Correlation of acute myeloid leukemia (AML) stem cell phenotype with cytogenetic/molecular features and prognosis.

7000 Background: Emerging evidence supports the clinical significance of leukemia stem cells (LSCs).We previously found that patients with AML exhibited 1 of 3 distinct LSC phenotypes based on CD34, CD38, and aldehyde dehydrogenase (ALDH): 1. CD34-, 2. CD34+CD38-ALDHintermediate (ALDHint), or 3. CD34+CD38-ALDHhigh (ALDHhigh) [Gerber, et al. Blood, 2012]. We hypothesized that LSC phenotypes might correlate with cytogenetic/molecular features and treatment outcomes. Methods: Diagnostic samples from 98 patients with newly diagnosed normal or unfavorable cytogenetic AML, enrolled on clinical protocol NCT01413880, were analyzed by FACS. Sorted cell populations were assayed by FISH and/or PCR for leukemia-specific abnormalities. Fisher’s exact and Mantel-Haenszel tests were used to analyze differences in risk factors and outcomes by LSC phenotype. Results: LSCs were CD34- in 21 cases; ALDHint in 44; and ALDHhigh in the remaining 33. Poor risk cytogenetics and/or FLT3-ITD mutations were uncommon in the CD34- (4/...