Direct Serum Assay for MicroRNA-21 Concentrations in Early and Advanced Breast Cancer

Abstract

BACKGROUND: MicroRNAs (miRs) are a class of small noncoding RNAs whose expression changes have been associated with cancer development and progression. Current techniques to isolate miRs for expression analysis from blood are inefficient. We developed a reversetranscription quantitative real-time PCR (RT-qPCR) assay for direct detection of circulating miRs in serum. We hypothesized that serum concentrations of miR-21, a biomarker increased in breast tumors, would correlate with the presence and extent of breast cancer.

Identification of Serum MicroRNA-21 as a Biomarker for Early Detection and Prognosis in Human Epithelial Ovarian Cancer

“…Serum miR-21 was also found to be significantly higher in patients with hepatocellular carcinoma (HCC) than in healthy controls (Xu et al, 2011). Asaga et al found that serum miR-21 has diagnostic and prognostic potential in breast cancer (Asaga et al, 2011). In Zheng's study, patients with gastric cancer display a significantly higher level of miR-21 in peripheral blood than those from controls.…”

MicroRNAs in breast cancer: oncogene and tumor suppressors with clinical potential

“…Knocking down its expression could attenuate its contribution in the cancer process. Recent studies also found high levels of miR-21 in breast cancer patient serum (Wang et al, 2010;Asaga et al, 2011). Its increased expression can also be detected in a variety of other malignancies including glioblastoma, ovarian cancer, lung cancer, and colorectal cancer (Chan et al, 2005;Yanaihara et al, 2006;Iorio et al, 2007;Schee et al, 2012;Wang and Zhang, 2012), indicating that miR-21 may have diagnostic and prognostic values.…”

Circulating microRNAs: New biomarkers in diagnosis, prognosis and treatment of cancer (Review)

“…Since cellular miRNAs play a fundamental role in regulation of a variety of cellular, physiological, and developmental processes, it is easy to understand that their aberrant expression can lead to a variety of human diseases including cancer. A number of cellular miRNAs were shown in fact to be located in fragile regions of the human genome that are associated with cancer (70), and dysregulated miRNAs have been shown to play a crucial role in tumor initiation, progression, and metastasis, and are often associated with diagnosis, prognosis, and response to therapy (71)(72)(73) (Table II). Lu et al developed a method for bead-based miRNA profiling.…”