What is Genetics?
Genetics is the study of how traits such as hair color, eye color, and risks for health
problems are inherited or passed from parents to their children.
Cancers develop due to changes, called mutations, in genes. Only a small number of
cancers are from inherited mutations that are passed down in families. Most cancers
are from acquired mutations. Acquired means that the mutations happen at the cellular
level after birth.
This can be the result of:
Environmental exposures, such as radiation
Lifestyle behaviors, such as smoking, eating poorly, or not exercising
Acquired changes happen only in the tissue that is affected by cancer. For example,
colon cancer cells. Acquired changes are not passed down to children. Mutations in
a person's DNA build up over time. If mutations affect genes that control cell growth,
it may cause a cell to grow out of control. It then becomes a cancer cell.
Therefore, all cancers are genetic. This means that the cancer develops because of
a build-up of mutations in genes. But most are not inherited. The number of cancers
that comes from a single inherited factor varies depending on the type of tumor. For
the more common cancer types, like breast and colon cancer, less than 10% are inherited.
The Human Genome Project is an international scientific research project that began
in 1990. The project’s goal of mapping the location of all the genes on a cell’s chromosomes
was completed in 2003. The analysis of these data will continue for years. It will
give scientists the building blocks to determine how diseases, such as cancer, are
caused. It will also hopefully, tell scientists how they can be treated and prevented.