CDO1 Gene Methylation as a Biomarker for Disease Severity and Outcome of Endometrioid Adenocarcinoma

The purpose of the study was to evaluate the levels of CDO1 promoter methylation between normal endometrium, atypical hyperplasia, and endometrioid adenocarcinoma. The relationship between the levels of CDO1 promoter methylation and the clinico-pathologic parameters of patients was also discussed. We aimed to investigate whether CDO1 gene methylation takes part in carcinogenesis and can be a biomarker for disease severity and outcome of endometrioid adenocarcinoma. Specimens of endometrial tissues include 6 normal endometrium, 4 atypical hyperplasia and 147 endometrioid adenocarcinoma. The CDO1 expressions and promoter methylation levels were determined by methylation-specific PCR, semi-quantitative RT-PCR, quantitative real-time PCR, and mass array. The clinico-pathologic parameters of these patients were also analyzed. Scoring was used to evaluate the correlations between 10 CpG sites of CDO1 promoter and clinico-pathologic parameters. The sums of score were higher in endometrioid adenocarcinoma tissue than those of normal endometrium. Patients with menopause, advanced stages, depth of myometrial invasion >1/2, or recurrence had significantly higher scores compared to those without menopause, early stages, depth of myometrial invasion ≦1/2, or no recurrence. In addition, by using multi-variate analysis, patients with high scores of CDO1 methylation had significantly shorter progression free survival (PFS). In conclusion, CDO1 can be a potential prognostic biomarker for predicting the outcomes of the patient with endometrioid adenocarcinoma.