Clinical Implication of the Relationship Between High Mobility Group Box-1 and Tumor Differentiation in Hepatocellular Carcinoma

BACKGROUND/AIM: High mobility group box-1 (HMGB1) induces the release of proinflammatory cytokines and chemokines as a late-acting mediator of inflammation. Hepatocellular carcinoma (HCC) is a typical inflammation-related cancer. However, little is known about the relationship between HCC and HMGB1 and its receptor RAGE (receptor for advanced glycation end products). This study analyzes the clinicopathological relevance of HMGB1 expression level and the effect of HMGB1 expression on the characteristics of HCC. MATERIALS AND METHODS: Samples from 75 HCC patients including 13 with positive hepatitis B surface antigen and 36 with hepatitis C antibody were studied. The expression of HMGB1 in paired cancer and non-cancerous tissues from patients with HCC was assessed using reverse-transcription polymerase chain reaction (RT-PCR) and western blotting. Quantitative RT-PCR data were analyzed in association with the clinicopathological factors of patients with HCC. RESULTS: The expression of HMGB1 mRNA in HCC was high in well-differentiated tumors, but declined as tumors dedifferentiated to moderately and poorly differentiated HCC. The levels of HMGB1 mRNA showed a negative correlation with the presence of portal invasion (p=0.005) and the rise of serum PIVKA-II (p=0.034). There was no clear correlation between HMGB1 expression and proliferation activity of HCC using Ki-67 staining. CONCLUSION: In HCC, HMGB1 expression level correlated inversely with tumor differentiation. The RAGE-HMGB1 interaction may play a greater role in the early stages of HCC tumorigenesis than during cancer development.