CTSS and glioblastoma: Notably, MR analyses revealed putative causal associations between higher genetically predicted plasma levels of three hub proteins-CD63, CTSS, and S100A4-and an increased risk of GBM, with S100A4 showing the strongest effect (odds ratio [OR] = 2.03, 95% confidence interval [CI] 1.15-3.58, <i>p</i> = 0.0149).