Is Cancer Contagious?

Cancer is not contagious and it does not spread from person to person. It cannot be caught by touching, kissing, or breathing the same air as someone who has cancer.

There are rare instances, though, when cancer genes can be passed from parent to child or from an organ donor to an organ recipient. It is also possible to catch a contagious virus that puts you at risk of developing cancer, such as the human papillomavirus (HPV). 

Female doctor in discussion with senior male patient and adult daughter in exam room - stock photo

Thomas Barwick / Getty Images

How Cancer Develops

Normally the cells in our bodies grow and divide to keep us healthy. When older cells die, new ones often take their place. Cancer occurs when cells in the body change and start to divide and multiply without normal regulatory controls.

When a cell’s DNA is damaged, the cell doesn't function as it should, and it can produce abnormal copies that grow into and invade normal tissue.

Mutations (damage to a cell’s DNA) can occur in a number of ways. Factors like UV sun exposure or smoking can damage the DNA, potentially leading to cancer. Gene mutations can also be inherited. 

DNA damage, illustration - stock illustration


From a Parent

Cancers of the ovaries, breast, colon, and prostate have been associated with hereditary gene mutations. 

In hereditary cancers, an individual inherits a gene with a cancer-associated mutation from one or both parents. Inheriting this gene puts the person at a higher risk of developing cancer, but does not mean that a cancer diagnosis is inevitable.

Most cancers are not hereditary. Typically, genetic mutations in the cell's DNA develop due to environmental or hormonal exposures.

Tumor Suppressor Genes

Tumor suppressor genes are responsible for controlling the growth of cells. They regulate cell division and cell life span. They can also help repair damaged DNA. When these genes don’t work as they should, cell regulation can be disrupted, potentially resulting in cancer. 

Most mutations in tumor suppressor genes are acquired and develop over a lifetime. There are times, though, when these genes are inherited. For example, mutations in the TP53 gene can be hereditary. This mutation is found in about half of all cancer cases. 

DNA Repair Genes

DNA repair genes are responsible for repairing damage to a cell’s DNA and protecting the DNA from future damage. Once DNA is damaged, it can lead to problems, such as uncontrolled cell division.

Mutations in BRCA1 and BRCA2 (breast cancer 1 and 2) are hereditary mutations in DNA repair genes. Women who inherit one of these genes from their parents are at higher risk for developing breast and ovarian cancer. 

During Pregnancy

Developing cancer while pregnant is rare. Usually, if a mother is being treated for cancer during her pregnancy, the baby will not require special preventive treatment. 

Some cancers can spread through the placenta, the organ that connects the mother and baby, but most cannot reach the fetus. There have been rare cases of melanoma, small cell lung cancer, non-Hodgkin lymphoma, and leukemia that were passed from mother to child.

If a mother with cancer is breastfeeding, cancer cells will not enter the baby. But the mother’s cancer treatments can be ingested through breastmilk; talk with your oncologist and pediatrician about the best plan for feeding your baby if you are being treated for cancer.

From an Organ Transplant

There have been rare cases of an organ donor recipient developing cancer after receiving an organ from someone with a history of cancer. This is rare, partly because of the strict requirements and screening processes for organ donors.

If you receive an organ transplant, you would need to take medications that suppress your immune system. This helps prevent the rejection of the new organ, but it can increase the risk of cancer.

A weakened immune system cannot recognize and destroy precancerous cells as effectively as a healthy one. So immunosuppression increases the risk of developing cancer. Studies show that the longer a patient’s immune system is suppressed, the more at risk they are for being diagnosed with cancer.

According to the National Institutes of Health, organ transplant recipients are at higher risk for 32 types of cancers. Studies have found that the most common cancers experienced after an organ transplant are non-Hodgkin lymphoma, lung cancer, liver cancer, and kidney cancer. The risk varies by what type of organ is received.

