Among these, only lesion dimension (OR 1.678; 95%CI 1.019–2.145; WALD: 7.588; p = 0.006) and the ratio of lesion dimension to the Ki67 proliferation index (OR 0.08; 95%CI 0.011–0.141; WALD: 11.004; p = 0.001) remained independent predictive factors for a higher axillary tumor burden. This evidence concerns the gene MKI67 and neoplasm.