**1. Introduction**

Liver cancer is one of the major cancers in the world [1]. Hundreds of thousand people are diagnosed each year with liver cancer. Unfortunately, liver cancer is the second most common cause of deaths associated with cancer complications, accounting for more than 70%. Hepatocellular carcinoma (HCC) is the most prevalent type of liver cancer [2]. More than twothird of patients newly diagnosed with HCC are aged >65 years, and this number is expected to increase as the world population ages [3]. Furthermore, there is heterogeneity in the aging process, which further contributes to the complexity of treatment decisions [4, 5].

HCC originates from normal hepatocytes. Hepatocytes are the cells forming the parenchymal tissue of the liver and make up the majority of liver's mass. Hepatocytes play a crucial role in liver functions [6]. They are involved in many biological processes including the metabolism of carbohydrates and lipids, protein synthesis, and notably body detoxification from harmful substances. Important proteins such as serum albumin, prothrombin, transferrin, fibrinogen, and complement are generated by hepatocytes. In addition to their main role in glycogenesis, hepatocytes make fatty acids from carbohydrates leading to triglyceride synthesis. Hepatocytes are highly involved in lipid metabolism and cholesterol synthesis. The detoxifying activity of hepatocytes includes drug metabolism, modification of endogenous compounds such as steroids and ammonia. However, hepatocytes might be overwhelmed with harmful agents and targeted with many hepatic viruses, leading to liver damage and ultimately to HCC [7]. The hepatocytes are commonly used for research in both academia and pharmaceutical industry in order to investigate the mechanisms of carcinogenesis, viral infections, and drug metabolism. Currently, highly innovative research in epigenetics and immunology is taken place in order to explore further liver diseases and develop novel therapies for HCC.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
