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NABL Accredited Laboratory

BRCA 2

BRCA2 Mutation Test

Mutations in the BRCA1 and BRCA2 genes profoundly increase the risk of developing breast and/or ovarian cancer among women.

Diagomet DNA test can help identify patients with mutations in BRCA1/BRCA2 genes that predispose them to breast/ovarian cancer

Purpose of the Test

BRCA2 mutation status will help predict the risk of developing breast and ovarian cancer.

Background

In India over 80,000 women are diagnosed with breast cancer every year. A number of genetic risk factors have been associated with the incidence of breast cancer. About 5-10% of breast cancer cases are linked to inherited mutation in two genes called BRCA1 and BRCA2. BRCA1/BRCA2 genes have been linked to almost 45% of sporadic breast cancers and about 90% of breast and ovarian cancer families. Also, mutations in the BRCA1 and BRCA2 genes profoundly increase the risk of developing ovarian cancer among women. Screening for BRCA1 and BRCA2 mutations can provide valuable information needed for preventive monitoring and therapy. In high-risk patients early detection of the disease through regular mammograms and breast self-examinations can detect the cancer when as it arises and has not spread. This significantly increases the chances of survival.

Inhibitors of a cellular enzyme called PARP (a cellular enzyme) are being developed to treat cancer. It has recently been shown that breast cancer patients with mutations in BRCA1/2 show a positive response to PARP inhibitors. Hence BRCA status will be a useful marker for patient selection in clinical trials and also subsequently for identifying patients who are likely to benefit from PARP inhibitors.

Exceptions

Not all patients with BRCA2 mutation will develop breast cancer.

Test Method

PCR and sequencing of the BRAC2 coding exons from the patient blood drived DNA.

Sample Requirements

We require 5-8mls of blood collected in EDTA containing tubes. Blood should be shipped within 48 hours after collection of blood on ice. You may send 10ug of genomic DNA derived from blood, prepared using a Qiagen blood DNA preparation kit (or equivalent) and should have a A260/A280 value of 1.8.

References

1. Antoniou, A., Pharoah, P. D., Narod, S., Risch, H. A., Eyfjord, J. E., Hopper, J. L, Loman, N, & Olsson, H. Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case Series unselected for family history:a combined analysis of 22 studies; Am. J. Hum. Genet.72 1117–1130 (2003).

2. Brose, M. S., Rebbeck, T. R., Calzone, K.A., Stopfer, J. E., Nathanson, K.L, & Weber, B. L. Cancer risk estimates for BRCA1 mutation carriers identified in a risk evaluation program. J. Natl. Cancer Inst. 94 1365–1372 (2002).

3. Fackenthal, J.D, & Olopade, O.I., Breast cancer risk associated with BRCA1 and BRCA2 in diverse populations. Nat Rev Cancer. 7:937-948 (2007).

4. Deffenbaugh, A.M., Frank, T.S., Hoffman, M., Cannon-Albright, L., Neuhausen, S.L. Characterization of common BRCA1 and BRCA2 variants. Genet Test 6:119-121(2002).

5. Fong PC, Boss DS, Yap TA, Tutt A, Wu P, Mergui-Roelvink M, Mortimer P, Swaisland H, Lau A, O'Connor MJ, Ashworth A, Carmichael J, Kaye SB, Schellens JH, de Bono JS. Inhibition of poly(ADP-ribose) polymerase in tumors from BRCA mutation carriers. N Engl J Med. 361:123-34 (2009).