Even small wounds like paper cuts can rouse dormant cancer cells into forming a tumour, according to scientists at the University of California, San Francisco.
To determine how cancerous genetic mutations become tumours, Sunny Wong and colleagues engineered mice to express a human cancer gene in hair follicle stem cells.
They then sliced a small patch of skin on some of the mice, while leaving the others unharmed. Only the wounded mice developed tumours, which were clustered around their injury.
When skin is cut, hair-follicle stem cells migrate to the injury. Wong says pre-cancerous cells can lie dormant in the body until a trigger, such as radiation or a build up of mutations, pushes them into forming a tumour.
"In this case, wounding got cancerous cells out of their resting phase," New Scientist quoted him as saying.
The study appears in Proceedings of the National Academies of Science journal.