In addition to the many controllable risk factors, there are a number of factors that increase a person’s risk for developing cancer that are outside a person’s control. These include:

• Age. The risk of many cancers, such as breast, prostate, colorectal and others increase with age.
  

  

• Ethnicity. Certain cancers are more prevalent in specific populations. For example, although it is not known why, prostate cancer is more common among African American men than among white men. Women from an Ashkenazi (Eastern European) Jewish background are more likely to have a genetic mutation that increases their risk for breast cancer.
  
  
• Family history of cancer. Some cancers are said to “run in families.” Ovarian cancer and breast cancer are two common examples. Women with a mother or sister who has had either disease are more likely to develop the disease themselves.
  
  
• Genetic conditions. Hereditary cancer syndrome is a term used when several members of a family have cancer because of an inherited abnormal (mutated) gene. Increased risk of cancer is associated with hundreds of hereditary conditions, according to the National Cancer Institute (NCI), including von Hippel-Lindau disease, Li-Fraumeni syndrome, Turcot syndrome or neurofibromatosis. The more prominent cancers that may have a genetic link include breast cancer, prostate cancer, colorectal cancer and melanoma.
  
  Conditions that may increase cancer risk include:
  
  

  Condition	Type of cancer
  Hereditary retinoblastoma	Retinoblastoma
  Xeroderma pigmentosum	Skin cancer
  Wilms’ tumor	Kidney cancer
  Li-Fraumeni syndrome	Sarcomas, brain cancer, breast cancer, leukemia
  Familial adenomatous polyposis	Colorectal cancer
  Paget’s disease of bone	Bone cancer
  Fanconi’s aplastic anemia	Leukemia, liver cancer, skin cancer

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  In some cases, tests are available to detect whether a person carries certain genetic mutations that can increase the risk for cancer. Women may be tested for mutations to certain genes, including BRCA1 and BRCA2, which may indicate an increase risk for breast cancer. For patients with a family history of a certain type of cancer, taking such a test may provide more information about their risks. However, these tests have advantages and disadvantages and their use should be discussed with appropriate physicians.
  
  
• Gender. While many cancers show equal prevalence among gender lines, some are exclusively male or female, while some favor a particular gender. For example, all men are at risk for prostate cancer while all women (but many fewer men) are at risk for breast cancer.
  
  
• Previous history of cancer. After a person has had cancer, the risk of recurrence, depending on the type of cancer can be considerable for the first two to three years following diagnosis and treatment. It is also possible to be predisposed for other cancers after being diagnosed with a first cancer. It may be the actual cancer or treatment for the cancer that increases a person’s risk of a second cancer.
  
  
• Radiation or chemotherapy. According to the NCI, children who received chemotherapy or radiation therapy for cancer are at risk for developing a second primary cancer. Accidental exposure to high doses of ionizing radiation has also been linked to increased risk of childhood cancers. Additionally, certain chemotherapy drugs may lead to an increased risk of leukemia.
  
  
• Infectious exposure. Some forms of cancer may be related to exposure to viral or bacterial infections and could be prevented by lifestyle changes or vaccines. The bacterium Helicobacter pylori occurs in the stomach and is responsible for many peptic ulcers and is closely associated with stomach cancer. H. pylori infection can be treated with antibiotics. It is more common in developing countries, where people may have more limited access to antibiotics. These areas have corresponding higher rates of stomach cancer.
  
  The Epstein-Barr virus, which causes mononucleosis, has a close association with lymphoma and other cancers. Human papillomaviruses (HPVs) are not a single virus, but rather are a group of more than 100 types of viruses. Certain HPVs  have a close association with the development of cervical cancer and anal cancer. In 2006, a vaccine was introduced to protect against the strains of HPV most closely associated with cervical cancer. Studies have also shown a link between children and adults with AIDS and an increased risk of non-Hodgkin’s lymphoma, leiomyosarcoma (a type of muscle cancer) and Kaposi's sarcoma, among other cancers. Only a small number of viruses are considered a cause of cancer, including:
  
  

  Virus	Type of cancer
  Epstein-Barr virus	Burkitt’s lymphoma
  Hepatitis B and C virus	Liver cancer
  Human papillomavirus	Cervical cancer
  Human T-cell lymphotrophic virus	Adult T-cell leukemia
  Kaposi’s sarcoma-associated herpesvirus	Kaposi’s sarcoma