As shown in Fig. 4, the four-gene based risk signature could serve as a promising candidate for predicting the survival of breast cancer in different subtypes stratified by the clinical factors, including N0-1 type (p = 0.0014), N2-3 (p = 0.026), T1-2 (p = 0.0006) T3-4 (p = 0.04), stage I-II (p = 0.0022), stage III (p = 0.0078), PR positive (PR+, p < 0.0001) patients, respectively. This evidence concerns the gene PGR and breast cancer.