Yu et al. Journal of Experimental & Clinical Cancer Research 2010, 29:119 http://www.jeccr.com/content/29/1/119 Table 4 Relationship between the expression of Slug, Twist, Snail and E-cadherin and clinicopathological parameters in human bladder cancer Sex Stage Grade Variables Male Female Age (years) ≤ 70 > 70 pTa, pT1 ≥PT2 LG HG Nodal involvement yes no Recurrence(n = 76) yes no Progression A(n = 76) yes no Progression B(n = 44) yes no Death C(n = 44) yes no Patients n 18 102 87 33 64 56 76 44 41 79 23 53 8 68 15 29 17 27 + 56 19 43 32 51 24 30 45 16 59 15 30 3 46 9 16 Slug - 31 14 21 24 25 20 11 34 2 43 8 23 5 22 8 11 p 0.493 0.257 0.171 0.082 0.012 0.483 0.124 0.760 + 37 16 30 23 19 34 8 45 10 43 12 20 6 21 11 15 Twist - 50 17 34 33 57 10 33 34 8 59 11 33 2 47 6 12 p 0.557 0.523 0.000 0.000 0.291 0.242 0.021 0.754 + 13 6 10 9 12 7 7 12 13 6 5 12 3 27 5 10 Snail - 74 27 54 47 64 37 34 67 5 96 18 41 5 41 12 17 p 0.664 0.947 0.986 0.789 0.931 1.000 0.748 0.000 + 65 24 47 42 56 33 25 64 17 72 16 39 7 55 13 17 Page 6 of 9 E-cadherin - p 0.824 22 9 17 14 20 11 16 15 1 30 7 14 1 13 4 10 0.845 0.874 0.017 0.040 0.719 1.000 0.509 0.000, respectively (Table 6). In multivariate OS analysis, only Slug and E-cadherin expression was an indepen- dently significant prognostic factor (OR, 0.409;95% CI, 0.017-0.140; P = 0.000; OR, 3.435;95% CI, 1.421-8.305, P = 0.005) (Table 6). Discussion Recent studies have shown the role of Snail and Slug as strong repressors of E-cadherin gene expression in var- ious cancer cell lines, including esophageal adenocarci- noma, lung, breast, endometrioid adenocarcinomas hepatoma HepG2 and human extrahepatic hilar cholan- giocarcinoma, thus inducing tumor malignancy[23-28]. In addition, Twist is up-regulated in several types of epithelial cancers, including esophageal adenocarcinoma, malignant parathyroid neoplasia, hepatocellular carci- noma [29-31]. In our study, we have shown that the expression of Snail and Slug was significantly increased in human BT tissue than that of in background tissue. Moreover, the patients with strong E-cadherin expression showed no or less staining of Slug and Snail. A correlation between expression levels of Slug and E-cadherin was obvious in these human specimens(P = 0.013). which confirmed a previous study [32]. However, expression of Snail in BT showed no significant relation to the expression of E- cadherin. We have also shown that more patients with high Twist (46/53)expression displayed low E-cadherin expression (7/67), and high E-cadherin expression(43/ 67) displayed low Twist expression(24/53) in human BT tissue. There was an inverse relationship between Twist overexpression and loss of E-cadherin expression (P = 0.005), which confirmed a previous study [33,34]. We further studied the expression of Snail, Slug, Twist, E- cadherin in well established human BT cell lines. At the mRNA and protein level, BT cells with a high Slug and Twist expression had no or only weak E-cadherin expression, whereas no expression of Snail in BT cells was seen. Snail did not repress E-cadherin, neither at the RNA nor at the protein level. Comparing the expression levels of Twist, Slug and E-cadherin, there is evident that Slug and Twist is the strong repressor of E-