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UICC World Cancer Congress 2006
Bridging the Gap: Transforming Knowledge into Action
July 8-12, 2006, Washington, DC, USA
Methods: MCM7 and Ki-67 were evaluated using an immunohistochemical method. Blocks of 86 GBM cases were archived from two institutions. Slides were immunostained with anti-MCM7 and anti-Ki-67 antibodies. MCM7 and Ki-67 labeling indices were quantified based upon counting positive stained cells per 500-3000 tumor cells in each case. Statistical analyses were performed using Cox proportional hazards analysis methods, Kaplan-Meier curves, and log rank tests.
Results: Indices of Ki-67 and MCM7 were 26.50 ± 14.03 and 45.02 ± 21.36 in these cases (n=86). Both indices were strongly correlated (r=0.79, p<0.0001), but MCM7 index was consistently higher than Ki-67. Both proliferation markers correlated with patient prognosis, in that there were significant survival differences for patients with an MCM7 index cutoff of 25% (p= 0.025), and a Ki-67 index cutoff of 15% (p= 0.017). Ki-67 index was <15% in some GBM cases, but MCM7 index was >25% in those cases. In 11 cases, both indices were less than cutoffs (Ki-67, 15%; MCM7, 25%). The survival in those patients was longer. Results suggest both Ki-67 and MCM7 indices are useful and should be used in GBM diagnosis and survival prediction, and MCM7 index is a superior marker.