Does Hepatocyte Paraffin 1 expression stand a role in determining the site origin of an adenocarcinoma from unknown gastrointestinal primary.

Background: Hepatocyte Paraffin 1 (Hep Par 1) was being extensively used to recognize the hepatocellular carcinomas, until recognition of its expression in tumors without hepatocellular differentiation. Aims and Objectives: The aim of this study was to analyze if Hep Par 1 stain can serve as a specific marker of the small intestinal (SI) adenocarcinomas, versus other gastrointestinal tract (GIT) primary tumors. Materials and Methods: In this retrospective cross‑sectional study, normal GIT mucosa (n ‑ 60), corresponding adenocarcinomas (n ‑ 60) and nodal metastatic foci (n ‑ 60) from the same patients, including 10 cases each from the esophagus, stomach, SI periampullary region, colon, rectum, and gall bladder were included. H‑score was calculated by multiplying the stain distribution and intensity scores. The H‑scores were compared with other clinical and histological parameters. Results: While normal SI mucosa showed diffuse strong Hep Par 1 staining, normal esophageal and gastric epitheliums were negative and normal colon, rectal, and biliary epithelium showed weak focal positivity. Adenocarcinomas from all these sites, however, showed Hep Par 1 expression, irrespective of the tumor type, site or origin, and tumor stage. The corresponding metastatic sites also showed variable Hep Par 1 positivity, without any site specificity. Conclusion: Hep Par 1 stain cannot help to determine the exact site of origin of primary GIT tumors. Its expression in adenocarcinomas across the GIT and their metastatic foci proves that it cannot be regarded as a marker of SI differentiation, especially in malignancy.

Hepatocyte Expressions in Hepatocellular Carcinomas, Gastrointestinal Neoplasms, and Non-neoplastic Gastrointestinal Mucosa: its Role as a Diagnostic Marker

We performed immunohistochemical staining against Hepatocyte (Hep) and CD10 antibodies in 75 hepatocellular carcinoma (HCC), 50 cholangiocarcinomas, 49 colorectal adenocarcinomas, and 308 gastric adenocarcinomas by tissue array method. We also evaluated the various non-neoplastic adult tissues and fetal digestive organs. Hep was expressed in 80% of HCCs, and HCCs without Hep expression were more likely to have a higher Edmondson & Steiner grade than HCCs with Hep expression (p=0.004). In non-HCCs, 16% of cholangiocarcinomas, 8.2% of colorectal carcinomas, and 44.2% of gastric carcinomas expressed Hep. Gastric carcinomas with Hep expression were significantly associated with early gastric carcinomas (p<0.001). In non-neoplastic tissues, Hep was found expressed in normal hepatocytes, small intestinal mucosa, and intestinal metaplasia of the stomach. Fetal hepatocytes expressed Hep after 19 weeks of gestation. CD10 was detected in 46.7% (35/75) of HCCs, and canalicular staining pattern was predominant in HCCs. In conclusion, the expression of Hep and CD10 may help to distinguish HCCs from non-HCCs.