Liver cancer is a disease in which malignant cells form in the tissues of the liver. Cancer that forms in other parts of the body and spreads to the liver is not primary liver cancer. The liver is one of the largest organs in the body. It has two lobes and fills the upper right side of the abdomen inside the rib cage. The main functions of the liver include making bile to help digest fat from food, storing glycogen (sugar) the body uses for energy, and filtering harmful substances from the blood so they can ba passed from the body.