Cancer is a common disease and most individuals will have family members who have had cancer. But the question is, should we be concerned if cancer is running in our family, and if so, when? Most cancers, actually, are not inherited. These types of cancers are called sporadic cancer, and these account for about 70-80% of all cancers. A common example of sporadic cancer is lung cancer in a smoker. Another type of cancer is familial cancer. This type of cancer occurs in clusters in families due to different environmental factors. For example, if a family lives in a small city where the only source of water is polluted, they may be at risk for cancer due to that environmental factor. Hereditary cancer, which is about 10% of all cancers, is the type of cancer that can run in a family. A common example of hereditary cancer is hereditary breast and ovarian cancer. Most cancers are caused by changes in genes, and these changes are known as mutations. Genetic mutations can interfere with the normal functioning of the cells leading to different diseases such as cancer. Most of these mutations are acquired during a lifetime, which can lead to sporadic cancer. If a person inherits a cancer-causing mutation from their parents and develops cancer due to this inherited mutation, this is known as hereditary cancer. Genetic testing can be done for different hereditary cancers to find out whether a particular cancer was caused by an inherited mutation or even to find out if someone has inherited mutation from their parents which puts them at a risk to develop cancer in the future. It is important to remember, however, that not all individuals with an inherited mutation develop cancer. Inherited mutations only increase the likelihood for a person to develop cancer. The likelihood is different depending on what gene the mutation is in. For example, if a woman has a BRCA1 mutation, their likelihood to develop breast cancer over their lifetime can be up to 85%. Although genetic testing for such cancer syndromes is not yet available in our country, if you suspect that cancer may be running in the family, there are screenings and interventions that can be done to prevent cancer. Hence, it is very important to learn if a cancer that a family member had could or could not be hereditary. Do not hesitate to ask your doctor about the screening options if you suspect that your family history is suggestive of hereditary cancer.