A study of six human melanoma cell lines (Yang and Melton, unpublished) showed that, although mRNA levels of both ERCC1 and XPF were increased by cisplatin treatment as we had reported previously [30], the correlation with ERCC1 and XPF protein levels varied between the cell lines, raising the possibility that post-translational modification may also play an important role in the regulation of ERCC1-XPF repair activity. Here, ERCC4 is linked to melanoma.