In multivariate analysis, tumor necrosis turned out to be a strong and independent prognostic factor (HR 2.3, p = 0.001) when included along with basic prognostic factors like tumor thickness (using median as cut-off value, i.e ≤ vs > 3.55 mm), Clark's level of invasion, tumor ulceration, vascular invasion, p16 expression and tumor cell proliferation by Ki-67. The gene discussed is MKI67; the disease is neoplasm.