CD44 and glioblastoma: We confirmed that the mean value of the P/C ratio of CD44 expression in the GBM of the high-invasive type (all patients in the ER group) was significantly higher than that in the GBM of the low-invasive type (all patients in the LN group) (HI/ER: 11.12 ± 4.18 (mean ± SD), LI/LN: 1.12 ± 0.42, p = 0.00017) (Figure 4).