Analysis of change in circulating microRNAs in mice during breast tumor development. Mus musculus

The aim of this study was to analyse alterations in circulating microRNA expression during breast tumour progression in a murine model, and to apply significantly altered miRNAs to patient samples to identify novel circulating microRNA markers or tumour progression. Athymic nude mice (n=10) received an injection of 2 x 105 MDA-MB-231 cells. Tumour volume was monitored weekly and blood sampling performed at weeks 1 and 6 following tumour induction. A microRNA array was performed comparing circulating 384 microRNAs in animals with early (week 1, n=5) versus late (week 6, n=5) disease. Overall design: Five animals were included in the study (n=2 samples from each, total n=10 microArrays performed), with whole blood sampled one week following tumor induction and again at 6 weeks in the presence of established disease. The change in microRNA profile was then compared at week 1 and week 6, which the "early" sample providing the baseline measurements for each animal.