Balanced chromosomal rearrangements define distinct entities in acute myeloid leukemia (AML). Here, we present 13 AML cases with t(8;16)(p11;p13) with observed low incidence (13/6124 patients), but more frequent presentation in therapy-related AML than in de novo AML (7/438 versus 6/5686, P=0.00001). Prognosis was poor with median overall survival of 4.7 months. Cytomorphology was characterized by parallel positive myeloperoxidase and non-specific esterase staining, therefore, French-American-British (FAB)-classification was impossible and origin of the AML with t(8;16) from an early stem cell with myeloid and monoblastic potential is hypothesized. Erythrophagocytosis was observed in 7/13 cases. Using gene expression profiling on 407 cases, patients with t(8;16) were compared to AML FAB subtypes with normal karyotype. Principal component analyses demonstrated that AML with t(8;16) were distinct from FAB subtypes M1, M4, M5a/b. When further compared to AML showing balanced rearrangements, that is, current WHO categories t(15;17), t(8;21), inv(16) and t(11q23)/MLL, AML with t(8;16) cases were clustered close to t(11q23)/MLL sharing commonly expressed genes. Subsequently, a pairwise comparison discriminated AML with t(8;16) from AML with t(11q23)/MLL, thus defining a highly unique signature for AML with t(8;16). In conclusion, AML with t(8;16) demonstrates unique cytomorphological, cytogenetic, molecular and prognostic features and is a specific subtype of AML.
Balanced chromosomal rearrangements define distinct entities in acute myeloid leukemia (AML). Here, we present 13 AML cases with t(8;16)(p11;p13) with observed low incidence (13/6124 patients), but more frequent presentation in therapy-related AML than in de novo AML (7/438 versus 6/5686, P=0.00001). Prognosis was poor with median overall survival of 4.7 months. Cytomorphology was characterized by parallel positive myeloperoxidase and non-specific esterase staining, therefore, French-American-British (FAB)-classification was impossible and origin of the AML with t(8;16) from an early stem cell with myeloid and monoblastic potential is hypothesized. Erythrophagocytosis was observed in 7/13 cases. Using gene expression profiling on 407 cases, patients with t(8;16) were compared to AML FAB subtypes with normal karyotype. Principal component analyses demonstrated that AML with t(8;16) were distinct from FAB subtypes M1, M4, M5a/b. When further compared to AML showing balanced rearrangements, that is, current WHO categories t(15;17), t(8;21), inv(16) and t(11q23)/MLL, AML with t(8;16) cases were clustered close to t(11q23)/MLL sharing commonly expressed genes. Subsequently, a pairwise comparison discriminated AML with t(8;16) from AML with t(11q23)/MLL, thus defining a highly unique signature for AML with t(8;16). In conclusion, AML with t(8;16) demonstrates unique cytomorphological, cytogenetic, molecular and prognostic features and is a specific subtype of AML.