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Chromosome 1p aberrations are frequent in human primary hepatocellular carcinoma
ELSEVIER
Chromosome l p Aberrations are Frequent in Human Primary Hepatocellular Carcinoma Hui-Ling Chen, Yueh-Chun Chen, and Ding-Shinn Chen ABSTRACT: To investigate the chromosomal changes in hepatocellular carcinoma in humans,
metaphase chromosomes obtained directly from short-term culture of resected human primary hepatocellular carcinoma tissues were studied in seven patients. Among the five successfully karyotyped cases, cytogenetic analysis showed highly different and complex chromosomal changes in the cancer tissue in four patients. Structural aberrations of chromosome 1 and deletion of lp with breakpoints at p22 or p32 were the most common abnormalities, and were found in the four successfully analyzed cases. Loss of lp m a y be important in hepatocarcinogenesis, and warrants further characterization by molecular genetic analysis.
INTRODUCTION Hepatocellular carcinoma (HCC) is one of the most prevalent cancers in humans [1] and is extremely common in Taiwan [2, 3]. Although much is known concerning its association with chronic hepatitis B or C virus infection [3-51, the mechanism of hepatocarcinogenesis remains nearly unknown. Association of specific chromosomal changes and cellular carcinogenesis has been documented in several cancers [6]. However, little is known about HCC. To date, chromosomal changes in primary HCC tissues have been reported in only five patients [7-9]. To reduce the secondary chromosomal changes which might have occurred during long-term cultures of cell lines, we studied cytogenetic changes of metaphase chromosomes directly from short-term cultured human HCC samples obtained from surgery. The chromosomal changes were different and complex in each case, however, chromosome 1 was most consistently found to be abnormal in the present study. Deletion was the major chromosome change, and breakpoints at p22 and p32 were identified in four of five cases in our study. MATERIALS AND METHODS
Human liver tumor tissues were obtained from partial hepatectomy and disaggregated. Disaggregated cells were
From the Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan. Address reprint requests to: Prof. Ding-Shinn Chert, Hepatitis Research Center, National Taiwan University Hospital, 7 ChungShah S. Rd., Taipei, Taiwan, R.O.C. Received October 11, 1994; accepted June 29, 1995. Cancer Genet Cytogenet 8 6 : 1 0 2 - 1 0 6 (1996) © Elsevier Science Inc., 1996 655 Avenue of the Americas, N e w York, NY 10010
resuspended and maintained in DMEM-1% FCS with supplements. The HCC cells were harvested after 3-7 days, depending on the condition of cell proliferation (Fig. 1). Chromosomes were prepared and karyotyped with the use of trypsin-Giemsa banding [10], according to the guidelines of the International System for Human Cytogenetic Nomenclature 1991 [11]. A total of seven patients were studied, including six men and one woman with ages ranging from 47 to 80 years. Patients 1 and 6 were positive for serum HCV-RNA and were negative for hepatitis B surface antigen (HBsAg). Patients 2, 3, 4, and 7 were positive for HBsAg. Among the HBsAg-positive patients, patients 2 and 7 were also positive for hepatitis B e antigen. The diagnosis of HCC was confirmed after histologic examinations. Patients 2, 3, and 5 had coexisting cirrhosis. RESULTS
Among the HCC specimens from the seven patients, karyotyping was done successfully in five (patients 1-5). A highly complex hyperpentaploidy karyotype was observed in patient 1, with chromosome numbers ranging from 106 to 113 by the analysis of 10 metaphase cells. Full karyotype of patient 1 with 109 chromosomes is shown in Figure 2. The cell with 109 chromosomes contained consistent chromosomal aberrations including del(1)(p22), i(8q), i(9q), add(9)(p24), and add(21)(q10). Additional numerical aberrations were observed commonly, except chromosomes 3, 6, 11, 14, and 19. To be regarded as clonal changes, several marker chromosomes were also consistently observed among different metaphases. In patient 2, a hypertriploid karyotype with chromosome numbers from 72 to 76 was detected among 12 metaphase cells, and consistent chromosomal aberration del(1)(p32) (Fig. 4) was also included.
