Studies revealed that small-cell lung cancers (SCLCs) with high levels of ASCL1 may be further classified into two categories based on the expression of hairy and enhancer of split-1 (HES1): SCLC-A (HES1-low) and SCLC-A2 (HES-1 high), respectively. This evidence concerns the gene ASCL1 and small cell lung carcinoma.