Objective To investigate the effect of tissue factor pathway inhibitor-2(TFPI-2)on invasiveness and apoptosis of renal cell carcinoma,to analysis the relationship between promoter methylation and expression of TFPI-2.Methods Immunohistochemistry,Western blot and real-time RT-PCR were performed to detect the expression of TFPI-2 in 37 renal cell carcinoma tissues and 11 normal kidney tissues.TUNEL was used tO study the apoptosis status of renal cell carcinoma.Real-time methylation specific PCR was performed to analysis the methylation status of TFPI-2 gene promoter.Results The optical density of Western-blot strip in renal cell carcinoma and normal kidnev was 0.92±0.36,1.6l±0.13.The relative expression of TFPI-2 mRNA in renal cell carcinoma and normal kidney was 0.0019±0.0011,0.0065±0.0008.Compared with normal kidney,lower expression of TFPI-2 was detected in renal cell carcinoma.The correlation between expression of TFPI-2 and stage of renal cell carcinoma was negative.Apoptosis index of renal cell carcinoma specimens was 2.41%(TFPI-2 expression:grade 1),3.90%(TFPI-2 expression:grade 2),6.78%(TFPI-2 expression:grade 3),9.57%(TFPI-2 expression:grade 4).The expression of TFPI-2 was positively correlated with the apoptosis index of renal cell carcinoma.The relative expression of TFPI-2 mRNA in methylated and unmethylated tumors was 0.0015±0.0011,0.0024±0.0009.The optical densitv of Western-blot strip in methylated and unmethylated tumors was 0.82±0.35,1.04±0.34.Expressions of TFPI-2 mRNA and protein were significantly lower in methylated tumors than those in unmethylated tumors.Conclusions The expression of TFPI-2 is negatively correlated with the invasiveness of renal cell carcinoma.Overexpression of TFPI-2 may induce tumor cell apoptosis in renal cell carcinoma.Lower expression of TFPI-2 in renal cell carcinoma is partially due to hypermethylation of gene promoter.