Detection of Low-Abundant MicroRNAs with Hybridization Microchips.

The effect of low concentrations of miRNA on the ability of GeneChip miRNA 4.0 hybridization chips to evaluate their representation in the sample was studied. It is shown that the evaluation of the expression of 61 miRNAs is statistically significantly associated with the multiplicity of plasma dilution. Only 12 miRNAs showed very high Pearson correlation coefficient (>0.95) and they all decreased in response to dilution. High abundance of has-miR-4532 miRNA in plasma was demonstrated. This miRNA was never detected during sequencing of similar samples. It was concluded that in case of miRNA expression <1.12±0.33 units in log2 scale, dilution was not followed by further decrease in the signal intensity in GeneChip miRNA 4.0 chips.