Luis Antonio Parada

Frequent rearrangements of chromosomes 1, 7, and 8 in primary liver cancer

Fifteen primary liver carcinomas (PLCs), including 12 hepatocellular carcinomas and three cholangiocellular carcinomas, were investigated cytogenetically after short‐term culture. Ten tumors displayed clonal chromosomal abnormalities, whereas only normal karyotypes were detected in four cases, and one sample failed to grow in vitro. Structural rearrangements most often involved chromosomes 1, 7, and 8 and chromosome bands 1p36, 1q25, 3q10, 5q13, 6p10, 7p15, 7q22, 7q32, 8q10, 8q13, 14q10, and 17p11. Frequent genomic imbalances included gains of 1q, 3q, 6p, 7p, and 8q and losses of 1p, 8p, 10q, 14p, 17p, and 19p. A compilation of findings for all 19 cytogenetically abnormal PLCs reported to date, including the present cases, reveals that structural aberrations particularly affect 1p11, 1p22, 1p32, 1p34, 1p36, 1q25, 7p15, 7q22, 8q10, 8q13, 14q10, 16q24, and 17p11, and that the abnormalities frequently result in overrepresentation of 1q, 3q, 6p, 7p10–14, 8q, and 17q and underrepresentation of 1p34–36, 6q27, 7q32–qter, 8p, 13p, 14p, 16q24, and 17p. These genomic regions are likely to harbor genes of importance in hepatocarcinogenesis, and the present cytogenetic mapping may hence be of value for further molecular genetic investigations of PLC. Genes Chromosomes Cancer 23:26–35, 1998.

Cytogenetics of hepatoblastoma: further characterization of 1q rearrangements by fluorescence in situ hybridization: an international collaborative study

BACKGROUND Hepatoblastoma (HBT) is the most common hepatic neoplasm in children. This notwithstanding, little is known about pathogenetic factors, such as genetic abnormalities, of importance for the development and progression of this tumor type. To date, only 33 cytogenetically abnormal HBT have been published, and trisomies for chromosomes 2 and 20 have been shown to be the most frequent aberrations. Recently, unbalanced translocations involving proximal 1q have been described in several HBT, suggesting that a pathogenetically important gene maps to 1q. PROCEDURE Six primary and one recurrent HBT were cytogenetically analyzed after short-term tissue culture. In addition, fluorescence in situ hybridization (FISH) studies, using locus-specific probes, were performed on three of these pediatric HBT as well as on one previously reported adult HBT. RESULTS Total or partial trisomy 8, gain of chromosome 20, and structural rearrangements of chromosome 1 were detected in three HBT, and overrepresentation of chromosome 2 material was found in two HBT. The adjacent chromosome bands 1q12 and 1q21 were involved in three translocations, t(1;2), t(1;4), and t(1;11), which were all unbalanced and resulted in gain of 1q material. The previously reported adult HBT displayed 1q deletions with breakpoints at 1q12-21. FISH analyses of the 1q rearrangements revealed that all breakpoints were within the heterochromatic region. CONCLUSIONS These findings provide further support for the importance of trisomies 2, 8, and 20 and rearrangements of 1q in the development of HBT. Furthermore, the consistent localization of breakpoints within the heterochromatic segment of chromosome 1 suggests that the important pathogenetic consequence of 1q abnormalities is the resulting genomic imbalance rather than a specific gene rearrangement.

Cytogenetic comparisons of synchronous carcinomas and polyps in patients with colorectal cancer.

Thirty tumorous lesions from seven patients with colorectal cancer were short-term cultured and cytogenetically analysed: 16 non-adenomatous polyps, six adenomas, seven carcinomas, including one in polyp, and one lymph node metastasis. Clonal chromosome aberrations were found in 20 samples in 100% of the carcinomas, in 100% of the adenomas and in 37.5% of the non-adenomatous polyps, i.e. all ten lesions with a normal karyotype were histologically diagnosed as hyperplastic polyps. Although adenomas and carcinomas shared several karyotypic features, two chromosome aberrations, der(8;17)(q10;q10) and -14, were found in carcinomas but not in adenomas, indicating that they might be specifically associated with carcinoma development in the large bowel mucosa. The karyotypic similarity seen between the malignant and benign tumours in the same patient, and also sometimes among non-malignant polyps in the same case, indicates that these microscopically distinct lesions may be part of a single neoplastic clonal expansion.