0165-4608/96/$15.00 SSDI 0165-4608(95)00186-S
Chromosomal Changes in Primary HCC
Figure I
103
Human hepatocellular carcinoma cells in primary culture in patient 1.
Near-diploid and diploid karyotypes were observed in patients 3 and 4 in eight metaphase cells each. Karyotype analysis of patient 3 with 45 chromosomes (Fig. 3) revealed changes including del(1)(p22), del(1)(p34), - 4 , - 5 , - 1 3 , add(16)(q24), --Y, and +2mar. In patient 4, a normal karyotype was observed. Ten metaphase cells were analyzed for patient 5 with a chromosomal number from 66 to 72; del(1)(p32) (Fig. 4) was also observed.
DISCUSSION Cytogenetic analysis ha,; been proven useful in determining the underlying genetic changes, and also provides important information in the diagnosis and prognosis of cancer [12]. In HCC, these studies are still limited, and thus investigations of nonrandom chromosomal changes and the role of these changes will be important in future studies in clarifying the process of hepatocarcinogenesis. The cytogenetic findings in each patient were quite different; however, changes of chromosome 1 were the most common chromosomal aberrations, detected in four of the five cases (Table 1). Del(1)(p22) was observed in patients 1 and 3 (Figs. 2 and 3), while in patients 2 and 5, breakpoint of chromosome 1 was d,~tected at p32 (Fig. 4). In the third patient, chromosomal deletions involving del(1)(p22) and
del(1)(p34) were both observed in the cell as clonal changes. In patients 6 and 7, the poor resolution of Trypsin-Giemsa banding precluded adequate karyotype analysis. However, diploid range chromosomal numbers were observed in both patients. Overall, only one patient displayed a normal karyotype of his HCC. Chromosomal aberration del(1)(p22) has been reported in human hepatoblastoma cell line HepG2 [13] and a primary HCC tissue [7], as shown in Figures 2 and 3 by us. And the breakpoint at p32 has been observed in the same primary HCC [7]. Although the role of the aberration of chromosome lp in HCC is still unclear, the loss of l p frequently observed in human liver cancers suggests a possibly important role in hepatocarcinogenesis. Compared to the aberrations of chromosome 1, discrepancies of other cytogenetic findings were also detected. Chromosome 6 abnormality, del(6)(q15), was observed in one of our cases (Table 1, patient 2), and loss of one or more 6q loci have been reported not only in hepatocellular carcinoma [7, 14] but also in some other cancer cells [1517]. The i(14q), as a clonal change in patient 5, has been observed in cell line HCC36 [14] by us. In sum, aberrations of chromosome 1 were the most significant change discovered not only in established HCC cell lines but also in short-term cultured primary HCC tis-
104
H.-L. Chen et al.
4
!
ii
5
~ !
12
16
r!
0:0 18
r! 22
|
17
X
Y
OJ||
Markers
Figure 2 G-banded karyotype of patient i with the del(1)(p22), del(4p), i(7q), i(8q), der(8), i(9q), add(9)(q24), and add(21)(q10) indicated by arrows.
sues ([7, 8, 13, 18] and this study). Abnormalities of chromosome 1 have been reported in a variety of different tumors including neuroblastoma, melanoma, breast and cervical carcinoma, and uterine leiomyoma [6, 19]. Associated with chromosomal changes on lp, loss of heterozygosity in neuroblastoma was detected at lp36.1-36.2 [20, 21]. Recently, cytogenetically detectable loss of genetic information from lp36 was also found in early stage intestinal tumorigenesis [9]. Correlating with chromosomal changes on lp, loss of polymorphic alleles from distal l p in five of the six HCC patients was reported by Simon et al. [8], and a functional gene loss in hepatocellular carcino-
Table 1
genesis was suggested. To characterize the genomic basis of the morphologic abnormalities on lp, studies on the restriction fragment length polymorphism or microsatellite polymorphism of DNA extracted from both nontumor and tumor liver tissues of the same individual should be done. Actually, we have preliminarily demonstrated chromosome l p alterations in half of the HCCs with microsatellite polymorphism analysis, and the abnormalities seem to cluster at the distal part of the chromosome [22]. Cytogenetic studies should be extended to more primary HCCs to better delineate the genetic basis of h u m a n hepatocarcinogenesis.
