FoxM1 was detected both in the cytoplasm and nucleus of tumor cells with more prominent expression in nucleus, as previously reported.[27] To quantify FoxM1 protein level, we have applied an immunoreactive score (IRS) method (Fig 7A).[26, 31] FoxM1 protein level was rarely detected in low-grade glioma patients (15.4% of grade II was positive), whereas grade III and grade IV glioma specimens exhibited significantly higher FoxM1 level (64% of grade III and 75% of grade IV were positive) (Fig 7B). This evidence concerns the gene FOXM1 and central nervous system cancer.