ABSTRACT
Objective To investigate the expression levels of miR-494 in breast cancer tissues and cell lines,and its correlations with the clinical stages,metastasis and prognosis of breast cancer.Methods The expression levels of miR--494 in 5 breast cancer cell lines,including MDA-MB-231,MDA-MB-453,HCC-1937,MDA-MB-468 and MCF-7,and normal breast cell line HBL-100,were detected by quantitative real-time polymerase chain reaction (qRT-PCR).The breast cancer tissues and normal adjacent tissues from 54 patients with breast cancer were collected,and their expression levels of miR-494 were determined by qRT-PCR.Then,the correlations of miR-494 levels with clinical stages,metastasis and prognosis of breast cancer were analyzed.Results The expression levels of miR-494 in MDA-MB-231,MDA-MB-453,HCC-1937,MDA-MB-468 and MCF-7 cells were significantly lower than that in HBL-100 cells (t =212.9,37.73,27.53,10.61 and 19.46,respectively,and all P ＜0.05).The expression levels of miR-494 in breast cancer tissues were also significantly lower than that in normal adjacent tissues (t =5.80,P ＜ 0.01).Moreover,the expression of miR-494 was significantly related to the clinical stage (x2 =17.41,P ＜0.05),tumor grade (x2 =5.33,P ＜0.05),C-erbB-2 expression (x2 =9.83,P ＜ 0.05) and the percentage of Ki-67 positive cells ((2 =6.13,P ＜ 0.05) of breast cancer.Conclusion The expression levels of miR-494 are significantly dowrregulated in breast cancer tissues and cell lines,and related to the clinical stage,metastasis and prognosis of breast cancer,indicating that miR-494 may serve as a new biomarker for the diagnosis and prognosis of breast cancer.