VDR and oral cavity squamous cell carcinoma: In vitro studies on oral squamous cell carcinoma have found the calcitriol analogue eldecalcitol (ED-71) to inhibit the mitogenic effects of fibroblast growth factor (FGF1/2) by inhibiting NF-ĸB and inducing exosomal miR6887-5p, which down-regulates the mRNA 3′UTR of heparin-binding protein 17/FGF-1 (HBp17/FGFBP-1) via vitamin D3 receptor (VDR) in tumour cells [198,199].