Across tumor types, RBP4 expression was markedly lower in BLCA, BRCA, CHOL, GBM, HNSC, KICH, KIRC, LIHC, LUAD, LUSC, PCPG, and PRAD, whereas elevated expression was detected only in COAD and STAD (Figure 1D). Here, RBP4 is linked to glioblastoma.