Our results showed that the four histopathological subtypes, represented by 12 lung cancer cell lines, were well characterized by qPCR and PCA using 12 genes: AMY2A, CDH1, FOXG1, IGSF3, ISL1, MALL, PLAU, RAB25, S100P, SLCO4A1, STMN1, and TGM2. Based on their upregulation and the results of the PCA analysis, S100P and CDH1 were identified as candidate markers for AD tumors and for AD and SQ tumors, respectively. The gene discussed is ISL1; the disease is lung cancer.