This type of cancer occurs when cancer cells grow at an abnormal rate and form a tumor that can be malignant (cancerous) or benign (non-cancerous). The earlier these cancer cells start, the more likely a person is diagnosed with primary cancer. Hepatocellular carcinoma is a cancer with undifferentiated somatic cells. Most people with hepatocellular carcinoma (HCC) have no symptoms until the disease is advanced. The right side is below your diaphragm and above your abdomen.