Background: A number of putative roles, including the modulation of tumor growth, neovascularization, metastasis and oncogenic progression, have been correlated to relaxin-2 overexpression. However, the clinical significance of relaxin-2 expression in hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to investigate the expression of relaxin-2 in HCC and determine its correlation with tumor progression and prognosis.
Patients and methods: 180 HCC patients who had undergone curative liver resection were selected and immunohistochemistry was performed to analyze relaxin-2 expression in the respective tumors.
Results: Immunohistochemistry confirmed relaxin-2 overexpression in HCC tissues compared with their adjacent nonneoplastic tissues (p < 0.01). Additionally, immunostaining showed more relaxin-2 positive cells in the higher tumor grade (III) than in the lower tumor stage (I, II; p = 0.026). Moreover, HCC patients with high relaxin-2 expression were significantly associated with lower 5-year overall survival (p < 0.01) and lower 5-year disease-free survival (p < 0.01), respectively. Furthermore, immunostaining showed more relaxin-2 positive cells in the tumor recurrence (ETR) patients than non-ETR patients (p = 0.001). The Cox proportional hazards model further showed that relaxin-2 was an independent poor prognostic factor for both 5-year disease-free survival (hazards ratio [HR] = 1.872, 95% confidence interval [CI] = 1.18-5.146, p = 0.023) and 5-year overall survival (HR = 3.637, CI = 1.443-7.15, p = 0.001) in HCC.
Conclusions: Our data suggest for the first time that the overexpression of relaxin-2 protein in HCC tissues is of predictive value on tumor progression and poor prognosis.