An Overview of Genetic Tests for Breast Cancer Risk

Breast cancer is the second commonest cancer among American women and it is also the second commonest killer among all cancers in the same population. For most women, the lifetime risk of developing breast cancer is around 13% while certain underlying factors such as the presence of genetic mutations increase the risk by several folds. However, it is a disease which can be effectively treated if diagnosed early and genetic testing has played a major role in anticipating such a cancer among susceptible individuals.

What are the risk factors for developing breast cancer?

In the modern day medical practice, recognizing the risk of developing certain diseases would pave way for an early intervention and therefore towards an improved long-term clinical outcome. In relation to breast cancer, there are certain features present in the history and unraveled through DNA analysis, which can predict the risk of its occurrence.

Among some of the features gathered using a clinical interview, presence of two or more close family relatives with breast or ovarian cancers, detection of such cancers before the age of 50 years, and being a descendent of an Ashkenazi Jewish family have all been attributed with a higher risk. However, none of them findings can reliably predict the occurrence of a breast cancer than the detection of altered BRCA-1 and BRCA-2 genes along with a positive family history.

Is there other genes which can predict breast cancer apart from BRCA-1 and BRCA-2?

Apart from BRCA genes, there are other possible genetic sequences, which are still under investigations for their contribution towards causing breast cancer. However, at present, the scientists believe that only about 10% of all breast cancers are genetically inherited and it indicates the potential role played by ‘unknown’ genetic or non-genetic factors in precipitating breast cancer in the rest of the population.

What are BRCA-1 and BRCA-2?

These genes are believed to be responsible in preventing the occurrence of cancerous tumors in the breast as well as in the ovaries. They exist in pairs while both men and women posses copies of each of these genes. In certain instances, these genes may undergo alterations and in such instances, mutations may take place. This can lead to uninhibited growth of cancerous tumors in the breast, if allowed to proceed, can even cause death.

However, scientists also believe that, not all women who inherit a mutated BRCA-1 and/or BRCA-2 gene will develop breast cancer and according to available statistics, only one in 10 will develop the same. Incidentally, although BRCA screening was available for almost a decade, only 10% of those who fits the criteria to undergo such gene analysis have discussed it with their physicians. Among them, only 5% have received advice to undertake the test while only 2% have actually undergone the genetic analysis.

How does the BRCA analysis performed?

Although the process involved in detecting an abnormal BRCA gene is complex, the test is performed using a blood sample drawn in the same way as for any other blood test. It will take several weeks before the results are available and the interpretation of which should be done by a genetic counselor. At the same time, one should not undergo such tests without knowing the possible outcomes and without being adequately prepared for whatever the results it might present. Thus, initial genetic counseling is a vital part of the genetic evaluation process.

What are the other genetic tests, which can be useful for breast cancer screening?

As mentioned earlier, there are several other genetic investigations, which could be useful as breast cancer screening tests. Among these tests, screening for ATM gene (Ataxia-telangiectasia mutation gene), altered N-acetyl transferase 2 (NAT2) gene, mutated CYP17 gene, and mutated glutathione transferase (GST) gene have all given conflicting results which would require lot more research to prove their worth. However, the research done so far has presented the scientific world with enough encouragement to continue further on findings a genetic marker.