Chromosome aberrations in 35 primary ovarian carcinomas

Establishment of cancer cell line originating from a patient with high-grade serous ovarian carcinoma

Aim

Ovarian cancer is a serious malignancy with high prevalence and mortality.

Methods

We isolated and characterized an ovarian high-grade serous cancer cell line (M4) from a tumor of a Vietnamese patient with ovarian carcinoma.

Results

The M4 cancer cell line showed good proliferation and stability in culture. Morphologically, the M4 cells showed similar characteristics to tumor cells such as a polyhedral shape, large irregular nuclei, high nuclear/cytoplasmic ratio, high nuclear density and expressing cancer markers like CA125, p53 and Ki67 markers.

Conclusion

We have successfully isolated and characterized the M4 cell line from a Vietnamese patient with ovarian carcinoma.

Establishment and characterization of a novel ovarian high-grade serous carcinoma cell line-IPO43

Background

Epithelial ovarian cancer (EOC) is an aggressive and lethal malignancy and novel EOC cell lines with detailed characterization are needed, to provide researchers with diverse helpful resources to study EOC biological processes and cancer experimental therapies.

Methods

The IPO43 cell line was established from the ascitic fluid of a patient with a diagnosis of high-grade serous carcinoma (HGSC) of the ovary, previously treated with chemotherapy.

Cell immortalization was achieved in 2D cell culture and growth obtained in 2D and 3D cell cultures. The characterization of immortalized cells was done by immunocytochemistry, flow cytometry, cell proliferation, chromosomal Comparative Genomic Hybridization (cCGH), STR profile and Next Generation Sequencing (NGS).

Results

Characterization studies confirmed that IPO43 cell line is of EOC origin and maintains morphological and molecular features of the primary tumor. cCGH analysis showed a complex profile with gains and losses of specific DNA regions in both primary ascitic fluid and cell line IPO43. The cell line was successfully grown in a 3D system which allows its future application in more complex assays than those performed in 2D models. IPO43 cell line is resistant to standard drug treatment in vitro.

Conclusions

IPO43 is available for public research and we hope it can contribute to enrich the in vitro models addressing EOC heterogeneity, being useful to investigate EOC and to develop new therapeutic modalities.

IPOLFG-SOC43 cell line represents the heterogeneity of Epithelial Ovarian Cancer

Genetic alterations in cancer cells confer a selective advantage

3D cultures preserve the phenotypical features of the original tumor

Extrauterine Mesonephric-like Neoplasms: Expanding the Morphologic Spectrum

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms arising in the uterine corpus and ovary which have been added to the recent 2020 World Health Organization Classification of Female Genital Tumors. They have similar morphology and immunophenotype and exhibit molecular aberrations similar to cervical mesonephric adenocarcinomas. It is debated as to whether they are of mesonephric or Mullerian origin. We describe the clinical, pathologic, immunohistochemical, and molecular features of 5 cases of extrauterine mesonephric-like proliferations (4 ovary, 1 extraovarian), all with novel and hitherto unreported features. These include an origin of MLA in extraovarian endometriosis, an association of ovarian MLA with high-grade serous carcinoma, mixed germ cell tumor and mature teratoma, and a borderline ovarian endometrioid tumor exhibiting mesonephric differentiation. Four of the cases exhibited a KRAS variant and 3 also a PIK3CA variant. In reporting these cases, we expand on the published tumor types associated with MLA and report for the first time a borderline tumor exhibiting mesonephric differentiation. We show the value of molecular testing in helping to confirm a mesonephric-like lesion and in determining the relationship between the different neoplastic components. We provide further evidence for a Mullerian origin, rather than a true mesonephric origin, in some of these cases. We also speculate that in the 2 cases associated with germ cell neoplasms, the MLA arose out of the germ cell tumor.

Involvement of DPP9 in gene fusions in serous ovarian carcinoma

Background

A fusion gene is a hybrid gene consisting of parts from two previously independent genes. Chromosomal rearrangements leading to gene breakage are frequent in high-grade serous ovarian carcinomas and have been reported as a common mechanism for inactivating tumor suppressor genes. However, no fusion genes have been repeatedly reported to be recurrent driver events in ovarian carcinogenesis. We combined genomic and transcriptomic information to identify novel fusion gene candidates and aberrantly expressed genes in ovarian carcinomas.

Methods

Examined were 19 previously karyotyped ovarian carcinomas (18 of the serous histotype and one undifferentiated). First, karyotypic aberrations were compared to fusion gene candidates identified by RNA sequencing (RNA-seq). In addition, we used exon-level gene expression microarrays as a screening tool to identify aberrantly expressed genes possibly involved in gene fusion events, and compared the findings to the RNA-seq data.

Results

We found a DPP9-PPP6R3 fusion transcript in one tumor showing a matching genomic 11;19-translocation. Another tumor had a rearrangement of DPP9 with PLIN3. Both rearrangements were associated with diminished expression of the 3′ end of DPP9 corresponding to the breakpoints identified by RNA-seq. For the exon-level expression analysis, candidate fusion partner genes were ranked according to deviating expression compared to the median of the sample set. The results were collated with data obtained from the RNA-seq analysis. Several fusion candidates were identified, among them TMEM123-MMP27, ZBTB46-WFDC13, and PLXNB1-PRKAR2A, all of which led to stronger expression of the 3′ genes. In view of our previous findings of nonrandom rearrangements of chromosome 19 in this cancer type, particular emphasis was given to changes of this chromosome and a DDA1-FAM129C fusion event was identified.

Conclusions

We have identified novel fusion gene candidates in high-grade serous ovarian carcinoma. DPP9 was involved in two different fusion transcripts that both resulted in deregulated expression of the 3′ end of the transcript and thus possible loss of the active domains in the DPP9 protein. The identified rearrangements might play a role in tumorigenesis or tumor progression.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3625-6) contains supplementary material, which is available to authorized users.

Bilateral ovarian carcinomas differ in the expression of metastasis-related genes

The mechanisms behind bilaterality of ovarian carcinomas are not fully understood, as the two tumors could possibly represent two primary tumors, a primary tumor and a metastasis, or two metastases. The gene expression profiles from bilateral high-grade serous carcinomas (HGSCs) and clear cell carcinomas (CCCs) of the ovary were compared to study the association between the tumors of the two sides. A separate analysis of genes from chromosome 19 was also performed, since this chromosome is frequently rearranged in ovarian carcinomas. Tumors from four patients were included (three pairs of HGSC and one pair of CCC). The gene expression was analyzed at the exon level, and bilateral tumors were compared to identify within-pair differences. Gene expression data were also compared with genomic information on the same tumors. Similarities in gene expression were observed between the tumors within each pair, as expected if the two tumors were clonally related. However, certain genes exhibited differences in expression between the two sides, indicating metastasis involvement. Among the most differently expressed genes, one gene was common to all four pairs: Immunoglobulin J. In all HGSC pairs, serpin peptidase inhibitor, clade B (ovalbumin), member 2, serpin family E member 1 and phospholipase A2, group IIA (platelets, synovial fluid) were also among the differentially expressed genes. The specific analysis of chromosome 19 highlighted expression differences in the zinc finger protein 36 gene. These results indicate that bilateral ovarian tumors represent different stages during progression of a single clonal process. Several of the genes observed to be differently expressed are known to be metastasis-related, and are likely to be also involved in spreading from one side to the other in the bilateral cancer cases examined.

