Screening for immune-potentiating antigens from hepatocellular carcinoma patients after radiofrequency ablation by serum proteomic analysis

BACKGROUND: Radiofrequency ablation (RFA) can not only effectively kill hepatocellular carcinoma (HCC) tumour cells but also release tumour antigens that can provoke an immune response. However, there is no consensus regarding which antigens could constitutively be generated after RFA and could potentiate the immune response. The aim of this study was to identify these immune-potentiating antigens. METHODS: We performed two-dimensional electrophoresis (2-DE) and MALDI-TOF-MS/MS analyses on serum obtained before and after RFA from 5 HCC patients. Further validation for selected proteins was performed utilizing ELISA analysis on another 52 HCC patients. Disease-free survival (DFS) analysis according to the differential expression of the interested protein before and after RFA was performed. RESULTS: Twelve decreased and 6 increased proteins after RFA were identified by MS. Three proteins, including clusterin, Ficolin-3, and serum retinol binding protein-4, were further verified by ELISA on the 52 HCC patients. Only Ficolin-3 proved to be significantly changed after RFA. The 52 patients were divided into two groups according to the expression of Ficolin-3 before and after RFA. The 1-, 2- and 3-year DFS rates were 59.1%, 31.8%, and 22.7%, respectively, for patients in the low Ficolin-3 group (22 patients) and 73.3%, 60.0%, and 50.0%, respectively, for patients in the high Ficolin-3 group (30 patients) (P = 0.038). CONCLUSIONS: In conclusion, Ficolin-3 was overexpressed in the serum of most HCC patients after RFA. Ficolin-3 might be a biomarker for RFA treatment efficacy and a potential target for HCC immunotherapy.