A number of studies are underway assessing the safety and efficacy of CXCR4 antagonists in patients with solid tumors, such as glioblastoma multiforme, and cancers of the pancreas, ovaries, and colon (ClinicalTrials.gov identifiers NCT02179970, NCT02737072, NCT02765165). This evidence concerns the gene CXCR4 and glioblastoma.