All five SCLC cell lines studied - H69, H82, U1285, U1690, U1906 - were resistant to apoptotic effects of TRAIL (100 ng/ml), as demonstrated by the absence of PARP cleavage (Figure 1A) or caspase-3 processing (not shown) after 72 h of treatment. This evidence concerns the gene CASP3 and small cell lung carcinoma.