Dick and colleagues’ seminal discovery in 1997 uncovered that cells expressing surface markers CD34+CD38− were able to differentiate in vivo in severe-combined-immunodeficiency-disease (SCID) mice into leukemic AML blasts; however, this description was broad and preliminary, as studies later revealed this same set of surface marker is also shared by normal HSCs and progenitor cells, sparking interest in the search of cellular markers that specifically encapsulate LSCs [15,16,17]. Here, CD34 is linked to acute myeloid leukemia.