Genetic Profiling of Colorectal Cancer Liver Metastases by Combined Comparative Genomic Hybridization and G-Banding Analysis

The majority of genetic studies of colorectal carcinogenesis have focused on changes found in primary tumors. Despite the fact that liver metastases are a leading cause of colorectal cancer deaths, the molecular genetic basis of the advanced disease stages remains poorly understood. We performed comparative genomic hybridization (CGH) on 17 liver metastases from colorectal carcinomas and compared the quantitative profile with the qualitative profile previously obtained with chromosome banding. An average of 12.6 aberrations per tumor was found by CGH. Chromosome 18 and chromosome arms 4q, 8p, and 17p were most frequently lost, whereas chromosomes 7 and 20 and chromosome arms 6p, 8q, and 13q were most frequently gained. We compared the chromosome banding and CGH data after converting the karyotypes into net copy number gains and losses. Ten tumors showed agreement between the findings of the two techniques, whereas five tumors did not (in two cases, no mitotic cells were obtained for banding analysis). All five discordant cases had a “simple” abnormal or normal karyotype, but revealed multiple changes by CGH. A likely explanation for this discrepancy is that in vitro growth before G‐banding selected against the cancer cells. Interestingly, by comparing the CGH profiles of the “complex” vs. the “simple”/normal karyotype groups, deletion of 8p and gain of 16q were seen more frequently in the former group. The liver metastases had the same aberrations as seen in primary colorectal carcinomas, summarized in a literature survey. However, these aberrations were seen more frequently in liver metastases, which may be attributable to increased genetic instability.

Clonal chromosomal abnormalities in congenital bile duct dilatation (Caroli’s disease)

BACKGROUND Caroli’s disease is a rare congenital disorder characterised by cystic dilatation of the intrahepatic bile ducts and an increased risk of cholangiocellular carcinoma. The cause is unknown, but occasional familial clustering suggests that some cases are inherited, in particular when occurring in association with polycystic kidney disease and germline PKD1 gene mutations. To date, no gene responsible for familial isolated Caroli’s disease has been identified, and no genetic investigations of liver tissue from patients with Caroli’s disease have been reported. PATIENT/METHOD A liver biopsy specimen from a patient with isolated Caroli’s disease, without any signs of cholangiocellular carcinoma, was short term cultured and cytogenetically investigated after G banding with Wright’s stain. RESULT Cytogenetic analysis disclosed the karyotype 45-47,XX,der(3)t(3;8)(p23;q13), +2mar[cp6]/46,XX[18]. CONCLUSIONS The finding of an unbalanced translocation between chromosomes 3 and 8 suggests that loss of distal 3p and/or gain of 8q is of pathogenetic importance in Caroli’s disease. Alternatively, structural rearrangements of genes located in 3p23 and 8q13 may be of the essence. These chromosomal breakpoints may also pinpoint the location of genes involved in inherited forms of Caroli’s disease not associated with polycystic kidney disease.

Cytogenetic abnormalities and clonal evolution in an adult hepatoblastoma

Hepatoblastomas usually occur in children < 3 years of age, and only occasional adult cases have been described. To date, 20 cytogenetically abnormal childhood hepatoblastomas have been reported. Karyotypic investigations have shown that most hepatoblastomas are diploid or hyperdiploid, often displaying trisomies for chromosomes 2 and 20. We have cytogenetically investigated an adult hepatoblastoma for which no previous karyotypic data exist. A hypertriploid stemline with multiple numerical and structural chromosomal aberrations, including +2 and +20, was found. In addition, the tumor displayed extensive clonal evolution with 11 subclones. Although the tumor thus displayed some chromosomal abnormalities commonly observed in childhood tumors, providing further support for the importance of these abnormalities in the development of hepatoblastoma, the level of genomic complexity seen in the present case has never been described in childhood hepatoblastomas and may suggest a different etiology or pathogenesis.

Cytogenetic analyses of secondary liver tumors reveal significant differences in genomic imbalances between primary and metastatic colon carcinomas

