Expression of miR-126 and Crk in endometriosis: miR-126 may affect the progression of endometriosis by regulating Crk expression

To evaluate the relationship between miR-126 and Crk and discuss the role of miR-126 in the development and progression of endometriosis (EMs). The expression levels of miR-126 and Crk mRNA were quantified using real time fluorescent quantitative polymerase chain reaction (real time PCR) in ectopic endometrium (ECs) and eutopic endometrium (EUs) in patients with EMs and normal endometrium (ENs) in EMs-free subjects. The expression levels of Crk protein in all samples were evaluated by Western blot. The expression level of miR-126 was significantly downregulated in ECs versus EUs (p = 5.45E(-5)) in the experimental group and in EUs versus ENs (p = 0.019). The expression level of Crk mRNA did not distinguish ECs from EUs (p = 0.995) but was overexpressed in EUs versus ENs (p = 0.006). Crk protein was overexpressed in ECs versus EUs (p = 0.002) in the experimental group and in EUs versus ENs (p = 1.13E(-6)). The expression level of miR-126 had no correlation with Crk mRNA (p = 0.496) but was negatively correlated with Crk protein (p = 3.134E(-5)). The expression level of miR-126 in EUs and ECs was negatively correlated with American Fertility Society (AFS) stage (p = 0.022, p = 0.025) and AFS score (p = 0.002, p = 0.007). miR-126 expression decreased with the progression of EMs, but the decrease was not significantly different. miR-126 may play an initial role in the development and progression of EMs. Crk may be regulated by miR-126, and synergism between abnormal expressions may play an important role in the pathogenesis of EMs.