NEUROD1 and small cell lung carcinoma: Although not as well defined as in SCLC, recent studies have also explored transcriptomic subgroups in extra-pulmonary high grade neuroendocrine carcinoma and revealed transcriptomic subgroups defined by expression of NEUROD1 and ASCL1 (Kawasaki et al., 2020; Li et al., 2021c; Metovic et al., 2022).