BRCA1 and central nervous system cancer: Whereas there was no significant difference in the percentage of BRCA1+ cells in WHO grade III versus IV gliomas (mean positivity 39.85 and 41.6% of BRCA+ cells, respectively), both grade III and IV tumours (high-grade gliomas, HGG) exhibited higher percentage of BRCA1+ cells compared with either NB or WHO grade II gliomas (P<0.0001, One-way ANOVA and Tukey’s multiple comparisons test; low-grade gliomas, LGG; Fig. 6b).