Cytogenetic findings in the five cases
Patient no.
Karyotype 106-113,XXXYY,del{1)(p22),-4,- 5,-8,i(8)(q10),i(9),add(9}(p24),- 10,- 13,- 13,- 15,add(16)(q24), - 16,- 17,- 17,- 18,add(21)(q10)x2,- 22,+ 7-13mar [cpl0] 72- 76,XY,-X,del(1)(p32),+add(1)(q10),+del(6)(q15),+ 7,- 8 , - 9 , - 10,- 11,- 12,+ 13,+ 15,- 16,- 17,+ 18, + 20,- 21,-22,+4-8mar[cp12] 45,X,-Y,del(1)(p34),del(1)(p22),-4,- 5,- 13,der(16)add(16)(q24),+ 2mar[cp8] 46,XY[cpS] 6 6 - 72•xY•-x•+de•(1)(p32)•+add(1)(q1•)•-4'-6•
- 22,+ 1-3mar[cplO]
+ 7•-8•+11•der(13;15)(q1•;p1•)•i(14)(q1•)•-16•-17•-21•
Chromosomal Changes in Primary HCC
!
105
r
6
7
8
9
10
4
5
11
12
X
Y
Figure 3
G-banded karyotype of patient 3: 45,X,-Y, del(1)(p34),+del(1)(p22),-4,-5,-13,add(16)(q24), +2mar.
Figure 4
Partial karyotypes demonstrating structural abnormalities in patients 2 and 5 with del(1)[p32).
106 This study was supported by grants from the National Science Council and Department of Health, Executive Yuan, R.O.C. REFERENCES 1. Linsell, DA, Higginson J (1976): The geographic pathology of liver cell cancer. In: Cameron HM, Linsell DA, Warwick GP (eds.): Liver Cell Cancer. Elsevier, New York; 1976, pp. 1-16. 2. Lin TM, Tsu WT, Chen CJ (1986): Mortality of hepatoma and cirrhosis of liver in Taiwan. Br. J Cancer 54:969-976. 3. Chen DS (1987): Hepatitis B virus infection, its sequelae, and prevention in Taiwan. In: Okuda K, Ishak G (eds.): Neoplasms of the Liver. SpringerWerlag, Tokyo, pp. 71-80. 4. Beasley RP (1988): Hepatitis B virus: the major etiology of hepatocellular carcinoma. Cancer 61:1942-1956. 5. Chen DS, Kuo GC, Sung JL, Lai MY, Sheu JC, Chen PJ, Yang PM, Hsn HM, Chang MH, Chert CJ, Hahn LC, Choo QL, Wang TH, Houghton M (1990): Hepatitis C virus infection in an area hyperendemic for hepatitis B and chronic liver disease: the Taiwan experience. J Infect Dis 162:817-822. 6. Mitelman F (1991): Catalog of Chromosome Aberrations in Cancer, 4th Ed. Wiley-Liss, Inc., New York. 7. Simon D, Munoz SJ, Maddrey WC, Knowles BB (1990): Chromosomal rearrangements in a primary hepatocellular carcinoma. Cancer Genet Cytogenet 45:255-260. 8. Simon D, Knowles BB, Weith A (1991): Abnormalities of chromosome 1 and loss of heterozygosity on lp in primary hepatomas. Oncogene 6:765-770. 9. Bardi G, Pandis N, Fenger C, Kronborg O, Bomme L, Heim S (1993): Deletion of lp36 as a primary chromosomal aberration in intestinal tumorigenesis. Cancer Res 53:1895-1898. 10. Seabright M (1971): A rapid banding technique for human chromosomes. Lancet ii:971-972. 11. ISCN (1991) Guidelines for Cancer Cytogenetics: Supplement to An International System for Human Cytogenetic Nomenclature. Mitelman F, ed. Karger, Basel.
H.-L. C h e n et al.
