Objective To investigate the clinical significance of the differential expression of CD44 in glioblastoma(GBM),and the enrichment of related pathways combined with U87 cell verification.Methods Differential ex-pression and Cox analysis were used to find potential differences in CD44 expression between tumor patients and healthy people as shown by pancancer transcriptome and hazard ratio(HR).Immunoinfiltration and stem-cell re-lated scores of GBM patients with high and low CD44 expression groups were compared and the differences be-tween immune cell subsets,and their correlation with CD44 were further analyzed.Pathway enrichment of differen-tially expressed genes in high and low CD44 expression groups for GBM patients was performed.Over-expression(OE),knockdown(KD)and knockout(KO)of CD44 in U87 cells was done by constructing and packaging lenti-virus and using the electroribonucleoprotein complex;CD44 immunofluorescence staining was performed on U87 and U87 CD44 OE cells.The activity and apoptosis of U87 cells were detected by knocking down CD44 and the mi-gration and invasion ability of U87 cells were detected by knocking down CD44.Results The expression of CD44 in GBM patients was higher than that in healthy people(P＜0.05)and HR＞1.GBM patients with high CD44 ex-pression had higher stromal cell and immunoinfiltration scores,and GBM patients with high and low CD44 expres-sion had significant differences in the ratio of dendritic cells,CD4+memory T cells and regulatory T cells,all posi-tively correlated with CD44 expression(P＜0.05).Differential gene enrichment in GBM patients with high and low CD44 expression was further associated with pathways related to cell migration and apoptosis(P＜0.05).Experi-ments using U87 cells showed that CD44 was normally localized in the cell membrane,but for CD44 OE it accumu-lated in the cytoplasm.CD44 KD can lead to a decrease in cell viability,increased in cell apoptosis,with the cell migration and invasion ability of CD44 KO also decreasing(P＜0.05).Conclusions Low expression of CD44 can decrease viability,migration and invasion of U87 cells and promote apoptosis rate of U87 cells,which leads to the deterioration of GBM and is a related factor potentially affecting the prognosis of GBM patients.