Certain pathogens, like viruses and bacteria, can cause long-term inflammation or directly damage DNA in ways that eventually lead to cancer.

For example, hepatitis B and C viruses are key drivers of liver cancer. Some types of the human papillomavirus are responsible for cervical cancer. The bacterium H. pylori can cause stomach ulcers and cancers.

The International Agency for Research on Cancer estimates that around 13% of cancers overall are directly caused by infections, as the chart shows.

For some cancer types, they estimate that infections cause nearly all cases. They’re listed at the top of the chart and include cervical cancer, T-cell leukemia and lymphoma, and non-cardia stomach cancer.

This is an area where prevention can be very powerful: by tackling the infections that cause them, we can stop these cancers before they start.

Vaccines for human papillomavirus and hepatitis B have already been developed and have lowered cancer rates in younger generations. Additionally, antibiotics for H. pylori, antiviral treatments, and improved hygiene can dramatically reduce the risks of other infections.

Source: https://ourworldindata.org/data-insights/what-share-of-cancers-are-caused-by-infections