The procedure included background detection, background adjustment (BC-CG Adjust), quantile normalization, addition of small constants (CVStab), and summarization using a median polishing approach.
The normalization algorithm used was the default setting in the AffyMetrix miRNA QCTool program, which is background adjustment, BC-CG Adjust; normalization, Quantile; summarization, median polish.
The background adjustment is, as for the differentially expressed genes, adjusted for the "worst-case" scenario.
Following microarray hybridizations, CEL files were imported into Partek Genomics Suite Version 6.3 (Partek, St Louis, Missouri, USA) using the following parameters: Pre-background Adjustment: Adjust for GC Content; Background Correction: RMA Background Correction Quantile Normalizationn: Quantile Normalization; Log Probes using Base: 2; Probeset Summarization: Mean.
Background adjustment using variance-stabilizing transformation correction and quantile normalization was performed using the FlexArray package implemented in R (version 1.6.3).
The RMA method [19] consists of three steps: background adjustment, quantile normalization [20], and probe set summarization of the log-normalized data applying a median polishing procedure.
The background adjustment herein was to treat the blood pooling in the thyroid ROI as the delivery vehicle to the extravascular tissue within the same ROI for later washout.
RMA (RMAexpress version 0.3) consists of three steps: background adjustment, quantile normalization, and summarization [23].
Robust Multichip Average did background adjustment, quantile normalization, and summarization of 11 oligonucleotides per gene.