Genomic profile of ovarian carcinomas

Background

It is known that all tumors studied in sufficient number to draw conclusions show characteristic/specific chromosomal rearrangements, and the identification of these chromosomes and the genes rearranged behind the aberrations may ultimately lead to a tailor-made therapy for each cancer patient. Knowledge about the acquired genomic aberrations of ovarian carcinomas is still unsatisfactory.

Methods

We cytogenetically analyzed 110 new cases of ovarian carcinoma of different histological subtypes using karyotyping of G-banded chromosomes and high-resolution comparative genomic hybridization. We first compared the aberration patterns identified by the two genomic screening techniques using the so-called “classical” pathological classification in which the carcinomas are grouped as tumors of types I and II. We also broke down our findings according to the more “modern” classification which groups the carcinomas in five different categories.

Results

The chromosomal breakpoints identified by karyotyping tended to cluster to 19p/q and to 11q, but no unquestionably recurrent rearrangement could be seen. Common imbalances were scored as gains from 1q, 3q, 7q, and 8q and losses from 17p, 19q, and 22q. Gain of material from 8q23 and losses from 19q and 22q have previously been described at high frequencies in bilateral and borderline ovarian carcinomas. The fact that they were present both in “precursor” lesions, i.e., borderline tumors, as well as in tumors of more advanced stages, i.e., carcinomas, highlights the possibility of an adenoma-carcinoma sequence in ovarian carcinogenesis.

Conclusion

Based on the relatively simple genomic changes we identified in the low-grade serous carcinomas examined (n = 7) and which largely corresponded to the aberration pattern formerly identified in borderline tumors, one can interpret the cytogenetic data as supporting the view that the low-grade carcinomas represent a phenotypically more advanced stage of borderline tumors. Whether transition from low-grade to high-grade carcinoma also occurs, is a question about which the genomic data is still inconclusive.

mFISH analysis of chromosome aberrations in workers occupationally exposed to mixed radiation

We performed a study on the presence of chromosome aberrations in a cohort of plutonium workers of the Mayak production association (PA) with a mean age of 73.3 ± 7.2 years to see whether by multi-color fluorescence in situ hybridization (mFISH) translocation analysis can discriminate individuals who underwent occupational exposure with internal and/or external exposure to ionizing radiation 40 years ago. All Mayak PA workers were occupationally exposed to chronic internal alpha-radiation due to incorporated plutonium-239 and/or to external gamma-rays. First, we obtained the translocation yield in control individuals by mFISH to chromosome spreads of age-matched individuals and obtained background values that are similar to previously published values of an international study (Sigurdson et al. in Mutat Res 652:112-121, 2008). Workers who had absorbed a total dose of >0.5 Gy external gamma-rays to the red bone marrow (RBM) displayed a significantly higher frequency of stable chromosome aberrations relative to a group of workers exposed to <0.5 Gy gamma-rays total absorbed RBM dose. Thus, the translocation frequency may be considered to be a biological marker of external radiation exposure even years after the exposure. In a group of workers who were internally exposed and had incorporated plutonium-239 at a body burden >1.48 kBq, mFISH revealed a considerable number of cells with complex chromosomal rearrangements. Linear associations were observed for translocation yield with the absorbed RBM dose from external gamma-rays as well as for complex chromosomal rearrangements with the plutonium-239 body burden.

Chromosome 19 rearrangements in ovarian carcinomas: zinc finger genes are particularly targeted

Chromosome 19 is frequently rearranged in ovarian carcinomas, but the pathogenetic consequences of this are not clearly understood. We performed microarray gene expression analysis on 12 ovarian carcinomas that carry a rearranged chromosome 19 in their karyotype. These aberrant chromosomes have previously been microdissected and analyzed by array-based CGH. In the current study, we wanted to explore whether the genomic alterations thus detected correlated with changes in gene expression. The microarray gene expression analysis gave information on 407 genes mapping in gained genomic regions on chromosome 19, of which 92 showed association between DNA gain and upregulated expression. Of the genes showing this association, 39 (42%) showed gain in at least two samples. The majority of these 39 genes of interest (n = 24, 62%) encode zinc finger proteins, which otherwise make up only 15% of the approximately 1,400 genes on chromosome 19. The strongest association was found for ZNF223 which was upregulated in samples with genomic gain compared with samples without gain. We suggest that DNA copy number changes brought about by rearrangements of chromosome 19 contribute to ovarian carcinogenesis by leading to upregulation of ZNF223 and other zinc finger genes. © 2014 Wiley Periodicals, Inc.

Polymorphisms of MUC16 (CA125) and MUC1 (CA15.3) in relation to ovarian cancer risk and survival

Objective

To examine single nucleotide polymorphism (SNPs) in MUC16 (CA125) and MUC1 (CA15.3) in relation to ovarian cancer risk and survival.

Methods

We genotyped germline variants of MUC16 (rs2547065, rs1559168, rs12984471, rs2121133) and MUC1 (rs2070803, rs4072037, rs1045253) using samples collected from 758 ovarian cancer cases and 788 controls enrolled in the New England Case-Control Study between 2003 and 2008. We calculated age-adjusted odds ratios (OR) and 95% confidence intervals (CIs) for disease risk using unconditional and polytomous logistic regression and hazard ratios (HR) for survival using Cox proportional hazard ratios. In a subset of cases, we compared log-normalized CA125 values by genotype using generalized linear models.

Results

Cases homozygous for the variant allele of MUC16 SNP, rs12984471, had poorer overall survival (log-rank p = 0.03) and higher CA125 levels, especially cases over age 65 (p = 0.01). For MUC1 SNP, rs4072037, women homozygous for the G variant had a non-significantly decreased risk for serous invasive types but elevated risk for serous borderline tumors, mucinous borderline and invasive tumors, and endometrioid tumors. Women with the variant allele of MUC16 SNP, rs2547065, especially those who were homozygous had an elevated risk for ovarian cancer; but this association was not confirmed in an independent dataset.

Conclusion

This targeted screen of seven polymorphisms of MUC16 and MUC1 genes failed to identify and confirm effects on ovarian cancer risk overall. However, there may be effects of MUC16 rs12984471 on survival and MUC1 rs4072037 on risk for histologic types of ovarian cancer other than invasive serous. Further study is warranted.

Subtype specific elevated expression of hyaluronidase-1 (HYAL-1) in epithelial ovarian cancer

Background

Epithelial ovarian cancer (EOC) is morphologically heterogeneous being classified as serous, endometrioid, clear cell, or mucinous. Molecular genetic analysis has suggested a role for tumor suppressor genes located at chromosome 3p in serous EOC pathogenesis. Our objective was to evaluate the expression of HYAL1, located at chromosome 3p21.3, in these EOC subtypes, and to investigate its correlation with the expression of steroid hormone receptors.

