Molecular determinants of outcome in sorafenib-treated patients with hepatocellular carcinoma

Purpose: Preclinical studies show that sorafenib, a multitarget kinase inhibitor, displays anti-proliferative, anti-angiogenic, and pro-apoptotic properties in hepatocellular carcinoma (HCC). However, the determinants of sorafenib sensitivity in vivo remain largely unknown. Methods: We assessed the expression of Mcl-1, activated/phosphorylated extracellular signal-regulated kinase (pERK) 1/2, and activated/phosphorylated AKT (pAKT) in pretreatment tumor specimens from 44 patients with advanced HCC who received sorafenib. Furthermore, we assessed MYC and MET gene copy numbers (GCN) by fluorescence in situ hybridization. Results: Poorer overall survival (OS) times were correlated with pERK expression [hazard ratio (HR) 1.013; 95 % CI 1.003-1.035] and Mcl-1 expression (HR 1.016; 95 % CI 1.002-1.030) in pretreatment tumor samples. Expression levels of pERK and Mcl-1, however, were not correlated with time to tumor progression (TTP). Increased pERK expression was positively associated with higher Cancer of Liver Italian Program scores (P = 0.012) and was prognostic in patients with scores 2-6 but not in those with scores 0-1. pERK expression was significantly less frequent in specimens sourced from previous surgical procedures compared to biopsy samples (9.6 vs. 92.3 %, respectively; P < 0.0001). Analysis of pAKT expression, MET and MYC GCN, did not indicate any prognostic nor predictive values for these biomarkers in terms of survival. Conclusions: Expression levels of Mcl-1 and pERK are associated with reduced OS in HCC patients treated with sorafenib and might be useful markers for risk stratification. However, in contrast to previous findings, pERK expression levels, as well as other biomarkers tested, did not affect TTP.