Cancer is most curable when detected at an early stage. For example, there are genes for eye color, hair texture, and blood type as well as genes that give us a tendency or predisposition to develop certain disorders and diseases, such as heart disease, diabetes, and cancer. Normally, we have two copies of each gene. We get our genes from our parents, inheriting one copy of a gene from our mother and another copy from our father. Thus, if a mother or father has a gene mutation, this mutation could be passed on to their children.
Most cancers are due to an accumulation of damage to the DNA in our cells.
This occurs naturally as we age, thus most cancers occur at older ages. The development of cancer is a multi-step process. This means that several different changes have to occur in the cell's DNA before cancer develops. An individual who inherits a cancer gene mutation is one step along the way in this process. Thus, fewer steps have to happen before cancer develops, and cancer may be seen at younger ages than otherwise expected.