CD44 and glioblastoma: Similarly, the expression of mesenchymal subtype markers, such as FN, Vim, and YKL-40 (a marker for the mesenchymal subtype of glioblastoma [13], also known as Chitinase-3-like protein 1, CHI3L1), was induced by irradiation and suppressed by blocking CD44 expression (Figure 1H).