NR4A1 and neoplasm: The clinical and pathological factors that may affect non-SLN metastasis are complex, with the most commonly associated risk factors being age, clinically positive lymph nodes, tumor size, tumor location, multifocality, pathologic type, neurovascular invasion, histological grade, number of positive and negative SLNs, positive SLN ratio, size of the SLN metastases detected, hormone receptor status, SLN micrometastases, and extracapsular invasion in the SLN [10, 23–26].