Are All Liver Cancers Caused by Hepatitis B?

While not all liver cancers are caused by hepatitis B, there is a strong link between the disease and the development of this type of cancer. Other contributing factors include exposure to aflatoxins, liver fibrosis, long-term contact with certain chemicals such as vinyl chloride, nitrosamines, and phenols, as well as infections like liver fluke and tobacco use.

Hepatitis B Virus as a Major Contributor

The hepatitis B virus (HBV) is one of the leading causes of liver cancer. When HBV DNA integrates into the genetic material of liver cells, it can damage or disrupt key genes, activating oncogenes while deactivating tumor suppressor genes. This disruption can ultimately lead to the transformation of normal liver cells into cancerous ones.

Aflatoxins and Their Role

Aflatoxins, particularly aflatoxin B1, are toxic compounds produced by certain molds found in contaminated food supplies. Studies have shown that populations consuming food heavily contaminated with aflatoxins have higher rates of liver cancer. Aflatoxin B1 can alter the expression of important genes such as RAS and TP53, which play a role in regulating cell growth and preventing cancer.

Liver Fibrosis and Cirrhosis

Liver fibrosis, often resulting from chronic conditions like viral hepatitis, alcoholic liver disease, or non-alcoholic fatty liver disease, significantly increases the risk of liver cancer. As the liver becomes scarred and cirrhotic, the likelihood of abnormal cell growth and genetic mutations rises, creating a favorable environment for cancer development.

Exposure to Chemicals and Other Risk Factors

Long-term exposure to industrial chemicals like vinyl chloride, nitrosamines, and phenols has also been linked to liver cancer. Additionally, substances found in tobacco smoke, such as nicotine-derived nitrosamines, can contribute to the disease. These factors, along with chronic inflammation and fibrosis, create a cycle of liver damage, regeneration, and mutation that increases the risk of malignancy. The process often involves imbalances in cell proliferation and apoptosis, along with increased blood vessel growth, which supports the progression of liver cancer.