Methodology/Principal Findings

We determined the mRNA expression of HYAL1, estrogen receptor (ER)-α, ERβ and progesterone receptor (PR) in EOC tumor samples and cell lines using quantitative RT-PCR. We also examined the expression of these genes in a publicly available microarray dataset. HYAL-1 enzyme activity was measured in EOC cell lines and in plasma samples from patients. We found that HYAL1 mRNA expression was elevated in clear cell and mucinous EOC tissue samples, but not in serous and endometrioid samples, normal ovaries or benign tumors. Similar results were obtained by two different techniques and with tissue sample cohorts from two independent institutions. Concordantly, HYAL1 mRNA levels and enzymatic activity were elevated only in EOC cell lines derived from clear cell and mucinous subtypes. We also showed that HYAL1 mRNA was inversely correlated to that of ERα specifically in clear cell and mucinous EOCs. Additionally, ectopic expression of ERα in a clear cell EOC cell line (ER- and PR-negative) induced 50% reduction of HYAL1 mRNA expression, supporting a role of ERα in HYAL1 gene regulation. Significantly, HYAL-1 activity was also high in the plasma of patients with these EOC subtypes.

Conclusions/Significance

This is the first report showing high HYAL-1 levels in EOC and demonstrating HYAL1 gene repression by ERα. Our results identify Hyaluronidase-1 as a potential target/biomarker for clear cell and mucinous EOCs and especially in tumors with low ERα levels.

Genomic instability and copy-number heterogeneity of chromosome 19q, including the kallikrein locus, in ovarian carcinomas

Many tissue kallikrein (KLK) genes and proteins are candidate diagnostic, prognostic and predictive biomarkers for ovarian cancer (OCa). We previously demonstrated that the KLK locus (19q13.3/4) is subject to copy-number gains and structural rearrangements in a pilot study of cell lines and ovarian cancer primary tissues, shown to overexpress KLK gene family members. To determine the overall frequency of genomic instability and copy-number changes, a retrospective study was conducted using formalin-fixed paraffin embedded (FFPE) tissues. Eighty-one chemotherapy naïve serous OCas were examined using 3-colour fluorescence in situ hybridization (FISH) to identify structural and numerical changes on 19q, including the KLK locus; in addition to immunohistochemistry (IHC) for KLK6, which has been shown to be overexpressed in OCa. The KLK locus was subject to copy-number changes in ∼83% of cases: net gain in 51%, net loss in 30% and amplified in 2%; and found to be chromosomally unstable (p < 0.001). All cases showed a wide range of immuoreactivity for KLK6 by IHC. Although no strong correlation could be found with copy-number, the latter was contributing factor to the observed KLK6 protein overexpression. Moreover, univariate and multivariate analyses showed an association between the net loss of the KLK locus and longer disease-free survival. Interestingly, FISH analyses indicated that chromosome 19q was subjected to structural rearrangement in 62% of cases and was significantly correlated to tumor grade (p < 0.001). We conclude that numerical and structural aberrations of chromosome 19q, affect genes including the KLK gene members, may contribute to ovarian carcinoma progression and aggressiveness.

Characterization of the 3p12.3-pcen region associated with tumor suppression in a novel ovarian cancer cell line model genetically modified by chromosome 3 fragment transfer

The genetic analysis of nontumorigenic radiation hybrids generated by transfer of chromosome 3 fragments into the tumorigenic OV-90 ovarian cancer cell line identified the 3p12.3-pcen region as a candidate tumor suppressor gene (TSG) locus. In the present study, polymorphic microsatellite repeat analysis of the hybrids further defined the 3p12.3-pcen interval to a 16.1 Mb common region containing 12 known or hypothetical genes: 3ptel-ROBO2-ROBO1-GBE1-CADM2-VGLL3-CHMP2B-POU1F1-HTR1F-CGGBP1-ZNF654-C3orf38-EPHA3-3pcen. Seven of these genes, ROBO1, GBE1, VGLL3, CHMP2B, CGGBP1, ZNF654, and C3orf38, exhibited gene expression in the hybrids, placing them as top TSG candidates for further analysis. The expression of all but one (VGLL3) of these genes was also detected in the parental OV-90 cell line. Mutations were not identified in a comparative sequence analysis of the predicted protein coding regions of these candidates in OV-90 and donor normal chromosome 3 contig. However, the nondeleterious sequence variants identified in the transcribed regions distinguished parent of origin alleles for ROBO1, VGLL3, CHMP2B, and CGGBP1 and cDNA sequencing of the hybrids revealed biallelic expression of these genes. Interestingly, underexpression of VGLL3 and ZNF654 were observed in malignant ovarian tumor samples as compared with primary cultures of normal ovarian surface epithelial cells or benign ovarian tumors, and this occurred regardless of allelic content of 3p12.3-pcen. The results taken together suggest that dysregulation of VGLL3 and/or ZNF654 expression may have affected pathways important in ovarian tumorigenesis which was offset by the transfer of chromosome 3 fragments in OV-90, a cell line hemizygous for 3p.

Tumor spreading to the contralateral ovary in bilateral ovarian carcinoma is a late event in clonal evolution

Cancer of the ovary is bilateral in 25%. Cytogenetic analysis could determine whether the disease in bilateral cases is metastatic or two separately occurring primary tumors, but karyotypic information comparing the two cancerous ovaries is limited to a single report with 11 informative cases. We present a series of 32 bilateral ovarian carcinoma cases, analyzed by karyotyping and high-resolution CGH. Our karyotypic findings showed that spreading to the contralateral ovary had occurred in bilateral ovarian cancer cases and that it was a late event in the clonal evolution of the tumors. This was confirmed by the large number of similar changes detected by HR-CGH in the different lesions from the same patient. The chromosomal bands most frequently involved in structural rearrangements were 19p13 (n = 12) and 19q13 (n = 11). The chromosomal bands most frequently gained by both tumorous ovaries were 5p14 (70%), 8q23-24 (65%), 1q23-24 (57%), and 12p12 (48%), whereas the most frequently lost bands were 17p11 (78%), 17p13 (74%), 17p12 (70%), 22q13 (61%), 8p21 and 19q13 (52%), and 8p22-23 (48%). This is the first time that 5p14 is seen gained at such a high frequency in cancer of the ovary; possibly oncogene(s) involved in bilateral ovarian carcinogenesis or tumor progression may reside in this band.

