Hep par-1: a novel immunohistochemical marker for differentiating hepatocellular carcinoma from metastatic carcinoma.

OBJECTIVE To evaluate the diagnostic utility of Hep par-1 in differentiating hepatocellular carcinoma from metastatic carcinoma taking histopathology as a gold standard. STUDY DESIGN Comparative cross-sectional study. PLACE AND DURATION OF STUDY Pathology Department, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, from April 2007 to February 2008. METHODOLOGY Hep par-1 immunohistochemical stain was performed on 60 cases of liver carcinoma, 30 cases each of metastatic and hepatocellular carcinoma. Information regarding patient age, gender, sign and symptoms, radiographic findings, histological grade of tumour, and expression of Hep par-1 on hepatocellular and metastatic carcinoma were recorded on proforma sheet. Sensitivity, specificity, positive and negative predictive values, and accuracy of Hep par-1 were calculated using the formulas. RESULTS Hep par-1 expression was noted in 25 out of 30 cases of hepatocellular carcinoma (83%). Out of 30 cases of metastatic carcinoma, only one case expressed staining in < 5% tumour cells and remaining 29 cases showed no reactivity. The age of the patients with hepatocellular carcinoma ranged from 40 to 76 years with a median age of 60.5 years and 40 - 75 years for metastatic carcinomas with a median age of 57.5 years. CONCLUSION Hep par-1 is a reliable immunohistochemical marker for cases of hepatocellular carcinoma (HCC). It can be used along with other markers in morphologically difficult cases when differential diagnosis lies between poorly differentiated HCC and metastatic carcinoma of liver.