DNA microarray: introduction
Central to the MammaPrint^® technology is the use of DNA microarrays. A DNA microarray is a collection of tens of thousands of genes, printed onto a glass slide. Each spot on the slide contains a unique DNA fragment with a known sequence.

To assess the global gene expression pattern of a tumor sample, messenger RNA (mRNA) is extracted from the sample and labeled with a fluorescent dye. The labeled mRNA, together with the labeled mRNA from a reference sample, is hybridized to the DNA microarray.

MammaPrint® Specifications
Agendia uses customized microarrays, manufactured by Agilent. Each microarray contains three identical sets of the 70 genes to be analyzed. This enables three independent measurements of the 70-gene profile, increasing confidence in the test result.

In addition, the customized arrays contain several hundred carefully selected normalization genes. Finally, negative control genes are present on each microarray; these are DNA sequences to which no human mRNA can bind and are used to monitor various technical aspects of the microarray process.