Although only three out of six PFA ependymomas in this study were tested for the histone H3K27M mutation, these cases turned out to be negative, being in line with our observation that all PFA ependymoma cases stained negative for H3K27me3 and positive for CXorf67 in contrast to all other subgroups (Figure 2). The gene discussed is EZHIP; the disease is ependymoma.