Transcriptome analysis of serous ovarian cancers identifies differentially expressed chromosome 3 genes

Cytogenetic, molecular genetic and functional analyses have implicated chromosome 3 genes in epithelial ovarian cancers (EOC). To further characterize their contribution to EOC, the Affymetrix U133A GeneChip(R) was used to perform transcriptome analyses of chromosome 3 genes in primary cultures of normal ovarian surface epithelial (NOSE) cells (n = 14), malignant serous epithelial ovarian tumors (TOV) (n = 17), and four EOC cell lines (TOV-81D, TOV-112D, TOV-21G, and OV-90). A two-way comparative analysis of 735 known genes and expressed sequences identified 278 differentially expressed genes, where 43 genes were differentially expressed in at least 50% of the TOV samples. Three genes, RIS1 (at 3p21.31), GBE1 (at 3p12.2), and HEG1 (at 3q21.2), were similarly underexpressed in all TOV samples. Deregulation of the expression of these genes was not associated with loss of heterozygosity (LOH) of the genetic loci harboring them. LOH analysis of the RIS1, GBE1, and HEG1 loci was observed at frequencies of 14.3%, 13.7%, and 9.2%, respectively, in a series of 66 malignant TOV samples of the serous subtype. Reduced expression levels of RIS1, GBE1, and HEG1 were observed only in the tumorigenic EOC cell lines (TOV-21G, TOV-112D, and OV-90) and did not correlate with LOH. These results combined suggest that RIS1, GBE1, and HEG1, unlike classical tumor suppressor genes, are not likely to be primary targets of inactivation. This study provides a comprehensive analysis of chromosome 3 gene expression in NOSE and in EOC samples and identifies chromosome 3 gene candidates for further study.

Transcriptional upregulation of human tissue kallikrein 6 in ovarian cancer: clinical and mechanistic aspects

The human tissue kallikrein family (KLK for protein; KLK for gene) includes 15 members. Twelve kallikreins, including KLK6, are concurrently upregulated in ovarian cancer. However, the mechanism of this phenomenon remains unclear. In this study, we measured KLK6 expression in a large series of ovarian tissue cytosols and examined possible mechanisms of KLK6 up-regulation in ovarian cancer. Using a newly developed enzyme-linked immunosorbent assay (ELISA) with two monoclonal antibodies, we quantified KLK6 expression in ovarian tissue cytosols, and confirmed the upregulation of KLK6 in ovarian cancer and its unfavourable prognostic value. We then examined KLK6 mRNA expression using reverse transcription-polymerase chain reaction and established its good concordance with KLK6 protein expression. This finding suggested that the KLK6 gene is under transcriptional regulation. We then scrutinised a few mechanisms that could explain KLK6 upregulation. The relative abundance of two KLK6 mRNA transcripts was studied; we found the same differential expression pattern in all samples, regardless of KLK6 levels. Genomic mutation screening of all exons and the 5'-flanking region of the KLK6 gene identified two linked single-nucleotide polymorphisms in the 5'-untranslated region, but neither correlated with KLK6 expression. Ovarian cell lines were separately treated with five steroid hormones. None of the treatments produced significant effects on KLK6 expression. We conclude that KLK6 is transcriptionally upregulated in ovarian cancer, but probably not through alternative mRNA transcript expression, genomic mutation, or steroid hormone induction.

Comparative genome hybridization reveals specific genomic imbalances during the genesis from benign through borderline to malignant ovarian tumors

Ovarian cancer is one of the most common types of malignancy in women throughout the developed world. Despite recent therapeutic advances, long-term survival is poor because ovarian cancer is largely asymptomatic in its early stages. Comparative genomic hybridization (CGH) was applied to a series of 8 benign, 8 borderline, and 17 malignant ovarian to establish genomic imbalances associated with tumor progression. Benign and borderline tumors were characterized by losses at 1p32 approximately p11, 2q14 approximately q34, 4q13 approximately q34, 5q11 approximately q23, and 6q12 approximately q24, as well as gains of 6p and chromosome 12. Similar chromosomal changes were also detected in malignant tumors but included additional chromosomal changes: gains at 1q21 approximately q31, 2p, 3q, 5p, 7, 10p, 12p, 16p, 17, 19q, 20q, and 22q, as well as losses at X, 3p, 8p, 9, 11p, 13, 14, and 18. Some individual cases of benign and borderline tumors revealed no genetic alterations detectable by CGH, suggesting that these tumors may represent a subset of tumors that originate by an alternative mechanism of tumorigenesis. Furthermore, our findings reveal that borderline tumors are more similar to benign tumors than to malignant tumors with respect to their genetic profiles.

Transfer of chromosome 3 fragments suppresses tumorigenicity of an ovarian cancer cell line monoallelic for chromosome 3p

Multiple chromosome 3p tumor suppressor genes (TSG) have been proposed in the pathogenesis of ovarian cancer based on complex patterns of 3p loss. To attain functional evidence in support of TSGs and identify candidate regions, we applied a chromosome transfer method involving cell fusions of the tumorigenic OV90 human ovarian cancer cell line, monoallelic for 3p and an irradiated mouse cell line containing a human chromosome 3 in order to derive OV90 hybrids containing normal 3p fragments. The resulting hybrids showed complete or incomplete suppression of tumorigenicity in nude mouse xenograft assays, and varied in their ability to form colonies in soft agarose and three-dimensional spheroids in a manner consistent with alteration of their in vivo tumorigenic phenotypes. Expression microarray analysis identified a set of common differentially expressed genes, such as SPARC, DAB2 and VEGF, some of which have been shown implicated in ovarian cancer. Genotyping assays revealed that they harbored normal 3p fragments, some of which overlapped candidate TSG regions (3p25-p26, 3p24 and 3p14-pcen) identified previously in loss of heterozygosity analyses of ovarian cancers. However, only the 3p12-pcen region was acquired in common by all hybrids where expression microarray analysis identified differentially expressed genes. The correlation of 3p12-pcen transfer and tumor suppression with a concerted re-programming of the cellular transcriptome suggest that the putative TSG may have affected key underlying events in ovarian cancer.

Non-random structural chromosomal changes in ovarian cancer: i(5p) a novel recurrent abnormality

Ovarian cancer represents the leading cause of death among patients with gynecological cancer. The genetic changes underlying the initiation and progression of ovarian cancer have not been well defined. However, non-random structural chromosomal changes have been identified with common chromosomal breakpoints. We have studied cytogenetically 15 cases of ovarian adenocarcinomas by a direct culture of cancer cells and a G-banding technique investigating the presence of recurrent structural aberrations with common chromosomal breakpoints. Among very complex structural rearrangements found, we could recognize recurrent structural aberrations involving according to frequency chromosomal regions 3p13-14, 11p15, 19q13, 3q21, 11q23, 11q10, 1p13, 1p36, and 17q24-25. Isochromosomes i(5p), i(17q), i(8q) and i(11q) were also observed. Isochromosome i(5p), rarely reported in ovarian cancer was found in seven cases suggesting that it may be a novel recurrent abnormality. Translocations t(1;11), t(3;19), t(3;17), t(7;11) and t(11;17) were also identified. Conventional cytogenetics continues to be valuable detecting the presence of non-random chromosomal breakpoints and facilitating the identification of genes implicated in tumorigenesis.

