[Validation and clinical application of MammaPrint® in patients with breast cancer]

MammaPrint(®) is a micromatrix based test and the result classifies analyzed tumors as low or high risk for recurrence of breast carcinoma. By analyzing the individual activity of these genes, MammaPrint(®) estimates the response to chemotherapy and/or predicts the outcome of the breast neoplasia. We aimed to assess the clinical and analytical validity of MammaPrint(®) that determines individual risk of relapse of breast cancer.

Systematic review of the literature using a structured database search (MedLine, CRD, ECRI Institute, Cochrane Library) and Tripdatabase metasearch. The criteria for selecting report for inclusion were the following: population (breast carcinoma), intervention (MammaPrint(®) versus medical outcome systems and molecular techniques), and analytic (reproducibility and validity of the method) and/or clinical (the ability to predict mortality among patients, metastasis-free time) results.

We found 75 documents. After eliminating the studies that did not satisfied the inclusion criteria, 10 studies were evaluated. Only one paper analyzed MammaPrint(®) reproducibility, indicating reliability and validity of this methodology. The risk of distant metastasis associated with poor prognosis signature versus good prognosis, ranged from 5.7 (IC95%=1.6-20) for 5.8 year follow-up to 2.32 (IC95%=1.35-4.00) for 13.6 year follow up. MammaPrint(®) was identified as an independent predictor of risk for metastasis, as well as the tumor diameter and non-use of chemotherapy.

MammaPrint(®) test could bring benefits to the diagnosis and treatment of breast cancer patients but there was no evidence to conclude its clinical usefulness in patients who predicts an a priori advantage to chemotherapy.