ERCC5 and small cell lung carcinoma: Overall, studies in isogenic systems and human SCLC cell lines demonstrate that SLFN11, HR, and ERCC5/XPG are determinants for the response to lurbinectedin monotherapy, with ERCC5/XPG being a critical determinant of response to the lurbinectedin–berzosertib combination, that is, combination efficacy (Table EV3 and Fig EV3B).