Evaluation of immunohistochemistry

was independently carried out by two investigators (K.S. and Selleckchem Alvelestat I.S.) who were unaware of the clinical data or disease outcome. In cases in which the results of immunohistochemical expression differed between the two observers, slides were evaluated by a third observer (S.N.). For Twist, cytoplasmic immunoreactivity was scored by its extent and intensity. Staining intensity was graded as follows: negative (0), weak (1), moderate (2) and strong (3). Staining extent was rated according to the percentage of positive cells. Samples with no stained tumor cells were rated as 0, those with < 25% of stained tumor cells were rated as 1, those with 25-50% of stained tumor cells were rated as 2, those with 50-75% of stained tumor cells were rated as 3 and those with > 75% of stained tumor cells were rated as 4. The results of staining intensity and extent

gave an overall staining score. An overall staining PF-02341066 in vivo score of 0-5 and 6-7 were regarded as low and high Twist expression, respectively. For E-cadherin, cancer cells were divided into two groups: preserved expression, which indicates cells with the same level of expression as that of normal epithelium distant enough from tumor, and reduced expression, which indicates cells with weak or absent expression compared with normal epithelium (Fig. 1) [7]. To evaluate expression of Twist and E-cadherin, ten fields (within the tumor and at the invasive front) were selected and expression in 1000 tumor cells (100 cells/field) was evaluated using high-power (×200) microscopy. Figure 1 Expression of Twist and E-cadherin proteins in ESCCs.

(A) High expression of Twist. (B) Weak expression of Twist. (C) Negative expression of Twist. (D) Preserved expression of E-cadherin is detected in the cancer adjacent normal tissue. (E) Preserved expression of E-cadherin. (F) Reduced expression of E-cadherin (Original magnification, ×400). Statistical analysis Statistical analysis of group differences this website was done using the X2 and Wilcoxon tests. The Kaplan-Meier method was used for survival analysis and differences in survival were estimated using the log-rank test. Prognostic factors were examined by univariate and multivariate analyses (Cox proportional hazards regression model). P < 0.05 was considered to be statistically significant. All statistical analyses were done with the software package JMP 5 for Windows (SAS Institute, Inc., Cary, NC). Results Expressions of Twist and E-cadherin in esophageal squamous cell carcinoma Twist expression was observed in the cytoplasm of cancer cells in 42.0% of all patients (70 of 166; Fig. 1A). E-cadherin expression was observed on the cell membrane of cancer cells, indicating preserved expression, in 40.4% of all patients (67 of 166; Fig. 1B).