Zhang et al. (2019) reported the positive expression of MMP-2 in glioma was closely related to the tumor diameter, severity of peritumoral edema, degree of enhancement, and pathological grade of tumor observed in magnetic resonance imaging (MRI). In addition, MMP-2 was highly expressed in brain glioma, and it was considered as a negative factor for prognosis (Zhang et al., 2019). Here, MMP2 is linked to central nervous system cancer.