PMAIP1 and small cell lung carcinoma: Notably, resistance to ABT-737 in SCLC cell lines has been associated with increased expression of the anti-apoptotic Bcl-2 family member Mcl-1, which is not effectively inhibited by ABT-737, and decreased expression of NOXA, a pro-apoptotic Bcl-2 family member which inhibits Mcl-1 [34].