E-cadherin loss rather than beta-catenin alterations is a common feature of poorly differentiated thyroid carcinomas.
OBJECTIVE
To investigate the immunohistochemical and molecular genetic features of the cadherins/catenins complex in thyroid carcinoma based on the hypothesis that poorly differentiated carcinoma of the thyroid represents an intermediate step between well-differentiated and undifferentiated carcinomas.


RESULTS
Immunohistochemistry for E-, P- and N-cadherins and alpha-, beta- and gamma-catenins was performed in a series of 17 cases of poorly differentiated carcinoma of the thyroid. All cases showed absence of membranous expression of E-cadherin with no aberrant expression of P- or N-cadherins; regarding catenins there was heterogeneous loss of expression with membranous immunolocalization of the three catenins in most cases. Molecular analysis of the E-cadherin gene and exon 3 of the beta-catenin gene was also performed by polymerase chain reaction/single-strand conformation polymorphism and sequencing. No mutations in either gene were detected in any case.


CONCLUSIONS
In contrast to previous reports, our results suggest that loss of E-cadherin rather than beta-catenin mutation is the crucial event in determining the differentiation 'level' of thyroid carcinomas.
Rocha
A S
AS
IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Portugal.
Soares
P
P
Fonseca
E
E
Cameselle-Teijeiro
J
J
Oliveira
M C
MC
Sobrinho-Simões
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D042282:Microdissection; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin
D014408:Biomarkers, Tumor; C495270:CTNNB1 protein, human; D015820:Cadherins; D003598:Cytoskeletal Proteins; D004273:DNA, Neoplasm; D015534:Trans-Activators; D051176:beta Catenin