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Marker chromosomes in direct preparations of human large bowel tumors
Marker Chromosomes in Direct Preparations of Human Large Bowel Tumors Amelia Reichmann, Paulette Martin, and Bernard Levin
ABSTRACT: A survey of 257 marker chromosomes in 48 primary human large bowel adenocarcinomas showed that 44% were markers with recognized patterns. Chromosomes #1, #3, #5, #8, #9, #13, and #17 were involved most frequently. Markers related to chromosomes #7 and X were not seen in anyrecognizable form. The unidentified chromosomes were classified as markers with abnormal banding regions. In correlating tumor location and stage of invasion with markers, there were fewer markers in tumors from the right side. However, there was little difference in the number of markers seen in the left-sided tumors, irrespective of histopathologic stage, suggesting that function and microenvironmental conditions between various parts of the colon may be related to these differences. The most striking observation is that 21% of all tumors analyzed were without any obvious markers.
INTRODUCTION Markers are chromosomes that have undergone a structural modification, p r o d u c i n g a m o r p h o l o g i c a l l y abnormal chromosome. Presence or absence of markers, number, origin, m e c h a n i s m of formation, and m o r p h o l o g y are important elements related to tumor behavior [1]. There are several reports on marker chromosomes in cancer [1-5]. Early studies done on large bowel tumors, without b a n d i n g techniques, only demonstrated size, centromere location, and number of markers [6-10]. Currently, using b a n d i n g techniques, certain chromosomes involved in marker formation in the p r i m a r y colorectal tumors [11-15] and in cell lines [16] have been identified. In this study, we summarize detailed observations about the frequency and morphology of markers in large bowel adenocarcinomas and their correlation with location of tumor and stage of invasion. MATERIALS AND METHODS
Chromosomal analysis was carried out on tumor cells from 48 patients w i t h prim a r y large bowel adenocarcinomas. A detailed description of both the techniques and the c o m p l e t e d karyotypes can be found in prior publications [15,17]. Q-banding is the m e t h o d of choice in our laboratory for the recognition of markers. In addition, the procedure does not destroy the chromosomes, thus permitting further analyses.
From the Melamid Cytogenetics,Laboratory,Section of Gastroenterology,Department of Medicine, University of Chicago Hospitals and Clinics, Chicago,IL. Address requests for reprints to Dr. Amelia Reichmann, University of South Alabama, Department of Medical Genetics, 1070 MCSB, USAMC, 2451 Fillingim Street, Mobile, AL 36617. Received March 5, 1984; accepted July 9, 1984.
229 © 1985 Elsevier Science Publishing Co., Inc. 52 Vanderbilt Ave., New York, NY 10017
Cancer Genetics and Cytogenetics16, 229-233 (1985) 0165-4608/85/$03.30
230
A. Reichmann et al.
109_ 1 1` 2 E~' H i 8-~'~ 7-i l l 1 o T~ ~E~, 6 1`
1 3 f 1' I ~
~
1 T n Iiil [~,~
= Deletion m ~ : Translocation ~ = Duplication ~:.~|= Iso-ehromosome r~=lnversi°n ' =Doubl . . . . ker
t-
Chromosome oNumber 0~ t 5'~ 2 o~ 3
.~ F i g u r e 1 Histogram of identified marker chromosomes in 48 human large bowei adenocarcinomas; 19 tumors were located on the right colon and 29 on the ]eft. Numbers at the top of the arrows represent the number of cases with duplicated markers.
All abnormal chromosomes were called markers, regardless of their formation, and were separated into recognized chromosomes, those that involved any chromosome formation that was recognized (i.e., deletion, inversion, translocation, duplication, isochromosome), as well as those chromosomes that were partly recognizable. This can be seen in detail in Figure 1. The unrecognized markers were chromosomes that showed abnormal banding regions (ABRs) [18] and are presented in Table 1. We also divided the marker chromosomes by size and centromere position (Table 1). Table 1 Unidentified markers in large bowel adenocarcinomas ° Category Size A, A + B C D,D+ E,F Total Centromere position Acrocentric " B ''b
Submetacentric Metacentric Dicentric Total Banding patterns (ABRs) Repeated b a n d s Distinct bands Abnormal E,F Total
Right
Left
Total
3 2 8 -4 17
29 12 21 11 54 127
32 14 29 11 58 144 18
1
17
4
4
8
8 4 -17
18 85 3 127
26 89 3 144
2 11 4 17
16 57 54 127
18 68 58 144
°Unidentified markers divided according to size, centromere position, and banding patterns. bCentromere position between acrocentric and submetacentric.
