An effect on metastatic potential was revealed in only one study, which found that the vitamin D analogue MART-10 inhibited head and neck squamous cell carcinoma (HNSCC) cell migration and invasion into other tissues and reduced epithelial–mesenchymal transition by inhibiting Snail, Twist, and MMP-9 expression [18]. This evidence concerns the gene SNAI1 and head and neck squamous cell carcinoma.