PM marker positivity can be used to track disease progression and refine diagnostics. (A) PM marker expression (MFI) in de novo AML, MDS, sAML, and tAML (n = 289) vs NBM controls (n = 11). CD33 expression was determined in 50 cases (NBM, n = 11; AML, n = 50). Significant differences compared with NBM are indicated: *P < .05, **P < .01, ***P < .001. (B) Upregulation of PM markers in the AML cohort compared with NBM. Colors indicate a more than twofold increase in MFI compared with NBM (red), similar MFI compared with NBM (white), and not determined (gray). Percentages indicate the amount of patients that had increased expression of the marker at diagnosis (n = 256). (C and D) Disease progression of Patient 1 and Patient 2 portraying blast percentage and marker expression within CD34⁺ cells from diagnosis to treatment. Red indicates marker positivity. EuroFlow MRD was negative post–cycle 2 (EF MRD^–) based on EuroFlow criteria.