ASCL1 and small cell lung carcinoma: Pathological evaluation of immunohistochemical stainings for ASCL1 revealed that two specimens were from the SCLC-A subtype (P6 and P7), while the remaining three (P2, P3 and P5) were largely negative for ASCL1 and thus represented non-SCLC-A tumors (Supplementary Figure S20).