Decreased expression of type II tumor suppressor gene RARRES3 in tissues of hepatocellular carcinoma and cholangiocarcinoma

Abstract

AIM: To analyze the expression of retinoic acid receptor responder 3 (RARRES3) protein in paraffin-embedded tissues of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC), and the correlation of RARRES3 production with tumor differentiation. METHODS: Expression of RARRES3 in tissues from 21 CC (10 well-, 7 moderately- and 4 poorly-differentiated) and 32 HCC was determined by immunohistochemistry. RESULTS: Among 21 CC tissues, RARRES3 was detected in 8 (80%) of 10 well-differentiated tumors. Only 2 (18.2%) out of 11 tumors with moderate or poor differentiation showed positive RARRES3 expression. RARRES3 expression in well-differentiated CC was significantly higher than that in tumors with moderate or poor differentiation (Fisher exact test, PP<0.01). CONCLUSION: Expression of RARRES3 is positively correlated to well-differentiated CC, which supports the role of RARRES3 in malignant epithelial differentiation of the tumor. The decrease in RARRES3 expression in tissues of HCC and CC with moderate and poor differentiation suggests that altered RARRES3 expression may play a role in the carcinogenesis of the liver and biliary tract.