Newly Discovered Gene Is Associated With Inheritance Of Leukemia

Date: Jul-19-2012About 3,300 people are diagnosed every year with CLL, the most common form of leukemia in Western countries. Researchers have known for quite some time that certain families are more susceptible to sustaining CLL than others. However, the genetic basis for inherited predisposition to CLL has so far been unknown.

Researchers from London's Institute of Cancer Research (ICR) in the UK have now identified a heritable gene variant that is linked to a higher risk of developing chronic lymphocytic leukemia (CLL).  The study, published in the journal Blood, reports the researchers discovery of another key region of the genome that is associated with the inheritance of CLL.

The ICR team's recent studies have demonstrated that there is no single 'cancer gene responsible for CLL, but that susceptibility is potentially due to the co-inheritance of multiple risk variants that elevate the risk when inherited in combination. The researchers hope that better insight into the inheritable genetic factors that drive the development of cancer can help in designing new drugs and screening methods to target those who are at high-risk.

In a meta-analysis that consisted of combined data from three independent genome wide association studies (GAWAS), the researchers analyzed genetic data from 1,121 leukemia patients and 3,745 healthy controls and found a new CLL 'risk' inherited variant, which was situated at a very specific point on a single chromosome encoded as 6p21.33.

Leading researcher, Professor Richard Houlston, of the molecular and population genetics team at The Institute of Cancer Research, explained:

"We investigated the combined effect of this newly found risk variation and other known CLL related variants. There was no evidence of interaction between the genes, indicating that each locus plays an independent role in increasing risk. These gene variations contribute significantly to the development of CLL. While risks associated with each variant are individually modest, these variations are frequently carried by individuals of European ancestry.

This variant is the thirteenth that we have discovered - so while each one alone has a small effect on the risk of developing CLL, in combination these risks are important. The genetic variants we have found so far account for around 16 per cent of the inherited risk of CLL, so we believe there are more genetic variants still to be found."

The researchers found a strong link between the 'risk' locus at the 6p21.33 location and lower expression of the BAK1 gene, which has a vital impact in maintaining levels of B cells, i.e. healthy immune cells in the blood. BAK1 deficiency was noted to prevent natural cell death, which leads to an accumulation of immature and mature B cells. The discovery provides new insight into the biological development of CLL.

Professor Chris Bunce, Research Director of Leukemia & Lymphoma Research, concluded:

"This study offers more compelling evidence for the role of inheritable risk genes in hijacking the natural cell cycle.  More research is needed to establish just how significant this newly discovered risk gene variant is in the development of CLL."

Written by Petra Rattue

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