The short answer
Kaposi sarcoma herpesvirus (HHV-8) can cause Kaposi sarcoma, mainly in people with weakened immune systems, such as those with HIV. NCI says antiretroviral therapy can lower complications in people with HIV.
The National Cancer Institute says Kaposi sarcoma herpesvirus (KSHV) can cause Kaposi sarcoma.
The virus spreads mainly through saliva. In the United States and Northern Europe it is mostly spread by sexual contact.
Most people with the virus do not get Kaposi sarcoma. Risk is higher when the immune system is weakened.
A hazard is something that can cause cancer. It is not your personal risk.
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The whole article, with every detail and caution.
The simple version
Kaposi sarcoma herpesvirus is also called HHV-8. It is a virus that can cause a cancer called Kaposi sarcoma. This mostly happens in people whose immune systems are weakened. That includes people with untreated HIV and organ-transplant recipients.
What Kaposi sarcoma herpesvirus is
Kaposi sarcoma herpesvirus (KSHV/HHV-8) belongs to the herpes family. In people with healthy immune systems it rarely causes disease. When immunity is weakened, it can cause Kaposi sarcoma and some rare lymphomas.
How people are exposed
The National Cancer Institute says the virus spreads in a few ways:
- Mainly through saliva.
- In the United States and Northern Europe, mostly through sexual contact.
- Through organ or bone marrow transplants.
- It is more common in some regions and populations.
The cancer connection
NCI says KSHV can cause Kaposi sarcoma, which can affect the skin, mouth, lymph nodes, and internal organs. It can also cause primary effusion lymphoma and Castleman disease, which are rare. NCI says people who also have HIV, or whose immune systems are weakened for other reasons, are more likely to develop these diseases.
Hazard is not the same as risk
People often confuse hazard with risk. Saying this virus can cause cancer is a statement about hazard. It is not, by itself, a statement about your personal risk. Most people with the virus never get Kaposi sarcoma. Your risk depends on your immune health and other things.
How to lower your risk
NCI says there is no vaccine for KSHV. Your care team may suggest steps that fit your situation.
- NCI says people with HIV can lower complications by taking antiretroviral therapy.
- NCI recommends behavioral precautions to lower the chance of spreading the virus. Ask your care team what these mean for you.
To see where Kaposi sarcoma herpesvirus sits among all the things that affect cancer risk, read our overview of cancer prevention and what raises cancer risk.
The bottom line
Kaposi sarcoma herpesvirus can cause Kaposi sarcoma and some rare lymphoma-like diseases, according to NCI. These problems mostly happen when the immune system is weak. Antiretroviral therapy helps people with HIV lower their risk of complications.
Common questions
Does kaposi sarcoma herpesvirus cause cancer?
It can. The National Cancer Institute says KSHV (also called HHV-8) can cause Kaposi sarcoma. Most people with the virus do not get Kaposi sarcoma. It develops mainly when the immune system is weakened.
How are people exposed to kaposi sarcoma herpesvirus?
NCI says the virus spreads mainly through saliva. In the United States it is mostly spread sexually. It can also spread through organ or bone marrow transplants.
Which cancers are linked to kaposi sarcoma herpesvirus?
NCI says it can cause Kaposi sarcoma. It can also cause primary effusion lymphoma and Castleman disease, which are rare.
How can I reduce my risk from kaposi sarcoma herpesvirus?
NCI says there is no vaccine. People with HIV can lower complications by taking antiretroviral therapy. Ask your care team about your own situation.
Does a carcinogen label mean I will get cancer?
No. Saying a virus can cause cancer is not a prediction that any one person will get it. Your risk depends on your immune health and other factors.
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Last updated: 2026-10-16Next planned review: 2028-07-05
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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