MKI67 and lymphoma: ROC curve analysis established 37.50% as the cut-off value for pathologic IHC to distinguish indolent from transformed disease (area under the curve =0.853, P < 0.001); Therefore, when this value was used, the positive rates of Ki67 expression could identify transformed lymphomas with a sensitivity of 90.9% and a specificity of 64.6% (Figure 4E).