TP53 and carcinoma: A liver biopsy demonstrated a poorly differentiated carcinoma, with tumor cells positive for cytokeratin (CK) 7, synaptophysin and chromogranin, aberrant loss of P53 and RB protein expression, and a Ki67 proliferation index of 90%, consistent with a diagnosis of PDNEC carcinoma of pancreas origin, with no adenocarcinoma component (Fig. 2A–C).