High-grade neuroendocrine carcinomas display unique cytogenetic aberrations

Neuroendocrine tumors represent a spectrum of tumor types with different biologic and clinical features. The morphologic types include the low-grade typical and atypical carcinoids and the high-grade small cell and large cell neuroendocrine carcinomas (NECs). Cytogenetic descriptions of high-grade NECs are rare. Complete karyotypic descriptions of 34 high-grade NECs are reviewed: 7 extrapulmonary small cell NECs, 3 metastatic NECs of unknown primary, and 24 small cell lung carcinomas (SCLCs). Chromosomal deletions are more frequent than gains and often involve the entire chromosome arm. Typical aberrations are deletions of chromosome 3p, 5q, 10q, and 17p and gains of 1q, 3q, and 5p occurring as isochromosomes. Non-small cell lung cancers (NSCLCs) have different cytogenetic aberrations, but those with a metastatic phenotype display the identical aberrations as SCLC, a tumor known for its metastatic phenotype at onset. A genetic classification of lung cancer that incorporates the pattern of recurrent chromosome aberrations may be a better predictor of clinical outcome than a morphologic classification.

Telomere-mediated mitotic disturbances in immortalized ovarian epithelial cells reproduce chromosomal losses and breakpoints from ovarian carcinoma

Ovarian carcinomas (OCs) often exhibit highly complex cytogenetic changes. Abnormal chromosome segregation at mitosis is one potential mechanism for genomic rearrangements in tumors. In this study, OCs were demonstrated to have dysfunctional short telomeres, anaphase bridging, and multipolar mitoses with supernumerary centrosomes. When normal human ovarian surface epithelial (HOSE) cells were transfected with human papilloma virus 16 e6/e7 genes and subsequently driven into telomere crisis, the same set of mitotic disturbances occurred in a distinct sequence, initiated by telomere dysfunction, followed by anaphase bridging, and then supernumerary centrosomes and multipolar mitoses. The anaphase bridges resolved either by kinetochore-spindle detachment, corresponding to whole-chromosome losses in the HOSE karyotypes, or by extensive fragmentation of intercentromeric DNA sequences, corresponding to a high frequency of pericentromeric rearrangements. At later passages, the high degree of instability at telomere crisis was moderated by telomerase expression and centrosome coalescence, ultimately leading to a level of mitotic instability that was highly similar to that in OC cell lines and to complex karyotypes that were similar to those observed in high-grade OCs. This suggests that a significant proportion of the structural chromosome changes and genomic losses in OC are caused by a specific sequence of mitotic disturbances triggered by telomere crisis. That the model did not produce any of the whole-chromosome gains observed in OC indicates that these changes develop through a different mechanism.

Cytogenetic and molecular cytogenetic findings in 43 aneurysmal bone cysts: aberrations of 17p mapped to 17p13.2 by fluorescence in situ hybridization

Aneurysmal bone cyst is a benign, cystic lesion of bone composed of blood-filled spaces separated by fibrous septa. Relatively few cases of aneurysmal bone cyst have been cytogenetically characterized, yet abnormalities of the short arm of chromosome 17 appear to be recurrent. In this study, conventional cytogenetic analysis of 43 aneurysmal bone cyst specimens from 38 patients over a 12-year period revealed clonal chromosomal abnormalities in 12 specimens. Karyotypic anomalies of 17p, including a complex translocation and inversion, were identified in eight of these 12 specimens. In an effort to further define the aberrant 17p breakpoint, fluorescence in situ hybridization (FISH) analyses were performed using a series of probe combinations spanning a 5.1 Mb region between the TP53 (17p13.1) and Miller-Dieker lissencephaly syndrome (17p13.3) gene loci. These studies revealed the critical breakpoint locus at 17p13.2, flanked proximally by an RP11-46I8, RP11-333E1, and RP11-457I18 bacterial artificial chromosome (BAC) probe cocktail and distally by an RP11-198F11 and RP11-115H24 BAC and RP5-1050D4 P1 artificial chromosome (PAC) probe cocktail. Overall, abnormalities of the 17p13.2 locus were identified by metaphase and/or interphase cell FISH analysis in 22 of 35 (63%) aneurysmal bone cyst specimens examined including 26 karyotypically normal specimens. These cytogenetic and molecular cytogenetic findings expand our knowledge of chromosomal alterations in aneurysmal bone cyst, further localize the critically involved 17p breakpoint, and provide an alternative approach (ie FISH) for detecting 17p abnormalities in nondividing cells of aneurysmal bone cysts. The latter could potentially be utilized as an adjunct in diagnostically challenging cases.

Detection of genetic alterations in Korean ovarian carcinomas by degenerate oligonucleotide primed polymerase chain reaction-comparative genomic hybridization

Chromosomal aberrations in 22 Koreans with ovarian carcinomas were investigated by degenerate oligonucleotide primed-polymerase chain reaction comparative genomic hybridization. The common sites of copy number increases were 20q (90%), 17q23 approximately qter (86%), 8q22 approximately qter (68%), 3q25 approximately qter (59%), 6p21 (59%), 11q13 (54%), 16p (40%), 2q31 approximately qter (36%), 7q (36%), 14q31 (36%), 15q24 approximately qter (36%), and 1q32 approximately qter (31%). DNA amplification was identified in 18 carcinomas (82%). The frequent sites of amplification were 20q13.2 approximately qter, 8q24.1, 17q23 approximately qter, 3q25 approximately qter, and 6p21. The most frequent sites of copy number decreases were 4q21 approximately q31 (54%), 5q13 approximately q21 (50%), and 13q14 approximately q21 (45%). The recurrent gains and losses of chromosomal regions identified in this study provide candidate regions that may contain oncogenes or tumor suppressor genes, respectively.

Detection of differentially expressed HES-6 gene in metastatic colon carcinoma by combination of suppression subtractive hybridization and cDNA library array

The molecular mechanisms involved in the progression of colon carcinomas from a primary to a metastatic tumor have been only partially elucidated and poorly understood. This study combines suppression subtractive hybridization and cDNA array hybridization to identify genes with expression differences between a primary human colon tumor cell line (HT29) and three isogenic lung tumor metastases. The positive clones isolated in this screen were further validated and quantitated with real-time reverse transcription polymerase chain reactions. HES-6 was identified as up-regulated in each of the individual tumor metastases, as well as in a panel of primary human tumors derived from the lung, breast and kidney. These findings demonstrate that it is possible to utilize longitudinal samples from an in vivo model of colon carcinoma to identify genes up-regulated in metastases and that HES-6 may be an important marker of a range of primary cancers as well as metastatic colon carcinoma.

Comparative study of primary and recurrent ovarian serous carcinomas: comparative genomic hybridization analysis with a potential application for prognosis

OBJECTIVES

The purpose of this study is to comparatively characterize genomic imbalances in primary and recurrent ovarian serous carcinomas and to identify genomic alterations that may be used as a marker for prognosis.

METHODS

Twenty ovarian serous carcinomas were studied by comparative genomic hybridization (CGH).

