DPAGT1 and lip and oral cavity carcinoma: 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inhibition of DPAGT1 expression, suggesting epigenetic repression of DKK1 in oral cancer (Sengupta and Kukuruzinska, unpublished).