12. Heim S, Mitelman F (1987): Cancer Cytogenetics. Alan R. Liss, Inc., New York. 13. Simon D, Aden DP, Knowles BB (1982): Chromosomes of human hepatoma cell lines. Int J Cancer 30:27-33. 14. Chen HL, Chiu TS, Chen PJ, Chen DS (1993): Cytogenetic studies in human liver cancer cell lines. Cancer Genet Cytogenet 65:161-166. 15. Trent Jm, Thompson FH, Meyskens FL Jr. (1989): Identification of a recurring translocation site involving chromosome 6 in human malignant melanoma. Cancer Res 49:420-423. 16. Sandros J, Mark J, Happonen RP, Stenman G (1988): Specificity of 6 q - markers and other recurrent deviations in human malignant salivary tumors. Anticancer Res 8:637-644. 17. Pejovic T, Heim S, Mandahl N, Baldetorp B, Elmfors B, Flod'erus Um, Furgyik S, Helm G, Himmelmann A, Willen H, Mitelman F (1992): Chromosome aberrations in 35 primary ovarian carcinomas. Genes Chromosom Cancer 4:58-68. 18. Bardi G, Johanson B, Pandis N, Heim S, Mandahl N, Sand~ berg AA, H/igerstrand I, Mitelman F (1992): Cytogenetic findings in three primary hepatocellular carcinomas. Cancer Genet Cytogenet 58:191-195. 19. Human Gene Mapping 11 (1991): Cytogenet Cell Genet 58: 985-2200. 20. Fong C, Dracopoli NC, White PS, Merril PT, Griffith RC, Housman DE, Brodeur GM (1989): Loss of heterozygosity for the short arm of chromosome 1 in human neuroblastomas: correlation with N-myc amplification. Proc Natl Acad Sci USA 86:3753-3757. 21. Weith A, Martinsson T, Cziepluch C, Bruderlein S, Amler LC, Berthold F, Schwab M (1989): Neuroblastoma consensus deletion maps to lp36.1-2. Genes Chromosom Cancer 1:159166. 22. Yeh SH, Chen PJ, Chen HL, Lai MY, Wang CC, Chen DS (1994): Frequent genetic alterations at the distal region of chromosome lp in human hepatocellular carcinomas. Cancer Res 54:4188-4192.
Chromosome l p Aberrations are Frequent in Human Primary Hepatocellular Carcinoma Hui-Ling Chen, Yueh-Chun Chen, and Ding-Shinn Chen ABSTRACT: To investigate the chromosomal changes in hepatocellular carcinoma in humans,
metaphase chromosomes obtained directly from short-term culture of resected human primary hepatocellular carcinoma tissues were studied in seven patients. Among the five successfully karyotyped cases, cytogenetic analysis showed highly different and complex chromosomal changes in the cancer tissue in four patients. Structural aberrations of chromosome 1 and deletion of lp with breakpoints at p22 or p32 were the most common abnormalities, and were found in the four successfully analyzed cases. Loss of lp m a y be important in hepatocarcinogenesis, and warrants further characterization by molecular genetic analysis.