RESULTS

Genomic alterations were found in all of the tumors. The most common regions involving gain of DNA copy numbers are 1q41q44, 8q22q24, 19p12q13.1, 20q12q13, 3q26q29, 12p12p13, 2p22p25, 7p14p21, 5p15.2p15.3, and 17q22q25. The most common regions with loss of DNA copy numbers are Xp11.2q13, 4q31q35, Xp21p22.3, 18q22q23, 13q22q31, 9p22p24, and 16q22q24. High-level gains were detected at chromosomal regions of 1q41q44, 2p22p25, 3q26q29, and 19p12q13.1. Comparative analysis of primary and recurrent tumors showed that gains of 2p22p25, 19p12q13.1, and 20q12q13 and loss of 5q14q22 were more common in the recurrent high-grade tumors. About 85% of the tumors showed increases in DNA copy numbers in the regions (2p and 8q) harboring the myc family gene. Patients with tumor containing fewer than seven chromosomal aberrations showed longer survival time.

CONCLUSION

The myc oncogene family may play a role in the pathogenesis of ovarian serous carcinomas. Our study suggests that tumors with gains of 2p22p25, 19p12q13.1, and 20q12q13 and loss of 5q14q22 may be at high risk for recurrence. Furthermore, the patients' survival time inversely correlates with the numbers of chromosomal alterations found in their tumors. CGH analysis may have a clinical application in predicting prognosis and risk of recurrence in patients with ovarian serous carcinomas.

Cytogenetics and molecular genetics of ovarian cancer

Genetic alterations identified in human ovarian tumors by conventional banding, fluorescence in situ hybridization, comparative genomic hybridization, chromosome microdissection, loss of heterozygosity, chromosome microcell-mediated chromosome transfer, and microarray gene expression analysis are summarized and correlated. The significance of these findings with respect to pathologic classification and clinical application are discussed.

Genetic alterations in epithelial ovarian tumors analyzed by comparative genomic hybridization

The genetic changes involved in the pathogenesis of ovarian carcinoma are not completely understood. To investigate this matter, we studied paraffin-embedded, microdissected tissue of 47 ovarian epithelial tumors (9 adenomas, 11 tumors of low malignant potential [LMP], 14 serous carcinomas, and 13 nonserous carcinomas) using comparative genomic hybridization (CGH). (The primary data used in this study are available at our CGH online tumor database at http://amba.charite.de/cgh.) Chromosomal imbalances were found in 1 serous adenoma and in 7 LMP tumors. In the latter the alterations appeared randomly and showed no overlap with alterations found in invasive carcinomas. Although the mean aberration number of low-grade serous carcinomas was comparable to LMP tumors, the imbalances of the former occurred with high incidence (>50%) and were found at different localizations. High-grade serous carcinomas had more than twice as much chromosomal imbalances as low-grade serous carcinomas and also had pronounced alterations. In serous carcinomas, gains were found on 3q, 6p, 7, 8q, and 20, and losses were found on 4q, 6q, 12q, 13q, and 16q. Comparing serous and nonserous carcinomas, the mean aberration number was comparable, but the number of high incidence changes was lower, and the most frequent imbalances were losses on 13q and gains on 20p. Overlapping alterations occurring in serous and nonserous carcinomas were gains on 3q and 6p, as well as losses on 4q. Chromosomal imbalances associated with poor prognosis of ovarian carcinomas were gains on 6p, 7q, and 13q and losses on 15q, 17p, 18q, and 21q. Our data indicate that serous LMP tumors and invasive carcinomas have different genetic aberrations, indicating that invasive carcinomas do not arise from preexisting serous LMP tumors. On the other hand, there are common genetic abnormalities in serous and nonserous carcinomas, suggesting that they have very early lesions in common but take different paths of further development.

Comparative analysis of loss of heterozygosity of specific chromosome 3, 13, 17, and X loci and TP53 mutations in human epithelial ovarian cancer

We previously reported the identification of three minimal regions of deletion on the short arm of chromosome 3 (3p) in epithelial ovarian tumor specimens, suggesting that the inactivation of tumor-suppressor genes in these regions may be important in terms of ovarian tumorigenesis. Another previous study of ovarian cancer observed that allele loss of chromosome 179 was frequently found in ovarian tumors that also showed loss of heterozygosity (LOH) of chromosomes 3p, 13q, 17p, and Xp. In an independent study, we also reported a high frequency of LOH for selected chromosome 17 loci in high-grade and late-stage ovarian tumors. We have extended our LOH analysis of chromosome 3p to include 102 ovarian tumor specimens (29 and 73 samples were previously examined for LOH of chromosome 3p and 17 markers, respectively), using additional polymorphic markers, to assess the coordinate LOH of loci representing the three chromosome 3p minimal regions of deletions [von Hippel-Lindau syndrome (VHL), thyroid hormone receptor beta, and fragile histidine triad (FHIT)] and LOH of other important loci [tumor protein 53 (TP53), breast cancer 1 early onset (BRCA1), breast cancer 2 early onset, retinoblastoma 1, ornithine carbamoyltransferase, and androgen receptor] or somatic mutations in TP53. There was a significant association between LOH of any chromosome 3p marker and LOH of any chromosome 17 marker (P = 0.026). The frequency of LOH at the TP53 locus was higher in the group of samples that displayed LOH of a 3p marker (P = 0.019), as was the frequency of LOH at the BRCA1 locus (P = 0.014). LOH of chromosome 3p was noted in four specimens that did not display LOH of either the BRCA1 or the TP53 locus, indicating that LOH of these loci need not precede LOH of the chromosome 3p loci. We found a significant association between LOH of the VHL (3p25) locus and LOH of any chromosome 17 marker (P = 0.005), suggesting that there may be an important relationship, in the tumorigenesis of epithelial ovarian cancer, between a gene at 3p25 and a gene located on chromosome 17. Our results indicate that inactivation of p53 by somatic mutation is unlikely to be a prerequisite to chromosome 3p LOH, because we found no significant association between mutations in TP53 and LOH of the three chromosome 3p loci. The frequency of LOH at the FHIT locus at 3p14 increased significantly with advancing age at diagnosis (P = 0.018), as did the frequency of somatic TP53 mutations (P = 0.008).

Multicolor spectral karyotyping of serous ovarian adenocarcinoma

We applied multicolor spectral karyotyping (SKY) to decipher the chromosomal complexity of a panel of seven cell lines and four primary tumors derived from patients with high-grade serous adenocarcinoma of the ovary. By this method we identified a total of 188 unbalanced translocations, nine reciprocal translocations [t(2;15)(q13;q23), t(7;17) (q32;q21), t(8;22)(p11;q11), t(8;22) (q24;q13), t(10;19) (q24;q13.2), t(11;19) (q13;p11), t(12;21)(q13;q22),t(18;20) (q?11;q?11), t(18;22)(q?11;q?13)], 6 isochromosomes [i(1q), i(7q), i(8q), i(9p), i(17q), i(21q)], and 23 deletions. By detailed mapping of rearrangement breakpoints, it was possible to identify several recurring breakpoint clusters at chromosomal bands 1p36, 2p11, 2p23, 3p21, 3q21, 4p11, 6q11, 8p11, 9q34, 10p11, 11p11, 11q13, 12p13, 12q13, 17q21, 18p11, 18q11, 20q11, and 21q22. Recurrent interstitial deletion of chromosomal bands 8p11, 11p11, and 12q13 and a recurrent unbalanced translocation--der(6)t(6;8)(q11;q11)-were also identified. In addition, a homogeneously staining region localized in one cell line to 11q13 was found using SKY to be derived from genetic material originating from chromosome 12. Subsequent comparative genomic hybridization (CGH) studies on this tumor revealed the amplification of DNA sequences derived from the short arm of chromosome 12 at the 12p11.2 region. These studies demonstrate the power of SKY, CGH, and G-banding to resolve the full spectrum of chromosomal rearrangements in serous ovarian adenocarcinoma.

