Introduction. Recent research has demonstrated that the immunohistochemical nuclear β-catenin expression is a valid surrogate for CTNNB1 exon 3 mutation in endometrial carcinomas (ECs). This mutation is an independent prognostic factor which identifies a subgroup of low-grade endometrial carcinomas that have a tendency for recurrence and worse prognosis.
The objective of the study was to evaluate nuclear β-catenin expression in different molecular subgroups of ECs.
Material and methods. We tested immunohistochemical nuclear β-catenin expression in 50 cases of endometrial carcinomas diagnosed in two clinical institutions. Statistical analysis was performed between β-catenin expression and various clinical, demographic, pathological and immunohistochemical parameters (age, myometrial invasion, FIGO grade, histopathological subtype, hormone receptors – ER, PR etc). Additionally, we analysed what molecular subgroup of ECs (MSS, MSI, p53wt, p53abn) revealed the most frequent cases with β-catenin expression.
Results. Our study indicated that ECs with nuclear β-catenin positivity were observed in cases with higher FIGO grade (p=0.02), in endometrioid carcinomas (p=0.04) and in cases with lympho-vascular invasion (p=0.05). ER and PR were frequently expressed in the positive β-catenin subgroup (p=0.03, p=0.02). Our results show that ECs which express nuclear β-catenin correlate with parameters that are already considered unfavourable.
Conclusions. Immunohistochemical β-catenin nuclear expression is an excellent replacement for the CTNNB1 exon 3 mutation in ECs and helps to stratify and predict prognosis in certain cases of ECs. We believe that future research will include this marker as part of the routine immunohistochemical panel for ECs.
Keywords: endometrial carcinoma, β-catenin, prognosis.
Department of Pathology, CESITO Centre, “Sf. Maria” Clinical Hospital, Bucharest, Romania
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