Hepatic Bone Morphogenetic Protein and Activin Membrane-Bound Inhibitor Levels Decline in Hepatitis C but Are Not Associated with Progression of Hepatocellular Carcinoma.

BACKGROUND/OBJECTIVES: Bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) is an antagonist of transforming growth factor (TGF)-β type 1 signaling. BAMBI functions as an anti-fibrotic protein and exerts pro- as well as anti-cancerogenic activities. Our study aimed to correlate hepatocyte BAMBI protein levels in hepatocellular carcinoma (HCC) with T stage, lymph node invasion, vessel invasion, grading, tumor size and Union for International Cancer Control (UICC) stage, as well as with liver inflammation and fibrosis stages.

METHODS

Hepatocyte BAMBI protein expression was assessed by immunohistochemistry in HCC tissues of 320 patients and non-tumor tissues of 51 patients.

RESULTS

In the HCC tissues of the whole cohort and sex-specific analysis, BAMBI protein was not related to T stage, vessel invasion, lymph node invasion, histologic grade, UICC stage and tumor size. Accordingly, BAMBI was not associated with overall survival, recurrence-free and metastasis-free survival. BAMBI protein levels in tumor and non-tumor tissues were not related to inflammation and fibrosis grade. BAMBI protein levels in HCC tissues and non-tumor tissues from HCC patients, which were analyzed by immunoblot in a small cohort and by immunohistochemistry in the tissues of patients described above, were similar. Notably, BAMBI protein was low-abundant in HCC tissues of hepatitis C virus (HCV) compared to hepatitis B virus (HBV)-infected patients with comparable disease severity. Immunoblot analysis revealed reduced BAMBI protein in non-tumor tissues of patients with HCV in comparison to patients with HBV and normal human liver tissues.

CONCLUSIONS

In summary, this analysis showed that hepatocyte BAMBI protein levels of patients with HCC are related to HCV infection rather than the severity of the underlying liver disease and cancer staging.