MKI67 and lymphoma: ROC curve analysis established 65.00% as the cut-off value for pathologic IHC to distinguish aggressive from transformed disease (area under the curve =0.610, P = 0.055); Therefore, when this value was used, the positive rates of Ki67 expression could identify transformed lymphomas with a sensitivity of 50.0% and a specificity of 66.7% (Figure 4F).