Given the cisplatin-induced DNA interstrand crosslinks are mainly repaired by HRR [6], our finding that BRCA2, but not XPA downregulation, enhanced cisplatin sensitivity in PEO4 cells, indicates the minor interstrand crosslinks may be more important than major intrastrand crosslinks to the cell killing, further suggesting that targeting HRR pathway might be more efficient than targeting NER pathway in enhancing the cisplatin sensitivity of ovarian cancer cells [25,32,33]. This evidence concerns the gene XPA and ovarian cancer.