PARP4 and ovarian carcinoma: 52). More recently, PARP4 mRNA expression was found to be significantly upregulated in cisplatin-resistant ovarian cancer cell lines and depletion of its expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance, restoring the cisplatin-induced DNA fragmentation (Ref. 53). PARP4 expression levels correlate with the DNA methylation status at its specific promoter site, a feature that could be exploited as a novel biomarker for predicting the response to cisplatin in ovarian cancer patients (Ref. 53).