To confirm that methylation of the TFPI-2 gene is directly responsible for the loss of TFPI-2 transcription, the TFPI-2-silenced NPC cell lines (CNE1, CNE2 and C666-1) were treated with the demethylating agent 5-aza-dC for 4 days. This evidence concerns the gene TFPI2 and nasopharyngeal carcinoma.