Expression of beta-catenin, E-cadherin and APC in canine mammary tumors.
BACKGROUND
Mammary tumors are a very common neoplasm in the dog and show histological features and biological behaviour similar to human mammary carcinomas. Recently, a pathway named Wnt-1, involving beta-catenin and APC protein, has emerged as an important player in many human tumor types, including mammary neoplasms.


METHODS
Thirty-five samples of canine mammary tumors (10 benign and 25 malignant) were studied in order to evaluate the co-expression of beta-catenin, APC protein and E cadherin with confocal laser microscopical observation, by western blot analysis and by correlating data obtained with the histological grade of tumours.


RESULTS
A progressive decrease of E-cadherin together with disruption of beta-catenin expression was observed in less differentiated malignant tumors. In addition, a loss of beta-catenin membranous distribution and a cytoplasmic accumulation was often coexpressed with disrupted expression of APC protein. Western blot analysis showed a progressive increase of beta-catenin in malignant tumors, which could be the expression of disrupted /-catenin catabolism leading to cytoplasmic accumulation. In some less differentiated malignant tumors, a marked beta-catenin decrease was also observed. This feature could be linked to mutations in beta-catenin gene coding for a truncated and lighter protein.


CONCLUSIONS
These results may indicate the multifunctional role played by beta-catenin in canine mammary oncogenesis.
Restucci
Brunella
B
Departments of Pathology and Animal Health, Faculty of Veterinary Medicine, University Federico II, Naples, Italy.
Maiolino
Paola
P
Martano
Manuela
M
Esposito
Giuseppe
G
De Filippis
Daniele
D
Borzacchiello
Giuseppe
G
Lo Muzio
Lorenzo
L
D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D025601:Adenomatous Polyposis Coli Protein / Q000096:biosynthesis*; D000818:Animals; D015153:Blotting, Western; D015820:Cadherins / Q000096:biosynthesis*; D004283:Dog Diseases / Q000378:metabolism* / Q000473:pathology; D004285:Dogs; D005455:Fluorescent Antibody Technique; D015674:Mammary Neoplasms, Animal / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D051176:beta Catenin / Q000096:biosynthesis*
D025601:Adenomatous Polyposis Coli Protein; D015820:Cadherins; D051176:beta Catenin