By further comparing effects of API-1 on reducing Mcl-1 and survivin in 4 more NSCLC cell lines with different sensitivities to API-1, We found that API-1 reduced Mcl-1 levels effectively in H522 and A549 cells, which are sensitive to API-1, but only minimally in H226 and H1792 cells, which are insensitive to API-1. This evidence concerns the gene MCL1 and non-small cell lung carcinoma.