PTEN AND E-CADHERIN EXPRESSION ARE ASSOCIATED IN CANINE MAMMARY TUMORS

lntroduction: PTEN is a tumor suppressor protein that negatively regulates tumor growth and invasiveness. Ecadherin is a trans-membrane molecule known far its tumor invasion-suppressor role. In human medicine, it has been hypnotized that the expression of these two proteins is correlated. The aim of this study is to evaluate by immunohistochemistry if their expression is associated al so in canine mammary tumors. Materials and Methods: Fifty-four canine mammary samples {15 hyperplasias, 7 adenomas and 32 carcinomas) were submitted to immunohistochemistry far the evaluation of PTEN and E-cadherin expression. Subjects bearing mammary carcinoma were also submitted to a 2-year follow-up study to compare overall survival with PTEN and E-cadherin expression. Results: All the hyperplasias expressed both the markers, 100% of adenomas were positive far PTEN and 86% far E-cadherin, and 69% and 34% of carcinomas were positive far PTEN and E-cadherin, respectively. PTEN and E-cadherin expression was statistically correlated in ali the tumors (p <.01) and in the malignant ones (< .05). The group positively-stained far the two markers correlated with a longer overall survival (< .05) and with the absence of lymphatics invasion (<.05).Conclusions: Our results confirm the correlation between PTEN protein and E-cadherin expression and the tu m or suppressor effect of this association in canine mammary tumors.