Markers in Colon Cancers
231
A simplified histopathologic staging was used to classify each tumor and was as follows: (a) lesion confined to bowel wall; (b) extension through the wall; (c) lymph node involvement; (d) distant metastases. The large bowel was divided into right colon--from cecum to midtransverse col o n - and left colon--from midtransverse colon to rectum. This division is used for the anatomical location of the primary tumors. RESULTS Chromosomal markers are summarized in Figure 1 for recognized markers, and in Table 1 for the unidentified markers. Ten cases were apparently without "marker" chromosomes. The remaining 38 cases had a total of 257 markers; 44% were classified as markers with recognized patterns. The most frequent chromosomes involved were #1, #9, #17, #8, #5, #3, and #13. Markers involving chromosomes #7 and X were not seen in any recognizable form. The remaining 144 unidentified chromosomes (56%) were classified as markers with ABRs: (a) with repeated band sequences, (b) distinct band regions, and (c) abnormally banded E and F chromosomes. Table 1 shows the classification of 144 unknown markers with 17 markers from right colon and 127 from left colon. DISCUSSION Cytogenetic data from solid tumors appears to be confusing. Different types of tumors have different karyotypes, and even among the same tissue type, great variety exists. Our laboratory has done several correlative studies comparing the cytogenetic results of large bowel adenocarcinoma with the clinical and histopathologic features [14, 15, 19, 20]. As reported previously, there does not seem to be any specific chromosome abnormality that would characterize a large bowel adenocarcinema. There are, however, several chromosomes that are more often involved with marker formation [11-15, 19-21]. Our investigation into the phenomenon of "markers" has demonstrated several interesting features: there appears to be some significance in the presence or absence, the number, morphology, and identity of markers. The most striking thing is that 21% of all tumors analyzed were without any obvious markers: 9% of th~ total tumors that had "normal" karyotypes and 12% that had simple gains and one case with two gains and a loss. All of these were on the right side of the colon and most of them were Dukes' stage B2 [22]. Both the cytogenetic results and the pathologic classification indicated a better prognosis [19]. All of the patients in these groups are still alive, even 3-7 years after the original surgery. At the other end of the spectrum are the tumors that have many unidentified markers, and some of these markers have appeared to duplicate themselves. The most frequently observed aberration is the deletion of a chromosome (Fig. 1). Other abnormalities were isochromosomes, translocations, and duplications; an inversion was seen in only one case. Most of these abnormalities were seen in tumors of the hypotriploid or hypotetraploid range, with location on left side of the colon. In these cases, there was a greater tendency toward duplication of markers, possibly due to the triploid or tetraploid state. Our previous study of abnormal chromosomes in the diploid cases [15] showed a predisposition for chromosomes #1, #5, and #9 to have structural abnormalities. In addition, aberrations of chromosomes #3, #8, and #17 were seen. Specific chromosomes tend to become more susceptible to the mechanism of tumor growth, e.g., a summary of 218 neoplasms showed the involvement of chro-
232
A. Reichmann et al.
Table 2
Marker chromosomes in large bowel adenocarcinomas correlated with stage and location of tumor
Dukes' stage B C,D
Right colon
Left colon
12 markers/11 cancers (1)° 31 markers/8 cancers (4)
128 markers/17 cancers (8) 86 markers/13 cancers (7)
°Meannumber of markers per cancer.
