MKI67 and lymphoma: ROC curve analysis established 45.00% as the cut-off value for pathologic IHC to distinguish aggressive from indolent disease (area under the curve =0.937, P < 0.001); Therefore, when this value was used, the positive rates of Ki67 expression could identify aggressive lymphomas with a sensitivity of 92.5% and a specificity of 81.00% (Figure 4D).