Virginia Commonwealth University

VCU Massey Cancer Center

Cancer and family history

Genetics is the branch of medicine concerned with how hereditary and genetic factors play a role in causing a disease, birth defect or inherited susceptibility to a health problem such as cancer.

When working properly, genes promote normal, controlled cell growth. However, when an alteration or mutation occurs in a gene, cancer cells develop.

The majority of cancers can be attributed to acquired mutations. “Acquired” means that the mutations occur only in the tissue that is affected by cancer (e.g., colon cancer cells), and are not passed to children. These changes occur at the cellular level after birth, as a result of environmental exposures (e.g., smoking), lifestyle behaviors (e.g., eating poorly or not exercising) or chance alone. Mutations in a person’s DNA accumulate over time. If mutations affect genes that control cell growth, this may cause a cell to grow out of control and ultimately become a cancer cell.

Only a small percentage of cancers involve inherited mutations that are passed from generation to generation. Therefore, all cancers are genetic, in that they develop because of an accumulation of mutations in genes, but most are not inherited. The percentage of cancers that result 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 percent are inherited.

The Human Genome Project began in 1990 with the goal of mapping the location of all of the genes on a cell’s chromosomes. This monumental achievement will give scientists the building blocks to determine how diseases such as cancer are caused and, hopefully, how to treat them and, ultimately, prevent them.

Many people are curious about their risks for cancer based on their family’s health history. At VCU Massey Cancer Center's Familial Cancer Clinic — the only dedicated cancer genetics counseling clinic in the Richmond area — our specialists help you to get a comprehensive picture of your cancer risk and to develop a plan for prevention and treatment.