Prognostic significance of E-cadherin protein expression in pathological stage I-III endometrial cancer.

PURPOSE: Decreased expression of E-cadherin in endometrial cancer cells is associated with adverse prognostic features. This study aimed to evaluate the prognostic significance of decreased E-cadherin expression in patients with endometrial cancer. EXPERIMENTAL DESIGN: Between 1992 and 1999, 102 endometrial cancer patients with stage I-III disease underwent primary surgery at the University of Chicago. Representative tissue specimens were immunostained with a monoclonal antibody to E-cadherin. A semiquantitative evaluation scale was developed based on the percentage of endometrial cancer cells with membranous E-cadherin staining. Tissue sections were scored as "3" if >75%, "2" if 25-75%, "1" if 5-25%, and "0" if <5% of cells stained. E-Cadherin staining was correlated with overall survival (OS), cause-specific survival (CSS), progression-free survival (PFS), and extrapelvic progression. Multivariate Cox proportional hazards modeling was used to estimate hazard ratios, controlling for clinicopathological characteristics and adjuvant treatment. Median follow-up for the study group was 58.5 months. RESULTS: E-Cadherin staining was scored as 0, 1, 2, and 3 in 29.4%, 18.6%, 26.5%, 25.5% of cases, respectively. E-Cadherin expression was positively correlated with myometrial invasion (Kendall tau: 0.30, P < 0.01), and negatively correlated with grade (Kendall tau: -0.13, P = 0.15) and papillary serous or clear cell histology (Kendall tau: -0.14, P = 0.12). Five-year actuarial OS, CSS, PFS, and extrapelvic recurrence rates for negative (score = 0), heterogeneous (score = 1-2), and positive (score = 3) staining were as follows: OS, 69.2 versus 75.7 versus 81.0% (P = 0.64); CSS, 78.8 versus 91.2 versus 95.5% (P = 0.19); PFS, 69.1 versus 88.6 versus 92.2% (P = 0.079), and extrapelvic progression, 20.8 versus 7.3 versus 4.0% (P = 0.17). On multivariate Cox regression, a higher E-cadherin expression score was associated with decreased overall mortality hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.34-1.03; P = 0.066), and statistically significant decreases in endometrial cancer mortality (HR, 0.23; 95% CI, 0.055-0.94; P = 0.040), disease progression (HR, 0.28; 95% CI, 0.10-0.77; P = 0.014), and extrapelvic recurrence (HR, 0.24; 95% CI, 0.062-0.97; P = 0.045). CONCLUSIONS: Decreased E-cadherin expression is an independent prognostic factor for disease progression and mortality in pathological stage I-III endometrial cancer. Evaluation of E-cadherin expression may aid in the selection of patients for more aggressive adjuvant therapy.