C-Myc mRNA and protein levels were not grade-related, but validated subdivision of the 36 benign meningiomas into two groups, Groups IA and IB, based on histological and clinical features (Ki-67-proliferative index, absence or presence of mitoses, rate of recurrence and incidence of perilesional edema).
All cases of atypical and anaplastic meningiomas were positive for c-myc protein and mRNA by immunohistochemistry and in situ hybridisation, respectively, while all 10 benign meningiomas were negative for c-myc immunostaining, with only one benign tumour positive for c-myc mRNA.