[The mechanism of cisplatin-resistance in ovarian cancer]

Cisplatin and its analogues have been most frequently used for treatment of human cancer including ovarian cancer. Most advanced ovarian cancer which was fatal before introduction of cisplatin have become to be treated for cure by combination chemotherapy containing cisplatin and its analogues. Thus, combination chemotherapy containing cisplatin and carboplatin have become a standard chemotherapy for treatment of ovarian cancer. Initially, platinum-based combination chemotherapy is associated with a 60-70% clinical response rate. However, the overall 5-year survival rate for advanced ovarian cancer patients is still around 20-30%. This low survival rate is due to the fact that some primary tumors and most recurrent tumors develop drug resistance that leads to treatment failure. Thus, overcoming drug resistance is the key to successful treatment of ovarian cancer. The mechanism of cisplatin-resistance in ovarian cancer is multifactorial, and accumulation of multiple genetic changes may lead to the drug-resistant phenotype. In this review, we report several genetic factors conferring cisplatin-resistance which have been elucidated in our laboratory.