Role of radiotherapy and chemotherapy in the risk of leukemia after childhood cancer: An international pooled analysis.

Childhood cancer survivors are at increased risk for second primary leukemia (SPL), but there is little consensus on the magnitude of some risk factors because of the small size of previous studies. We performed a pooled analysis of all published studies with detailed treatment data, including estimated active bone marrow (ABM) dose received during radiation therapy and doses of specific chemotherapeutic agents for childhood cancer diagnosed from 1930 through 2000, in order to more thoroughly investigate treatment-related risks of SPL. A total of 147 SPL cases (of which 69% were acute myeloid leukemia [AML]) were individually matched to 522 controls, all from four case-control studies including patients from six countries (France, United Kingdom, United States, Canada, Italy and Netherlands). Odds ratios (OR) and corresponding 95% confidence intervals (CIs) were calculated using conditional logistic regression, and the excess OR per Gray (EOR/Gy) was also calculated. After accounting for the other therapies received, topoisomerase II inhibitor was associated with an increased SPL risk (highest tertile vs none: OR = 10.0, 95% CI: 3.7-27.3). Radiation dose to the ABM was also associated with increased SPL risk among those not receiving chemotherapy (EOR/Gy = 1.6, 95% CI: 0.1-14.3), but not among those who received chemotherapy (CT). SPL were most likely to occur in the first decade following cancer treatment. Results were similar when analyses were restricted to AML. The evidence of interaction between radiation and CT has implications for leukemogenic mechanism. The results for topoisomerase II inhibitors are particularly important given their increasing use to treat childhood cancer.

Heme oxygenase-1 plays a crucial role in chemoresistance in acute myeloid leukemia.

OBJECTIVES: The heme oxygenase-1 (HO-1) gene may contribute to the development of acquired chemoresistance in solid tumor cells, but its function in acute myeloid leukemia (AML) remains unclear. Therefore, we investigated whether the expressions of HO-1 mRNA and protein were associated with AML chemoresistance. METHODS: Bone marrow or peripheral blood was obtained from newly diagnosed (n = 26), relapsed (n = 10), and completely remitted (n = 18) patients with AML (M3 exclusion) and healthy donors (n = 10). Small interfering RNA was used to stably silence HO-1 gene expression in AML cell lines. The expressions of HO-1, hypoxia inducible factor-1ɑ (HIF-1ɑ), glucose transporter-1 (GLUT1) mRNA and proteins were measured by quantitative real-time PCR and Western blot. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis induction was analyzed by flow cytometry. RESULTS: The drug-resistant AML cell line HL-60R was significantly less sensitive to cytarabine and daunorubicin than HL-60 cells. HO-1 mRNA and proteins were highly expressed in HL-60R cells. However, down-regulating HO-1 significantly enhanced the sensitivity of HL-60R to chemotherapy, and the expressions of HIF-1ɑ and GLUT1 mRNA and proteins decreased. Meanwhile, the expressions of caspase-3 and caspase-8 proteins increased, while that of bcl-2 decreased. Overexpressions of HO-1, HIF-1ɑ, and GLUT1 were associated with poor response of AML to chemotherapy. Conclusions Overexpressions of HO-1, HIF-1ɑ, and GLUT1 might be involved in the chemoresistance of AML. HO-1 is a potential target to overcome the drug resistance of AML.

Depletion of L-ascorbic acid alternating with its supplementation in the treatment of patients with acute myeloid leukemia or myelodysplastic syndromes.

PURPOSE: L-ascorbic acid (LAA) modifies the in vitro growth of leukemic cells from approximately 50% of patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS). To test the hypothesis that depletion of LAA, alternating with supplementation to prevent scurvy, would provide therapeutic benefit, a single-arm pilot trial was conducted (ClinicalTrials.gov identifier: NCT00329498). Experimental results: During depletion phase, patients with refractory AML or MDS were placed on a diet deficient in LAA; during supplementation phase, patients received daily intravenous administration of LAA. An in vitro assay was performed pretherapy for LAA sensitivity of leukemic cells from individual patients. RESULTS: Of 18 patients enrolled, eight of 16 evaluable patients demonstrated a clinical response. Responses were obtained during depletion (four patients) as well as during supplementation (five patients) but at a pharmacologic plasma level achievable only with intravenous administration. Of nine patients for whom the in vitro assay indicated their leukemic cells were sensitive to LAA, seven exhibited a clinical response; compared with none of six patients who were insensitive to LAA. CONCLUSIONS: The clinical benefit, along with a conspicuous absence of significant adverse events, suggests that further testing of LAA depletion alternating with pharmacologic dose intravenous supplementation in patients with these and other malignancies is warranted.