INTRODUCTION Hepatocellular carcinoma (HCC) is one of the most prevalent cancers in humans [1] and is extremely common in Taiwan [2, 3]. Although much is known concerning its association with chronic hepatitis B or C virus infection [3-51, the mechanism of hepatocarcinogenesis remains nearly unknown. Association of specific chromosomal changes and cellular carcinogenesis has been documented in several cancers [6]. However, little is known about HCC. To date, chromosomal changes in primary HCC tissues have been reported in only five patients [7-9]. To reduce the secondary chromosomal changes which might have occurred during long-term cultures of cell lines, we studied cytogenetic changes of metaphase chromosomes directly from short-term cultured human HCC samples obtained from surgery. The chromosomal changes were different and complex in each case, however, chromosome 1 was most consistently found to be abnormal in the present study. Deletion was the major chromosome change, and breakpoints at p22 and p32 were identified in four of five cases in our study. MATERIALS AND METHODS
Human liver tumor tissues were obtained from partial hepatectomy and disaggregated. Disaggregated cells were
From the Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan. Address reprint requests to: Prof. Ding-Shinn Chert, Hepatitis Research Center, National Taiwan University Hospital, 7 ChungShah S. Rd., Taipei, Taiwan, R.O.C. Received October 11, 1994; accepted June 29, 1995. Cancer Genet Cytogenet 8 6 : 1 0 2 - 1 0 6 (1996) © Elsevier Science Inc., 1996 655 Avenue of the Americas, N e w York, NY 10010
resuspended and maintained in DMEM-1% FCS with supplements. The HCC cells were harvested after 3-7 days, depending on the condition of cell proliferation (Fig. 1). Chromosomes were prepared and karyotyped with the use of trypsin-Giemsa banding [10], according to the guidelines of the International System for Human Cytogenetic Nomenclature 1991 [11]. A total of seven patients were studied, including six men and one woman with ages ranging from 47 to 80 years. Patients 1 and 6 were positive for serum HCV-RNA and were negative for hepatitis B surface antigen (HBsAg). Patients 2, 3, 4, and 7 were positive for HBsAg. Among the HBsAg-positive patients, patients 2 and 7 were also positive for hepatitis B e antigen. The diagnosis of HCC was confirmed after histologic examinations. Patients 2, 3, and 5 had coexisting cirrhosis. RESULTS
Among the HCC specimens from the seven patients, karyotyping was done successfully in five (patients 1-5). A highly complex hyperpentaploidy karyotype was observed in patient 1, with chromosome numbers ranging from 106 to 113 by the analysis of 10 metaphase cells. Full karyotype of patient 1 with 109 chromosomes is shown in Figure 2. The cell with 109 chromosomes contained consistent chromosomal aberrations including del(1)(p22), i(8q), i(9q), add(9)(p24), and add(21)(q10). Additional numerical aberrations were observed commonly, except chromosomes 3, 6, 11, 14, and 19. To be regarded as clonal changes, several marker chromosomes were also consistently observed among different metaphases. In patient 2, a hypertriploid karyotype with chromosome numbers from 72 to 76 was detected among 12 metaphase cells, and consistent chromosomal aberration del(1)(p32) (Fig. 4) was also included.
0165-4608/96/$15.00 SSDI 0165-4608(95)00186-S
Chromosomal Changes in Primary HCC
Figure I
103
Human hepatocellular carcinoma cells in primary culture in patient 1.
Near-diploid and diploid karyotypes were observed in patients 3 and 4 in eight metaphase cells each. Karyotype analysis of patient 3 with 45 chromosomes (Fig. 3) revealed changes including del(1)(p22), del(1)(p34), - 4 , - 5 , - 1 3 , add(16)(q24), --Y, and +2mar. In patient 4, a normal karyotype was observed. Ten metaphase cells were analyzed for patient 5 with a chromosomal number from 66 to 72; del(1)(p32) (Fig. 4) was also observed.
DISCUSSION Cytogenetic analysis ha,; been proven useful in determining the underlying genetic changes, and also provides important information in the diagnosis and prognosis of cancer [12]. In HCC, these studies are still limited, and thus investigations of nonrandom chromosomal changes and the role of these changes will be important in future studies in clarifying the process of hepatocarcinogenesis. The cytogenetic findings in each patient were quite different; however, changes of chromosome 1 were the most common chromosomal aberrations, detected in four of the five cases (Table 1). Del(1)(p22) was observed in patients 1 and 3 (Figs. 2 and 3), while in patients 2 and 5, breakpoint of chromosome 1 was d,~tected at p32 (Fig. 4). In the third patient, chromosomal deletions involving del(1)(p22) and
del(1)(p34) were both observed in the cell as clonal changes. In patients 6 and 7, the poor resolution of Trypsin-Giemsa banding precluded adequate karyotype analysis. However, diploid range chromosomal numbers were observed in both patients. Overall, only one patient displayed a normal karyotype of his HCC. Chromosomal aberration del(1)(p22) has been reported in human hepatoblastoma cell line HepG2 [13] and a primary HCC tissue [7], as shown in Figures 2 and 3 by us. And the breakpoint at p32 has been observed in the same primary HCC [7]. Although the role of the aberration of chromosome lp in HCC is still unclear, the loss of l p frequently observed in human liver cancers suggests a possibly important role in hepatocarcinogenesis. Compared to the aberrations of chromosome 1, discrepancies of other cytogenetic findings were also detected. Chromosome 6 abnormality, del(6)(q15), was observed in one of our cases (Table 1, patient 2), and loss of one or more 6q loci have been reported not only in hepatocellular carcinoma [7, 14] but also in some other cancer cells [1517]. The i(14q), as a clonal change in patient 5, has been observed in cell line HCC36 [14] by us. In sum, aberrations of chromosome 1 were the most significant change discovered not only in established HCC cell lines but also in short-term cultured primary HCC tis-
104
H.-L. Chen et al.