mosome #1 [4]. In our experience in h u m a n large bowel tumors, changes in chromosome #1 were present in 39%, i n c l u d i n g both numerical and structural abnormalities. Neither chromosome # 7 nor X was identified in marker formation in either study. Our previous work indicates, however, that chromosome # 7 does appear in a supernumerary state (trisomy). A recent report by Chen et al [16] indicates that abnormalities of chromosome # 7 are frequently present i n cultured cell lines from adenocarcinomas of the large bowel. It is noteworthy that structural and numerical changes affecting chromosomes # 7 and #12 have been reported by Becher et al. [23] and Ochi et al. [24]; also, c-Ki-ras2 proto-oncogene was assigned to chromosome #12 by Sakaguchi et al. [25]. Other important observations correlated epidermal growth factor receptors, chromosome #7, and the Erb oncogene [26]. Approximately 43% of all ABRs were grouped as abnormal chromosome Es or Fs, and this could possibly explain why identified markers of #19, #20, #21, and #22 appeared to be absent (Fig. 1), as these chromosomes are very small and their banding patterns are not as distinct as the larger chromosomes. There was also a large n u m b e r of metacentric ABRs that could possibly suggest some type of abnormal centromeric function that is expressed in the k n o w n markers by the presence of the isochromosomes. This is also referred to in several other studies [27, 28]. Table 2 is a s u m m a r y of the correlation of histopathologic data with the presence or absence of markers and the location of the tumor. Fewer markers are present in right-sided colonic cancers, irrespective of Duke's staging. However, left-sided lesions show a high incidence of markers even at an early pathologic stage. Regional differences in colonic function and m i c r o e n v i r o n m e n t may be responsible for these results. Supported by the Melamid Foundation and by the Gastrointestinal Research Foundation, Chicago.
REFERENCES 1. Sandberg AA (1980): Solid tumors and metastatic cancer. In: The Chromosomes in Human Cancer and Leukemia, A.A. Sandberg, ed., Elsevier North Holland, New York, pp 458565. 2. Kakati S, Oshimura M, Sandberg AA (1976): The chromosomes and causation of human cancer and leukemia. XIX. Common markers in various tumors. Cancer 38:770-777. 3. Kakati S, Hayata I, Sandberg AA (1976): Chromosomes and causation of human cancer and leukemia. XIV. Origin of a large number of markers in a cancer. Cancer 37:776-782. 4. Brito-Babapulle V, Atkin NB (1981): Break points in chromosome #1: Abnormalities of 218 human neoplasms. Cancer Genet Cytogenet 4:215-225.
Markers in Colon Cancers
233
5. Brodeur GM, Tsiatis AA, Williams DL, Luthardt FW, Green AA (1982): Statistical analysis of cytogenetic abnormalities in h u m a n cancer cells. Cancer Genet Cytogenet 7:137-152. 6. Atkin NB (1974): Chromosomes in h u m a n malignant tumors: A review and assessment. In: Chromosomes and Cancer, J. German, ed., John Wiley, New York, pp 375-422. 7. Enterline HT, Arvan DA (1967): Chromosome constitution of adenoma and adenocarcinoma of the colon. Cancer 20:1746-1759. 8. Lubs HA, Clark R (1963): The chromosome complement of h u m a n solid tumors. I. Gastrointestinal tumors and technic. N Engl J Med 268:907-911. 9. Miles CP (1967): Chromosome analysis of solid tumors. II. Twenty-six epithelial tumors. Cancer 20:1274-1287. 10. Yamada K, Takagi N, Sandberg AA (1966): Chromosomes and causation of h u m a n cancer and leukemia. II. Karyotypes of h u m a n solid tumors. Cancer 19:1879-1890. 11. Sonta S, Oshimura M, Evans JT, Sandberg AA (1977): Chromosomes and causation of h u m a n cancer and leukemia. XX. Banding patterns of primary tumors. J Natl Cancer Inst 58:49-53. 12. Sonta S, Sandberg AA (1978): Chromosomes and causation of h u m a n cancer and leukemia. XXX. Banding studies of primary intestinal tumors. Cancer 41:164-173. 13. Kovacs G (1978): Abnormalities of chromosome number 1 in h u m a n solid malignant tumours. Int J Cancer 21:688-694. 14. Martin P, Levin B, Golomb HM, Riddell RH (1979): Chromosome analysis of primary large bowel tumors: A new method for improving the yield of analyzable metaphases. Cancer 44:1656-1662. 