ARID1A and neuroendocrine carcinoma: NEC-like IDH2 and NEC-like SMARCA4/ARID1A tumors also demonstrated strong overexpression of proteins specific for neurons or cells of the diffuse neuroendocrine system such as UCHL1, CRMP1 and ENO2 (Fig. 3B), strongly indicating a neuroendocrine differentiation for both tumor classes.