Many people believe that cancer strikes randomly. But that’s not always true. Sometimes hereditary or genetic factors increase an individual’s risk for cancer.

Recent advances in research clearly indicate a link between genes and cancer. This link is often strongest in families where:

• Cancer occurs at a much younger age than average
• Cancer occurs in several close relatives
• More than one type of cancer occurs in the same close relative
• Cancer occurs in paired organs (i.e. cancer in both breasts)
• Cancer occurs in more than one generation
• Several rare cancers occur in a family

Whereas some common types of cancer, such as breast, ovarian, colorectal or prostate cancer, may or may not be inherited, other types of cancer (usually much rarer), are almost always inherited, such as medullary thyroid cancer.