Expressions of PTEN and E-cadherin in breast cancer tissues and their clinical significance

Abstract

Objective To investigate the expressions of phosphatase and tensin homologue deleted on chromosome ten (PTEN) and epithelial cadherin (E-cadherin) in breast cancer tissues and explore their clinical significance. Methods We retrospectively analyzed the clinical data of 263 breast cancer patients admitted to the First Affiliated Hospital of Harbin Medical University from November 2012 to December 2014. The expressions of PTEN and E-cadherin were detected by immunohistochemistry. The relationship of protein expression with clinicopathological characteristics was analyzed by χ2 test or Fisher exact test. Contingency correlation analysis was used to analyze the correlation between PTEN and E-cadherin, and Kaplan-Meier was used to evaluate the relationship between their expressions and patients′ survival. COX regression model was used to analyze risk factors. Results The positive expression rates of PTEN and E-cadherin in breast cancer tissues were 68.4% (180/263) and 95.4% (251/263) respectively, lower than those in para-tumor breast tissues 77.9% (205/263) and 98.5% (259/263), with statistically significant differences (χ2=6.056, P=0.014; χ2=4.125, P=0.042). PTEN expression was associated with lymph node metastasis (χ2=8.443, P=0.015) and clinical stage (χ2=9.253, P=0.010). E-cadherin expression was not correlated with age, menopausal status, tumor maximum diameter, lymph node metastasis and clinical stage (all P>0.05). Contingency correlation analysis showed a positive correlation between PTEN and E-cadherin expressions in breast cancer tissues (C=0.125, P=0.041). Survival analysis showed that the 5-year tumor-free survival rate was 81.9% in the PTEN negative group, lower than 95.0% in the positive group (χ2=12.040, P=0.001). The 5-year tumor-free survival rate in the E-cadherin negative group was 66.7%, lower than 92.0% in the positive group (χ2=13.313, P<0.001). COX multivariate analysis showed that negative expressions of PTEN and E-cadherin and lymph node metastasis were independent risk factors for the prognosis of breast cancer patients (HR=2.554, 95%CI: 1.016-6.420, P=0.046; HR=3.573, 95%CI: 1.136-11.239, P=0.029; HR=3.622, 95%CI: 2.026-6.476, P<0.001). Conclusion PTEN is related to E-cadherin expression and low expressions of both may be one of the mechanisms of breast cancer development, invasion and metastasis. Combined detection can be used as an indicator to determine the prognosis of breast cancer. Key words: Breast neoplasms; PTEN phosphohydrolase; Cadherins; Prognosis