In order to clone a novel putative NPC associated gene on the smallest common deletion region of 7q32-ter.BAC clone was screened by PCR using STS D7S509 probe.The up-regulated expression of 3′ end expressed sequence tags(ESTs) localized within this smallest common deletion region were screened in NPC cell line HNE1 and NPC biopsies using EST-mediated positional candidate clone and bioinformatics.The full-length cDNA of candidated EST was cloned through cDNA clone sequencing and bioinformatics.Southern blot and methylation analysis were used to study the machanism of up-regulated expression of NAG18 in NPC. The results showed that the full-length cDNA of NAG18 is 802bp,its encoding protein is 227 amino acids. It is highly homologous to human and mouse TAXREB107 and RPL6.Loss of gene copies and aberrant methylation are not the machanism of its up-regulated expression. It can be concluded that the gene NAG18 located in this region may be a putative NPC associated gene. It is a highly conserved gene. It may participate in Tax-mediated tran-activation of transcription.