CHI3L1 and central nervous system cancer: They found, by PCR analysis, that the expression of collagen, MMP-9, smooth muscle α-actin (α-SMA), CD44, FN, and YKL-40 are elevated in the recurrent glioma samples, and using IHC staining, they demonstrated that the expression level of VIM, α-SMA, and CD44 is increased in 22 cases of clinically recurrent gliomas [69].