Patients who have undergone a lung transplant are at the highest risk of developing cancer later on. Researchers believe this increased cancer risk is due to the remaining cancerous lung tissue in the recipient, rather than the new lung.

Patients who receive liver transplants are at higher risk for liver cancer. 

How Common Is It?

According to a study from the National Institutes of Health, patients who have received organ transplants are at two-fold risk of developing certain types of cancers. Of the patients they studied, 14% developed non-Hodgkin lymphoma, 13% developed lung cancer, 9% developed liver cancer, and 7% developed kidney cancer. The risks for these cancers depend on which organ was transplanted.

From an Infection

Certain infections can raise your cancer risk. A pathogen (infectious organism) cannot create cancer in the body—but when it is combined with a weakened immune system or environmental risk factor like smoking, the risk for cancer goes up.

Infections organisms can be transmitted through touching, kissing, having sex, sharing food, or breathing the same air. Each virus has its own methods of spreading.

It’s important to remember that being diagnosed with an infection that's associated with cancer does not mean that you will develop cancer.

Most cancers are not caused by infections.

 Microbe Types of Cancer
Parasitic worms Bladder and bile duct cancer
Human papillomavirus (HPV) Cancers of the cervix, vagina, vulva, penis, anus, and some cancers of the head, and neck
Epstein-Barr virus (EBV) Nasopharyngeal cancer, lymphoma of the stomach, Hodgkin lymphoma, and Burkitt lymphoma
Hepatitis B virus (HBV) and hepatitis C virus (HCV) Liver cancer
Human herpes virus type 8 (HHV-8) Kaposi sarcoma (only with a weakened immune system)
Human T-lymphotropic virus-1 (HTLV-1) Adult T-cell leukemia/lymphoma (ATL)
Merkel cell polyomavirus Merkel cell carcinoma
Helicobacter pylori (H. pylori) Stomach cancer
Chlamydia trachomatis Cervical cancer

A Word From Verywell

If you have a loved one with cancer, you are probably feeling overwhelmed with worry and responsibility. It’s helpful to remember that cancer is not contagious and you cannot catch it from another person. To protect yourself from developing cancer, take efforts to avoid environmental exposures, such as too much time in the sun or cigarette smoke. In addition, take precautions to avoid the viruses that can lead to cancer. Your healthcare provider can help you learn more about your cancer risk and how to reduce them. 

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. Is Cancer Contagious?

  2. National Cancer Institute. Common Cancer Myths and Misconceptions.

  3. National Cancer Institute. What Is Cancer?

  4. Memorial Sloan Kettering Cancer Center. Hereditary Cancer & Genetics.

  5. UConn Health. What Is Hereditary Cancer?

  6. American Cancer Society. Oncogenes and Tumor Suppressor Cells.

  7. Genetic Testing.

  8. Greaves M, Hughes W. Cancer cell transmission via the placenta. Evol Med Public Health. 2018 Apr 14;2018(1):106-115. doi: 10.1093/emph/eoy011

  9. Canadian Cancer Society. Cancer During Pregnancy.

  10. National Institutes of Health. Organ Transplants and Cancer Risk.

  11. Chapman JR, Webster AC, Wong G. Cancer in the transplant recipient. Cold Spring Harb Perspect Med. 2013 Jul 1;3(7):a015677. doi: 10.1101/cshperspect.a015677.  (ADD READING)

  12. Engels EA, Pfeiffer RM, Fraumeni JF Jr, Kasiske BL, Israni AK, Snyder JJ, Wolfe RA, Goodrich NP, Bayakly AR, Clarke CA, Copeland G, Finch JL, Fleissner ML, Goodman MT, Kahn A, Koch L, Lynch CF, Madeleine MM, Pawlish K, Rao C, Williams MA, Castenson D, Curry M, Parsons R, Fant G, Lin M. Spectrum of cancer risk among US solid organ transplant recipients. JAMA. 2011 Nov 2;306(17):1891-901. doi: 10.1001/jama.2011.1592

Additional Reading

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.