Breast cancer is the most common cancer in women around the world, and novel prognosis strategies is needed to control more accurate and effective of this malignant disease. Among the latest prognostic markers is E-cadherin, which mediates cell-cell adhesion by associating with catenins. Loss of E-cadherin gene (CDH1) function by genetic or epigenetic alteration leads to tumorigenesis. The aim of our study was to investigate E-cadherin gene promoter methylation in breast cancer, and its correlation with E-cadherin protein expression. Fifty primary breast cancers tissue with ductal type and 50 normal breast sample from the same patients that was located adjacent to tumor region as controls were provided by Imam Reza-based referral and teaching hospital affiliated to Tabriz University of Medical Sciences, Tabriz, Iran. CDH1 promoter region CpG sites methylation and E-cadherin protein expression were determined by bisulfite-specific polymerase chain reaction and Western blot analysis, and the resulting products were sequenced on an ABI automated sequencer for firm conclusion. CDH1 hypermethylation in breast tumor specimen (ductal type) was observed in 94 % (47 of 50) comparing with normal samples methylation, and the significant difference was (p = 0.000). Protein expression in tumor samples tends to diminish with the CDH1 promoter region methylation. In the group of 50 ductal carcinomas cases, most of the cases showing CDH1 hypermethylation correlated inversely with the reduced levels of expression of E-cadherin proteins (95 % of full-methylated tumor samples had no protein expression, and 4.5 % of them had weak expression levels). Possible association was observed between CDH1 methylation and its protein expression (p = 0.000). The results of methylation analysis in promoter region in ten CpG sites (863, 865, 873, 879, 887, 892, 901, 918, 920, and 940) suggested that abnormal CDH1 methylation occurs in high frequencies in ductal breast tumors probably sounds the process of carcinogenesis progression.
Detection of micrometastasis in sentinel lymph nodes (SLNs) is a very useful tool for appropriate assessment of the clinical stage of disease in breast cancer patients. Early identification of clinically relevant disease could lead to early treatment or staging approaches for breast cancer patient. Micrometastases in SLNs of women with invasive breast cancer are of great significance in this context. In this study we examined SLN biopsies considered to have small numbers of cancerous cells by real time RT-PCR. All of the samples underwent immunohistochemical staining for cytokeratin for confirmation of the presence or absence of micrometastases. BUB1b expression assay of selected patients with and without metastasis showed overexpression in the former, but not in normal breast and lymph node tissue. Our results may be taken into account in the discussion about the merits of routine use of molecular assessment in pathogenetic studies of SLNs.
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