The CD79α (HM47/A9) antibody is effective in distinguishing between primary hepatocellular carcinoma and primary intrahepatic cholangiocarcinoma

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) are two major forms of primary liver cancer. The aim of this study was to investigate CD79α (HM47/A9) antibody expression patterns in normal liver, HCC and ICC samples. HM47/A9 expression was examined in tissues surrounding liver cancer in adults, 8-week embryos and 20-week embryos. In total, 82 cases of HCC, 31 cases of ICC and 11 cases of combined HCC and cholangiocarcinoma (cHCC-CC) were reviewed. HM47/A9 expression was observed as early as 8-week embryo liver tissue and exhibited focal granular cytoplasmic positivity, which was maintained throughout life. All 82 HCC cases demonstrated cytoplasmic granular positivity for HM47/A9, while no ICC cases were immunostained with HM47/A9. No CC components in cHCC-CC expressed the HM47/A9 antibody. A high number of HCC components in cHCC-CC showed positive staining for HM47/A9 [10/11 (90.9%)]. Our results suggest that HM47/A9 may be employed effectively to differentiate HCC from ICC.