Hepatocellular Carcinoma: Review of Targeted and Immune Therapies.

Abstract

Hepatocellular carcinoma is the fifth most common cancer globally and the second leading cause of cancer-related mortality worldwide. Despite the established efficacy of screening programs for at-risk individuals, most patients are diagnosed at later stages of disease, wherein the tumor characteristics or liver disease progressions do not allow for curative interventions. Many cytotoxic chemotherapeutic agents have been tested in patients with advanced disease with disappointing outcomes and poor tolerance; therefore, no standard systemic therapy emerged until the approval of sorafenib in 2006. Despite the toxicity and low response rate, sorafenib had shown a significant survival benefit in phase III clinical trials, thus encouraging clinical research aimed at advancing the field of molecular therapy. Disrupted signaling pathways related to hepatocellular carcinoma (HCC) include the Wnt/β-catenin, Ras/Raf/MAPK, phosphatidyl inositol 3-kinase/Akt/mechanistic target of rapamycin, hepatocyte growth factor/c-mesenchymal-epithelial transition, IGF, vascular endothelial growth factor, and platelet-derived growth factor pathways, and a variety of agents targeting these pathways are currently under investigation. Additionally, better comprehension of the complex mechanisms underlying the ability of tumor cells to escape immune surveillance has led to impressive results with immunotherapy in many types of cancer, and this treatment strategy is currently being developed for HCC patients. Previous and ongoing targeted therapy and immunotherapy trials for HCC are discussed in this review.