When the mutation analysis was performed separately on NSCLC and SCLC samples to compare the similarities/differences, similarities were observed in the high number of alterations depicted in TP53, PIK3CA, and KDR; and in the high number of patients harboring mutations in TP53, PIK3CA, KDR, FLT3, and CSF1R in tumor samples. The gene discussed is PIK3CA; the disease is small cell lung carcinoma.