, and high officials.” More recently in Britain, Wakefield and associates”’ on the basis of positive cytology and Beral’ on the basis of standardized mortaiity rates have shown an almost linear correlation between incidence and husband’s occupation based on the classification of the Registrar General. There was an over threefold difference of incidence between the wives of manual laborers compared with those of men in professional occupations (Table I).
Derivation of the mokm& It seems justified to speak of the existence of a group in the male population at high risk”-‘” in the same wa? although with less documentation, as epidemiologists have delimited a female counterpart.“.“ A multidisciplined attack at the biological and molecular level on the latter problem has allowed a more precise definition of the tissue at risk and possibly of the stem celi of the neoplasm itself.“” 31 It has thus gone some way toward an understanding of why such a group of women is so predisposed. In the more recent course of this research a general theory of neopfasia has been constructed,33 some elements of which enable a hypothesis to be proposed on the rcaasom for the exist-
112 Singer, Reid, and Coppleson
02)
Fig. 1. Arrangement of surface filaments of the normal [A) and cancerous (B) cell as theoretically predicted.” It is proposed that histones of sperm origin (H in (C)) in the environment of the differentiating metaplastic cell rapidly evoke the appearance of excessive DNA-containing filaments at its surface and these specifically determine its neoplastic destiny. Different males may have qualitative or quantitative differences in their gamete histones (H, h) of more or less efficacy in the proposed reaction. ence of males more prone to produce cervical cancer in their sexual partner.
an associated
Role of cell surface DNA The evidence for such a theory is documented elsewhere,33 but its essentials can be summarized as follows: 1. The majority of the DNA of the eukaryote cell possesses a base sequence fitting it for the combined function of cytoskeleton and environmental sensor. The minor portion of the cellular DNA has a base sequence which is more suitable as a code for the synthesis of amino acids by the familiar transcriptiontranslation mechanism. 2. At any given time a very small fraction of the total cellular DNA, probably less than 1 percent, exists throughout the cytoplasm and also on the surface of the cell in the form of a deoxyribonucleoprotein network. 3. The reservoir for this surface network is the nucleus from which its component filaments are drawn to this site during cellular differentiation by the familiar process of ameboid movement. This ameboid activity by the differentiating cell represents a piecemeal
exposure of the genome to the cellular ambient t.nvironment whereby a small but specific fraction of the DNA available in the reservoir is selected. Integration of this fraction with the environment both retains it outside the nucleus as a superficial network and pry grams it for the activation of the protein-synthesizing component of the cellular DNA. This network with which the protein-synthesizing-function DNA is proposedly colinear is thus a type of’ selective switch. ~l‘he coincidence of proportionate amounts of these tl\ o functional types of DNA, namely, switchgear and protein-synthetic, results respectively in the production of both the mucoid coat (glycocalyx) and the cytoplasmic coat of the differentiated cell. Earlv in the differentiation process, DNA not so utilized retreats to the nucleus where it is insulated from further activation IJ\ the cytoplasmic and mucoid coats. 4. Carcinogens in the cell environment cause the projection by a variety of mechanisms of disproportionately increased amounts of sensory or switchgrar type DNA toward the cell surface followed by its subsequent retention in this site (Fig. 1, .d and B). Two end results are thereby made possible: (1) an increased potential for activation of that DNA fraction concerned with protein synthesis and (2) alteration in the surface properties of the cell contingent on an increased content of surface DNA.