15. Reichmann A, Martin P, Levin B (1981): Chromosomal banding patterns in h u m a n large bowel cancer. Int J Cancer 28:431-440. 16. Chen TR, Hay RJ, Macy ML (1982): Karyotype consistency in h u m a n colorectal carcinoma cell lines established in vitro. Cancer Genet Cytogenet 6:93-117. 17. Reichmann A, Riddell RH, Martin P, Levin B (1980): Double minutes in h u m a n large bowel cancer. Gastroenterology 79:334-339. 18. Biedler JL (1981): Homogeneously staining regions. Karyogram 7:77-81. 19. Reichmann A, Levin B, Martin P (1982): Human large-bowel cancer: Correlation of clinical and histopathological features with banded chromosomes. Int J Cancer 29:625-629. 20. Reichmann A, Martin P, Levin B (1984): Chromosomal studies on direct preparations of 12 primary h u m a n large bowel cancers. (submitted for publication). 21. Reichmann A, Martin P, Levin B (1982): Karyotypic findings in a colonic villous adenoma. Cancer Genet Cytogenet 7:51-57. 22. Astler VA, Coller FA (1954): The prognostic significance of direct extension of carcinoma of the colon and rectum. A n n Surg 139:846-855. 23. Becher Z, Gibas Z, Sandberg AA (1983): Involvement of chromosomes 7 and 12 in large bowel cancer: Trisomy 7 and 1 2 q - . Cancer Genet Cytogenet 9:329-332. 24. Ochi H, Takeuchi J, Holyoke D, Sandberg AA (1983): Possible specific chromosome changes in large bowel cancer. Cancer Genet Cytogenet 10:121-122. 25. Sakaguchi AY, Naylor SL, Shows TB (1983): Human c-Ki-ras2 proto-oncogene on chromosome 12. Science 219:1081-1083. 26. Marx JL (1984): Oncogene linked to growth factor receptor. Science 223:808. 27. Mark J, Ekedahl C, Dahlenfors R (1978): Characteristics of the banding patterns in nonHodgkin and non-Burkitt lymphomas. Hereditas 88:229-242. 28. Evans HJ (1977): Some facts and fancies relating to chromosome structure in man. In: Advances in Human Genetics, vol 8, H. Harris, K. Hirschhorn, eds., Plenum Press, New York, pp 347-438.
ABSTRACT: A survey of 257 marker chromosomes in 48 primary human large bowel adenocarcinomas showed that 44% were markers with recognized patterns. Chromosomes #1, #3, #5, #8, #9, #13, and #17 were involved most frequently. Markers related to chromosomes #7 and X were not seen in anyrecognizable form. The unidentified chromosomes were classified as markers with abnormal banding regions. In correlating tumor location and stage of invasion with markers, there were fewer markers in tumors from the right side. However, there was little difference in the number of markers seen in the left-sided tumors, irrespective of histopathologic stage, suggesting that function and microenvironmental conditions between various parts of the colon may be related to these differences. The most striking observation is that 21% of all tumors analyzed were without any obvious markers.
INTRODUCTION Markers are chromosomes that have undergone a structural modification, p r o d u c i n g a m o r p h o l o g i c a l l y abnormal chromosome. Presence or absence of markers, number, origin, m e c h a n i s m of formation, and m o r p h o l o g y are important elements related to tumor behavior [1]. There are several reports on marker chromosomes in cancer [1-5]. Early studies done on large bowel tumors, without b a n d i n g techniques, only demonstrated size, centromere location, and number of markers [6-10]. Currently, using b a n d i n g techniques, certain chromosomes involved in marker formation in the p r i m a r y colorectal tumors [11-15] and in cell lines [16] have been identified. In this study, we summarize detailed observations about the frequency and morphology of markers in large bowel adenocarcinomas and their correlation with location of tumor and stage of invasion. MATERIALS AND METHODS
Chromosomal analysis was carried out on tumor cells from 48 patients w i t h prim a r y large bowel adenocarcinomas. A detailed description of both the techniques and the c o m p l e t e d karyotypes can be found in prior publications [15,17]. Q-banding is the m e t h o d of choice in our laboratory for the recognition of markers. In addition, the procedure does not destroy the chromosomes, thus permitting further analyses.
