In the bivariate analysis, metastatic node was associated with palpable suspicious lymph node in the clinical exam (P < 0.001), tumor size (P = 0.045), histological grade (P = 0.013), perineural invasion (P < 0.001), vascular invasion (P = 0.010), tumor depth (P = 0.002) and SOD2 expression (P = 0.002). This evidence concerns the gene SOD2 and neoplasm.