Minor myeloid component in Ph chromosome-positive acute lymphoblastic leukaemia: correlation with cytogenetic pattern and implication for poor response to therapy

Additional clonal abnormalities in Philadelphia-positive ALL and CML demonstrate a different cytogenetic pattern at diagnosis and follow different pathways at progression

The cytogenetic patterns in addition to the Philadelphia translocation in Philadelphia-positive (Ph+) ALL and chronic myeloid leukemia (CML) is heterogenous. We investigated 154 patients with Ph+ ALL at diagnosis or at relapse and 174 patients with different phases of CML. Ph+ ALL at diagnosis demonstrated a heterogenous pattern with a high frequency of numerical and structural chromosomal aberrations. CML at diagnosis presented with rare additional chromosomal changes. In Ph+ ALL, the pathway from diagnosis to relapse was characterized by the acquisition of a higher number of chromosomal aberrations, but the pattern of frequent aberrations at relapse did not differ from that observed at diagnosis. In contrast, in CML the pathway from chronic to the advanced phases was characterized by the acquisition of new chromosomal changes and by the development of karyotype complexity. In addition, the investigation of 10 cases of lymphoid blast crisis of CML showed significant differences in the karyotype in comparison to Ph+ ALL at diagnosis. Therefore, the karyotype can be helpful in discriminate de novo lymphoid blast crisis of CML from de novo Ph+ ALL. In conclusion, we were able to demonstrate that the cytogenetic patterns of Ph+ ALL and of CML are different at diagnosis and furthermore follow different pathways during progression or relapse.

Additional cytogenetic abnormalities in adults with Philadelphia chromosome-positive acute lymphoblastic leukaemia: a study of the Cancer and Leukaemia Group B

We analysed the nature and prognostic significance of secondary cytogenetic changes in 111 newly diagnosed adults with acute lymphoblastic leukaemia (ALL) and t(9;22)(q34;q11.2) or its variants. Secondary aberrations were seen in 75 (68%) patients. They included, in order of descending frequency: +der(22)t(9;22), +21, abnormalities of 9p, high hyperdiploidy (>50 chromosomes), +8, -7, +X and abnormalities resulting in loss of material from 8p, gain of 8q, gain of 1q and loss of 7p. Eighty patients (72%) had > or =1 normal metaphase in their karyotype. There were four balanced and 12 unbalanced translocations previously unreported in ALL with t(9;22). The t(2;7)(p11;p13) and der(18)t(8;18)(q11.2;p11.2) were seen in two cases each, and have never before been reported in haematological malignancy. All but four patients were treated on front-line Cancer and Leukaemia Group B clinical protocols. The presence of -7 as a sole secondary abnormality was associated with a lower complete remission (CR) rate (P = 0.004), while the presence of > or =3 aberrations was associated with a higher CR rate (P = 0.009) and +der(22)t(9;22) with a higher cumulative incidence of relapse (P = 0.02). It will be of interest to see if newly diagnosed t(9;22)-positive adult ALL patients with these and other secondary aberrations respond differently to treatment regimens that include imatinib mesylate.

Clinical sensitivity to anthracyclines in PH/BCR+ acute lymphoblastic leukemia

Translocation t(9;22) or Philadelphia chromosome (Ph)/BCR-ABL rearrangement positive acute lymphoblastic leukemia (Ph/BCR+ ALL) is associated with a very short survival of about one year in most patients. We analyzed long-term outcome of 76 adults with Ph/BCR+ ALL, in order to detect which factors were associated with longer survival. Modifiable prognostic factors included type of treatment, allogeneic marrow transplant (allo-BMT), and early anthracycline dose intensity (high = H/A, low = L/A); unmodifiable factors were age, gender, FAB morphology, phenotype, blast count, P190/210 transcript, hepatospleno-lymphadenopathy, LDH level. Median patient age was 43 years (range 15-71). Four favorable prognostic factors (FPF) were found associated with greater likelihood of complete remission (blast count < 50 x 10(9)/l, p = 0.08), longer remission duration (age < 50 years, p < 0.001; H/A, p < 0.05), and lower relapse rate (allo-BMT, p = 0.017). Age and anthracycline dose intensity exerted a synergistic prognostic effect. According to the cumulative incidence of FPF in each patient (FPF 0-1 = 29, 2-3 = 42, 4 = 5), the probability of survival increased from nil to 0.22 to 0.60 at 5 years (p < 0.005). Adult Ph/BCR+ ALL is relatively sensitive to anthracyclines, which therefore should be prescribed at full dosage to patients not eligible to allo-BMT or in the waiting list for unrelated donor transplantation.

