Among the 111 investigated ependymal tumors, we observed three distinct patterns of HOXB13 immunostaining, namely, strong nuclear immunoreactivity (dark brown staining in the vast majority or all tumor cells), weak nuclear immunoreactivity (faint staining of variable numbers of tumor cells), and no nuclear immunoreactivity (Fig. 1). This evidence concerns the gene HOXB13 and ependymal tumor.