Background: Endometrial cancer (EC) is the second most common female genital tract malignancy and has adverse outcome in the advanced stage. A prognostic marker is needed for marking an accurate prognostic.

Objective: To evaluate expression and clinical outcome of CTNNB1 (β-catenin) and FAT atypical cadherin 1 (FAT1), by using immunohistochemical staining in EC type I.

Materials and Methods: Seventy-two EC type I cases were selected from Songklanagarind Hospital with clinical data collection. All cases were evaluated by immunohistochemistry using antibodies against β-catenin and FAT1.

Results: All cases of EC type I were β-catenin positive and FAT1 negative. Moderate and strong intensity (2+ and 3+) β-catenin cytoplasmic staining showed statistically significant association with low grade EC, and low risk of recurrence disease or metastasis (p<0.05). β-catenin nuclear staining was present in 19 of 28 cases (68%) of EC grade 1 and associated with low grade EC. β-catenin and FAT1 expression were not associated with 5-year overall survival in both univariate and multivariate analyses.

Conclusion: β-catenin cytoplasmic staining may be associated with low grade EC, and helpful to predict recurrent risk. However, FAT1 and β-catenin expressions have no statically significant correlation with 5-year overall survival and cannot be used to determine the prognosis in type I EC patients.

Keywords: β-catenin, FAT1, Immunohistochemistry, Metastasis, Recurrence, Survival outcome, Type I endometrial cancer

DOI: doi.org/10.35755/jmedassocthai.2021.05.12037

Received 21 September 2020 | Revised 16 February 2021 | Accepted 22 February 2021