To further substantiate the validity of cell cycle checkpoint abrogation as a viable therapeutic concept for the treatment of SCLC, we next examined CHK1 mRNA expression levels in a collection of 970 human cancer cell lines from the COSMIC cell line project43, including 61 SCLC, 109 NSCLC and 800 non-lung cancer cell lines. Here, CHEK1 is linked to small cell lung carcinoma.