Abstract:

Objective
To observe the relationship between the expression of E-cadherin (E-cad) protein in breast cancer tissue and the clinical characteristics, pathological features and the methylation of E-cad gene promoter of invasive breast cancer,and to investigate the feasibility and clinical significance of E-cad protein as an indictor for early diagnosis and prognosis evaluation of breast cancer. Methods The samples from 62 cases of breast cancer tissue and 20 cases of breast hyperplasia tissue were collected.The expressions of E-cad protein in samples were detected with immunohistochemical assay and the  methylation of E-cad gene promoter was detected with methylation-specific polymerase chain reaction (MSP).Results The expression of E-cad protein  was mainly in membrane.The positive expression  rate of E-cad protein in cancer tissue was lower than that in hyperplasia tissue (51.6%   vs  80.0%,P<0.05).The incidence of methylation of E-cad gene promoter in cancer tissue was higher than that in the  breast hyperplasia tissue (62.9%   vs 35.0%,P<0.05).The expression level of E-cad protein was correlated with TNM stage,histological differentiation degree  and lymph node metastasis (P<0.05).There was no correlation between the patient’s age,tumor size,lesion location and the expressions of estrogen receptor(ER),progesterone receptor(PR),and epidermal growth factor receptor(Her-2) (P>0.05).The methylation rate of E-cad gene promoter in E-cad protein negative expression tissue was higher than that in E-cad protein positive expression tissue(P<0.05).Conclusion The decrease of E-cad protein expression caused by  E-cad gene promoter methylation is involved in the occurrence and development of breast cancer.E-cad may be one of the predictors for early diagnosis and prognosis evaluation of breast cancer.

Key words: breast neoplasms, E-cadherin, methylation, prognosis, promoter