Induced modification of surface DNA by histone For several reasons we have incriminated basic proteins of the sperm head as those substances in the environment of the stem cell of the metaplastic process which are capable of evoking an excessive amount of the DNA of the metaplastic cell to the cell surface.‘” The idea was based on the avidity shown by molecular DNA in vitro under the electron microscope to aggregate and become densely concentrated on films of polystyrene containing histone as contrasted with the behavior of these molecules on films containing other proteins. 3’ Proceeding from such studies to the use of’ histones in cell cultures it was found that a few minutes’ contact with low doses (50 to 100 pg per milliliter) of histone but not with other proteins (e.g., albumin. globulin, gelatin) resulted in the enlargement of the nucleus with the production of an extensive mucoid coat which resulted in cell aggregation (Fig. 1, L’).“’ Such a mucoid coat was shown in previous studies to contain a DNA skeleton derived in turn from the cell nucleus.“6 Hamster kidney cells exposed to low doses of histones behave in the same way with nuclear enlargcment. Cells so treated show tumorigenic and invasive properties.“‘, ”
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Role of high-risk
male in cervical carcinoma
Fig. 2A. Photomicrograph of human melanoma cell from tissue culture rotary shadowed and viewed under the light microscope. The surface coat growing in vitro is extensively covered w-ith microfilaments. Intervening smooth areas of the cell surface are more extensive in normal cellz. ( x 1,000.)
Fig.
2B. Photomicrograph
of human
colonic
cancer
cell. See legend
of Fig. 2A.
113
114
Singer,
Reid,
and Coppleson
Based on a similar argument, the polyamines spermine and spermidine of seminal plasma may be expected to show the same sort of activity as the basic proteins of the sperm head. These basic substances which reach high concentrations in human semen have a similar avidity for DNA.‘”
Comment Correlation of epidemiological findings indicating the existence of variation among different males with the proposed importance of histones in causing the initial cellular events associated with neoplasia poses the question of the existence of a variation in the content of these basic proteins among the sperm of different males. Histones exist in close association with DNA when the latter is in a condensed state, such as in heterochromatin, and, indeed, vary in linear fashion as the heterochromatin content of the nucleus varies.” Not surprisingly, some of the richest sources of very basic proteins are found in association with the condensed DNA of the sperm head.“’ It seems reasonable then to attempt a correlation between quantitative or qualitative variations in sperm histones and those diverse behavioral and sociological attributes of the individual which have been uncovered by epidemiological and other evidence such as occupation group, premature widowhood, and perhaps sexual promiscuity. Methods are available for the extraction of histones from the sperm head4’ and for their further characterization on polyacrylamide gels by electrophoresis”” which are adaptable to human sperm.“” It is thus possible to compare both the types and quantities of the sperm histones of partners of known cases of precancerous and cancerous women with a control
series. Similar quantitative studies are possible in seeking differences in the basic polyamine content of different semen samples. At the cellular level it should be possible to add sperm basic proteins to cultures of normal differentiating cells and examine their subsequent fate on reinjection into the host in the same way as Latner and co-workers3* have done. Hamster kidney cells so treated were shown to produce a tumor upon reinjection which actively invaded host tissues. Evidence of an equally indirect type is afforded by morphological study of the surface coat of histone-treated cells. On theoretical grounds potentially neoplastic cells should be covered by a coat with an increased content of surface filaments (Fig. 1, B), a prediction which has been realized in some recent studies both of ours (Fig. 2)” and of some American groups.‘6 Variations in the sperm head content of DNA have recently been reported between different strains of mice using cytophotometric means.” It is possible that some of this variation is reflected in variations in histone content with which the DNA is associated and this too may be resolvable with cytochemical techniques of the type used for showing quantitative strain difference in histones in plant cells” and in the human cervix uteri.“’ We wish to thank Prof. Martin Vessey and Prof. Sir Richard Doll of Oxford for the constructive and critical comments on the manuscript; Mr. Robert Markham and Mr. Peter Blackwell of Sydney and the editor of Pathologyfor kind permission to reproduce Fig. 2, anti for their assistance in many of the studies on which this hypothesis is based.
