Objective      To determine the mRNA and protein expression of thrombospondin 1 (THBS1) and its aberrant DNA methylation in  nasopharyngeal carcinoma (NPC)

and then analyze the relationship of its aberrant DNA methylation with clinicopathological features of NPC.       Methods      A total of 51 NPC tissue samples and 18 normal nasopharyngeal (NNP) tissues were collected. The mRNA expression of THBS1 in NPC tissues and NNP tissues was detected by reverse-tran

scription polymerase chain reaction (RT-PCR)

and its protein expression was detected by Western blotting. The DNA methylation of the CpG island promoters of THBS1 in NPC tissues and NNP tissues was detected by the DNA methylation specific polymerase chain reaction.       Results      The mRNA and protein levels of THBS1 were significantly decreased in the NPC tissues than the NNP tissues (

P

0.01). The positive rate of the hypermethylation of THBS1 gene was significantly higher in the NPC tissues than that the NNP tissues (

P

0.01). The decreased expression of THBS1 at mRNA and protein levels was associated with the hypermethylation of its gene promoter (

P

0.01). THBS1 gene hypermethylation status was positively correlated with NPC TNM staging

local invasion

lymphatic metastasis and distant metastasis (each for

P

0.05).       Conclusion      The aberrant hypermethylation of the CpG island promoter of THBS1 gene and their lower expression in NPC tissues may play a crucial role in carcinogenesis and development of NPC.