CD8A and neoplasm: Clinical sample verification showed that after HBOT treatment in patients with glioblastoma, the concentration of MMP-9 in tumor stroma fluid increased from a baseline of 87 ± 12 ng/mL to 145 ± 18 ng/mL, positively correlating with the infiltration rate of CD8+ T cells in the tumor tissue (r=0.71, P<0.05) (27).