Squamous cell differentiation markers, cytokeratin 5/6, p40, and p60 were diffusely positive in SCC, but extremely limited in NEC (Fig. 4E, F) Regard to tumor suppressor proteins (Fig. 6A–F), both components revealed diffusely, generally, and focally immunoreactivity toward Rb, p16, and p53, respectively. Here, TP53 is linked to neuroendocrine carcinoma.