CD44 and central nervous system cancer: Subgroup analyses showed that higher tumor CD44 expression significantly predicted poor OS in patients with World Health Organization (WHO) stages II–III glioma (HR: 2.99, 95% CI: 1.53–5.89, P=0.002), but not in patients with glioblastoma (HR: 1.26, 95% CI: 0.76–2.08, P=0.47; P for subgroup difference = 0.03).