The robustness of gene expression profiling for biomarker research in peripheral blood has been demonstrated in multiple previous reports, showing a significant correlation of expression levels between array-based gene expression analysis and reverse transcription-PCR, such as the MAQC Consortium33 and also previous publication of outcomes with this same set of samples.5, 34 Along these lines, Herold et al.9, 10 showed significant correlation of MZB-1 expression in CLL samples when comparing array-based expression profiling with reverse transcription-PCR. Here, MZB1 is linked to B-cell chronic lymphocytic leukemia.