SCLC has recently been classified by the expression of ASCL1, NEUROD1, and POU2F3, but YAP1 does not exclusively define a subtype in scRNA-seq studies with small sample sizes.9 We found that among the tumor samples from 39 patients, one patient was classified as SCLC-Y, suggesting the need to further dissect SCLC subtypes in more patients. The gene discussed is NEUROD1; the disease is neoplasm.