Proteomic analysis on recurrence-associated proteins for large hepatocellular carcinoma following radical resection

Abstract

Objective Using comparative proteomic approach to analyze proteins relevant to the recurrence of large hepatocellular carcinoma (HCC). Methods The HCC samples of group R≤6 m (n=9), R6-12 m (n=9), R>24 m (n=6) were analyzed using the technique of isobaric tags for relative and absolute quantification (iTRAQ)-two dimensional liquid chromatography tandem mass spectrometry (2DLC-MS/MS). The differentially expressed proteins were confirmed by real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) and Western blotting using frozen tissues (n=30). To further analyzed the differentially expressed proteins, immunohistochemical experiment was performed using paraffin-embedded tissue (n=201), and the results were analyzed using clinical-pathological characteristics. Results We screened 10 differentially expressed proteins with the different time of recurrence. Five proteins were up-regulated [calcium binding protein A9 (S100A9), myeloperoxidase (MPO), apolipoprotein A4 (APOA4), transmembrane protein 97 (TMEM97), human nuclear receptor hblf (NR5A2)] and five proteins were down-regulated [dehydrogenase / reductase 2 (DHRS2), three or four amino acid repeat domain 4 (TTC4), chromatin remodeling factor (CHD2), 4-hydroxybenzoate dioxygenase (HPD), methylamine transferase-cyclase deaminase (FTCD)]. The FQ-PCR and Western blot assays showed that the expression level of TMEM97 was consistent with the that of proteomic. The immunohistochemical experiment showed that the high expression level of TMEM97, the high level of serum alpha fetal protein (AFP), multiple tumor, larger tumor diameter, portal vein tumor thrombus (PVTT), microvascular tumor thrombus (MVI), incomplete tumor capsule, transfusions were the independent risk factors of tumor recurrence. Conclusion There are many proteins associated with the recurrence of large HCC. TMEM97 might be used as a potential alternative marker for recurrence. Key words: Hepatocellular carcinoma; Recurrence; Proteomic; Transmembrane protein 97