Original story from the Center for Genomic Regulation (Barcelona, Spain). Ancient genetic fragments reshape cancer genomes years before diagnosis. A study published in the journal Science reveals how jumping fragments of human DNA, a type of genetic parasite, destabilize the cancer genome. Unstable genomes are a fertile playground for cancer evolution, giving malignant cells more opportunities to grow, adapt and evade treatment. The researchers analyzed genome sequences from tumors with unusually high activity of LINE-1 (L1) elements, fragments of DNA that copy themselves and paste that copy into other locations within the genome. Previously thought to be a source of local mutations that occasionally disrupt individual genes when inserted into the wrong place, the researchers now find evidence that L1 activity can also drive large-scale architectural modifications that seed genomic chaos. “Cancer genomes are more influenced by these jumping fragments of DNA parasites than we previously thought,” explained José Tubio, researcher at the Centro de Investigación en Medicina Molecular y Enfermedades Crónicas at the Universidade de Santiago de Compostela (A Coruña, Spain) and coordinator of the study. The findings challenge the long-held assumption that L1 activity is a by-product of an already chaotic cancer genome. Rather than just appearing in late stages of cancer, the study found two in three (65%) L1 events occurred during the early stages of tumor evolution. The discovery could help explain how cancer reshapes the genome, and vice versa, at the early stages of the disease, knowledge that could eventually lead to new strategies for…
