TFPI2 and nasopharyngeal carcinoma: To detect the methylation status of individual CpG sites in the NPC samples relative to the normal control biopsies, the detailed methylation status of the TFPI-2 promoter region - 178 to + 166 bp relative to the translation start site of the TFPI-2 gene was determined by bisulphite genomic sequencing in 2 NPC cell lines (CNE2 and C666-1), 2 NPC biopsies (NPC24 and NPC34) and 1 NNE sample (NNE7).