Nevertheless, of these eligible studies, the study by McKean-Cowdin et al. [18] combined the genetic data for XRCC1 polymorphisms (including Arg194Trp, Arg399Gln) from four centers in the United States that have conducted case-control studies on glioblastoma multiforme, including the National Cancer Institute (NCI), the National Institute for Occupational Safety and Health (NIOSH), the University of Texas M. D. Anderson Cancer Center (MDA), and the University of California at San Francisco (UCSF). Here, XRCC1 is linked to glioblastoma.