The tumor on North Carolina basketball coach Roy Williams' left kidney is noncancerous, the school announced Thursday night. The results of a Wednesday biopsy showed the tumor is an oncocytoma, which is often indistinguishable from kidney cancer on X-rays. It is the same kind of noncancerous tumor the Hall of Fame coach had removed from his right kidney during a 3½-hour operation Sept. 19. Unlike cancerous tumors, oncocytomas do not spread.