CD99 and acute myeloid leukemia: Among the subsets of AML subtypes characterised by the expression of the CD34 stem/progenitor marker, AML-LSCs exhibit a CD34+CD38- phenotype and can express other markers, including CD123, CD45RA, CD96, CLL-1, TIM-3, CD93 and CD99 [3, 4, 11, 12].