Randomized comparison of cooked and noncooked diets in patients undergoing remission induction therapy for acute myeloid leukemia.

PURPOSE: A neutropenic diet is often used to prevent infection in patients with acute myeloid leukemia (AML). Although such a diet potentially entails inconvenience, its value is uncertain. PATIENTS AND METHODS: One hundred fifty-three patients admitted to a high-efficiency particulate air-filtered room (protected environment [PE]) to receive induction therapy for newly diagnosed AML were randomly assigned to a diet containing no raw fruits or vegetables (cooked diet) or to a diet containing fresh fruit and fresh vegetables (raw diet). Stratification was based on the patients' early risk of mortality (ERM) score. All patients received antibacterial and antifungal prophylaxis and remained on study until they were discharged from the PE. The outcomes of principal interest were major infection (pneumonia, bacteremia, or fungemia) and death; if the true probability of either event was 20% on the cooked arm and 40% on the raw arm, then the probability that the cooked arm would be selected as superior was 83%. RESULTS: Seventy-eight patients were randomly assigned to the cooked arm, and 75 were assigned to the raw arm. The two groups were similar with respect to age, ERM, chemotherapy received, and days at risk. Twenty-nine percent of patients in the cooked group and 35% of patients in the raw group developed a major infection (P = .60). Time to major infection and survival time were similar in the two groups. Fever of unknown origin occurred in 51% of the cooked group and 36% of the raw group. CONCLUSION: In patients treated in a PE, a neutropenic diet did not prevent major infection or death.

Sensitivity toward sorafenib and sunitinib varies between different activating and drug-resistant FLT3-ITD mutations.

OBJECTIVE: Activating mutations in FLT3 are known to be a frequent transforming event in acute myeloid leukemia. Small molecule-inhibitor therapy targeting the FLT3 kinase is, therefore, an attractive strategy. FLT3 kinase inhibitors, such as PKC412, have already entered clinical trials. Even though results are encouraging, emergence of primary and secondary resistance does occur in the majority of patients. Thus, it will be crucial to carefully characterize the activity of every single compound against different activating and resistance FLT3-internal tandem duplication (ITD) mutations. Here we tested the efficacy of sunitinib and sorafenib to inhibit primary FLT3 activating mutations (ITD and D835Y) and of secondary resistance mutations. METHODS: Ba/F3 cell lines stably expressing oncogenic FLT3 mutations were used to calculate cellular IC(50) values for sunitinib and sorafenib using cell proliferation assays. Differential IC(50) values for sorafenib toward FLT3-ITD and FLT3-D835Y were confirmed by Western blotting. Cell death was measured by propidium-iodide staining and flow cytometry. RESULTS: Sorafenib inhibits FLT3-ITD more potent than FLT3-D835Y, while sunitinib is equally effective against both mutant forms of FLT3. Importantly, sensitivity toward sorafenib and sunitinib varies between the different secondary FLT3-ITD resistance mutations. CONCLUSIONS: These results establish sensitivity profiles for the FLT3 inhibitors sunitinib and sorafenib. This may help to develop rational treatment strategies for acute myeloid leukemia with these compounds.

Complete remission achieved in a case of both primary and recurrent adult acute myelogeneous leukemia by a novel nutritional therapy.

OBJECTIVES: The aim of this study was to determine the possible clinical benefit of molasses-based dietary compositions (designated as MSQ 13, MSQ 15, and MSQ 18) in a case of both primary and recurrent adult AML. DESIGN: The design was a single case study. SETTINGS/LOCATION: The setting was in the home. INTERVENTIONS: The regime of dietary compositions initially was administered as follows: MSQ-13 1 tbsp t.i.d. for 1 mo, MSQ-15 2 tbsp t.i.d. for 3 mo. After recurrence, MSQ-18 was taken at 2 tbsp t.i.d. for 3 mo. OUTCOME MEASURES: Clinical improvement and regression of AML were the outcome measures. CONCLUSIONS: Treatment with the MSQ dietary compositions resulted in disease regression and the reversal of clinical manifestations over two episodes of AML. Therefore, further studies are warranted to evaluate the utility of this approach for the clinical management of AML.