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Introduction
Breast cancer
is the most
common
female cancer
affecting
approximately
one out of eight women
(less than 12 percent.) The
majority of breast cancer
cases occur by chance
and are also referred to as
sporadic.
We all carry certain genes-
or instruction codes-that are
normally protective against
cancer. These correct any DNA
damage that naturally occurs
when cells divide. Inheriting faulty
A PATIENT’S GUIDE TO TESTING FOR BREAST CANCER
Written By: Sonika
Sachanandani-Phulwani
Genetic Counselor at Matar
& Rosset Healthcare Solutions
SHOULD I HAVE
GENETIC TESTING
FOR
BREAST CANCER
?
versions or “variants” of these genes
– mutations, significantly raises your
risk of developing cancer because
the altered genes cannot repair the
damaged cells which can build up
and form a tumor; or cancer.
Cancer is not usually inherited;
however some types – mainly breast,
ovarian, colorectal and prostate
cancers – can be strongly influenced
by genes and can run in families.
Of diagnosed breast cancer cases,
only 5 to 10 percent are hereditary;
meaning they occur because of
an inherited genetic change in the
family.
Panel Testing
Multiple genes responsible for
hereditary breast cancer have been
discovered. Approximately 25
percent of hereditary breast cancer
is due to mutations in one of two
genes called BRCA1 and BRCA2.
Another 20 percent of hereditary
breast cancer is due to other known
hereditary cancer genes. The
application of ‘panel testing’ for
breast cancer genetic testing is still a
matter of discussion.
Standard practice still follows; in
a first step, carrying out a BRCA 1
and 2 genetic test to identify any
breast cancer causing mutations.
However, if the woman tests
negative, in a second step, she could
Inherited
versus Non-
Inherited
Cancer
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Sep/Oct 2015