Numerous articles and several reviews have been published on the role of antioxidants, and diet and lifestyle modifications in cancer prevention. However, the potential role of these factors in the management of human cancer have been largely ignored. Extensive in vitro studies and limited in vivo studies have revealed that individual antioxidants such as vitamin A (retinoids), vitamin E (primarily alpha-tocopheryl succinate), vitamin C (primarily sodium ascorbate) and carotenoids (primarily polar carotenoids) induce cell differentiation and growth inhibition to various degrees in rodent and human cancer cells by complex mechanisms. The proposed mechanisms for these effects include inhibition of protein kinase C activity, prostaglandin E1-stimulated adenylate cyclase activity, expression of c-myc, H-ras, and a transcription factor (E2F), and induction of transforming growth factor-beta and p21 genes. Furthermore, antioxidant vitamins individually or in combination enhance the growth-inhibitory effects of x-irradiation, chemotherapeutic agents, hyperthermia, and biological response modifiers on tumor cells, primarily in vitro. These vitamins, individually, also reduce the toxicity of several standard tumor therapeutic agents on normal cells. Low fat and high fiber diets can further enhance the efficacy of standard cancer therapeutic agents; the proposed mechanisms for these effects include the production of increased levels of butyric acid and binding of potential mutagens in the gastrointestinal tract by high fiber and reduced levels of growth promoting agents such as prostaglandins, certain fatty acids and estrogen by low fat. We propose, therefore, a working hypothesis that multiple antioxidant vitamin supplements together with diet and lifestyle modifications may improve the efficacy of standard and experimental cancer therapies.
Chronic myeloid leukemia patients with different BCR-ABL transcripts might respond differently to Imatinib mesylate. This prompted us to study BCR-ABL transcripts in chronic myeloid leukemia (CML) patients and their correlation with response to Imatinib. Eighty-seven chronic phase CML patients (median age, 35 years; range, 13-62 years; M/F, 59:28) were included in this study; 57 patients had received interferon-alpha and/or hydroxyurea, and 30 were previously untreated. All patients received Imatinib mesylate (Gleevec) 400 mg daily. Complete hematological remission rate and major cytogenetic response (CGR) rates were 99% and 72%, respectively. B3a2 transcript was present in 53% of patients, b2a2 in 39%, and both transcripts in 8% of patients. Twenty of 34(59%) patients with b2a2 type achieved complete CGR compared to 15 of 53 (28%) patients with b3a2, p = 0.04. Among 24 patients with minor or no CGR, six (25%) had b2a2 compared to 18 (75%) b3a2 type, p = 0.04. Expression of BCR-ABL/ABL% was higher in b3a2 patients compared to b2a2, p = 0.120. Pre-treatment characteristics-mean spleen size (6.6 vs. 6.4 cm, p = 0.868), mean hemoglobin (G/dl; 12.0 vs. 11.8, p = 0.690), mean WBC count (83 x 10(9) vs. 77 x 10(9)/L, p = 0.923), and mean platelets counts (360x10(9) vs. 340 x 10(9)/L, p = 0.712)-were not significantly different in the b3a2 vs. b2a2 transcripts groups. Our preliminary findings suggest that CML patients with b2a2 BCR-ABL transcript might have higher CGRs to Imatinib mesylate (Gleevec).
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