Nuclear beta-catenin expression was found in 31.2% of EECs and 3% of NEECs (P=0.002), and was significantly associated with beta-catenin gene exon 3 mutations (P<0.0001). beta-catenin gene exon 3 mutations were associated with the endometrioid phenotype, and were detected in 14 (14.9%) EECs, but in none of the NEECs (P=0.02). gamma-catenin nuclear expression was found in 10 ECs; it was not associated with the histological type but was associated with more advanced stages (P=0.042).
These data indicate that stabilization of beta-catenin due to mutations in exon 3 of the beta-catenin gene and other mechanisms may have an important role in development of endometrial carcinomas.
A tissue microarray was constructed from paraffin wax-embedded blocks from 95 endometrial carcinomas (EC), previously studied for microsatellite instability, as well as for alterations in PTEN, k-RAS and beta-catenin.
Several molecular alterations, most commonly PTEN mutations but also K-ras mutations, microsatellite instability, and beta-catenin mutations have been detected in endometrioid endometrial carcinoma (EEC).
The activation of the adenomatous polyposis coli (APC)/beta-catenin/T-cell factor (Tcf) pathway due to beta-catenin gene mutation has been recently implicated in the development of some endometrial carcinomas. beta- and gamma-catenin are structurally and functionally related molecules that participate in cell adhesion and signal transduction.
To evaluate the expression of four genetic markers (PTEN, BCL2, MLH1, and CTNNB1), linked to endometrial carcinogenesis, in endometrial polyps of patients with and without postmenopausal bleeding in order to determine whether symptomatic endometrial polyps have a genetic phenotype similar to that of endometrial cancer.
Only six (46%) of the endometrial carcinomaCTNNB1 mutations occurred at residues directly phosphorylated by GSK-3beta, and only one of these was at either codon 41 or 45.
Compared to controls, CTNNB1 mutation is present at significantly higher rates in recurrent stage I, grade 1 endometrial cancers and is found most commonly in MSS tumors.
Given the clinical utility of identifying endometrial carcinomas with CTNNB1 mutation, the purpose of this study was to determine if immunohistochemistry could act as a surrogate for CTNNB1 gene sequencing.
Thirty-nine CTNNB1 mutated EECs and 40 CTNNB1 wild-type EECs were identified from a cohort of previously sequenced endometrial carcinomas using a targeted next-generation sequencing panel.
Nuclear expression of β-catenin is an accurate immunohistochemical surrogate of CTNNB1 exon 3 mutations and thus might be considered in the risk stratification of endometrial cancer.
Accumulation of mutant beta-catenin could contribute to the development of a subset of endometrial carcinomas, particularly those of the early-onset type.
This is the first report of frequent somatic mutation of the CTNNB1 gene at codons adjacent to those encoding to Ser/Thr residues in endometrial cancer.
Forty-nine ECs (three tumour blocks/case) were selected with alterations in POLE (n=10), CTNNB1 (n=8), p53 (n=10), mismatch repair (n=11), L1CAM (n=10), and ECs without any of these markers (n=9).
Our previous study indicated that nuclear beta-catenin accumulation provides an initial signal for trans-differentiation toward the squamoid phenotype of endometrial carcinoma (Em Ca) cells in a TCF4-dependent manner, which makes this a possible factor for a positive prognosis.
The results suggest that the nuclear localization of beta-catenin observed in endometrial hyperplasia and endometrial cancer, as in other tumors, implies that beta-catenin/Wnt-1 signal transduction is highly activated in carcinogenesis of the endometrium as well as in normal physiological conditions.
Further experiments indicated miR-652 overexpression can activate the Wnt/β-catenin pathway and RORA can downregulate β-catenin and function as a tumor suppressor in endometrial cancer.
The beta-catenin/TCF4/p300 pathway is involved in early signalling for trans-differentiation towards the morular phenotype of endometrial carcinoma cells, but little is known about the upstream regulators.
The three components associated with the Wnt pathway--i.e., adenomatous polyposis coli (APC), beta-catenin, and E-cadherin--were evaluated in a case-control study of 28 patients with stage-I endometrial carcinomas to determine their involvement in the development of recurrent disease.
We studied the expression of phosphorylated mammalian target of rapamycin, PTEN, and β-catenin and their relationship with clinicopathologic features, molecular factors (microsatellite instability, mismatch repair, and BRAF genes) and patients' survival in a series of 260 nonconsecutive endometrial carcinomas.