Independent predictive factors significantly associated with non-SLN metastasis were: TTL (log10(TTL + 1)), treatment response (defined as patients with HER2-negative status and Ki67 ≤ 20% from needle biopsy), and maximum tumor diameter (p = 0.0206, 0.0069 and 0.0080, respectively). The gene discussed is ERBB2; the disease is neoplasm.