TSPO and oral cavity squamous cell carcinoma: Abbreviation: CS, cigarette smoke; CSE, cigarette smoke extract; CSC, cigarette smoke condensate; NOD1, nucleotide-binding oligomerization-domain 1; miRNA, micro-RNA; MMP, matrix metalloproteinase (MMP); TSPO, translocator protein 18kDa; RIP2, receptor-interacting protein 2; NF-κB, nuclear factor κB; MZF1, myeloid zinc finger 1; VFGF, vascular endothelial growth factor (VEGF); BiP, binding immunoglobulin protein; miR-30a, miRNA-30a (miR-30a); OSCC, oral squamous cell carcinoma; RAGE, receptor for advanced glycation end-products