CSF1R and cancer: Small-molecule inhibitors targeting key components of the ERK1/2pathway, such as Raf and MAPK/ERK kinase (MEK), have been developed and are being evaluated in clinical trials for various cancer types.Because PLX3397 targets upstream regulators of ERK1/2 signaling, such as c-Kit and CSF1R, it may also have therapeutic potential incertain cancers by indirectly modulating ERK1/2 activity.