May 18, 2026 -- USA News Group News Commentary — For more than two decades, B7-H3 sat on the shortlist of theoretically perfect cancer drug targets that nobody could quite figure out how to hit. The protein is broadly overexpressed across some of the most common — and most lethal — solid tumors, including prostate, lung, breast, ovarian, head and neck, and pancreatic cancers. It is largely absent from healthy tissue. It correlates with poor prognosis. On paper, it has every quality a drug develo