Certain genetic changes in Dravidian women make them more susceptible to breast cancer than their counterparts living in north India

By Syed Akbar
Hyderabad:  Certain genetic changes in Dravidian women make them
more susceptible to breast cancer than their counterparts living in
north India.

A team of researchers from the city-based Centre for Cellular and
Molecular Biology (CCMB) and the Central Drug Research Institute,
Lucknow, has observed that ethnic variations in some genes in
Dravidian women are linked to the increased incidence of breast cancer.

“Genetic polymorphisms are created by errors during DNA replication.
Polymorphisms exist in all populations at little or large frequency.
Therefore, the polymorphism might exist in a population with or
without influence on disease susceptibility. If we talk about why
these polymorphisms increased breast cancer risk in Dravidian women,
we have to stress on differences in the genetic make up between north
Indian and south Indian populations,” Dr Rituraj Konwar of CDRI told
this correspondent.

He said susceptibility to a disease is defined by thousands of
polymorphisms (variations) in the entire human genome and not by a
single polymorphism. Therefore, it is possible that the genetic risk
factors between north and south Indian populations are different. The
present study identifies one such factor for south Indian populations.

“South Indian women’s breast cancer risk may partly be explained by
TNF (tumour necrosis factor) polymorphisms. North Indian women may
have equal risk of breast cancer, but it is possible that the
underlying genetic risk factor is different,” Dr Rituraj pointed out.

The study identified one of the several possible genetic risk factors
for breast cancer. The risk with this polymorphism seems strong in the
south Indian population and it does not seem to affect breast cancer
risk in north Indian women. However, it needs to be stressed that this
does not suggest increased breast cancer risk in south Indian women,
he explained.

The overall risk of a disease is affected by several variations and
the risk due to a particular polymorphism may be aggravated or
alleviated by other polymorphisms in related or un-related genes. The
researchers recruited subjects from Andhra Pradesh, Tamil Nadu and
Karnataka for the study.