Background: Endometrial carcinomas (EC) differ in etiology, clinical course and prognosis.
Objectives: This multi-center study aimed at a closer recognition of molecular factors linked to heterogeneity of EC by evaluating estrogen and progesterone receptors, proteins dependent on MMR genes, proteins linked to poor prognosis and metastases, and mutations in BRCA1.
Material and methods: Using sections of paraffin-embedded preparations, in 115 patients with EC type I and 31 with EC type II, expression of ERα, ERβ1, PR, MLH1, and MSH2 proteins, as well as ARID1A, c-MET and BRCA1, was estimated by immunohistochemistry using specific antibodies.
Results: Expression of ERβ1 was augmented in EC type II, in poorly differentiated cancers and with growing clinical advancement. An augmented expression of ERα was noted in well-differentiated EC and at lower clinical stage. An increased expression of PR and decreased of MLH1 were detected in type I EC. The expression of ARID1A and c-MET proteins showed no differences between the types of EC, stages of clinical advancement or grading. In 51.6% patients with type II EC, a loss of BRCA1 expression was disclosed; in this group of cancers a decreased expression of ERα was noted.
Conclusions: An augmented expression of ERβ1 was linked to type II EC. A higher expression of ERα in EC cancers was associated with a lower histopathological grade. A decreased expression of MLH1 protein was estimated in EC type I. Type II EC may be connected to BRCA1 mutation.
Keywords: ARID1A; BRCA1; MMR; endometrial cancer; estrogen receptors.