Role of CD68 in Tumor Immunity and Prognosis Prediction: A Pan-Cancer Analysis

CD68 plays a critical role in promoting phagocytosis. However, the function of CD68 in tumor immunity and prognosis remains unknown. This study systematically analyzed CD68 expression among 33 tumor and normal tissues from the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) datasets. In addition, the relationship between the expression of CD68 and cancer prognosis, immune infiltration, checkpoint markers, drug response were explored. Upregulated levels of CD68 were observed in various cancer types, which were verified through tumor tissue chips using Immunohistochemistry. High expression of CD68 in tumor samples correlates with an adverse prognosis in GBM, KIRC, LGG, LIHC, LUSC, THCA, and THYM while with a better prognosis in KICH. The top three negatively enriched KEGG terms in the high CD68 subgroup were chemokine signaling pathway, cytokine-cytokine receptor interaction, cell adhesion molecules cams, and the top negatively enriched HALLMARK terms included complement, allograft rejection, and inflammatory response. Based on CD68 levels, a series of targeted drugs and small molecule drugs with promising therapeutic effects were predicted. The clinical prognosis and immune infiltration of high expression levels of CD68 differ across different tumor types. Inhibiting the CD68-dependent signaling could be a promising therapeutic strategy of immunotherapy in many tumor types.