A moderate-to-high FKBP4 expression was detected in the majority of grade 2 (82.8%) or grade 3 (85.7%) tumors, compared to grade 1 (46.7%), demonstrating that FKBP4 is associated with faster growing, moderately or poorly differentiated grade breast cancer, and an aggressive phenotype. This evidence concerns the gene FKBP4 and breast cancer.