The MicroArray Quality Control (MAQC) project shows inter- and intraplatform reproducibility of gene expression measurements


Over the last decade, the introduction of microarray technology has had a profound impact on gene expression research. The publication of studies with dissimilar or altogether contradictory results, obtained using different microarray platforms to analyze identical RNA samples, has raised concerns about the reliability of this technology. The MicroArray Quality Control (MAQC) project was initiated to address these concerns, as well as other performance and data analysis issues. Expression data on four titration pools from two distinct reference RNA samples were generated at multiple test sites using a variety of microarray-based and alternative technology platforms. Here we describe the experimental design and probe mapping efforts behind the MAQC project. We show intraplatform consistency across test sites as well as a high level of interplatform concordance in terms of genes identified as differentially expressed. This study provides a resource that represents an important first step toward establishing a framework for the use of microarrays in clinical and regulatory settings.

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Figure 1: Repeatability of expression signal within test sites.
Figure 2: Signal variation within and between test sites.
Figure 3: Concordance of detection calls within and between test sites.
Figure 4: Agreement of gene lists.
Figure 5: Agreement of log ratios across platforms and test sites.
Figure 6: Correlation between microarray and TaqMan data.

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All MAQC participants freely donated their time and reagents for the completion and analysis of the MAQC project. Participants from the National Institutes of Health (NIH) were supported by the Intramural Research Program of NIH, Bethesda, Maryland. D.H. thanks Ian Korf for BLAST discussions. This study utilized a number of computing resources, including the high-performance computational capabilities of the Biowulf PC/Linux cluster at the NIH ( as well as resources at the analysis sites.

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Correspondence to Leming Shi.

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Competing interests

Many of the MAQC participants are employed by companies that manufacture gene expression products and/or perform testing services. J.C.W. is a consultant for and has significant financial interest in Gene Express, Inc.

Supplementary information

Supplementary Table 1

cRNA Size and Yields Collected from Microarray Platforms (XLS 45 kb)

Supplementary Table 2

Genes-to-NM Accession List for All Probes (TXT 2629 kb)

Supplementary Table 3

Most 3′ Probe-to-NM Accession List for 23,971 Common Probes (TXT 3272 kb)

Supplementary Table 4

One Probe-to-One Gene List for All Genes (TXT 1718 kb)

Supplementary Table 5

One Probe-to-One Gene List for 12,091 Common Genes (TXT 1211 kb)

Supplementary Methods

BLAST Analysis for the MAQC Project (PDF 67 kb)

Supplementary Notes

README for Probe Mapping Files (PDF 11 kb)

Supplementary Data

Supplementary Information on MAQC Study (PDF 663 kb)

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