Repair of cisplatin interstrand crosslinks in H1299 (A) and H1355 (B) 2008 (C) and MDA-MB-231 (D) cell lines. Untransfected (UT, open squares), siXPF (filled circles), siERCC1 (open circles) and siXPF–siERCC1 siRNA (filled triangles, denoted as siX + siE) transfected cells were treated with cisplatin for 2 h and the comet assay was performed as described at different time intervals (0, 24, 48 and 72 h). The percentage of interstrand crosslinks remaining was calculated using olive tail moment. Results are represented as mean ± SEM of three independent experiments.