An Australian study has discovered 45 new genetic variants that put people at a greater risk of developing basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).
The research by scientists at QIMR Berghofer Medical Research Institute more than doubles the genetic information now available on these cancers.
Study senior author and the head of QIMR Berghofer’s Statistical Genetics group, Associate Professor Stuart MacGregor, said researchers examined data from 48,000 people who were treated for BCCs and/or SCCs in Australia, the United Kingdom and the United States.
“We compared the genetic information of patients treated for BCCs and SCCs to that from 600,000 people without these cancers – which allowed us to identify which genes were different between the two groups,” Associate Professor MacGregor said.
“We identified 45 new genes which had not previously been linked to these cancers. Most affected both BCCs and SCCs, although a few were specific to one or the other. Previously only about 40 genetic variants for these skin cancers had ever been identified.
“While solar ultra violet radiation exposure is the biggest risk factor for developing skin cancers, this study shows there are important inherited contributions underlying BCCs and SCCs.”
New loci included common variants in BRCA2 (distinct to known rare high penetrance cancer risk variants), and in CTLA4, a target of immunotherapy in melanoma.
Lead researcher, Dr Upekha Liyanage, said the discovery of new genetic variants may help to explain why some people developed these skin cancers, while others who may have similar features, such as pale skin or freckles, did not.
“On the flip side, although the study looked only at the genetic information of light skinned people, identification of genetic markers could also explain why some people with darker skin types still get BCCs and SCCs,” Dr Liyanage said.
“Currently there’s no genetic testing for skin cancers, but if we can get a clearer understanding of which genes are responsible and where on the DNA these genes are located, other scientists can start working on finding better treatments and preventative strategies.
“This research, which is the largest study to date into the genetic variants influencing BCCs and SCCs, is also valuable because it could be used to repurpose drugs that have already been approved for some conditions or that are under clinical trial, to speed up treatment options.”
The study findings are published in Human Molecular Genetics.