Wednesday, June 22, 2016

Osteoporosis drug can prevent the development of breast cancer in women who are BRCA1 mutation carriers.

Individuals who carry a mutation in breast cancer susceptibility gene(BRCA1) are highly prone to develop breast cancer.  As compared to general population who have 8% chance of developing breast cancer, women who harbor this germline mutation have a 55-65% chance of developing breast cancer by the age 70.[1]

These women frequently undergo prophylactic risk reducing surgeries ( (bilateral prophylactic mastectomy and bilateral prophylactic salpingo-oophorectomy) to minimize the chances of developing breast cancer.[2]

Scientist around the world are long looking for chemoprevention to reduce the risk of cancer in BRCA1 mutation carriers. Currently Tamoxifen is in use for chemoprevention.  

 A recent paper published in Nature[3] offers a breakthrough for millions of next generation women with BRCA1 mutation carrier. Researchers are already considering it as ‘holy grail’ of breast cancer prevention.

Denosumab is a human monoclonal antibody for the treatment of osteoporosis. It is also a RANKL signaling inhibitor, RANKand RANK−  are two subsets of luminal progenitors present in the histological normal breast tissue of BRCA1 mutation carriers. RANK+ cells are highly proliferative, have grossly aberrant DNA repair and bear a molecular signature similar to that of basal-like breast cancer. Denosumab inhibited the RANKsignaling and stopped the progesterone induced proliferation of pre-neoplastic cells and also tissues from breast biopsies of BRCA1 mutation carriers. The same effect was also seen in mouse model of mammary tumorigenesis. Denosumab is already in use for treatment of osteoporosis and for patients with bone metastasis of breast cancer. 

Geoff Lindeman, a clinician-scientist at the Walter and Eliza Hall Institute and a co-author of the study said "Over the last few years, it has become increasingly clear from the work of several groups that RANK ligand, which switches on RANK, is an important regulator of cell growth in the breast. We have now been able to pinpoint the precise culprit cells and were very excited to see that they express the RANK protein."

As a part of pilot study three women were also treated with Denosumab and the results are encouraging days Dr. Lindeman.

Dr. Francisco Esteva (researcher at NYU Langone Medical Center and a part of the pilot study) and his colleagues are looking forward to conducting large scale clinical trials. "The new study does not change any management or clinical use of any drugs at this point, but it provides data that can be tested in a clinical trial," he said. "The data are compelling."

He also added that we are looking at least 10 years down the lane, but it offers hope for future generations of women.



[1]http://ww5.komen.org/BreastCancer/InheritedGeneticMutations.html
[2] http://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet

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