From the Melamid Cytogenetics,Laboratory,Section of Gastroenterology,Department of Medicine, University of Chicago Hospitals and Clinics, Chicago,IL. Address requests for reprints to Dr. Amelia Reichmann, University of South Alabama, Department of Medical Genetics, 1070 MCSB, USAMC, 2451 Fillingim Street, Mobile, AL 36617. Received March 5, 1984; accepted July 9, 1984.
229 © 1985 Elsevier Science Publishing Co., Inc. 52 Vanderbilt Ave., New York, NY 10017
Cancer Genetics and Cytogenetics16, 229-233 (1985) 0165-4608/85/$03.30
230
A. Reichmann et al.
109_ 1 1` 2 E~' H i 8-~'~ 7-i l l 1 o T~ ~E~, 6 1`
1 3 f 1' I ~
~
1 T n Iiil [~,~
= Deletion m ~ : Translocation ~ = Duplication ~:.~|= Iso-ehromosome r~=lnversi°n ' =Doubl . . . . ker
t-
Chromosome oNumber 0~ t 5'~ 2 o~ 3
.~ F i g u r e 1 Histogram of identified marker chromosomes in 48 human large bowei adenocarcinomas; 19 tumors were located on the right colon and 29 on the ]eft. Numbers at the top of the arrows represent the number of cases with duplicated markers.
All abnormal chromosomes were called markers, regardless of their formation, and were separated into recognized chromosomes, those that involved any chromosome formation that was recognized (i.e., deletion, inversion, translocation, duplication, isochromosome), as well as those chromosomes that were partly recognizable. This can be seen in detail in Figure 1. The unrecognized markers were chromosomes that showed abnormal banding regions (ABRs) [18] and are presented in Table 1. We also divided the marker chromosomes by size and centromere position (Table 1). Table 1 Unidentified markers in large bowel adenocarcinomas ° Category Size A, A + B C D,D+ E,F Total Centromere position Acrocentric " B ''b
Submetacentric Metacentric Dicentric Total Banding patterns (ABRs) Repeated b a n d s Distinct bands Abnormal E,F Total
Right
Left
Total
3 2 8 -4 17
29 12 21 11 54 127
32 14 29 11 58 144 18
1
17
4
4
8
8 4 -17
18 85 3 127
26 89 3 144
2 11 4 17
16 57 54 127
18 68 58 144
°Unidentified markers divided according to size, centromere position, and banding patterns. bCentromere position between acrocentric and submetacentric.
Markers in Colon Cancers
231
A simplified histopathologic staging was used to classify each tumor and was as follows: (a) lesion confined to bowel wall; (b) extension through the wall; (c) lymph node involvement; (d) distant metastases. The large bowel was divided into right colon--from cecum to midtransverse col o n - and left colon--from midtransverse colon to rectum. This division is used for the anatomical location of the primary tumors. RESULTS Chromosomal markers are summarized in Figure 1 for recognized markers, and in Table 1 for the unidentified markers. Ten cases were apparently without "marker" chromosomes. The remaining 38 cases had a total of 257 markers; 44% were classified as markers with recognized patterns. The most frequent chromosomes involved were #1, #9, #17, #8, #5, #3, and #13. Markers involving chromosomes #7 and X were not seen in any recognizable form. The remaining 144 unidentified chromosomes (56%) were classified as markers with ABRs: (a) with repeated band sequences, (b) distinct band regions, and (c) abnormally banded E and F chromosomes. Table 1 shows the classification of 144 unknown markers with 17 markers from right colon and 127 from left colon. DISCUSSION Cytogenetic data from solid tumors appears to be confusing. Different types of tumors have different karyotypes, and even among the same tissue type, great variety exists. Our laboratory has done several correlative studies comparing the cytogenetic results of large bowel adenocarcinoma with the clinical and histopathologic features [14, 15, 19, 20]. As reported previously, there does not seem to be any specific chromosome abnormality that would characterize a large bowel adenocarcinema. There are, however, several chromosomes that are more often involved with marker formation [11-15, 19-21]. Our investigation into the phenomenon of "markers" has demonstrated several interesting features: there appears to be some significance in the presence or absence, the number, morphology, and identity of markers. The most striking thing is that 21% of all tumors analyzed were without any obvious markers: 9% of th~ total tumors that had "normal" karyotypes and 12% that had simple gains and one case with two gains and a loss. All of these were on the right side of the colon and most of them were Dukes' stage B2 [22]. Both the cytogenetic results and the pathologic classification indicated a better prognosis [19]. All of the patients in these groups are still alive, even 3-7 years after the original surgery. At the other end of the spectrum are the tumors that have many unidentified markers, and some of these markers have appeared to duplicate themselves. The most frequently observed aberration is the deletion of a chromosome (Fig. 1). Other abnormalities were isochromosomes, translocations, and duplications; an inversion was seen in only one case. Most of these abnormalities were seen in tumors of the hypotriploid or hypotetraploid range, with location on left side of the colon. In these cases, there was a greater tendency toward duplication of markers, possibly due to the triploid or tetraploid state. Our previous study of abnormal chromosomes in the diploid cases [15] showed a predisposition for chromosomes #1, #5, and #9 to have structural abnormalities. In addition, aberrations of chromosomes #3, #8, and #17 were seen. Specific chromosomes tend to become more susceptible to the mechanism of tumor growth, e.g., a summary of 218 neoplasms showed the involvement of chro-
