CD34 and acute myeloid leukemia: To identify widely applicable and naturally presented LPC antigens, we used a well-established mass spectrometry-based immunopeptidomics workflow within a large cohort of primary AML samples (taken from patients at first diagnosis as well as in a relapse situation), to identify frequent HLA class I- and HLA class II-restricted antigenic peptides presented exclusively on the CD34+CD38- LPC subpopulation or on both LPCs and AML blasts (20).