Most of the research that drives today’s medical recommendations is based only on what is known about the BRCA mutations. With more than 1,200 different types of mutations discovered to date in each of the BRCA genes, researchers do not yet have enough information to stratify cancer risk for each of those specific mutations. Nor, can they give a definitive picture regarding cancer risk levels for mutations in the newly discovered risky genes. As a result, cancer risk data tends to be reported only on BRCA research and in broad, average ranges. And, those statistics may differ, depending on the source.
It is important to know that personal cancer risk may fall above or below the average ranges reported in your health care region and are based on a variety of factors in addition to the gene affected and the particular mutation within it.
Some of those factors are:
■ previous breast biopsies (especially if the biopsy showed atypical cells or Lobular Carcinoma in Situ (LCIS))
■ having dense breast tissue
■ number of first-degree relatives with cancer
■ young onset of menarche
■ very high exposure to radiation
■ absence of a healthy lifestyle
Hereditary breast, ovarian and prostate cancer is far more common than most people think.An estimated 5-25% of these cancers are known to be hereditary, which translates to 3-5 times more people than are affected by multiple sclerosis! When considering the other cancers risky gene carriers are also susceptible to, plus the portion of carriers that aren't expected to be diagnosed with cancer, the incidence of HBOC syndrome carriers is even higher.
Certain ethnic groups have a much higher chance of carrying risky genes than in the general population. For example, people of Ashkenazi (Eastern European) Jewish ancestry have a 1 in 40 chance of carrying one of three founder BRCA risky gene mutations associated with that population. Other ethnic groups include, but are not limited to: French Canadian, Bahamian, Polish, Icelandic and African American.
Many genes have been discovered that fall under the HBOC syndrome umbrella. Researchers suggest only about half of this type of hereditary cancer has been explained, leaving many morerisky genes to be discovered.
We all carry the same genes. Some of those genes are responsible for cell division in certain areas of our bodies. Mutations in those genes greatly affect a person's ability to ward off or fight breast, ovarian and prostatecancer. Depending on the mutation carried, a person may also be at slightly higher risk of some other types of cancer.
There is a 50% chance of inheriting a gene mutation from a carrier parent.
The way we inherit genes explains why it is important to look at the history of cancer on both sides of a family. A woman can inherit an increased risk of breast cancer or ovarian cancer from her father in the same way that she can inherit it from her mother. Alternately, a man can inherit an increased risk of prostate and breast cancer from his mother the same way he can from his father.