232
A. Reichmann et al.
Table 2
Marker chromosomes in large bowel adenocarcinomas correlated with stage and location of tumor
Dukes' stage B C,D
Right colon
Left colon
12 markers/11 cancers (1)° 31 markers/8 cancers (4)
128 markers/17 cancers (8) 86 markers/13 cancers (7)
°Meannumber of markers per cancer.
mosome #1 [4]. In our experience in h u m a n large bowel tumors, changes in chromosome #1 were present in 39%, i n c l u d i n g both numerical and structural abnormalities. Neither chromosome # 7 nor X was identified in marker formation in either study. Our previous work indicates, however, that chromosome # 7 does appear in a supernumerary state (trisomy). A recent report by Chen et al [16] indicates that abnormalities of chromosome # 7 are frequently present i n cultured cell lines from adenocarcinomas of the large bowel. It is noteworthy that structural and numerical changes affecting chromosomes # 7 and #12 have been reported by Becher et al. [23] and Ochi et al. [24]; also, c-Ki-ras2 proto-oncogene was assigned to chromosome #12 by Sakaguchi et al. [25]. Other important observations correlated epidermal growth factor receptors, chromosome #7, and the Erb oncogene [26]. Approximately 43% of all ABRs were grouped as abnormal chromosome Es or Fs, and this could possibly explain why identified markers of #19, #20, #21, and #22 appeared to be absent (Fig. 1), as these chromosomes are very small and their banding patterns are not as distinct as the larger chromosomes. There was also a large n u m b e r of metacentric ABRs that could possibly suggest some type of abnormal centromeric function that is expressed in the k n o w n markers by the presence of the isochromosomes. This is also referred to in several other studies [27, 28]. Table 2 is a s u m m a r y of the correlation of histopathologic data with the presence or absence of markers and the location of the tumor. Fewer markers are present in right-sided colonic cancers, irrespective of Duke's staging. However, left-sided lesions show a high incidence of markers even at an early pathologic stage. Regional differences in colonic function and m i c r o e n v i r o n m e n t may be responsible for these results. Supported by the Melamid Foundation and by the Gastrointestinal Research Foundation, Chicago.
REFERENCES 1. Sandberg AA (1980): Solid tumors and metastatic cancer. In: The Chromosomes in Human Cancer and Leukemia, A.A. Sandberg, ed., Elsevier North Holland, New York, pp 458565. 2. Kakati S, Oshimura M, Sandberg AA (1976): The chromosomes and causation of human cancer and leukemia. XIX. Common markers in various tumors. Cancer 38:770-777. 3. Kakati S, Hayata I, Sandberg AA (1976): Chromosomes and causation of human cancer and leukemia. XIV. Origin of a large number of markers in a cancer. Cancer 37:776-782. 4. Brito-Babapulle V, Atkin NB (1981): Break points in chromosome #1: Abnormalities of 218 human neoplasms. Cancer Genet Cytogenet 4:215-225.
