RB1 and neoplasm: Those models showing the greatest sensitivity to volasertib carried concomitant amplification or CN gains of CCND1 and CCNE2 both of which are involved in RB inactivation driving tumour cells through the S phase, as well as CN gains in CCNB1 and CDK7 (HBCx-139) or AURKA (HBCx-124), genes required for G2/M progression26.