The short answer
People who receive an organ transplant take medicines that suppress the immune system so the body does not reject the new organ. NCI explains that these drugs make the immune system less able to detect and destroy cancer cells, or to fight off infections that cause cancer. The four most common cancers in transplant recipients are non-Hodgkin lymphoma and cancers of the lung, kidney and liver.
Anti-rejection medicines deliberately turn down the immune system so a transplanted organ is not attacked.
NCI states that these drugs make the immune system less able to detect and destroy cancer cells or fight off infections that cause cancer.
The four most common cancers in transplant recipients are non-Hodgkin lymphoma and cancers of the lung, kidney and liver.
Some of these cancers trace back to viruses: Epstein-Barr virus for non-Hodgkin lymphoma, hepatitis B and C for liver cancer.
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The trade-off at the heart of transplantation
A transplanted kidney, liver or heart looks foreign to your immune system. Left alone, the immune system would attack it. That is why anti-rejection medicines exist. NCI says many people who receive organ transplants take medicines to suppress the immune system so the body does not reject the organ.
This page is about the cost of that arrangement. The National Cancer Institute puts it directly: these immunosuppressive drugs make the immune system less able to find and destroy cancer cells, or to fight off infections that cause cancer.
The same dialed-down immune system that protects the organ also does less policing elsewhere.
Two different jobs the immune system stops doing well
It helps to separate these two jobs, since they lead to different kinds of cancer.
The first job is watching your own cells. Cells pick up damage all the time, and immune cells help spot and clear the abnormal ones. Turn that down, and more abnormal cells survive.
The second job is keeping infections in check. Several viruses can push cells toward becoming cancerous, and a healthy immune system keeps them quiet for a lifetime. When it is suppressed, those viruses get more room to do harm.
What that looks like in practice
NCI reports that transplant recipients face a higher risk of several cancers. The four most common are:
- non-Hodgkin lymphoma
- lung cancer
- kidney cancer
- liver cancer
The virus connection explains part of this list, but not all of it. Non-Hodgkin lymphoma in this setting can come from Epstein-Barr virus infection. Liver cancer can come from hepatitis B and hepatitis C viruses. Lung and kidney cancers, on the other hand, are not thought to come from infection. They show up through the surveillance route instead.
A useful comparison
NCI covers HIV in the same discussion, and the comparison is useful. HIV also weakens the immune system and raises the risk of certain cancers. Some are driven by infections, such as human herpesvirus 8, hepatitis viruses, and human papillomavirus (HPV). Others, such as lung cancer, are not thought to come from an infection at all.
These are two very different situations. But they share one underlying theme: a weakened immune system changes which cancers become more likely.
What this does not mean
It does not mean the transplant was a mistake. Stopping immunosuppression risks losing the organ.
It does not mean cancer is inevitable either. A higher risk across a whole group of transplant recipients is not a prediction about you specifically.
And it is not a reason to skip doses. Adjusting immunosuppression is a transplant team decision. Stopping medicines puts the organ at risk, and more immune suppression means the effects described here may be stronger. Any change is a decision for your transplant team.
What is worth doing
Stay in the follow-up system. Regular follow-up visits are a natural place to raise cancer concerns.
Report new things rather than filing them away. A lump that has not gone down, a cough that will not quit, or blood where there should not be any are worth reporting. Coughing up blood or heavy bleeding needs care right away, so call 911 or go to an emergency room. None of these means cancer on its own.
Ask specifically whether your team wants any extra checks beyond what people without a transplant get.
Skin deserves its own mention
The NCI page we checked does not give skin advice. Ask your own team what they recommend for your skin, how often they want it checked, and by whom.
Sources
NCI, Risk Factors: Immunosuppression (cancer.gov).
Common questions
Should I stop my anti-rejection medicine to lower my cancer risk?
No. Stopping these medicines puts the transplanted organ itself at risk. Any change to the dose or the combination is a decision for your transplant team, made with your whole situation in view.
Why does a weaker immune system lead to cancer?
NCI describes two routes: immunosuppressive drugs make the immune system less able to detect and destroy cancer cells, or to fight off infections that cause cancer.
Which cancers show up most often after a transplant?
NCI names non-Hodgkin lymphoma along with cancers of the lung, kidney and liver as the four most common in transplant recipients.
Is this the same as the raised cancer risk in people with HIV?
The mechanism overlaps. NCI notes that HIV also weakens the immune system and raises the risk of certain cancers, including ones linked to viruses such as human herpesvirus 8, hepatitis viruses and HPV, as well as cancers not thought to be caused by infection, such as lung cancer.
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Sources last checked: 2026-10-02 what this meansLast updated: 2026-10-02Next planned review: 2027-08-11
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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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