Exploring the Role of Macrophage Marker CD68 in Pediatric Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (pedAML) is a childhood malignancy with relapse rates of approximately 30%. CD68, a macrophage marker involved in phagocytosis and macrophage recruitment, may contribute to AML biology. We analyzed CD68 expression using the TARGET database and performed survival analyses, mRNA/protein profiling, and functional assays in AML cell lines, pedAML samples, and cord blood samples. High CD68 transcript levels correlated with KMT2A-rearrangements and inversion 16. Survival analysis showed that high CD68 predicted worse event-free survival, though not independently in a multivariate analysis. Flow cytometry confirmed higher CD68 expression in 7/8 pedAML samples compared to cord blood samples. Functionally, CD68 knockdown reduced proliferation and increased drug sensitivity, while overexpression promoted growth and resistance. Gene set enrichment analysis (GSEA) indicated enrichment of MAPK signaling, AP-1-mediated stress response, and epithelial-mesenchymal transition (EMT)/migration-associated pathways in CD68-high models. Together, these findings suggest that CD68 contributes to a pro-tumorigenic and stress-adaptive phenotype in pedAML and may represent a biologically relevant therapeutic target.