Many of us don't think of cancer being caused by viruses. A recent study reported that an estimated 2.3 million new cancer cases throughout the world were from infections. Which is about 12% of all cancer cases.
An oncovirus is a virus that can cause cancer. Helicobacter pylori (H pylori) and human papillomavirus (HPV) caused the largest share of these cancers - each causing 4% of new cancers. Vaccines already exist for HPV and HBV (hepatitis B virus) and have been shown to reduce the incidence of cancer.
From CIDRAP: More than 2 million new cancer cases caused by infections in 2024, study finds
Many people fear cancer and want to know what they can do to prevent it. In some cases, genetics, random mutations, or environmental factors are to blame, making it difficult to avoid a diagnosis. A paper published yesterday in The Lancet Oncology, though, calls attention to a preventable cause of cancer—infections.
“An estimated 2.3 million new cancer cases were attributable to infections globally in 2024, which is equivalent to 12% of all cancer cases,” wrote the authors, led by researchers from the International Agency for Research on Cancer in France. “Our findings highlight the importance of infection control to achieve cancer prevention.”
H pylori, HPV cause largest share of cancers
Using data from the Global Cancer Observatory’s Cancer Today (GLOBOCAN) database about 2024 cancer incidence, the scientists estimated the number of cancers caused by one of 12 pathogens considered group 1 carcinogens. These include:
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- Helicobacter pylori (H pylori)
- Human papillomavirus (HPV)
- Hepatitis B virus (HBV)
- Hepatitis C virus (HCV)
- Epstein–Barr virus (EBV)
- Kaposi's sarcoma-associated herpesvirus
- Schistosoma haematobium
- Human T-cell lymphotropic virus
- Opisthorchis viverrine
- Clonorchis sinensis
- Merkel cell polyomavirus
- HIV
These infectious diseases contributed to approximately 2.3 million new cancer diagnoses in 2024. H pylori and HPV were responsible for the biggest share of cases, each causing 4%. EBV led to 1% of cancers, while HCV contributed to less than 1%. Low- and middle-income countries reported three-quarters of all infectious disease–related cancers.
Vaccines exist for HPV and HBV and have been shown to reduce cancer. The authors urge the development of new vaccines for other infectious agents, such as EBV, H pylori, and Kaposi’s sarcoma, to reduce the number of cancers caused by these pathogens. But they note that, in some cases, prevention measures exist already and should be better implemented.