4
!
ii
5
~ !
12
16
r!
0:0 18
r! 22
|
17
X
Y
OJ||
Markers
Figure 2 G-banded karyotype of patient i with the del(1)(p22), del(4p), i(7q), i(8q), der(8), i(9q), add(9)(q24), and add(21)(q10) indicated by arrows.
sues ([7, 8, 13, 18] and this study). Abnormalities of chromosome 1 have been reported in a variety of different tumors including neuroblastoma, melanoma, breast and cervical carcinoma, and uterine leiomyoma [6, 19]. Associated with chromosomal changes on lp, loss of heterozygosity in neuroblastoma was detected at lp36.1-36.2 [20, 21]. Recently, cytogenetically detectable loss of genetic information from lp36 was also found in early stage intestinal tumorigenesis [9]. Correlating with chromosomal changes on lp, loss of polymorphic alleles from distal l p in five of the six HCC patients was reported by Simon et al. [8], and a functional gene loss in hepatocellular carcino-
Table 1
genesis was suggested. To characterize the genomic basis of the morphologic abnormalities on lp, studies on the restriction fragment length polymorphism or microsatellite polymorphism of DNA extracted from both nontumor and tumor liver tissues of the same individual should be done. Actually, we have preliminarily demonstrated chromosome l p alterations in half of the HCCs with microsatellite polymorphism analysis, and the abnormalities seem to cluster at the distal part of the chromosome [22]. Cytogenetic studies should be extended to more primary HCCs to better delineate the genetic basis of h u m a n hepatocarcinogenesis.
Cytogenetic findings in the five cases
Patient no.
Karyotype 106-113,XXXYY,del{1)(p22),-4,- 5,-8,i(8)(q10),i(9),add(9}(p24),- 10,- 13,- 13,- 15,add(16)(q24), - 16,- 17,- 17,- 18,add(21)(q10)x2,- 22,+ 7-13mar [cpl0] 72- 76,XY,-X,del(1)(p32),+add(1)(q10),+del(6)(q15),+ 7,- 8 , - 9 , - 10,- 11,- 12,+ 13,+ 15,- 16,- 17,+ 18, + 20,- 21,-22,+4-8mar[cp12] 45,X,-Y,del(1)(p34),del(1)(p22),-4,- 5,- 13,der(16)add(16)(q24),+ 2mar[cp8] 46,XY[cpS] 6 6 - 72•xY•-x•+de•(1)(p32)•+add(1)(q1•)•-4'-6•
- 22,+ 1-3mar[cplO]
+ 7•-8•+11•der(13;15)(q1•;p1•)•i(14)(q1•)•-16•-17•-21•
Chromosomal Changes in Primary HCC
!
105
r
6
7
8
9
10
4
5
11
12
X
Y
Figure 3
G-banded karyotype of patient 3: 45,X,-Y, del(1)(p34),+del(1)(p22),-4,-5,-13,add(16)(q24), +2mar.
Figure 4
Partial karyotypes demonstrating structural abnormalities in patients 2 and 5 with del(1)[p32).
