We conclude that CBFB/MYH11 fusion transcript detection, as a surrogate for the favorable prognosis and treatment planning implied by inv(16) in AML M4Eo, should not be exclusively relied upon in AML M1 in the absence of prospective study of this specific (M1) category of AML.     ///    Clinical aspects of expression of inversion 16 chromosomal fusion transcript CBFB/MYH11 in acute myelogenous leukemia subtype M1 with abnormal bone marrow eosinophilia..     ///    "However, the CBFB/MYH11 fusion transcript was not detected in the relapsed specimen. "    ///    We expand upon our prior abstract of a case of AML subtype M1 with abnormal eosinophils that expressed the inversion 16 fusion transcript CBFB/MYH11. 