FGFR3 and urinary bladder cancer: FGFR3 mutations are prevalent in low-grade, non-muscle invasive bladder cancers (NMIBC), but are less frequent in muscle-invasive bladder cancers (MIBC), which are prone to progression and metastasis28, 29.recent studies indicates that increased serine synthesis in FGFR3-mutant bladder cancer cells drives macrophages towards an immune-inert phenotype30, 31.