Background: Chromosome abnormalities are significant in the diagnosis, prognosis, and treatment of patients with hematologic malignancies. Rearrangements of the mixed lineage leukemia gene (KMT2A; i.e. MLL) can occur in acute myeloid leukemia cases and are associated with a poor prognosis in all leukemias.
Methods: We report a case of a 78 year old female with a past medical history of congestive heart failure, who presented with severe anemia (hemoglobin level of 6.4 g/dL), thrombocytopenia (platelet count of 57k/μL), and 17% blasts in the peripheral blood.
Results: The bone marrow core biopsy showed sheets of blasts consistent with acute myeloid leukemia with minimal maturation (AML M1). Flow cytometry showed a myeloid phenotype and expressed CD 33, 34, 38, 15, 135, 123, and 117. Cytogenetics showed a complex karyotype and G-banded chromosome analysis performed on bone marrow revealed: 47~52,X,-X,del(5)(q13q33),+6,+8,del(11) (q21q23.1),+13,der(16)t(16;18)(p10;q10),i(17)(q10),+1~3r(11)(p15q23)[cp15]. These cells had 1 to 3 ring chromosomes with amplified KMT2A and a deletion of KMT2A on one of the chromosome 11 homologs. FISH identified a deletion of the 5q31 (EGR1) region of chromosome 5, three copies of 8q21 (RUNX1T1), and 1-3 copies of 11q23 (KMT2A).
Conclusions: KMT2A amplification with ring chromosome 11 has been rarely reported. However, ring chromosome 11 in conjunction with the deletion of 11q (KMT2A) to our knowledge has never been reported. The patient completed Cycle 1 of Decitabine (5-aza-2’-deoxycytidine) but had to discontinue chemotherapy due to multiple complications, and subsequently expired in home hospice.
Keywords: KMT2A (11q23), MLL, ring chromosome 11, complex karyotype