All cancers develop because something has gone wrong with one or more of the genes in a cell. But most of these gene changes happen during our lives. They happen as we get older or because of something we are exposed to, such as cigarette smoke or sunlight. These substances are called carcinogens because they bring about changes in the genes that make body cells more likely to become cancerous. These gene changes don’t affect all body cells. They are not inherited and cannot be passed on to your children.

Human Papillomavirus (HPV) increases the risk for Cervical, vaginal, penile, anal and oropharyngeal (affecting the middle part of the throat, which includes the base of the tongue, the tonsils, the soft palate, and the walls of the pharynx) cancers.

• Hepatitis B and hepatitis C viruses increase the risk for liver cancer.
• Epstein-Barr virus increases the risk for Burkitt lymphoma.
• H. pylori bacteria increases the risk for gastric cancer.

Studies have shown that drinking alcohol is linked to an increased risk of:

• Oral cancer,
• Esophageal cancer
• Breast cancer —the level of risk rises as the amount of alcohol consumed rises
• Colorectal cancer (in men)

Drinking alcohol may also increase the risk of liver cancer and female colorectal cancer.

Studies show that obesity is linked to a higher risk of:

• Breast cancer, typically in postmenopausal women who haven’t used replacement hormone therapy.
• Colorectal cancer
• Endometrial cancer
• Esophageal cancer
• Kidney cancer
• Pancreatic cancer

Many studies have looked at specific foods and their role in cancer, both as risk factors and possible prevention. Results of successive studies often contradict previous ones. However, there are health merits to eating well and minimizing processed foods since this approach is key to avoiding obesity, and obesity is a cancer risk factor. For more, see the Eat Healthy section.