YKL-40 Protein Levels and Clinical Outcome of Human Endometrial Cancer

The secreted glycoprotein YKL-40 is a member of the chitinase family and elevated serum YKL-40 levels have been reported to be associated with reduced survival in several malignancies, including endometrial cancer. This study investigated immunoreactivity to YKL-40 protein and its prognostic implications in endometrial cancer. Levels of YKL-40 protein in normal endometrium (n = 42), endometrial hyperplasia (n = 40) and endometrial adenocarcinoma (n = 68) were examined using immunohistochemistry. YKL-40 immunoreactivity was significantly higher in endometrial adenocarcinoma compared with hyperplastic and normal endometrium. In addition, high immunoreactivity of YKL-40 protein was associated with advanced stage, high histological grade, lymph node metastasis and lymphovascular invasion. Moreover, positive immunoreactivity for YKL-40 was a significant predictor of poor prognosis, as measured by estimated progression-free survival and estimated overall survival, compared with negative immunoreactivity. In conclusion, high YKL-40 immunoreactivity in endometrial cancer may be associated with poor prognosis.