Guide to Genetic Testing for Cancer

Genetic testing is a kind of medical testing used to identify alteration in chromosomes, genes or proteins. Most often genetic testing is done to identify changes that are linked to inherited disorders. The main purpose of genetic testing is to determine an individual’s probability of developing or inheriting a genetic disorder.

Genetic testing for breast cancer

Almost 80 percent of women who suffer from breast cancer have no particular risk factor other than age. And the remaining 20 percent of women may have close blood relations with breast cancer. Only 5 to 10 percent of women who develop breast cancer have an evidently identifiable inherited genetic factor.

Families with heredity cancer susceptibility syndromes, cancers occur at an early age, may be in multiple generations. The disease may be inherited to multiple members in each generation. This syndrome is caused due to inherited genetic changes or mutations in specific genes.

Genes are present on chromosomes that encode specific proteins for performing various body functions. Half of the genes are inherited from the father and half from the mother side. The most important genes responsible for cancer are tumor suppressor genes. The main function of these genes is to make sure that cells stop growing after a specific time period. However, in case of defective tumor suppressor genes, the cells grow and form tumors.

Scientists have identified hereditary cancer susceptibility genes (BRCA1 and BRCA2) to be responsible for breast cancer and ovarian cancer. A woman with BRCA1 mutation is at increased risk of breast cancer. Women with altered BRCA1 gene are 85 per cent higher at risk of developing breast cancer. However, mutations in BRCA2 account for up to 15 percent of families with hereditary breast cancer.

Having a family history of breast cancer is one of the most important risk factors for the disease. The risk increases if the first-degree relative, like a mother or sister, has had breast cancer.

Women who go for genetic testing for cancer must get genetic counseling for correct and fair information about the advantages and limitations of genetic testing.

If a woman is going through a test for BRCA1 and BRCA2 mutations, the test does not prevent a woman who carries the mutation from getting breast cancer. Genetic testing for cancer cannot cure the disease. Not all genetic tests can be interpreted as normal or detrimental. However, if a woman tests negative for gene mutation, it does not mean that she will not develop breast cancer. On the other hand, if a woman tests positive to gene mutation, she may have a high risk of developing breast cancer depending on the gene that has been identified in the family. In addition, the genetic testing for cancer is quite expensive.

Advantage of genetic testing for cancer:

The potential advantage of genetic testing for cancer is that it helps in making well-versed decisions about managing the health care. In addition, an individual can go through the necessary prevention, monitoring and treatment options.

(Web): Genetic Testing for Breast and Ovarian Cancer Risk: It's Your Choice -- http://www.cancer.gov/cancertopics/genetics/genetic-testing-for-breast-and-ovarian-cancer-risk

(Web): Genetic testing for cancer risk -- http://www.macgn.org/factsheets/genetic%20testing%20for%20cancer%20risk.pdf