Scientists unlock cancer's ancestry

NEW YORK: Could the secret to better cancer therapies lie in understanding where your ancestors come from? Then again, where would that key fit?

How can we link the ancestors of cancer with current treatments? Alexander Krasnitz, a research professor at Cold Spring Harbor Laboratory (CSHL), believes that the solutions may be hidden within enormous databases and medical archives that hold hundreds of thousands of tumour samples.

Krasnitz and CSHL Postdoctoral Fellow Pascal Belleau are investigating racial or ethnic ancestry-cancer relationships. They’ve created new algorithms that use tumour DNA and RNA to precisely deduce ancestry from the continents. Their work may also assist medical professionals in creating fresh methods for early cancer identification and individualised care.

“Why do people of different races and ethnicities get sick at different rates with different types of cancer?” Krasnitz said, adding, “They have different habits, living conditions, exposures–all kinds of social and environmental factors. But there may be a genetic component as well.”

Krasnitz’s team trained their software tools using hybrid DNA profiles. They created these profiles from cancerous and unrelated cancer-free genomes of a known background. They then tested the software’s performance against pancreatic, ovarian, breast, and blood cancer specimens from patients with known ancestry. The team found the software matched their hybrid profiles to continental populations with over 95 per cent accuracy.

“We have a good model to build on,” Krasnitz said, adding, “But very few individuals come from a single ancestry. We’re all mixed to some extent. So now we’re working to look deeper, test tumour samples of unknown ancestry, reveal ancestral mixtures, and achieve more regional specificity.”

How specific? For now, think of West Africa as opposed to East Africa.

Krasnitz and Belleau recently joined a colorectal cancer study in collaboration with Northwell Health and SUNY Downstate Medical Center. The study allows them to explore how colorectal cancer mutates genes in different ways depending on specific races or ethnicities. They hope to further refine their software to infer ancestry of not only whole genomes but every individual sequence therein.

“If we can identify more localized ancestries that are susceptible to different cancers or other aggressive diseases, it could help us pinpoint the specific part of the genome responsible and target it for treatment,” Belleau said.

Right now, a simple DNA swab can tell you where you came from and which diseases you stand to inherit. In the future, it might give you the means to beat them, too.