Chemotherapy Leaves a Genetic Fingerprint in Childhood…

Chemotherapy Leaves a Genetic Fingerprint in Childhood Cancer, and It Can Predict Which Tumours Will Come Back When childhood cancer relapses, doctors have long known that prior chemotherapy plays some role in how the disease evolves. What has remained unclear is exactly how much genetic damage that treatment leaves behind, and whether that damage can actually predict outcomes. A major new study published in Nature provides the most detailed answer yet. The scale of this research: Researchers analysed 611 whole genome sequenced tumours from 544 children across three major international precision medicine programmes in Canada, Australia, and the United States. Alongside the genetic data, they collected more than 3,200 detailed treatment records for each patient, exact drug, dose, and timing, allowing them to directly connect specific chemotherapy exposure to specific genetic damage. The core finding, chemotherapy leaves a measurable mark: Tumours that had already been treated carried nearly three times as many unique mutation patterns, and roughly twice the total number of mutations,