MIB1 and central nervous system cancer: In contrast, WHO grade is a direct index of the malignancy grade, based on the consideration of various pathological factors, including the presence of necrosis, nuclear polymorphism, microvascular proliferation, mitotic activity, etc. The present investigation found that the T/N ratio of 18F-FAMT PET was not correlated, but the T/N ratio of 18F-FDG PET was correlated with MIB-1 LI in all gliomas.