Womens Health

Genetics and Breast Cancer

Breast Cancer Risk

Rare is the family these days which has not been impacted with cancer - in any one of its many varieties.  Breast cancer is the most common cancer in women and following lung and colorectal cancer, it is the most deadly.  The focus of media on the one in eight chance of a woman developing breast cancer during her lifetime has driven women to seek whatever means possible to be protected and prepared.  Indeed, women are concerned and should be.  However, it's important to remember that the one in eight risk is a cumulative risk.  The percentages were established based on the lifetime risk for a woman living to 110.  Fortunately, there are means by which a woman can be kept informed of her breast health.  With the increased use of mammography and diagnostic testing, discovering the disease at earlier stages has dramatically improved the cure rate. 

What Are Genes?

Think of an instruction manual providing information for cell growth and function.  Genes are similar.  They are thread-like spirals of DNA (deoxyribonucleic acid).  DNA carries the data for building proteins which ultimately control the development, structure and function of all the cells in your body.  Genes carry this data in chromosomes.  Most of the cells in the body have two copies of every chromosome which means the cells also have two copies of every gene.  You get one gene from your mother and one from your father.

If there is something abnormal in the DNA then misinformation is dispensed to the cell which means a fault in the growth or function of that cell.  If there's an error in a gene then that error will appear in all of the cells with that gene and this will cause a mutation.

Can I Inherit The Cancer Gene?

About 90% of breast cancer cases are the result of one or more mutations incurred during the cell division process in the breast tissue.  These changes are called "somatic" or body cell changes.  Science hasn't figured out exactly what causes these mutations.

The remaining 10% of breast cancer cases has been associated with inherited mutations.  There are two specific genes identified with breast cancer, BRCA1 and BRCA2 (BReast CAncer 1 and 2).  These genes are passed down through the generations with the mutation already in them.  These genes are, in their normal state, found in everyone but when they are mutated the risk of breast or ovarian cancer is more likely.

What's My Risk?

Let's say one of your parents has an abnormal BRCA1 or BRCA2 gene.  You stand a 50% risk of inheriting that gene.  If you have children, your children have a 25% risk of inheriting it, provided the children's father doesn't have an abnormal gene.  Remember, even if one member of the family has an abnormal gene, it does not mean everyone in the family will have it as well.

There are both benefits and drawbacks to having genetic testing done.  However, it is an option and something you could explore with the help of your health care provider.

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