The MLL1 (mixed lineage leukemia 1) protein, which is often disrupted in leukemia, both activates and represses Hox genes during hematopoiesis. Now, Wang et al. (2010) demonstrate that the cyclophilin CyP33 underpins this regulatory switch by altering the state of MLL1 through cis-trans proline isomerization in the linker region between MLL1's third PHD finger and bromodomain.

BACKGROUND The hierarchical organization of hematopoiesis with unidirectional lineage determination has become a questionable tenet in view of the experimental evidence of reprogramming and transdifferentiation of lineage-determined cells. Clinical examples of hematopoietic lineage plasticity are rare. Here we report on a patient who presented with an acute B-lymphoblastic leukemia and develope...

Over a two-year period, immunophenotypic patterns of 266 acute leukemia cases were analyzed using a panel of tests including TdT, SmIg and 9 surface antigens by the immunofluorescence stains for the assessment of the incidence and grade of phenotypic ambiguity (lineage infidelity) and the possible clinical significance of unusual immunophenotypes. Immunophenotypes were classified into four grou...

Mice with severe combined immunodeficiency (SCID) provide a model system to examine the in vivo homing, engraftment, and growth patterns of normal and malignant human hematopoietic cells. The relation between leukemic cell growth in this model and the treatment outcome in patients from whom cells were derived has not been established. Leukemic cells from 42 children with newly diagnosed high-ri...

Since mid-1990s, the field of cancer immunotherapy has seen steady growth and selected immunotherapies are now a routine and preferred therapeutic option of certain malignancies. Both active and passive cancer immunotherapies exploit the fact that tumor cells express specific antigens on the cell surface, thereby mounting an immune response specifically against malignant cells. It is well estab...

A new recurring chromosome abnormality was identified in 8 of 621 consecutive successfully karyotyped adults with de novo acute leukemia. These eight patients had trisomy 13 as the sole cytogenetic abnormality. On central morphologic review, five cases were classified as subtypes of acute myeloid leukemia, one as acute mixed lymphoid and myeloid leukemia, one as acute lymphoid leukemia, and one...

BACKGROUND Patients with acute leukemia can express aberrant markers, defined as antigens that are normally restricted to a different lineage. The reported significance and frequency of these markers is inconclusive. We assessed the frequency and impact of aberrant markers in patients with acute leukemia in a referral institution in Mexico City. METHODS We included 433 patients, diagnosed and...

A recent report by Pui et all focused on the biologic and clinical relevance of acute mixed-lineage leukemia; namely, acute lymphoblastic leukemia expressing myeloid-associated antigens (My+ ALL) and acute myeloid antigens expressing lymphoid antigens (Ly+ AML) were analyzed in a pediatric series. In our opinion, a major point in the field of hybrid acute leukemia remaining undetermined is whic...

GOALS Cell population data (CPD) are new morphologic parameters including volume, conductivity, and five light scattering characteristics used for leukocyte classification by an automated hematology analyzer, the UniCel DxH 800. We developed a discriminating CPD model to predict the leukemia lineage during routine complete blood cell count (CBC). PROCEDURES We analyzed the CPD of 405 blood sa...

Erythrophagocytosis by neoplastic cells in acute leukemia has been most frequently associated with FAB M4 and M5 subtypes, with the t(8;16) and with C-MOZ rearrangements, however it is exceptional in acute lymphoblastic leukemia and has not been previously reported in Philadelphia-positive (Ph+) acute leukemia. We herein present a case of Ph+ acute leukemia of ambiguous lineage in which erythro...