FGFR1 and cancer: For example, recently reportedR4Fu-Q65R-MMAE targets three different receptors, leucine-rich repeatcontaining G-protein-coupled receptors 4, 5, and 6 (LGR4–6),and shows promising results both in vitro and in vivo.63 LGR4–6, similar to FGFR1, are overexpressedin cancer cells.