REFERENCE6 1. Rigoni-Stern, D.: Fatti staristici relativi alle mallartie cancrose the servirono di base alle poche case dette dal Dott. G. Servire, Prog. Pathol. Terap. Ser. 2: 507, 1842. 2. Rotkin, I.: A comparison review of key epidemiological studies in cervical cancer related to current searches for transmissible agents, Cancer Res. 35: 1353, 1973. 3. Kessler, I.: Perspectives on the epidemiology of cervical cancer with special reference to the herpes virus hypothesis. Cancer Res. 34: 1091, 1974. 4. Conpleson, M.: Carcinoma of the cervix: Epidemiology ani*aetiology, Br. J. Hosp. Med. 2: 961, 1969. 5. Wvnder. E. L.. Cornfield. T., Schroff, P., and Doraiswami, K./R.: Study oienvironn&& factors in carcinoma of the cervix, AM. J. OBSTET. GYNECOL. 68: 1016, 1954. 6. Reid, B. L.: Cancer of the cervix uteri: Review of causal factors with an hypothesis for its origin, Med. J. Aust. 1: 375, 1965. 7. Coppleson, M., and Reid, B.: Preclinical Carcinoma of the Cervix, Oxford, 1967, Pergamon Press, p. 254. 8. Reid, B. L., and Coppleson, M.: In McDonald, R. M.,
editor: Oxford,
Scientific Basis of Obstetrics 1971, J. & A. Churchill, Ltd,
and Gynaecotogy, p. 415.
9. Beral, V.: Cancer of the cervix: A sexually transmitted disease,
Lancet
2: 1037,
1974.
10. Boyd, J. T., and Doll, R.: A study of the aetiology of carcinoma of the cervix uteri, Br. J. Cancer 18: 419, 1964. 11. Singer, A.: The male factor in cervical cancer, Oxford Med. Sch. Gaz. 25: 18, 1973. 12. Singer, A.: Carcinoma of the cervix and herpes virus, Br. Med. J. 3: 290, 1972. 13. Singer, A.: Cancer of the cervix: A sexually transmitted infection? Lancet 2: 41, 1974. 14. Singer, A.: Multifactorial Aspects of the Cause and Nature of Cervical Precancer. London. 1975, Edgar-GentilIi Prize Essay, Royal College of Ob&et&ians and Gynaecologists. 15. Martinez, L.: Relationship of squamous cell carcinoma of the cervix uteri to squamous cell carcinoma of the penis, Cancer 24: 777, 1969. 16. Feminella, J.: An apparent increase in genital carcinomas
Volume Number
17.
18. 19. 20.
21. 22.
23. 24.
25. 26.
27.
28. 29.
30.
31.
32.
33
126 1
amongst wives of men with prostatic cancer: An epidemiological study, Bull. Clin. Med. 20: 6 3, 1973. Btythe-Smith, D., and Jenkins, R.: Cervical cancer in a housing project: Report of a cluster of cases, AM. J. OBSTET.GYNECOL. 104:603, 1969. Martin, C.: Marital and coital factors in cervical cancer, Am. J. Pub. Health 27: 803, 1967. Martin, C.: Marital and Coital Factors in Cervical Cancer, Ann Arbor, Mich., 1967, University Microfilm. Pridan, H., and Lilienfeld, A. M.: Carcinoma of the cervix in Jewish women in Israel 1960-1967: An epidemiological survey, Isr. J. Med. SC;. 7: 1465, 1971. Ravich, A.: Viral carcinogenesis in venereally susceptible organs, Cancer 27: 1493. 197 1. Kaplan, G.. and O’Conor. V.: The incidence of carcinoma of the prostate in Jews and Gentiles, J. A. M. A. 196: 804, 1966. Kook, N., and Kook, H.: Carcinoma of the prostate in Israel: Preliminary report, Br. J. Ural. 34: 322, 1962. Steinitz, R., and Costin. C.: Cancer in Israel, Fact and figures, 1960-1966, Jerusalem, 1970, Ministry of Health and Israel Cancer Association. Singer, A.. Heitner, C., Coppleson, M., Smith, P., and Reid, B. L.: Unpublished. Aitken-Swan, J., and Baird, D.: Cancer of the uterine cervix in Aberdeenshire: