专题：Science报道
科学家最近发现了引起儿童常见白血病―T细胞急性淋巴细胞白血病（T-ALL）的关键细胞。针对这些细胞进行治疗可以改善治疗的效果，并能防止复发。
澳大利亚皇家墨尔本医院和墨尔本大学的科学家最近发现了引起儿童常见白血病―T细胞急性淋巴细胞白血病（T-ALL）的关键细胞。针对这些细胞进行治疗可以改善治疗的效果，并能防止复发。马修麦科马克博士与其他研究人员对有这种白血病发展倾向的小鼠进行研究时有了上述发现。研究结果发表在21日的《科学》杂志网络版上。
研究人员发现，当给这些动物模型进行放射治疗时，胸腺中99%的细胞会被杀死，但这些像干细胞样的细胞会很快又重新出现，说明这些细胞能逃脱治疗并与治疗后疾病的复发密切相关。
目前对患有T-ALL儿童的治疗需要持续2~3年时间，目的就是防止其复发。有针对性地对胸腺细胞进行治疗可以缩短治疗时间、减少治疗的副作用，并能防止复发。国际儿童白血病专家麦科马克说：“这种类型白血病的细胞起源还不是很了解。我们发现这些细胞与正常干细胞非常相似，说明这可能就是它们能长期生存的原因，也是对治疗能明显耐受的原因。”
澳大利亚每年有T-ALL新诊断病例接近50例，其中三分之二为儿童和青少年。成年人也会患T-ALL，该病的主要问题是治疗耐受和疾病的复发。
研究人员说：“发现这些细胞将有助于新治疗方法的开发和测试。” 目前，研究人员将重点放在了具有杀死这些细胞的新方法研究上，并有可能在未来5年内进入临床试验。
推荐原始出处：
Science January 21, 2010 DOI: 10.1126/science.1182378
The Lmo2 Oncogene Initiates Leukemia in Mice by Inducing Thymocyte Self-Renewal
Matthew P. McCormack,1,2,* Lauren F. Young,1 Sumitha Vasudevan,1 Carolyn A. de Graaf,3 Rosalind Codrington,4 Terence H. Rabbitts,4 Stephen M. Jane,1,2 David J. Curtis1,2
The LMO2 oncogene causes a subset of human T cell acute lymphoblastic leukemias (T-ALL), including four cases that arose as adverse events in gene therapy trials. To investigate the cellular origin of LMO2-induced leukemia, we used cell fate mapping to study mice in which the Lmo2 gene was constitutively expressed in the thymus. Lmo2 induced self-renewal of committed T cells in the mice more than 8 months prior to the development of overt T-ALL. These self-renewing cells retained the capacity for T cell differentiation but expressed several genes typical of hematopoietic stem cells (HSCs), suggesting that Lmo2 might reactivate an HSC-specific transcriptional program. Forced expression of one such gene, Hhex, was sufficient to initiate self-renewal of thymocytes in vivo. Thus, Lmo2 promotes the self-renewal of preleukemic thymocytes, providing a mechanism by which committed T cells can then accumulate additional genetic mutations required for leukemic transformation.
1 Rotary Bone Marrow Research Laboratories, Royal Melbourne Hospital, Grattan Street, Parkville, Victoria 3050, Australia.
2 Department of Medicine, University of Melbourne, Parkville, Victoria 3010, Australia.
3 The Walter " Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia, and Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
4 Leeds Institute of Molecular Medicine, Wellcome Trust Brenner Building, St. James’s University Hospital, Leeds LS9 7TF, UK.
