Targeting chronic myeloid leukemia stem cells.

Chronic myeloid leukemia (CML) arises as a consequence of a chromosomal translocation giving rise to the Philadelphia chromosome and Bcr-Abl oncogene. CML is a clonal disease of stem cell origin and an excellent example of a malignancy in which tumor-initiating cells may hold the key to disease eradication. The known molecular basis of CML has enabled the development of Abl-specific tyrosine kinase inhibitors, such as imatinib mesylate. However, the success of tyrosine kinase inhibitors, as rationally designed first-line therapies, has been tempered by problems of disease persistence and resistance. Residual disease has been shown to be enriched within the stem cell compartment and to persist at stable levels for up to 5 years of complete cytogenetic response. This finding has led to further searches for novel strategies aimed at eliminating these cells; such strategies may be essential in achieving cure. The most significant recent findings are discussed in this review.

Analysis of human leukaemias and lymphomas using extensive immunophenotypes from an antibody microarray.

A novel antibody microarray has been developed that provides an extensive immunophenotype of leukaemia cells. The assay is a solid phase cell-capture technique in which 82 antigens are studied simultaneously. This paper presents the analysis of 733 patients with a variety of leukaemias and lymphomas from peripheral blood and bone marrow. Discriminant Function Analysis of the expression profiles from these 733 patients and 63 normal subjects were clustered and showed high levels of consistency with diagnoses obtained using conventional clinical and laboratory criteria. The overall levels of consensus for classification using the microarray compared with established criteria were 93.9% (495/527 patients) for peripheral blood and 97.6% (201/206 patients) for bone marrow aspirates, showing that the extensive phenotype alone was frequently able to classify the disease when the leukaemic clone was the dominant cell population present. Immunophenotypes for neoplastic cells were distinguishable from normal cells when the leukaemic cell count was at least 5 x 10(9) cells/l in peripheral blood, or 20% of cells obtained from bone marrow aspirates. This technique may be a useful adjunct to flow cytometry and other methods when an extensive phenotype of the leukaemia cell is desired for clinical trials, research and prognostic factor analysis.

A randomized trial of high-versus conventional-dose cytarabine in consolidation chemotherapy for adult de novo acute myeloid leukemia in first remission after induction therapy containing high-dose cytarabine.

The value of administering sequential courses of chemotherapy containing high-dose cytarabine in both induction and consolidation therapy for acute myeloid leukemia (AML) has not been assessed in a prospective randomized trial. Two hundred ninety-two AML patients aged 15 to 60 years were enrolled in the Australasian Leukaemia and Lymphoma Group (ALLG) AML trial number 7 (M7) protocol to evaluate this question. All received induction therapy with the ICE protocol (idarubicin 9 mg/m2 x 3; cytarabine 3 g/m2 twice a day on days 1, 3, 5, 7; etoposide 75 mg/m2 x 7). Complete remission was achieved in 234 (80%) patients. Two hundred two patients in remission were then randomized to either a further identical cycle of ICE or 2 attenuated courses (cytarabine 100 mg/m2 daily x 5, idarubicin x 2, etoposide x 5 [IcE]). ICE consolidation therapy was more toxic than IcE, however, the treatment-related death rate was not significantly different. There was no difference between the 2 consolidation arms for relapse-free survival at 3 years (49% for ICE vs 46% for IcE; P = .66), survival following randomization (61% vs 62%; P = .91), or the cumulative incidence of relapse (43% vs 51%; P = .31), and there was no difference within cytogenetic risk groups. Intensive induction chemotherapy incorporating high-dose cytarabine results in high complete remission rates, but further intensive consolidation treatment does not appear to confer additional benefit.

Unusual case of subcutaneous panniculitis-like T-cell lymphoma.

An unusual case of subcutaneous panniculitis-like T-cell lymphoma is presented involving multiple organ systems, which eventually culminated in rapid demise from the haemophagocytic syndrome, after an initial protracted course. A 44-year-old man presented in April 2001 with bronchiolitis obliterans organising pneumonia that initially responded well to corticosteroids. However, the condition relapsed on attempted prednisone withdrawal in January 2002 and the patient was noted to have developed truncal subcutaneous nodules. Initial skin biopsy revealed lobular panniculitis, with negative microbiological culture. In July 2002, mononeuritis multiplex was diagnosed after the patient presented with paresthesiae and was treated with pulse cyclophosphamide therapy. By November 2002 there was ulceration of the subcutaneous nodules. Repeat skin biopsy revealed subcutaneous panniculitis-like T-cell lymphoma. The clinical manifestations were supportive of an unifying diagnosis of malignancy involving pulmonary, cutaneous and nervous systems. Combination chemotherapy with fludarabine, mitoxantrone and dexamethasone was commenced. However, the patient deteriorated, with fevers, weight loss, pancytopenia and laboratory features consistent with the haemophagocytic syndrome. Despite maximal supportive therapy the patient succumbed to his disease.