106 This study was supported by grants from the National Science Council and Department of Health, Executive Yuan, R.O.C. REFERENCES 1. Linsell, DA, Higginson J (1976): The geographic pathology of liver cell cancer. In: Cameron HM, Linsell DA, Warwick GP (eds.): Liver Cell Cancer. Elsevier, New York; 1976, pp. 1-16. 2. Lin TM, Tsu WT, Chen CJ (1986): Mortality of hepatoma and cirrhosis of liver in Taiwan. Br. J Cancer 54:969-976. 3. Chen DS (1987): Hepatitis B virus infection, its sequelae, and prevention in Taiwan. In: Okuda K, Ishak G (eds.): Neoplasms of the Liver. SpringerWerlag, Tokyo, pp. 71-80. 4. Beasley RP (1988): Hepatitis B virus: the major etiology of hepatocellular carcinoma. Cancer 61:1942-1956. 5. Chen DS, Kuo GC, Sung JL, Lai MY, Sheu JC, Chen PJ, Yang PM, Hsn HM, Chang MH, Chert CJ, Hahn LC, Choo QL, Wang TH, Houghton M (1990): Hepatitis C virus infection in an area hyperendemic for hepatitis B and chronic liver disease: the Taiwan experience. J Infect Dis 162:817-822. 6. Mitelman F (1991): Catalog of Chromosome Aberrations in Cancer, 4th Ed. Wiley-Liss, Inc., New York. 7. Simon D, Munoz SJ, Maddrey WC, Knowles BB (1990): Chromosomal rearrangements in a primary hepatocellular carcinoma. Cancer Genet Cytogenet 45:255-260. 8. Simon D, Knowles BB, Weith A (1991): Abnormalities of chromosome 1 and loss of heterozygosity on lp in primary hepatomas. Oncogene 6:765-770. 9. Bardi G, Pandis N, Fenger C, Kronborg O, Bomme L, Heim S (1993): Deletion of lp36 as a primary chromosomal aberration in intestinal tumorigenesis. Cancer Res 53:1895-1898. 10. Seabright M (1971): A rapid banding technique for human chromosomes. Lancet ii:971-972. 11. ISCN (1991) Guidelines for Cancer Cytogenetics: Supplement to An International System for Human Cytogenetic Nomenclature. Mitelman F, ed. Karger, Basel.
H.-L. C h e n et al.
12. Heim S, Mitelman F (1987): Cancer Cytogenetics. Alan R. Liss, Inc., New York. 13. Simon D, Aden DP, Knowles BB (1982): Chromosomes of human hepatoma cell lines. Int J Cancer 30:27-33. 14. Chen HL, Chiu TS, Chen PJ, Chen DS (1993): Cytogenetic studies in human liver cancer cell lines. Cancer Genet Cytogenet 65:161-166. 15. Trent Jm, Thompson FH, Meyskens FL Jr. (1989): Identification of a recurring translocation site involving chromosome 6 in human malignant melanoma. Cancer Res 49:420-423. 16. Sandros J, Mark J, Happonen RP, Stenman G (1988): Specificity of 6 q - markers and other recurrent deviations in human malignant salivary tumors. Anticancer Res 8:637-644. 17. Pejovic T, Heim S, Mandahl N, Baldetorp B, Elmfors B, Flod'erus Um, Furgyik S, Helm G, Himmelmann A, Willen H, Mitelman F (1992): Chromosome aberrations in 35 primary ovarian carcinomas. Genes Chromosom Cancer 4:58-68. 18. Bardi G, Johanson B, Pandis N, Heim S, Mandahl N, Sand~ berg AA, H/igerstrand I, Mitelman F (1992): Cytogenetic findings in three primary hepatocellular carcinomas. Cancer Genet Cytogenet 58:191-195. 19. Human Gene Mapping 11 (1991): Cytogenet Cell Genet 58: 985-2200. 20. Fong C, Dracopoli NC, White PS, Merril PT, Griffith RC, Housman DE, Brodeur GM (1989): Loss of heterozygosity for the short arm of chromosome 1 in human neuroblastomas: correlation with N-myc amplification. Proc Natl Acad Sci USA 86:3753-3757. 21. Weith A, Martinsson T, Cziepluch C, Bruderlein S, Amler LC, Berthold F, Schwab M (1989): Neuroblastoma consensus deletion maps to lp36.1-2. Genes Chromosom Cancer 1:159166. 22. Yeh SH, Chen PJ, Chen HL, Lai MY, Wang CC, Chen DS (1994): Frequent genetic alterations at the distal region of chromosome lp in human hepatocellular carcinomas. Cancer Res 54:4188-4192.