Markers in Colon Cancers
233
5. Brodeur GM, Tsiatis AA, Williams DL, Luthardt FW, Green AA (1982): Statistical analysis of cytogenetic abnormalities in h u m a n cancer cells. Cancer Genet Cytogenet 7:137-152. 6. Atkin NB (1974): Chromosomes in h u m a n malignant tumors: A review and assessment. In: Chromosomes and Cancer, J. German, ed., John Wiley, New York, pp 375-422. 7. Enterline HT, Arvan DA (1967): Chromosome constitution of adenoma and adenocarcinoma of the colon. Cancer 20:1746-1759. 8. Lubs HA, Clark R (1963): The chromosome complement of h u m a n solid tumors. I. Gastrointestinal tumors and technic. N Engl J Med 268:907-911. 9. Miles CP (1967): Chromosome analysis of solid tumors. II. Twenty-six epithelial tumors. Cancer 20:1274-1287. 10. Yamada K, Takagi N, Sandberg AA (1966): Chromosomes and causation of h u m a n cancer and leukemia. II. Karyotypes of h u m a n solid tumors. Cancer 19:1879-1890. 11. Sonta S, Oshimura M, Evans JT, Sandberg AA (1977): Chromosomes and causation of h u m a n cancer and leukemia. XX. Banding patterns of primary tumors. J Natl Cancer Inst 58:49-53. 12. Sonta S, Sandberg AA (1978): Chromosomes and causation of h u m a n cancer and leukemia. XXX. Banding studies of primary intestinal tumors. Cancer 41:164-173. 13. Kovacs G (1978): Abnormalities of chromosome number 1 in h u m a n solid malignant tumours. Int J Cancer 21:688-694. 14. Martin P, Levin B, Golomb HM, Riddell RH (1979): Chromosome analysis of primary large bowel tumors: A new method for improving the yield of analyzable metaphases. Cancer 44:1656-1662. 15. Reichmann A, Martin P, Levin B (1981): Chromosomal banding patterns in h u m a n large bowel cancer. Int J Cancer 28:431-440. 16. Chen TR, Hay RJ, Macy ML (1982): Karyotype consistency in h u m a n colorectal carcinoma cell lines established in vitro. Cancer Genet Cytogenet 6:93-117. 17. Reichmann A, Riddell RH, Martin P, Levin B (1980): Double minutes in h u m a n large bowel cancer. Gastroenterology 79:334-339. 18. Biedler JL (1981): Homogeneously staining regions. Karyogram 7:77-81. 19. Reichmann A, Levin B, Martin P (1982): Human large-bowel cancer: Correlation of clinical and histopathological features with banded chromosomes. Int J Cancer 29:625-629. 20. Reichmann A, Martin P, Levin B (1984): Chromosomal studies on direct preparations of 12 primary h u m a n large bowel cancers. (submitted for publication). 21. Reichmann A, Martin P, Levin B (1982): Karyotypic findings in a colonic villous adenoma. Cancer Genet Cytogenet 7:51-57. 22. Astler VA, Coller FA (1954): The prognostic significance of direct extension of carcinoma of the colon and rectum. A n n Surg 139:846-855. 23. Becher Z, Gibas Z, Sandberg AA (1983): Involvement of chromosomes 7 and 12 in large bowel cancer: Trisomy 7 and 1 2 q - . Cancer Genet Cytogenet 9:329-332. 24. Ochi H, Takeuchi J, Holyoke D, Sandberg AA (1983): Possible specific chromosome changes in large bowel cancer. Cancer Genet Cytogenet 10:121-122. 25. Sakaguchi AY, Naylor SL, Shows TB (1983): Human c-Ki-ras2 proto-oncogene on chromosome 12. Science 219:1081-1083. 26. Marx JL (1984): Oncogene linked to growth factor receptor. Science 223:808. 27. Mark J, Ekedahl C, Dahlenfors R (1978): Characteristics of the banding patterns in nonHodgkin and non-Burkitt lymphomas. Hereditas 88:229-242. 28. Evans HJ (1977): Some facts and fancies relating to chromosome structure in man. In: Advances in Human Genetics, vol 8, H. Harris, K. Hirschhorn, eds., Plenum Press, New York, pp 347-438.