Changes in gene expression during progression of ovarian carcinoma

The molecular events leading to the development and progression of serous ovarian carcinoma are not completely understood. We performed a large scale survey for the identification of differentially expressed genes in serous ovarian carcinoma by using cDNA array analysis. Differences in gene expression between serous adenocarcinoma and benign serous adenoma, and between advanced and/or moderately or poorly differentiated and local, highly differentiated serous adenocarcinoma were assessed. The most striking difference between adenocarcinoma and benign adenoma was upregulation of RHOGDI2 in the carcinomas irrespective of the clinical tumor stage. Other changes in carcinoma were upregulation of MET and Ne-dlg, and downregulation of HGFAC, desmin, and PDGFA. The most prominent differences between advanced and local adenocarcinoma were upregulation of COL3A1, CFGR, and MET in advanced carcinoma, and downregulation of HGFAC, FZD3, and BFL1 in the same tumors. In conclusion, significant differences were found in the gene expression between benign and malignant serous ovarian tumors, and between local, highly differentiated and advanced and/or moderately or poorly differentiated serous adenocarcinomas. The differentially expressed genes may be related to the carcinogenesis and progression of the malignant growth.

Comparison of serous and mucinous ovarian carcinomas: distinct pattern of allelic loss at distal 8p and expression of transcription factor GATA-4

Using comparative genomic hybridization (CGH), we have previously demonstrated frequent loss of 8p, especially its distal part, in ovarian carcinoma. To compare the deletion map of distal 8p in serous and mucinous ovarian carcinomas, we performed allelic analysis with 18 polymorphic microsatellite markers at 8p21-p23. In serous carcinoma, loss of heterozygosity (LOH) was detected in 67% of the samples, and the majority of the carcinomas showed loss of all or most of the informative markers. In contrast, only 21% of mucinous carcinomas showed allelic loss, with only one or two loci showing LOH in each sample. In serous carcinomas, LOH was associated with higher grade tumors. Three distinct minimal common regions of loss could be defined in serous carcinomas (at 8p21.1, 8p22-p23.1, and 8p23.1). Expression of a transcription factor gene, GATA4, located at one of these regions (8p23.1) was studied in serous and mucinous ovarian carcinomas by Northern blotting and immunohistochemical staining of tumor microarray. Expression was found to be lost in most serous carcinomas but retained in the majority of mucinous carcinomas. Our results suggest distinct pathogenetic pathways in serous and mucinous ovarian carcinomas and the presence of more than one tumor suppressor gene at 8p involved in the tumorigenesis of serous carcinoma.

Prognostic significance of cell cycle proteins and genomic instability in borderline, early and advanced stage ovarian carcinomas

Disturbed cell cycle-regulating checkpoints and impairment of genomic stability are key events during the genesis and progression of malignant tumors. We analyzed 80 epithelial ovarian tumors of benign (n = 10) and borderline type (n = 18) in addition to carcinomas of early (n = 26) and advanced (n = 26) stages for the expression of Ki67, cyclin A and cyclin E, p21WAF-1, p27KIP-1 and p53 and correlated the results with the clinical course. Genomic instability was assessed by DNA ploidy measurements and, in 35 cases, by comparative genomic hybridization. Overexpression of cyclin A and cyclin E was observed in the majority of invasive carcinomas, only rarely in borderline tumors and in none of the benign tumors. Similarly, high expression of p53 together with undetectable p21 or loss of chromosome arm 17p were frequent events only in adenocarcinomas. Both borderline tumors and adenocarcinomas revealed a high number of chromosomal gains and losses. However, regional chromosomal amplifications were found to occur 13 times more frequently in the adenocarcinomas than in the borderline tumors. The expression pattern of low p27 together with high Ki67 was found to be an independent predictor of poor outcome in invasive carcinomas. The results provide a link between disturbed cell cycle regulatory proteins, chromosomal aberrations and survival in ovarian carcinomas.

BRCA1 and BRCA2 mutations in ovarian cancer: Covariation with specific cytogenetic features

We analyzed 37 primary invasive carcinomas for BRCA1 and BRCA2 mutations by screening the entire coding regions of both genes. Seven predicted truncating mutations (four in BRCA1 and three in BRCA2) and one novel BRCA1 missense variant (S1542C) were identified (8/37, 22%). Two of the BRCA1 mutations were somatic changes, whereas the remaining three BRCA1 changes and all mutations of BRCA2 were found to be of germline origin. All eight BRCA-positive tumors were serous or seropapillary carcinomas (8/27 serous tumors, 30%), and all but one were poorly differentiated. The correlation between tumor karyotype and BRCA status showed that clonal chromosomal aberrations were present in all BRCA-positive tumors (8/8) compared with 20 of 29 BRCA-negative ones. The most consistently affected region in BRCA-positive tumors was the long arm of chromosome 6; alterations within this arm with a breakpoint in band 6q21 were seen in four of five BRCA1-positive and in two of three BRCA2-positive tumors, but only in four of 20 karyotypically abnormal tumors without BRCA mutations, suggesting that the genetic pathways of tumor progression differ in the two groups. The high frequency of germline BRCA mutations detected in this pilot study (16% of 37 invasive carcinomas) points to the need for more extended analyses of population-based series of patients to determine the true contribution of these predisposing genes to the overall incidence of ovarian cancer in this population.

Ovarian metastases from colorectal carcinoma. Clinicopathologic profile, immunophenotype, and karyotype analysis

Ovarian metastases from colorectal carcinoma frequently mimic primary ovarian carcinomas. The present study was performed to identify possible criteria helpful in differential diagnosis. Twenty-three ovarian metastases from colorectal carcinomas and 23 primary ovarian carcinomas were evaluated clinicopathologically and immunostained with antigastric M1 antigen, cathepsin E, CA125, vimentin, estrogen and progesterone receptors, cytokeratins 7 and 20, and alpha-inhibin antibodies. We performed a conventional and molecular cytogenetic study on 5 ovarian metastases from colorectal carcinoma using direct preparation, Q banding techniques, and fluorescence in situ hybridization. Integration of clinicopathologic, immunohistochemical, and cytogenetic features is helpful for the differential diagnosis of metastases of colorectal carcinomas from primary ovarian carcinomas. Bilaterality, extrapelvic spreading, high mitotic index, and cytokeratin 20 immunoreactivity, and lack of M1, CA125, and cytokeratin 7 immunoreactivity favor the diagnosis of ovarian metastases from colon carcinomas. The identification of 13q gain as a peculiar, sensitive, and specific marker of colorectal carcinomas seems relevant.

