Test Technology
DNAmicroarray: 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, as shown on left. The labeled mRNA, together with the labeled mRNA from a reference sample, is hybridised to the DNA microarray.
After Agendia receives the fresh tumor sample:
- Isolation of RNA
- DNAse treatment of isolated RNA
- Transcription into cDNA and then into cRNA
- Fluorescent-labeling of tumor and reference cRNA
- cRNA purification; hybridisation of the cRNAs of tumor and reference sample to the MammaPrint®
- microarrayScanning the MammaPrint® microarray and data acquisition
- Calculation and determination of the risk of recurrence in breast cancer patients
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MammaPrint® Specifications
Agendia uses customised microarrays, manufactured by Agilent. Each microarray contains three identical sets of the 70 genes to be analysed. This enables three independent measurements of the 70-gene profile, increasing confidence in the test result.
In addition, the customised arrays contain several hundred carefully selected normalisation 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.
MammaPrint®: Key features
Specimen processing: A review of specimen histology and RNA quality is carried out prior to microarray analysis to confirm test suitability.
Test confidence: Triplicate gene expression measurements and also duplicate sample measurements, incorporating a dye-swap step.
Test consistency: Each patient sample is tested using a constant, standardised reference, normalised to a constant set of breast cancer specific normalisation genes.
Rapid turn-around: In general, a results will be available within 10 working days after receiving the sample.
ISO 17025 certification: Ensures our laboratory processes are maintained at the world's best practice standards.