To investigate if karyotypic features of secondary liver tumors may provide diagnostic information and if the cytogenetic patterns of primary and metastatic colorectal carcinomas (CRC) are different, 33 liver metastases were analyzed: 25 CRC, 4 small intestine carcinoids, 1 ovarian carcinoid, 1 lobular breast cancer, 1 head-and-neck squamous cell carcinoma, and 1 uveal malignant melanoma. Chromosomal aberrations were detected in 24 cases, whereas 5 had normal karyotypes and 4 were uninformative due to lack of mitoses. Trisomy 12 was detected in 2 small intestine carcinoids, suggesting that +12 may be of pathogenetic importance in this tumor type. The breast and head-and-neck carcinomas and the uveal melanoma displayed aberrations previously reported as characteristic in primary tumors, e.g., der(1;16) and deletion of 3p in the breast cancer, losses of 3p and 8p and partial gain of 8q in the head-and-neck carcinoma, and monosomy 3 and i(8)(q10) in the uveal melanoma, indicating that cytogenetic investigations provide important diagnostic information in secondary liver tumors. In the 18 CRC metastases with chromosomal abnormalities, the cytogenetic findings agreed well with previously reported primary CRC. Common numerical abnormalities included gains of chromosomes 7, 11, 13, and 20, and losses of Y, 4, 18, 21, and 22. Structural rearrangements most often affected chromosome bands 1p13, 1q10, 3p21, 5q10, 5q11, 7q10, 8q10, 8q11, 12q13, 16p13, 17p11, 20p13, 20p11, and 20q10, and frequently resulted in losses of 1p, 8p, and 17p, and gains of 5p, 6p, 7p, 8q, and 20q. Comparing the present cases with primary CRC previously analyzed in our department revealed that additional gains of 6p, 6q, 7p, and 20q, and losses of 1p, 4p, 4q, 8p, 18p, 18q, and 22 were more common (P<0.05) in the metastases, suggesting that these genomic sites harbor genes of importance in the metastatic process of CRC.

Nonrandom chromosomal aberrations and cytogenetic heterogeneity in gallbladder carcinomas.

Chromosome banding analysis of 11 short‐term cultured gallbladder carcinomas revealed acquired clonal aberrations in seven tumors (five primary and two metastases). Three of these had one clone, whereas the remaining four were cytogenetically heterogeneous, displaying two to seven aberrant clones. Of a total of 21 abnormal clones, 18 had highly complex karyotypes and three exhibited simple numerical deviations. Double minutes and homogeneously staining regions were observed in one and two carcinomas, respectively. To characterize the karyotypic profile of gallbladder cancer more precisely, we have combined the present findings with our three previously reported cases, thereby providing the largest cytogenetic database on this tumor type to date. A total of 287 chromosomal breakpoints were identified, 251 of which were found in the present study. Chromosome 7 was rearranged most frequently, followed by chromosomes 1, 3, 11, 6, 5, and 8. The bands preferentially involved were 1p32, 1p36, 1q32, 3p21, 6p21, 7p13, 7q11, 7q32, 19p13, 19q13, and 22q13. Nine recurrent abnormalities could, for the first time, be identified in gallbladder carcinoma: del(3)(p13), i(5)(p10), del(6)(q13), del(9)(p13), del(16)(q22), del(17)(p11), i(17)(q10), del(19)(p13), and i(21)(q10). The most common partial or whole‐arm gains involved 3q, 5p, 7p, 7q, 8q, 11q, 13q, and 17q, and the most frequent partial or whole‐arm losses affected 3p, 4q, 5q, 9p, 10p, 10q, 11p, 14p, 14q, 15p, 17p, 19p, 21p, 21q, and Xp. These chromosomal aberrations and imbalances provide some starting points for molecular analyses of genomic regions that may harbor genes of pathogenetic importance in gallbladder carcinogenesis. Genes Chromosomes Cancer 26:312–321, 1999.

Cytogenetic findings in metastases from colorectal cancer

Eighteen tumor samples from 11 patients with metastatic colorectal cancer were cytogenetically analyzed after short‐term culturing. Of the 13 metastases examined, 11 were from lymph nodes, 1 from the peritoneum and 1 from the lung. In 5 of the 11 patients, matched samples from the primary tumor and lymph node metastases were analyzed. Cytogenetic similarities between the primary and secondary lesions were found in all 5 cases, indicating that many of the chromosomal aberrations presumably occurred before disease spreading took place. Compared with the primaries, the metastases appeared to exhibit decreased clonal heterogeneity but, concurrently, an increase in the karyotypic complexity of individual clones. Among the aberrations recurrently found in metastatic lesions were del(1)(p34), i(17)(q10), −18, −Y, −21, +7 and +20, all of which have been seen repeatedly in previous series of primary colorectal carcinomas, and del(10)(q22) and add(16)(p13), which so far have not been associated with primary tumors and which may play a particular pathogenetic role in the metastatic process. Int. J. Cancer 72:604–607, 1997.

Cytogenetic abnormalities in a hemangiopericytoma of the spleen

To date, only 16 cytogenetically abnormal hemangiopericytomas (HP) have been reported. Despite this low number, some characteristic karyotypic features have already emerged: most HP are near-diploid and breakpoints in 12q13, 12q24, and 19q13 seem to be common, with t(12;19)(q13;q13) being a recurrent translocation. Here, we report the first case of a probably benign splenic HP with chromosomal abnormalities. The abnormal karyotype was 47,XX,t(5;22;11)(q31;q11;q13),+10. None of these abnormalities have previously been reported in HP, suggesting that the karyotypic pattern of splenic HP may differ from soft tissue HP.