| Breast cancer, a heterogeneous form of cancer among individual patients, is the most frequent tumor in women worldwide. The etiology of this tumor is complex, and both genetic and environmental factors contribute to the complicated scenario. Accurate identification of these different phenotypes is crucial to accurate diagnosis, selection of treatment strategies and prognosis. Despite the achievement of research on the elucidation of the molecular mechanisms involved and advances in detection and therapies, breast cancer is still the leading cause of cancer death in women all over the world. MicroRNAs (miRNAs) are involved in the initiation and progression of human malignancy and hold much potential for novel biomarkers in cancer detection, current diagnostic and therapeutic strategies in the management of patients with breast cancer. Howerer, the studies on cancer specific miRNA expression profiling have been still limited to tissue specimens by recent works. Clinical specimens of serum are more plentiful existence and conveniently obtained than tissue samples in many retrospective clinical sample repositories. Serum-derived miRNAs are validated to be stable present in human organization. It is significant to investigate the correlation of expression level of several deregulated miRNAs associated with breast cancer between matched tissue and serum samples and quantitation of the abrreant expression of serum-derived miRNA from patients with breast cancer perfomed by real-time PCR platform. It is prospective for significant discovery of novel effective blood-based biomarker for cancer detection, diagnosis and prognosis.In this study, forty-eight pairs of tumor tissues and adjacent non-tumor tissues and matched serum samples were collected from patients who were newly diagnosed breast tumor and had completed clinicopathologic information. Twenty unmatched, healthy serum controls were collected to serve as comparison. Six miRNAs (miRNA-21, 106a, 126, 155, 199a and 335) previously demonstrated as diagnostic, were selected and quantified their aberrant expression level both in tissue and matched serum samples of breast tumor using real-time PCR platform based on specific stem-loop primers and PCR primers.The selected miRNAs are stable and reproducibly consistent among individuals of the same species according to RT-PCR assay and a poor correlation in sera samples of males and females. The selected miRNAs were identified to be significantly differentially expressed both in tissue and matched serum samples compared with their corresponding normal controls. A high correlation of miRNA expression level was found between breast cancer tissues and sera (R~2=0.853). MiR-21, miR-106a and miR-155 were significantly over-expressed in the cancer specimens compared with normal controls, whereas, miR-126, miR-199a and miR-335 were significantly under-expressed (P<0.05). Additionally, expression of the selected miRNAs is closely associated with clinicopathologic features of breast tumor, such as histological tumor grade and hormone receptor status.In conclusion, our results suggested it is advantageous and rational for miRNAs as blood-based cancer biomarkers. The measurement of the abbreant expression of serum-drevied miRNAs can serve as clinical detection at early stage shared a few characteristics of sensitivtity, specificity and facility. Our results will provide an impetus for using humors, including serum samples, in target discovery studies. |
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