Objective To apply immunohistochemistry to detect the expressions levels and clinical significance of tumor suppressor genes PTEN and P27 in endometrial carcinoma and precancerous lesions. Methods 35 cases of cancer tissue wax were collected from June 2015 to January 2020 in the First Affiliated Hospital of Chengdu Medical College. Meanwhile, 39 cases of endometrial hyperplasia (without atypical), 26 cases of atypical hyperplasia and 35 normal endometrial wax blocks were selected. They were divided into normal endometrium group, endometrial hyperplasia group, endometrial atypical hyperplasia group and EC group. The expression of PTEN and p27 in each group was detected by immunohistochemistry. The relationship between EC and the histopathological classification, clinical stage, depth of myometrial invasion, lymph node metastasis and histopathological type were analyzed. The correlation between PTEN and p27 protein expression in endometrial atypical hyperplasia and EC was analyzed. ResultsThe positive expression rates of PTEN and P27 in normal endometrium, endometrial hyperplasia, endometrial atypical hyperplasia and EC tissues gradually decreased (P＜0.05). The expressions of PTEN and P27 decreased significantly with the increase of EC pathological grade (P＜0.05). The positive rates of PTEN and P27 in endometrial carcinoma tissues were significantly lower than those in nonendometrium carcinoma tissues (P＜0.05). The expressions of PTEN and P27 had nothing to do with EC pathological stage, basal invasion depth and lymph node metastasis (P＞0.05). There was a positive correlation between and PTEN protein expression and P27 protein expression in endometrial atypical hyperplasia and EC tissues (r=0.402, 0.712,P＜0.05).Conclusion Loss of expressions of tumor suppressor genes PTENand P27is an early event of endometrial carcinoma. The detection of PTEN and P27 genes by immunohistochemistry is helpful to distinguish EC and precancerous lesions, and has a certain role in assessing the canceration degree of EC.