Epidemiological aspects, Br. J. Cancer 20: 642, 1966. Dorn, H. F., and Cutler. S. J.: Morbidity From Cancer in the United States, Washington D.C., 1959, USPHS Publication No. 590, U.S. Govt. Printing Office. Wynder, E. L.: Epidemiology of carcinoma in situ of the cervix, Obstet. Gvnecol. Survey 24: 697, 1969. Theilhaber and Greischer, 191’0: quoted by Kennaway, E. L.: The racial and social incidence of cancer of the uterus, Br. J. Cancer 2: 177, 1948. Wakefield, J., Yule, R.. Smith, A., and Adelstein, A. M.: Abnormal cytological smears, carcinoma of the cervix uteri.and husbands’occupation, Br. Med. J. 2: 142, 1973. Coppleson, M., and Reid, B. L.: The origin and nature of premalignant lesions of the cervix uteri, in Taymor, M. L.. and Green, T. H., editors: Progress in Gynaecology, New York, 1975, Grune % Stratton, Inc. Reid, B. L., and Coppleson, M.: The natural history of cervical carcinoma, in Jordan, J., and Singer, A., editors: The Cervix, London, 1976. W. 8. Saunders Company. Reid, B. I,.: Integration of the living cell with its environment: Speculation on the function of the DNA content of surface mucoids. Biosvstems 5: 207, 1974.
Role of high-risk
34.
35.
36.
37.
38.
39.
40. 41. 42.
43.
44. 45.
46. 47.
48.
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carctnoma
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Reid, B. L.. and Blackwell, P. XI.: The behaviour of DNA molecules on polvstyrene films. .4ust. J. Med. I‘echnol. 4: 168. 1973. Reid, B. L., and BlackweIl, P. M.: Histone and polyaminoacid DNA interactions at molecubr and cellular levels, Proc. Eighth Int. Congr. Electron tlic-roscopv. Canberra 2: 270, r974. ’ Reid. B. L.. and Blackwell, P. M.: Nuclear extensions of cultured cells: A possible mechanism of cellular differentiation, in Ledoux, ‘L., editor: Informative hfolecules in Biological Systems, Amsterdam, 195 1. Norrlr Holland Publishing Co., p. 285. Latner, A. L., and Longstaff. E.: ‘Transformation ot mammalian cells bv crude histones, Br. J, (;anr:et- 25: 280, 1971. Lamer, A. L., Longstaff-, E., and Turner, A. G.. Enhanced malignant behaviour of cells treated v+ith crude rat histone. Br. J. Cancer 27: 218, 1973. Tabor, H.: The protective effect of spermme and other polyamines against heat denaturation of deosvribonucleic acid. Biochemistrv 1: 497. 1962. Himes, M.: An analysis of heterochromatin in maize root tips, J. Cell Biol. 35: 175. 1967. Bloch, D. P.: A catalog of sperm histones, (;enetics 61: suppl. 93, 1969. Coelingh, J. P., Rozijn, T. H., and Montonrt, C. R.: lsotation and partial characterisation of a basic protein from bovine sperm heads, Biochem. Biophvs. Acta 188: 353. 1969. Pan+, S., and Chalkley, R.: High resolution acrvlamide gel electrophoresis of histones. Arch. Biochrm. Biophys. 130:337, 1969. Reid, B. L.: Unpublished. Markham, R.. Blackwell, P. Xf., and L’sher, G.: A shadow-casting technique for the examination of the surface topography of cultured cells. Pathology 7: 45. 1975. Kalata, G. B.: MicroviIli: A major difference between normal and cancer cells, Science 188: Hl!). 1975. Moore, G. P. M., and Beatty, R. A.: The DNA content of spermatozoa from different strains of mice. J. Reprod. Fez-m. 38: 473, 1974. Hertzog, R. E.: Zur Bestimmung von Arginin im Zellkern des menslichen Portio Epithels. .4rch C;vn,rekol. 217: 437, 1974.