All these variables were included in the exploratory logistic regression (Table 4), which identified the following independent predictive factors of lymph node metastasis: palpable suspicious nodes (OR = 8.9; 95% CI: 2.7 – 29.2), tumor depth greater than 5 mm (OR = 11.6; 95% CI: 1.4 – 97.1), perineural invasion (OR = 9.6; 95% CI: 2.7 – 33.6) and SOD2 expression greater than 50% (OR = 3.4; 95% CI: 1.1 – 10.1). The gene discussed is SOD2; the disease is neoplasm.