Validation of gene profiling of breast tumors using the 21-gene panel for use in a population of patients treated in the Unified Health System (SUS)

• Grant number: 23/11927-0
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2024
• End date: January 31, 2026
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Auro del Giglio
• Grantee: Auro del Giglio
• Host Institution: Centro Universitário FMABC (FMABC). Santo André , SP, Brazil
• Associated researchers: Beatriz da Costa Aguiar Alves Reis ; Fernando Luiz Affonso Fonseca

Abstract

Gene profiling with the 21-gene panel known as Oncotype® is currently being routinely used for prognostic stratification of patients with hormone receptor-positive, HER2/neu-negative breast tumors, typically with negative axillary lymph nodes. For patients with a score above 25 in postmenopausal or 20 in premenopausal stages, Oncotype is used to indicate adjuvant chemotherapy. In addition to its prognostic value, the Oncotype score is also predictive of chemotherapy sensitivity. However, despite the cost-effectiveness of performing the Oncotype test in several healthcare scenarios, the high cost of this molecular test prohibits its broader application by the Unified Health System (SUS). Our group has managed to replicate this test based on the expression of the same 21 genes used by Oncotype, and in our setting, we have shown that high test scores also have prognostic value. This test, in our hands, performed using the multiplex PCR technique, can be executed at a fraction of the price of Oncotype, which could potentially make its application viable in the context of patients treated by SUS. To achieve this, we need to standardize the test in order to determine the correspondence between the score of our test and the original Oncotype test. In addition to this external validation of our results, we also need to evaluate how the values of this test stratify the risk of recurrence in patients with early-stage breast tumors, receptor-positive and negative axillary lymph nodes, who were underrepresented in our two previous studies. (AU)