PGR and breast cancer: Other previous studies also used clinic-pathological characteristics to establish models in predicting LN metastasis of breast cancer patients, such as lymphovascular invasion and serum miRNA expression (37, 38), which might have a limited clinical implication, because characteristics such as molecular subtype, PR status, lymphvascular invasion, and miRNA was usually obtained by biopsy or other examinations, which to some extent limited the clinical application of these prediction models.