Taking advantage of ASCL1/NEUROD1 double-positive SCLC cells, we assessed the possibility of reciprocal regulations between ASCL1 and NEUROD1; however, we did not observe statistically significant changes in ASCL1 target genes by NEUROD1 knockout or in NEUROD1 target genes via ASCL1 silencing (data not shown) [21]. The gene discussed is NEUROD1; the disease is small cell lung carcinoma.