Elevated PLXDC2 expression in radioresistant HNSCC cells is mediated by c-Met-ERK1/2 activation, which phosphorylates the downstream effector ELK1, promoting it to translocate into the nucleus and bind to the PLXDC2 gene promoter to initiate the gene transcription. This evidence concerns the gene PLXDC2 and head and neck squamous cell carcinoma.