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How do HPV and hepatitis B vaccines help prevent certain cancers?

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Precancerous growth in a human colon — cancer View through an endoscope of a polyp, a benign precancerous growth projecting from the inner lining of the colon.

Vaccines help prevent certain cancers by training the immune system to recognize and defend against specific viruses that are known to cause or contribute to the development of malignant tumors.1

Human Papillomavirus (HPV) Vaccines

High-risk strains of human papillomavirus (such as HPV-16 and HPV-18) are linked to more than 90 percent of cervical cancer cases. These viruses produce proteins that interfere with the body's natural tumor-suppressor genes, allowing cells to grow uncontrollably. Vaccines like Gardasil and Cervarix prevent these infections by prompting the body to generate antibodies against these high-risk strains. By preventing the initial viral infection, the vaccine effectively stops the virus from integrating its DNA into host cells and initiating the cancer-causing process.231

Hepatitis B Vaccine

There is a clear association between the hepatitis B virus (HBV) and liver cancer, particularly in regions where the virus is endemic. While the exact mechanism is still being studied, evidence suggests that HBV proteins disrupt cell signaling, leading to deregulated growth. Vaccination prevents HBV infection, thereby eliminating the viral trigger that can lead to hepatocellular carcinoma.41