查看文章

MicroRNA-21 (miR-21) is considered an onco-microRNA given its abilities to suppress the actions of several tumor suppressor genes and to promote tumor cell growth, invasion and metastasis. Recently, transforming growth factor-beta (TGF-β) is found to up-regulate the expression of miR-21, and elevated miR-21 expression is seen frequently in breast cancer. To evaluate the effect of miR-21 on disease progression and its association with TGF-β, we analyzed miR-21 expression in breast cancer. Fresh tumor samples were collected during surgery from 344 patients diagnosed with primary breast cancer. The expression of miR-21 in tumor samples was measured with a TaqMan^® microRNA assay using U6 as reference. Levels of miR-21 expression by disease stage, tumor grade, histology, hormone receptor status and lymph node involvement were compared. Cox proportional hazards regression analysis …