ESR1 and neoplasm: We investigated the relationship between NSLN metastatic status and biomarkers, such as estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor type 2 (HER2), vascular invasion, lymphatic invasion, nuclear grade, ki-67, tumor size (T-factor), histological type, patient age, the maximum copy number of metastatic SLNs, total tumor load and SLN metastasis, as determined by OSNA.