These tumors are genetically distinct; NET G3 often presents ATRX/DAXX mutations and lacks the p53 and Rb mutations commonly found in NEC [6]. The guidelines suggest the use of MEN1/ATRX/DAXX and RB1/TP53 to differentiate NET G3 from NEC [2,7]. The gene discussed is TP53; the disease is neuroendocrine carcinoma.