While small-cell lung carcinoma (SCLC) and large-cell neuroendocrine carcinoma (LCNEC) frequently harbor TP53 and RB1 mutations, EP-NECs demonstrate greater genetic heterogeneity, often involving KRAS, PIK3CA, or MEN1 alterations, which may influence treatment response [12,13,14]. The gene discussed is PIK3CA; the disease is large cell neuroendocrine carcinoma.