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One in Eight Cancers Worldwide Linked to Infections, IARC Study Finds
A new IARC analysis estimates that about 2.3 million cancer cases in 2024 were caused by infections. Here is what the study reports, what NCI says about infections and cancer, and what the numbers do not mean for one person.
Original commentary from the Cancer Explained editorial team.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
What the study reported
The International Agency for Research on Cancer (IARC) is the cancer research agency of the World Health Organization. On September 29, 2026, it announced a new study. IARC estimates that about 2.3 million new cancer cases worldwide in 2024 were caused by infections. That is about 12% of all new cancer cases, or roughly one in eight.
The study was published in The Lancet Oncology. IARC says it is the most complete picture so far of the cancer burden linked to infections. It adds infections that earlier estimates left out, such as HIV and Merkel cell polyomavirus. It also adds newer findings, such as recent evidence linking Epstein–Barr virus with stomach cancer. The estimates are based on IARC's Global Cancer Observatory database.
What the news coverage added
Fox News reported on the study on October 1, 2026. It said the researchers named 12 infections linked to cancer. Fox listed five as the main contributors and gave these approximate case counts:
- Helicobacter pylori (H. pylori): about 760,000 cases.
- Human papillomavirus (HPV): about 750,000 cases.
- Hepatitis B virus: about 360,000 cases.
- Epstein–Barr virus: about 260,000 cases.
- Hepatitis C virus: about 160,000 cases.
We did not open the full paper, so these figures come from Fox's report of the study. Fox also quoted a study author, Dr. Harriet Rumgay of IARC. She said the findings show the major role that infection control can play in reducing the global cancer burden. Fox reported that the burden falls most heavily on people in low- and middle-income countries.
What NCI says about infections and cancer
The National Cancer Institute (NCI) explains that some infections can lead to cancer. Chronic infection and the long-term inflammation it causes are one way this can happen. Most of the viruses linked to cancer spread through blood or other body fluids. NCI says people can lower their risk of infection by getting vaccinated, not having unprotected sex, and not sharing needles.
NCI describes how this works for several infections:
- HPV. High-risk types of HPV cause nearly all cervical cancers. They also cause most anal cancers and many cancers of the throat, vagina, vulva and penis. Most HPV infections go away on their own without causing cancer. Vaccines can prevent infection with the HPV types that cause most HPV-related cancers.
- Hepatitis B and C. Long-term infection with these viruses can lead to liver cancer. A vaccine protects against hepatitis B. There is no vaccine for hepatitis C, but NCI says highly effective antiviral treatment is available.
- H. pylori. This bacterium can cause a type of stomach cancer and a type of lymphoma in the stomach lining. It can also cause stomach ulcers.
- Epstein–Barr virus. More than 90% of people worldwide are infected during their lifetime, and most have no symptoms. There is no vaccine.
What this does not mean
This is a study of populations, not of individuals. It does not mean that an infection will cause cancer in any one person. NCI says most people infected with some of these viruses never develop cancer. For example, most HPV infections clear on their own.
The numbers also come from estimates, not from following individual patients. Fox reported that the researchers said the results depend on the quality of cancer data in each country. They also said that counting only infections already proven to cause cancer may leave the true total higher.
The study does not say that any one test or treatment is right for you. Whether a vaccine, test or treatment makes sense depends on your age, health and history. That is a question for your own care team.
Why this matters
Many of these cancers can be prevented in principle, because the infections behind them can be prevented or treated. Vaccines against HPV and hepatitis B, and treatment for hepatitis C, are examples NCI describes. You can read more on our pages about HPV and cancer, H. pylori and cancer, hepatitis and liver cancer, and hepatitis B vaccination and liver cancer prevention.
Questions to ask your care team
- Am I up to date on the vaccines that help prevent infection-related cancers, such as HPV and hepatitis B?
- Should I be tested for hepatitis B or hepatitis C?
- Does my history of infection change which cancer screening I need?
- If I have been told I have one of these infections, what follow-up do I need?
Sources
- International Agency for Research on Cancer, "Global burden of cancer attributable to infections in 2024: One in eight cancers worldwide linked to infections," September 29, 2026: https://www.iarc.who.int/news-events/global-burden-of-cancer-attributable-to-infections-in-2024-one-in-eight-cancers-worldwide-linked-to-infections/
- The Lancet Oncology, "Global burden of cancer attributable to infections in 2024: a worldwide incidence analysis" (cited by IARC; we did not open the paper): https://doi.org/10.1016/S1470-2045(26)00307-4
- Fox News, "Surprising culprit tied to 1 in 8 cancer cases worldwide, major study reveals," October 1, 2026: https://www.foxnews.com/health/surprising-culprit-tied-1-8-cancer-cases-worldwide-major-study-reveals
- National Cancer Institute, "Infectious Agents and Cancer": https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents
- National Cancer Institute, "HPV and Cancer": https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/hpv-and-cancer
How this article was prepared
An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.
Cancer Explained is published by the National Cancer Information Foundation. It is not medical advice and does not suggest a test or treatment.
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Put the story in context
Prevention, possible warning signs, screening, and diagnosis
This story relates to Infections and cancer risk. The information below is general: it does not reveal anything else about a public person’s health, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
Learn about this story’s cancer topic
A public story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.