Platform Comparison Study

Microarray technology is a powerful tool able to measure RNA expression for thousands of genes at once. Various studies have been published comparing competing platforms with mixed results: some find agreement, others do not. As the number of researchers starting to use microarrays and the number of cross platform meta-analysis studies rapidly increase, appropriate platform assessments become more important. Here we present results from a comparison study that offers important improvements over those previously described in the literature. In particular, we notice that none of the previously published papers consider differences between labs. For this paper, a consortium of ten labs from the DC and Baltimore area was formed to compare three heavily used platforms using identical RNA samples. Each lab was given identical RNA samples (A1 and B1) which were processed according to what each lab considered best practice. Five of the labs used Affymetrix GeneChips, three used two-color spotted cDNA arrays, and two used two-color long oligo arrays. Samples 1 and 2 represent unique mixtures of total RNA from four knockout cell lines: PEX1, PEX6, PEX7, and PEX12. Each of the four cell lines is deficient for one of four PEX genes (required for peroxisome biogenesis/mutations cause peroxisome biogenesis disorders). Appropriate statistical analysis demonstrates that relatively large differences exist between labs using the same platform, but that the results from the best performing labs agree rather well. Keywords: other