title: Retraction Note to: The Clinical Utility of Matrix Metalloproteinase 9 in Evaluating Pathological Grade and Prognosis of Glioma Patients: A Meta-Analysis.
authors.affiliation: Department of Pathology, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan, Shandong, China.
authors.forename: Xiangshan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Shandong University School of Medicine, Jinan, Shandong, China.
authors.forename: Shunzeng
authors.initials: S
authors.lastname: Lv
authors.affiliation: Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, Affiliated Hospital of Shandong Academy of Medical Sciences, Jinan, Shandong, China.
authors.forename: Daotang
authors.initials: D
authors.lastname: Li
authors.affiliation: Shandong University School of Medicine, Jinan, Shandong, China.
authors.forename: Ranran
authors.initials: R
authors.lastname: Shi
authors.affiliation: Shandong University School of Medicine, Jinan, Shandong, China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Shandong University School of Medicine, Jinan, Shandong, China.
authors.forename: Jianzhen
authors.initials: J
authors.lastname: Fan
authors.affiliation: Department of General Surgery, Affiliated Hospital of Shandong Academy of Medical Sciences, 38# wuyingshan Road, Jinan, Shandong, China. yangxiangshan163@163.com.
authors.forename: Zhongfa
authors.initials: Z
authors.lastname: Xu