New Genetic Regions Active In Cancer

Cancer Center researchers at Massachusetts General Hospital, USA, have discovered that certain DNA sequences, known as 'satellite repeat', experience a massive overexpression when they appear in the tumors. The investigation of this phenomenon is an important step in better diagnosis and understanding of cancer.
"The satellite repeats make up a large part of our genome, but were thought to be inactive," says David Ting, a researcher at the Massachusetts Cancer Center and co-author. However, this research developed new techniques for sequencing, shows that these regions are very active in cancer.

Researchers have found that overexpression of satellite repeats starts early in tumor development, so it is essential to achieve early detection in the patient. To carry out the study, researchers have used a digital gene expression analysis called "single molecule sequencing of next generation."

Possible cancer biomarker

With this system, they demonstrated, in a mouse pancreatic cancer, the satellite DNA was expressed at levels exceeding 100 times the values ​​recorded in normal tissues. On the other hand, when analyzing samples of epithelial cancer (the most common type of tumor) was found both in colon tumors as lung, mouse repeated the same levels.

"Our hope is that this anomaly (hitherto unknown) serve as a biomarker in cancer diagnosis and shed light on the mechanisms by which tumors develop," says Daniel Haber, director of the Cancer Center and lead author.

The study in human cancer cells obtained similar results in most cancers studied, including tumors of the pancreas, lung and prostate. If confirmed in prospective clinical trials, "the satellite RNA expression may provide a new and highly specific biomarker related to several types of epithelial cancers," he says Ting.