LOH and mutation analysis of CDKN2 in primary human ovarian cancers.

The CDKN2 gene encodes a cell cycle regulatory protein and is located on chromosome 9p21, a region deleted in a wide variety of primary tumours. While mutations in the CDKN2 gene itself are frequently observed in tumour cell lines, they are less common in primary tumours. We have investigated the role of the CDKN2 gene in ovarian cancer by analysis for allelic loss of 9p21 and single-strand conformational polymorphism analysis of exons 1 and 2 of CDKN2 in 67 primary ovarian tumours. Loss of heterozygosity on 9p21 was frequently observed (24/50 informative tumours) and was common in early-stage tumours, suggesting that it is an early event in ovarian tumorigenesis. Homozygous deletion of the CDKN2 gene was detected in only 1 tumour. No somatic or germline mutations were observed in CDKN2, though a codon 140 polymorphism was detected in 2 cases. This suggests that CDKN2 is not involved in ovarian tumorigenesis and that another gene(s) may be the target of the frequent 9p allelic losses observed.