Background: miR-200b has been reported to be a tumor suppressor and a promising therapeutic target in cancer.
miR-200b has been associated with epithelial- mesenchymal transition (EMT) and chemo-resistance in cancer.
Aim of work: To determine the expression of miR-200b in breast cancer, invasive duct carcinoma (IDC) tissues in
comparison to normal adjacent breast tissues. Also, the prognostic role of miR-200b expression in breast cancer
patients was evaluated.
Material and Methods: Quantitative real time polymerase chain reaction (qRT-PCR) was used to detect the
expression level of miR-200 b in 48 tumor tissues and 14 adjacent normal tissues from breast cancer patients with
IDC.
Results: The expression of miR-200b in breast cancer tissues was significantly lower than in normal tissues
(p < 0.005). In comparison with the normal tissues, miR-200b was down regulated in 75% (36 /48) of the tumor
samples. Low expression of miR - 200b were insignificantly higher in patients with distant metastases (75% vs
25%), vascular invasion (71.1% vs 28.9%), estrogen receptor expression (77.8% vs 22.2%), progesterone receptor
expression (84 % vs 16%) and lymph nodes metastasis (72.2% vs 27.8%) in comparison to those with high
expression of miR- 200b.
Conclusion: Reduced miR- 200b expression is a frequent event in human breast cancer tissues and could be
involved in breast cancer carcinogenesis. miR-200b could be a prognostic factor in breast cancer patients.