CDK9-inhibitory drugs, which target both CDK9 isoforms [134] (42 kD and 55 kDa), sensitized a panel of TRAIL-resistant NSCLC cell lines, irrespectively of their mutation status, to TRAIL-induced apoptosis by concomitant downregulation of two anti-apoptotic factors, Mcl-1 and cFLIP [132]. The gene discussed is CDK9; the disease is non-small cell lung carcinoma.