Since we found a significant association between a specific genetic variant in FOXP3 gene and a high expression of this protein in the tumor microenvironment, which would agree with the fact that TNBC patients do not present the overexpression of HER2 oncogene, and also a positive correlation between FOXP3-positive infiltrate and the prognostic parameter tumor size, we suggest that this transcript factor could be a promising marker of susceptibility and prognosis in human breast cancer pathogenesis, especially in the triple-negative molecular subtype. The gene discussed is FOXP3; the disease is breast carcinoma.