MammaGene®

a quantitative 21-gene assay for prognostic of breast cancer estrogen receptor-positive

Abstract

Objectives: To standardize a homemade RT-PCR-based 21-gene assay and to describe the prelimi- nary experience with 95 early positive estrogen receptor breast cancer consecutive cases. Methods: The test was developed using the reports described by Cronin et al. (2004) and Paik at al. (2004) for the evaluation of gene expression in fixed, paraffin-embedded tumor tissue. The test was performed in a consecutive cohort of 95 positive estrogen receptor breast carcinomas, and the final scores were com- pared with the patient’s age, tumor size, histological type, histological degree, estrogen receptor immu- nohistochemical expression, Ki-67 expression, and molecular luminal subtype. Results: Final scores ranged from 3 to 90 and risk categories of recurrence in ten years were: low (34 cases), intermediate (38 cases), and high (23 cases). There was no association between score categorical distribution and age, lymph node status, or histological type. Mean tumor size was higher in the high score group (2.0 versus 1.2 cm). We have observed an overall concordance between the score obtained by the test, and the histological degree, Ki-67, estrogen receptor level, and molecular subtype. Conclusion: The devel- oped 21-gene assay is a feasible test to be performed in a homemade setting. Besides, the preliminary data from this study suggest, in comparison with data from the literature, that this test has the poten- tial to be a useful tool to evaluate the risk of breast cancer distant recurrence. However, further data are necessary in order to compare this paper’s results with larger series published in the literature.