Chromosomal breakage-fusion-bridge events cause genetic intratumor heterogeneity

It has long been known that rearrangements of chromosomes through breakage-fusion-bridge (BFB) cycles may cause variability of phenotypic and genetic traits within a cell population. Because intercellular heterogeneity is often found in neoplastic tissues, we investigated the occurrence of BFB events in human solid tumors. Evidence of frequent BFB events was found in malignancies that showed unspecific chromosome aberrations, including ring chromosomes, dicentric chromosomes, and telomeric associations, as well as extensive intratumor heterogeneity in the pattern of structural changes but not in tumors with tumor-specific aberrations and low variability. Fluorescence in situ hybridization analysis demonstrated that chromosomes participating in anaphase bridge formation were involved in a significantly higher number of structural aberrations than other chromosomes. Tumors with BFB events showed a decreased elimination rate of unstable chromosome aberrations after irradiation compared with normal cells and other tumor cells. This result suggests that a combination of mitotically unstable chromosomes and an elevated tolerance to chromosomal damage leads to constant genomic reorganization in many malignancies, thereby providing a flexible genetic system for clonal evolution and progression.

Chromosomal aberrations in ovarian malignant brenner tumor cell line using chromosome painting

Cytogenetic changes in an ovarian malignant Brenner tumor cell line, SNU-840, were investigated by chromosome painting and G-banding. All chromosome alterations were confirmed by the use of multiple chromosome paintings, which also demonstrated a number of additional alterations.

Trisomy of chromosome 10 in two cases of ovarian carcinoma

Simple numerical chromosome aberrations have been observed in tumorigenesis and may point to indicative initiating or early events in tumorigenesis. We have identified two cases of ovarian carcinomas with trisomy of chromosome 10 using conventional GTG-banding and fluorescence in situ hybridization. This is, to our knowledge, the first report of trisomy 10 as a simple karyotypic abnormality observed in ovarian carcinoma. These results suggest that further studies investigating whether chromosome 10 genes are associated with the pathogenesis of some ovarian tumors are warranted.

Well-differentiated mucinous carcinoma of the ovary and a coexisting Brenner tumor both exhibit amplification of 12q14-21 by comparative genomic hybridization

Although the coexistence of mucinous ovarian neoplasms and Brenner tumors is well established, the histogenesis and developmental relationship between the two remain unknown. We used comparative genomic hybridization to analyze two such tumors occurring simultaneously, one in each ovary, in a patient. Amplification of 12q14-21 sequences was found in both tumors; in addition, both tumors also had other, different changes, four identified in the Brenner tumor and six in the mucinous carcinoma. The occurrence of the same genetic alteration in both tumors in this woman suggests that the mucinous carcinoma and Brenner tumor may be clonally related, i.e., one arose from the other by means of metastatic spreading of transformed cells from one ovary to the other. An alternative explanation is that some unknown, putative tumorigenic agent induced similar and synchronous pathogenetic changes in the epithelium of both ovaries. The phenotypic differences between the tumors are presumably attributable to the other unique genetic abnormalities identified in both tumor types.

Changes of chromosomes 1, 3, 6, and 11 in metastatic effusions arising from breast and ovarian cancer

This cytogenetic study deals with cell material obtained from 15 pleural fluids from 11 patients with breast cancer and 27 ascitic fluids from 16 patients with ovarian cancer; in addition, 8 pleural, 5 ascitic, and 1 pericardial fluid from patients with tuberculosis, liver cirrhosis, and heart insufficiency, were studied. Using mainly direct methods, as well as short-term cell cultures, the chromosome spreads were GTG-banded. Cancerous biopsies showed a plethora of numerical and structural chromosome anomalies and exhibited broad aneuploidy. Chromosomes participating more often in numerical and structural aberrations were 1, 3, 6, 7, 8, 9, 11, 12, and 17. This study provides further cytogenetic evidence for the involvement of these chromosomes in breast and ovarian malignancy.

Expression of FHIT in primary cultures of human epithelial ovarian tumors and malignant ovarian ascites

Abnormal FHIT gene expression has been reported in a variety of epithelial tumors shown to harbor deletions of chromosome 3p14, the chromosomal assignment of this gene. Recently, we described loss of heterozygosity of 3p in a subset of epithelial ovarian cancers. To investigate a potential role of the FHIT gene in ovarian cancer, we examined primary cell cultures derived from normal ovarian surface epithelium, ovarian tumors, and the cellular fraction of malignant ascites to determine the expression of FHIT by using reverse transcription-polymerase chain reaction. Included in this analysis were four spontaneously immortalized cell lines: three derived from malignant epithelial ovarian tumors (TOV21G, TOV112D, and TOV81D) and one from malignant ovarian ascites (OV90). OV90 was previously shown to harbor a deletion of the whole p arm of chromosome 3. The FHIT transcript was not detectable in two of 11 primary cultures derived from normal ovarian surface epithelium or in a primary culture derived from malignant ovarian ascites, whereas the remaining samples (34 malignant, eight borderline, and three benign specimens), exhibited identical expression patterns. In each case, this pattern was consistent with the co-expression of a normal FHIT transcript and a smaller transcript. DNA sequencing revealed that the abnormal-sized message lacked exons 4-7 (inclusive), which were deleted at their exact intron-exon splice sites. The aberrant-sized transcript was detectable by Northern blot analysis. There was no concordance between FHIT expression and loss of heterozygosity at the FHIT locus. Northern blot analysis also revealed that FHIT was differentially expressed, and the spontaneously immortalized cell lines TOV21G and TOV112D showed the highest level of expression. Because the same reverse transcription-polymerase chain reaction expression pattern was observed in both normal and tumor-derived primary cell cultures, these results argue against a significant role for FHIT in epithelial ovarian tumorigenesis.

Interphase fluorescence in situ hybridization studies of ovarian adenocarcinomas using the midisatellite probe

The genes involved in ovarian carcinogenesis are largely unknown. Cytogenetic studies have shown a large number of chromosomal abnormalities in ovarian cancers. Molecular studies have additionally found abnormalities. Few in situ hybridization studies have been performed on ovarian cancer tissues. We chose to study the distal region of chromosome 1p with the midisatellite probe and interphase fluorescence in situ hybridization. A total of 35 patient samples, including various controls and cancers, was collected from our pathology archives. Our cancer cases included some patients with stage I disease, in whom tumors arose in endometriotic cysts. In these cases, both tumor tissue and areas in the cyst distant from the tumor mass were examined. Results showed clear cell carcinoma nuclei to have an increase in both number and size of probe signals, interpreted as representing amplification of the probed region of chromosome 1. Serous carcinomas showed an increase in the number of signals, up to four. We felt this could be a result of amplification, or, because these cells exhibited the highest mitotic counts, to DNA doubling in preparation for mitosis. Endometrioid carcinomas resembled controls in showing up to two small probe signals, but not more. We conclude that amplification in distal chromosome 1p occurs in ovarian clear cell, and possibly serous, carcinomas and may not be important in endometrioid carcinomas. Because alteration was not found in the various control epithelia, including nonmalignant-looking areas from cysts which also contained cancer, we believe that the change, when present, may not be an early step in carcinogenesis.