The expression of the steroidogenic enzymes P450 cholesterol side‐chain‐cleavage and P450‐aromatase (P450arom) in glioma cell lines and tumour biopsies also accounts for the possible participation of steroid hormones in GBM. Papadoupulos et al.11confirmed the presence of cytochrome P450 cholesterol side‐chain‐cleavage enzyme by immunoblotting in the mitochondria of the rat GB C6 cell line. The gene discussed is CYP19A1; the disease is central nervous system cancer.