There are genetic tests that assess probability of relapse of breast tumors between 5 to 10 years of the original diagnosis.
One of them, “Mammaprint®”, is a model in 70 “microarrays” genes of DNA.
What are the “microarrays”? are tens of thousands series of genes put into a portalobject. Each “point” in the portalobject is a set of known DNA (see figure).
Analysis of the levels of expression of these sequences in a breast tumor surgically resected gives information about its aggressiveness profile and allows the construction of a “score” to infer the probability of tumor recurrence and determine the potential benefits of chemotherapy for a patient on an individual way.
Another available test is the “Oncotype®”, analyzing the expression of 21 genes and allows the construction of a “score” to determine risk of relapse and benefits of treatment of chemotherapy.
Both tests are validated, Ie in retrospect were applied in populations of patients with early breast cancer that others who participated in therapeutic trials to test its feasibility. Another trial showed equivalence between these two and other genetic test applicable in breast cancer.
Both tests provide useful prognostic information to make proper treatment to each patient individually irrigation they differ in the manner of processing tumor tissue (fresh versus fixed).
What would be its potential application? They would be useful for determining therapeutic benefit of chemotherapy in early breast cancer without axillary node metastases (axilla negative) in hormone dependent tumors (receivers positive) and without other characteristics of high risk.
There are two randomized studies evaluating the use of each test for therapeutic decision in Europe (Mammaprint – Mindact) and the United States (Oncotype – Tailorx).
Alexander Fleming Institute