Coexpression of lymphoid and myeloid markers on cell surfaces

Cells coexpressing lymphoid and myeloid cell surface markers have been described for various leukemias and non-Hodgkin's lymphomas. It is unclear whether these mixed lineage characteristics are due to malignancies of early progenitor cells or alternatively to malignant cells with lineage infidelity. Recently, it has been shown that cells coexpressing lymphoid and myeloid markers can be generated from peripheral blood lymphocytes from normal individuals as well. In this review, consequences of this surprising fact are discussed.

FLAG (fludarabine, cytarabine, G-CSF) as a second line therapy for acute lymphoblastic leukemia with myeloid antigen expression: in vitro and in vivo effects

Thirteen consecutive adult patients with primary refractory (n = 5) or relapsed (n = 8) acute lymphoblastic leukemia (ALL) were treated by an induction schedule (FLAG) consisting of Fludarabine (30 mg/sqm/d) plus high dose Cytarabine (HD-ara-C: 2 g/sqm/d) (d 1-5) and G-CSF (from d O to polymorphonuclear recovery). Patients achieving complete remission (CR) were administered a second FLAG course as consolidation and were then submitted to an individualized program of post-remission therapy, depending on the patient's age and performance status. CR was achieved in 8/12 evaluable cases (67%). The median CR duration was 22.5 w. CR attainment was significantly related to the co-expression of lymphoid and myeloid antigens. ALL/My+ patients achieved CR in 6/6 evaluable cases vs. 2/6 for ALL/My+. In vitro 3H ara-C incorporation into cellular DNA resulted significantly increased by Fludarabine (in 7/9 tested cases) and, furthermore, by the association of Fludarabine G-CSF in 5 evaluable ALL/My+ cases; in contrast, no effect of G-CSF addition to Fludarabine was observed in 4 ALL/My. Myelosuppression was observed in all patients: the median time to neutrophils > 0.5 x 10(9)/1 was 16.3 d (range 13-22) and 16.2 d (range 9-29) to platelets > 20 x 10(9)/1. Nonhematological toxicity was minimal. In conclusion, FLAG is an active and tolerable combination in refractory ALL, particularly in cases with myeloid antigen expression where G-CSF appears to improve efficacy, probably increasing ara-C incorporation into the DNA of leukemic cells.

Cytogenetics of hybrid acute leukemias

Although the recognition of hybrid acute leukemia (HAL) is still controversial, several reports have described cytogenetic findings in these leukemias over the last 3 years. A distinct chromosomal profile appears to be associated with different immunologic subsets of HAL. The classical t(15;17), and inv(16) as well as abnormalities of the long arm of chromosome 5 and/or 7 are preferentially associated with acute myeloid leukemia (AML) with T-cell features; the t(8;21)(q22;q22), the Ph chromosome, and 11q23 rearrangements are more frequently found in AML with B-cell features; the Ph chromosome, t11q23 and 14q32 breaks without rearrangements of the immunoglobulin heavy chain gene may be associated with acute lymphoblastic leukemia (ALL) with myeloid markers. In addition, some chromosome aberrations may be encountered more frequently in acute leukemia with major phenotype deviations than in unselected cases of acute leukemia: namely the Ph chromosome, 11q23 rearrangements, and +13. These chromosome changes appear to be associated with a low complete remission (CR) rate. An association has been documented in some patients with ALL between the presence of the t(9;22) and a minor myeloid component consisting of 5-15% blast cells with myelomonocytic features, raising the possibility that a diagnosis of bilineal acute leukemia would be more appropriate in such cases. These patients appear to have a severe outcome with significantly lower CR rate than similar cases of Ph-positive ALL without a minor myeloid component.(ABSTRACT TRUNCATED AT 250 WORDS)