Although the mechanism underlying the loss of DKK-1 in OSCC is unknown, treatment of OSCC CAL27 cells with a methylation inhibitor, 5-aza-2′-deoxycytidine, results in the inhibition of DPAGT1 expression, suggesting epigenetic repression of DKK1 in oral cancer (Sengupta and Kukuruzinska, unpublished). This evidence concerns the gene DKK1 and lip and oral cavity carcinoma.