Answer:
Not all cancer is hereditary, but genetic experts are beginning to see a pattern in some cancers. There are some inherited factors or genes that contribute to the development of certain cancers, such as breast, ovarian and colorectal.
10% to 15% of cancers are hereditary for the following: breast, ovarian, and colorectal. The two genetics that are specifically checked are the BRCA1 and the BRCA2. These two account for 85% of all hereditary breast and ovarian cancers. 5% to 10% of all breast cancers are hereditary as well.
Not all cancers have anything to do with heredity. Cervical cancer is caused by a virus that is an STD. Other cancers like lung, pancreas and prostate also don't link up with heredity as strongly. If cancer does have a tendency to run in your family, it is best to have regular check ups and discuss how to lower the risks.