Moreover, the patients with strong SLCO1B3 expression tended to have negative lymph node metastasis, AJCC stage I, and histological grade 1 (P < 0.05), while in the SLCO1B3 negative patients, there were more cases with positive lymph node metastasis, especially with the number of metastases ≥ 3, and the percentage of patients with histological grade 3 breast cancer was higher (P < 0.05). This evidence concerns the gene SLCO1B3 and breast cancer.