Clinical Significance Of MiR-21Expression In Invasive Ductal Carcinomas Of The Breast

Objective: MicroRNAs are a class of small, noncoding RNA moleculesof about22-25nucleotides in length that function as posttranscriptional generegulators, Widespread in plants and animals,miRNAs regulate various bio-logical processes, including development, differentiation, cell proliferationand apoptosis. miR-21is overexpressed in very diverse types of humanmalignancy in the more than500kinds of microRNAs, It was demonstratedthat miR-21may affect tumor differentiation, proliferation and apoptosis, haveclosely related to tumorigenesis, The relationship between the clinicalpathology of the breast infiltrating ductal carcinoma, In this study, weinvestigate the expression of miR-21in breast invasive ductal carcinoma,adjacent tissues and benign breast lesions, analysis the correlation betweenexpression of miR-21and the clinicopathological features of breast cancer,have significance with the diagnosis, gene therapy and prognosis of breastcancer.Methods: From Mar2009to Mar2011,48cases invasive ductalcarcinomas specimens, and adjacent tissues(specimens distance from the foci2cm),and25cases of benign breast lesions were collected. All patients hadcomplete clinical and pathological data, did not receive any treatment beforesurgery. All patient were female, average age50.3years, the age range from30to81years. Material was saved in liquid nitrogen immediately after surgeryand transferred in-80℃refrigerator and stored. Real-time polymerase chainreaction(RT-PCR) detect the expression of miR-21in breast invasive ductalcarcinoma and adjacent tissues and benign breast lesions; ER,PR,Her-2expression status were detected with immunohistochemical；Real-time polym-erase chain reaction(RT-PCR) detect the expression of miR-21in highly invasive breast cancer cell line MDA-MB-231and low invasive cell lineMCF-7; SPSS18.0software were used to analyze the correlation betweenexpression of miR-21with the clinicopathological features of patientsResults:(1)Expression of miR-21in breast invasive ductal carcinoma washigher than non-tumor tissues (including breast benign lesions and adjacenttissues)(p=0.000,0.007)；there is no significant differences between benignbreast lesions and adjacent tissues;(2)Higher miR-21expression is associatedwith advanced stage、Lymph node metastasis and Her2expression;have norelation with tumor size, nuclear grade, ER and PR (P＞0.05).(3) Theexpression of miR-21in MDA-MB-231cell line was higher than the amount ofexpression in MCF-7cell lines, the differences have statistically significant(p=0.03).Conclusion:(1)) High expression of miR-21in infiltrating ductal breast cancer,indicating that it’s plays an important role in the development of breast cancer,it can be used as one of the indicators in differentiating benign and malignant.(2) The expression of miR-21have positive correlation with TNM staging,lymph node metastases and Her-2overexpression, miR-21can be used as oneof the indicators for prognosis of survival.(3) The expression of miR-21in MDA-MB-231higher than in MCF-7cellline expression; Showed that miR-21expression and invasive breast cancer,which may become the target of treatment for breast cancer.