title: Comments on Li H et al. "A systematic review of matrix metalloproteinase 9 as a biomarker of survival in patients with osteosarcoma".
abstract: With great interest, we read the article "A systematic review of matrix metalloproteinase 9 as a biomarker of survival in patients with osteosarcoma" (by Li H et al.). This article suggests that high expression of matrix metalloproteinase 9 (MMP-9) is associated with a poor prognosis for patients with osteosarcoma [1]. The result is encouraging. Nevertheless, some flaws existed in this meta-analysis that we would like to point out.
authors.affiliation: Department of Orthopedics, Qilu Hospital Shandong University, No.107, West Wenhua Road, Jinan, 250012, Shandong, China, zqy2008512@163.com.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Li
authors.forename: Fanxiao
authors.initials: F
authors.lastname: Liu
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Li
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001859:Bone Neoplasms / Q000401:mortality*; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000032:analysis*; D012516:Osteosarcoma / Q000401:mortality*
chemical_list: D014408:Biomarkers, Tumor; D020780:Matrix Metalloproteinase 9