ObjectiveTo investigate the relationship of lymphotoxin β receptor (LTβR) and classical nuclear factor-κB (NF-κB) activation pathway in the pathogenesis and progress of cystitis and bladder cancer.MethodsThe LTβR and P65 mRNA expression were detected by Real-time quantitative PCR in 108 cases of fresh bladder tissue specimens (75 cases of bladder cancer,10 cases of inflammation and 23 normal bladder mucosa cases grouped by the tissue classification ),and protein expression were analyzed by immunohistochemistry assay in 118 cases of paraffin-embedded biopsy specimens (73 cases of bladder cancer,30 cases of cysitis and 15 normal bladder mucosa cases).The correlation analysis between the expressions of LTβR and P65 with clinical pathological data was then performed.Differences between LTβR and P65 mRNA and protein expression level were compared in different groups of bladder tissues using Kruskal-Wallis H test and the Chi-square test.Results( 1 )The mRNA expressions of LTβR and NF-κB/P65were higher in bladder cancer than those in normal group ( LTβR:29.4 ( 14.2 - 46.7 ) × 10 - 3/1.2 ( 0.3 -7.0) ×10-3,Z=-5.508; P65:9.7 (2.7 -21.1) ×10-3/1.0(0.8 ～1.8) ×10-3,Z=-5.030,P＜0.05 ).There were significantly differences between bladder cancer with different histological grades ( LTβR:18.2(2.1-31.3) × 10-3/ 28.4(16.6-36.2) × 10-3/47.9(34.3 -70.5) ×10-3,x2K-W=20.378;P65:4.9(1.3 - 12.0) × 10-3/7.4(3.0-21.9) × 10-3/17.0(10.0 ～28.3)× 10-3 ,x2K-W2 =15.219,P all ＜0.05) and lymph node metastasis (LTβR:27.2(9.7-40.1) ×10-3/39.4(26.7 -52.6) ×10-3,Z=-2.552; P65:7.4(2.3-15.6) ×10-3/13.4(6.7-23.3) ×10-3,Z=-2.026,P＜0.05).(2)The positive rates of LTβR and phosphorylated P65 ( p-P65 ) protein in cancer were higber than those of normal group (LTβR:69.8％/13.3％,x2 =16.600 ; p-P65:56.2％/6.7％,x2 =12.220,P ＜ 0.05 ).Upregulation of LTβR and p-P65 were associated with the histological grade (LTβR:56.3％/70.0％/90.4％,x2 =7.055; p-P65:40.6％ /60.0％/76.2％,x2 =6.679,P ＜0.05) and with lymph node metastasis (LTβR:58.3％/92.0％,x2 =8.849; p-P65:52.1％/64.0％,x2 =5.088,P ＜0.05).(3)There was a positive correlation between LTβR and P65 expression ( mRNA:r =0.654,P ＜ 0.05,protein:r =0.399,P ＜ 0.05 )in the bladder cancer and cystitis (r =0.521,P＜0.05).ConclusionsThe activation of LTβR and P65 was associated with progression and metastasis of bladder cancer.The activation of classical NF-κB pathway by LTβR may be achieved by P65.