THY1 and chronic myelogenous leukemia, BCR-ABL1 positive: In fact, in contrast to other tested antigens such as CD90 and IL-1RAP, which are co-expressed on CML LSCs, acute myeloid leukemia (AML) LSCs and normal HSCs, CD26 was the only marker, expressed in all tested CP CML patients, which was not present on CD34+/CD38− SC in normal BM or on LSCs of other myeloid neoplasms (17, 18).