Why colorectal cancer breaks the immune system’s rules

Colorectal cancer has long baffled scientists because, unlike most tumors, patients often do better when their cancers are packed with immune-suppressing regulatory T cells. New research finally explains why. Scientists discovered that these T cells aren’t all the same: one subtype actually helps keep tumors in check, while another shields cancer from immune attack. The balance between these “good” and “bad” cells can determine whether a tumor grows or shrinks.