There are some genes which help protect humans from developing
cancer. Examples of these genes are: APC, MLH1, MSH2, MSH6,
STK11, or BRCA. These genes, and others like them, are located
on the autosomes. This means that an inherited predisposition
for cancer can come from either your mother or your father,
because you have one gene from each. Some people are born with
an alteration (mutation) in one of these genes. A mutation is
essentially a mis-spelling of the gene. Mutations prevent genes
from performing their jobs, which means proteins the body needs
may not be made, or if they are made they may be formed
incorrectly. Usually, people will only have a mutation in one
copy of the gene. This means that they still have one working
copy of the gene. However, this single copy of the gene is not
able to make up for the mutated copy. Over time, the working
copy of the gene also acquires mutations, which are random and
happen by chance as people age; these types of mutations, which
are acquired after birth, are no