MammaPrint

MammaPrint is a molecular cancer prognostic test used in breast cancer to estimate the risk of distant metastasis. It analyzes a 70-gene expression signature to classify a tumor as low risk or high risk for metastatic spread within five to ten years after diagnosis. The test is intended to inform adjuvant chemotherapy decisions for patients with early-stage disease.

The test was developed by Dirk van’t Veer and colleagues at Erasmus Medical Center in Rotterdam and was first described in 2002. It was initially based on analysis of fresh-frozen tumor tissue and was later adapted to use formalin-fixed, paraffin-embedded samples, expanding its clinical applicability. The assay is commercially offered by Agendia and has been evaluated across multiple cohorts and settings.

How MammaPrint works centers on extracting RNA from tumor tissue and profiling gene expression to yield a binary risk category. The 70-gene signature is used to predict the likelihood of distant metastasis, aiding clinicians in deciding whether chemotherapy is likely to provide benefit for a given patient.

Clinical validation includes retrospective studies and prospective trials. A key study, the MINDACT trial, assessed whether MammaPrint-guided adjuvant therapy could spare some patients from chemotherapy. Results indicated that, among patients with clinically high risk but genomically low risk, chemotherapy could be omitted without compromising five-year distant metastasis-free survival, supporting its role in personalizing treatment.

Regulatory status and use vary by region. MammaPrint is CE-marked for use in several jurisdictions and is marketed by Agendia; in the United States, adoption and reimbursement policies differ, reflecting ongoing debates about risk-based therapy in breast cancer.