CD34 and cancer: To evaluate if uORFs encode HLA-presented peptides that might serve as antigenic targets for cancer immune surveillance and immunotherapeutic approaches, mass spectrometry-based immunopeptidome profiling of primary malignant [n = 45, AML (n = 15), CLL (n = 15), OvCa [44] (n = 10), and Mel [45] (n = 5)] as well as benign tissue samples [n = 45, PBMCs (n = 30), CD34-enriched HPC (n = 5), and OvN (n = 10)] was applied (Fig. 3a).