While MDM2 inhibitors alone were not effective in the in vitro screens of SCLC cell lines [24, 38] and TP53 is nearly universally inactivated in SCLC [3, 5], surprisingly, the combination of the MDM2 inhibitor JNJ-27291199 with etoposide and carboplatin resulted in enhanced cytotoxicity against SCLC cell lines [38]. This evidence concerns the gene TP53 and small cell lung carcinoma.