MAPK10 and ossification of the posterior longitudinal ligament of the spine: The Toll-like receptor signaling pathway had the most significant changes in OPLL, with upregulations of some key members in Toll-like pathway such as Toll-like receptor 1 (TLR 1), TLR5, TLR7, and mitogen-activated protein kinases 10 (MAPK10) and phosphoinositide-3-kinase (PI3K), regulatory subunit 1 (PIK3R1), suggesting the crucial roles of PI3K in the development of OPLL [68].