Our KEGG analysis further investigated four platinum resistance–related genes, that is, TOP2A, CDKN2A, BIRC5, and MSH2. Among these, TOP2A and BIRC5 were included in module 1 and with 37 and 35 connections, respectively, suggesting that they potentially play critical roles in SCLC. This evidence concerns the gene CDKN2A and small cell lung carcinoma.