Inactivation of p16/CDKN2 and p15/MTS2 is associated with prognosis and response to chemotherapy in ovarian cancer.

To define the involvement of p16/CDKN2 and p15/MTS2 tumor-suppressor genes for response to chemotherapy in primary epithelial ovarian cancer, we analyzed alterations of the gene in 45 patients who were treated with primary cytoreductive surgery followed by 6 courses of cis-diamminedichloroplatinum (II) (cisplatin)-based combination chemotherapy. Homozygous deletion of p16/CDKN2 and p15/MTS2 genes was found in 8 (18%) and 15 (33%) cases, respectively. Response to the chemotherapy was confirmed by finding at second surgery after the chemotherapy in 26 patients, resulting in 17 responders and 9 nonresponders. The abundance of gene deletion in nonresponders (56%) was significantly higher (p = 0.0463) when compared to that in responders (18%). Moreover, the deletion of genes was a significant poor prognostic factor (p = 0.0441) in advanced ovarian cancer. These results suggest that deletion of p16/CDKN2 and/or p15/MTS2 is a potential indicator for poor chemotherapy response and adverse prognosis in ovarian cancer patients.