15P Loss of vimentin expression in preoperative biopsies independently predicts lymph node metastasis in endometrial cancer

Precise preoperative risk classification of endometrial cancer is crucial to guide selection of treatment. Still, 15-20% of tumors classified as low-risk recur. Loss of expression of vimentin was recently identified as a marker of recurrence in patients with low stage disease. We aimed to investigate if vimentin expression in preoperative biopsies could predict poor prognosis and lymph-node metastasis in a large, prospectively collected multicentre endometrial cancer cohort. Preoperative biopsies were collected from 1483 patients diagnosed and treated for endometrial cancer in 10 hospitals in Norway, Sweden, Belgium and Polen. Vimentin expression was investigated by immunohistochemistry and evaluated using the staining index method. Expression levels were analysed for association with clinical characteristics, and in uni- and multivariate analyses to predict disease-specific survival (DSS) and lymph node metastases. Loss of vimentin expression was significantly associated with histopathological parameters of aggressive disease and poor disease-specific survival. Vimentin expression had independent prognostic value in multivariate survival analysis, both when including all patients (hazard ratio (HR) 1.82, 95% CI 1.31-2.55, P<.001), in the subgroup of endometrioid patients (HR 3.59, 95% CI 2.19-5.88, P<.001) and for patients with FIGO stage 1 disease (HR 3.24, 95% CI 2.04-5.75, P<.001). Lymph node metastases were more frequent in patients with loss of vimentin expression compared to patients with positive vimentin expression (26% vs 13%, P<.001), and loss of vimentin expression independently predicted lymph node metastases (HR 1.91, 95% CI 1.10-3.34, P=0.021). Loss of vimentin expression in preoperative endometrial cancer biopsies independently predicts poor disease-specific survival and lymph node metastases and may aid in identifying high-risk patients otherwise classified as low risk.