MERTK and neoplasm: Aberrant regulation of the MerTK–PI3K–Akt–PPARγ, Gas6–Axl, NLRP3–ROS–Rac1, and CD47–SIRPα pathways not only perpetuates unresolved inflammation, but also establishes the molecular substrate for persistent NP, chronic neuroinflammation, and tumor progression [38,39,42,43,45,47].