Studies found that thymoquinone suppresses the level of VEGFR2; while ar-turmerone down-regulates VEGFR3.65,66 Curcumin down-regulates the transcriptional activity of HIF-1α under hypoxia, resulting in the suppression of VEGF level.67 Tetrahydrocurcumin decreases VEGF level in osteosarcoma cells and down-regulates HIF-1α, resulting in mesenchymal-epithelial transition/MET.68 This evidence concerns the gene HIF1A and osteosarcoma.