Kolkata scientists discover new breast cancer gene mutation

Scientist in Kolkata claim to have discovered a gene mutation that triggers tumour growth which in turn can lead to breast cancer. Exon 20, a component of BRCA 1 (Breast Cancer Associated Gene) mutates to disrupt the structural stability of proteins and helps cancerous cells proliferate. A paper on Exon 20 mutation will be published in Cellular and Molecular Biology Letters, next month.

The research team, which comprised scientists from the Indian Institute of Chemical Biology (IICB) and the Netaji Subhas Chandra Bose Cancer Research Institute (NSCBCRI), chanced upon the novel mutation while studying the genetic factors behind breast cancer. Exon 20, they found, hindered the stability of BRCA's protein structure. (Read: One sure-fire tip to beat breast cancer!)

Abhijit Chakraborty, senior research fellow at the NSCBCRI and a member of the research team told TOI: 'The protein helps cell cycle check point or controls the proliferation of cells. It also helps to repair DNA damage and prevents cancerous growth. Exon 20 mutation disrupts these two vital functions, allowing a proliferation of abnormal cells. This leads to tumoural growth and eventually breast cancer.' 'It could also be inherited from the mother to the daughter or the grand-daughter. The lone case that we have come across so far has a strong familial history of cancer,' said Ashis Mukhopadhyay. (Read: Breast cancer: Top 10 myths busted)

The patient, a 34-year-old woman who developed breast cancer five years ago, had the Exon 20 mutation. While her mother was also a breast cancer patient, her uncle, too, was a cancer patient. 'This suggests that while the BRCA gene is active in the family, an Exon 20 mutation is not ruled out in her mother's case either. It needs to be seen if the mutation is hereditary. There is also a possibility that it is specific to this region, since it has not been identified anywhere else in the world. We also need to further investigate the impact of the mutation,' said Chakraborty.

The BRCA Gene story

The BRCA gene was in the news because of Angelina Jolie who underwent a preventive double mastectomy because she had a faulty BRCA1 gene which had an 87% chance of developing breast cancer. At that time, a company called Myriad Genetics was fighting a legal battle to hold to a patent for BRCA genes. Thankfully, the Supreme Court invalidated the patent saying genes couldn't be patented.

Dr Prasad Raj Dandekar, a radiation oncologist at the L.H.Hiranandani Hospital in Mumbai tried to explain the importance of BRCA gene testing to us:

Why is genetic testing so important, especially so in the case of breast cancers?

Dr Prasad Raj Dandekar: It will now be possible to predict the risk of developing breast cancer in patients with family history of breast cancers easily by an affordable blood test. Some of the patients with breast cancer have a variation in genes called BRCA1 and BRCA2 which significantly increases their chances of developing breast and ovarian cancers. A lady with BRCA gene mutation will have 85% chance of developing breast cancer and 45% of developing ovarian cancer in her lifetime. This is significantly higher that compared to women who are not BRCA gene mutation positive. Women who are detected to be positive can prevent cancer development by taking some hormone therapy such as tamoxifen, or undergoing prophylactic surgery like celebrity Angelina Jolie did or be on regular follow up to detect cancer at early stage. The key factor here is to detect women who are BRCA gene mutation positive and explain them the risks associated.

What is breast cancer?

Breast cancer is a type of cancer originating from the breast tissues. Both men and women can be afflicted by it though it's rarer in men. Along with cervical cancer it's one of the most common types of cancer that afflicts women. One of the major issues with breast cancer is that it is often not detected soon enough. This is due to low awareness about the disease. Detecting it early can significantly reduce the death risk. (Read more..)

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