Our 24/7 cancer helpline provides information and answers for people dealing with cancer. We can connect you with trained cancer information specialists who will answer questions about a cancer diagnosis and provide guidance and a compassionate ear.
Our highly trained specialists are available 24/7 via phone and on weekdays can assist through video calls and online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
Since the start of the 20th century, it’s been known that certain infections play a role in cancer in animals. More recently, infections with certain viruses, bacteria, and parasites have been recognized as risk factors for several types of cancer in humans.
Worldwide, infections are linked to about 15% to 20% of cancers. This percentage is even higher in developing countries, but it is lower in the United States and other developed countries. This is partly because certain infections are more common in developing countries, and partly because some other risk factors for cancer, such as obesity, are more common in developed countries.
Infections can raise a person’s risk of cancer in different ways. For example:
Any of these changes might lead to a higher risk of cancer.
Even though the infections described here can raise a person’s risk of certain types of cancer, most people with these infections never develop cancer. The risk of developing cancer is also influenced by other factors. For example, infection with Helicobacter pylori (H pylori) bacteria might increase your risk of stomach cancer, but what you eat, whether or not you smoke, and other factors also affect your risk.
Many of the infections that influence cancer risk can be passed from person to person, but cancer itself cannot. A healthy person can’t “catch” cancer from someone who has it.
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Heymann DL (Ed.) Control of Communicable Diseases Manual, 19th ed. Washington DC: American Public Health Association; 2008:393–402.
International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 100B: A Review of Human Carcinogens: Biological Agents. 2012. Accessed at http://monographs.iarc.fr/ENG/Monographs/vol100B/index.php on September 19, 2014.
Trinchieri G. Inflammation. In DeVita VT, Lawrence TS, Rosenberg SA (eds). Cancer: Principles & Practice of Oncology, 9th ed. Philadelphia: Lippincott Williams & Wilkins; 2011: 193–202.
Last Revised: July 11, 2016