TP53 and small cell carcinoma: For the tissue of pancreas, abnormal cells were found in the coagulation tissue, which supported the diagnosis of small-cell neuroendocrine carcinoma (NEC), and immunohistochemistry analysis showed a positive staining for Ki-67 (approximately 40%), P53, CK, Syn, CD56, CK19, INSM1, and alpha-thalassemia mental retardation X-linked (ATRX) and a negative staining for CK7, CK20, villin, CEA, CgA, and RbGP (Figures 4A, B).