Team identifies a 'forcefield-like' defense system in solid tumors and the genetic elements that can switch it off

The tumor microenvironment—an ad hoc, messy amalgamation of signaling molecules, immune cells, fibroblasts, blood vessels, and the extracellular matrix—acts like a "powerful security system that protects solid tumors from invaders seeking to destroy them," says Michael Mitchell, a bioengineer at the University of Pennsylvania working on nanoscale therapeutics aimed at targeting cancers.