Chemo footprints reshape the genome of relapsed childhood cancers

A multi-institutional study of 611 pediatric tumors shows that prior cancer therapy, especially platinum-based chemotherapy, leaves distinct mutational signatures and markedly increases the mutation burden at relapse. The researchers identify both known and novel therapy-associated signatures, demonstrate that platinum-induced mutations can emerge rapidly (often within a year of treatment), and show that mutational patterns vary by drug class, revealing opportunities for treatment de-escalation and monitoring resistant clones in real time.