MKI67 and neoplasm: Tumor cell proliferation, when corrected for tumor cell density, showed a relative increase in Ki67 expression from the tumor core to the rim for MDA231Br-GFP (60.2%) and U87MG (32.4%) tumors, respectively; although this increase reached significance for the MDA231Br-GFP group (matched Wilcoxon test, P < 0.05; Fig. 1D) and not the U87MG group (Fig. 2D).