ERCC6 and cancer: Clonogenic survival assays revealed that all six cancer-associated CSB mutations except for G1484R impaired the ability of Myc-CSB to rescue survival of U2OS CSB-KO cells in response to treatment with cisplatin (Figure 5C–E), suggesting that the observed lack of an effect of D1425N, Q1444H, A1445S and R1462L mutations on RNAPII occupancy at PPP sites is unlikely due to their being silent mutations.