Comparative Immunohistochemical Analysis of Clinicopathological Subgroups in Hepatocellular Carcinomas from Japan and Indonesia

Background

Standardized pathological evaluation based on immunohistochemical (IHC) analysis could improve hepatocellular carcinoma (HCC) diagnoses worldwide. We evaluated differences in clinicopathological subgroups in HCCs from two academic institutions in Tokyo-Japan, and Jakarta-Indonesia.

Methods

Clinicopathological parameters and molecular expression patterns were evaluated in 35 HCCs from Indonesia and 41 HCCs from Japan. IHC analysis of biliary/stem cell (B/S) markers (cytokeratin 19, sal-like protein 4, epithelial cell adhesion molecule) and Wnt/β-catenin (W/B) signaling-related molecules (β-catenin, glutamine synthetase) could determine the IHC-based subgroups. For immuno-subtypes categorization, CD3/CD79α double immunohistochemistry was done to evaluate the infiltration of T and B cells. CD34 staining allowed identification of vessels that encapsulated tumor clusters (VETC).

Results

Indonesian HCC patients were mostly <60 years old (66%) with a hepatitis B virus (HBV) background (82%), in contrast to Japanese HCC patients (8% and 19%, respectively, both P < 0.001). In comparison with Japanese, Indonesian cases more frequently had >5 cm tumor size (74% vs 23%, P = 0.001), poor differentiation (40% vs 24%), portal vein invasion (80% vs 61%), and α-fetoprotein levels >500 ng/ml (45% vs 13%, P = 0.005). No significant differences were found in the proportions of B/S, W/B, and −/− subgroups from both countries. No immune-high tumors were observed among Indonesian cases, and immune-low tumors (66%) were more common than in Japanese cases (54%). VETC-positive tumors in Indonesia were significantly more common (29%), and most were in the HBV (90%) and −/− subgroups (90%), whereas Japanese VETC cases (10%, P = 0.030) were nonviral (100%) and W/B subgroups (75%).

Conclusion

IHC-based analysis more precisely reflected the clinicopathological differences of HCCs in Japan and Indonesia. These findings provide new insights into standardization attempts and HCC heterogeneity among countries.