Sporadic CDKN2 (MTS1/p16ink4) gene alterations in human ovarian tumours.

G Stoter,Jgm Klijn,Mel Vd Burg,M Schuyer,Il Van Staveren,Ja Foekens,Emjj Berns,Sc Henzen-Logmans

doi:10.1038/bjc.1996.491

G Stoter, Jgm Klijn + Show 6 more

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https://doi.org/10.1038/bjc.1996.491

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Abstract

The cell cycle regulatory proteins p16 and p21 cause cell cycle arrest at the G1 checkpoint by inhibiting activity of cyclin D-CDK4 complexes. The TP53 gene, regulating the p21 protein, is mutated at high frequency in ovarian cancer. The CDKN2 gene, encoding the p16 protein, has been mapped to chromosome 9p21 and encompasses three exons. To establish the frequency of CDKN2 gene abnormalities in ovarian tumour specimens, we have studied this gene in five ovarian cancer cell lines and in 32 primary and five metastatic ovarian adenocarcinomas. Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and sequencing techniques both exon 1 and 2 of the CDKN2 gene, encompassing 97% of the coding sequence, were analysed. In addition, the TP53 gene was studied for the presence of mutations. The cell line HOC-7 showed a 16 bp deletion in exon 2 of the CDKN2 gene, resulting in a stop codon, whereas in cell line SK-OV-3 this gene was found to be homozygously deleted. Nine primary tumour specimens showed a migration shift on SSCP. Sequencing revealed a common polymorphism (Ala148Thr) in seven of these ovarian tumour specimens. The two other tumour samples were found to contain silent mutations, one at codon 23 (GGT-->GGA) and the other at codon 67 (GGC-->GGT). Mutations in the TP53 gene were observed in 46% of the ovarian tumour specimens. We conclude that CDKN2 gene alterations are rare events in human ovarian cancer. The low prevalence of these alterations do not allow for analysis of an association of this gene with prognosis.

Highlights

To determine whether alterations of the CDKN2 gene are involved in ovarian carcinogenesis, we have studied this gene in 32 primary and five metastatic human epithelial ovarian tumour specimens and in an additional five ovarian cancer cell lines
Our results suggest that alterations of the CDKN2 gene play no major role in the initiation or progression of ovarian cancer
We have studied alterations in exons 1 and 2 of the CDKN2 gene in 32 primary and five metastatic ovarian adenocarcinomas and in five ovarian cancer cell lines using polymerase chain reaction (PCR)- single strand conformation polymorphism (SSCP) and sequencing techniques

Summary

Methods

The human ovarian cancer cell lines used in this study were SK-OV-3 (HTB-77), SK-OV-6, 2780, 2774, HOC-7 (a gift from Dr Gunther Daxenbichler, Innsbruck, Austria). The SK-OV-3 and HOC-7 cell lines originated from ascites, whereas the other cell lines were derived from (adeno)carcinomas (ATCC). Thirty-two primary and five metastatic ovarian adenocarcinomas were included in this study. One patient had bilateral adenocarcinoma of the same histological type. The mean age as well as the median age of the patients with ovarian tumours was 56 years (range, 26-85 years). Following the WHO (1979) classification the primary and metastatic carcinomas were subtyped into serous (n = 14 primary, n = 5 metastatic), mucinous (n = 4), endometroid (n = 7), clear cell (n = 2), mixed (n = 3), poorly differentiated (n = 1) and unknown (n = 1).

Results

Discussion

Conclusion