In the present study, we observed a prevalence of AGR3 positivity of 62% in breast cancer, which demonstrates the relevance of this protein in breast carcinogenesis, confirming the predominant expression previously reported.5, 11The expression of AGR3 in general seems to be associated with a less aggressive phenotype, with hormone receptor positivity, low histological grade, and low proliferation rate. This evidence concerns the gene AGR3 and breast cancer.