Profiling circulating microRNAs in early screen detected breast cancer


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Daniel Fernandez Garcia1,David S. Guttery1,Karen Page1,Allison Hills2,Laura Woodley2,Justin Stebbing2,R. Charles Coombes2,Jacqueline A. Shaw1
1University of Leicester,2Imperial College

Abstract

Background

The discovery of circulating nucleic acids marked the beginning of a new era in identifying easily accessible disease biomarkers. MicroRNAs (miRNAs) identified in plasma and other biofluids are one class of biomarker under active investigation as non-invasive biomarkers in cancer. This study aimed to discover whether candidate miRNAs could be a useful surrogate biomarker of cancer in early stage breast cancers detected by mammographic screening.

Method

miRNA profiles were compared in 70 healthy female controls and 54 patients with early stage breast cancer. MiRNAs were extracted from 250 ul of plasma using the Qiagen miRNeasy serum/plasma kit,  converted to cDNA using the TaqMan microRNA RT kit and pre-amplified for 12 cycles with Megaplex RT primers (Pool A/B) (Applied Biosystems). qPCR analysis was conducted using individual gene assays for miR-361, miR-15b and miR-26a  selected from previous published studies. miR-16 and  miR-484 were also profiled, as these have been reported previously to be stable in plasma. Results between cancer and controls were compared using the –dCt method.

Results

Candidate miRs (miR-361, miR15b and mir-26a) were compared in in 124 plasma samples from breast cancers and healthy controls relative to the mean of all other miRs (including mir-16 and mir-484 as controls). Results show that there was no significant difference in expression of any of the candidate miRs between cancers and controls.

Conclusion

This pilot study suggests that circulating miRNAs may not be a suitable biomarker for early stage breast cancer.