Unité d'Hématologie-Immunologie-Oncologie, Pole Enfant, CHU Angers, France.
Int J Lab Hematol. 2010 Jun;32(3):288-98. doi: 10.1111/j.1751-553X.2009.01189.x. Epub 2009 Sep 28.
The DNA index (DI) is a prognostic factor in childhood acute lymphoblastic leukemia (ALL). The accuracy of DI measurement is important for treatment stratification: hyperdiploidy with DI > or = 1.16 is predictive of favorable prognosis whereas hypodiploidy is associated with poor prognosis. The aim of this study was to validate the accuracy of the DI measured by flow cytometry (FCM) by comparison with the karyotype. From samples of 112 childhood ALL, we created a formula to calculate a theoretical DNA index (tDI) based on the blast cell karyotype, taking into account the additional or missing chromosome material of the major clone. FCM DI correlated with tDI calculated from karyotype (R = 0.987) and with modal chromosome number (DI = 0.0202 x Modal NB + 0.0675 and R = 0.984). In three cases a hypodiploid blast cell population was detected by FCM, while only the duplicated clone was identified by the karyotype. The strong correlation between tDI and DI validates the accuracy of FCM quantification, which is technically fast on fresh or frozen samples. If the karyotype is essential to analyze chromosomal abnormalities, FCM provides complementary information in aneuploid ALLs, either by confirming the cytogenetic data or by detecting additional clones not identified when only using cytogenetic data.
DNA 指数（DI）是儿童急性淋巴细胞白血病（ALL）的预后因素。DI 测量的准确性对于治疗分层很重要：DI≥1.16 的超二倍体预示预后良好，而亚二倍体与预后不良相关。本研究旨在通过与核型比较验证流式细胞术（FCM）测量的 DI 的准确性。从 112 例儿童 ALL 样本中，我们创建了一个公式，根据主要克隆的额外或缺失染色体物质，基于细胞遗传学计算理论 DNA 指数（tDI）。FCM DI 与核型计算的 tDI（R = 0.987）和模式染色体数（DI = 0.0202 x 模式 NB + 0.0675，R = 0.984）相关。在三种情况下，FCM 检测到低倍体原始细胞群体，而核型仅识别出加倍的克隆。tDI 与 DI 之间的强相关性验证了 FCM 定量的准确性，该方法在新鲜或冷冻样本上技术上快速。如果核型对于分析染色体异常是必需的，那么 FCM 可通过确认细胞遗传学数据或检测仅使用细胞遗传学数据时未识别到的额外克隆，为非整倍体 ALL 提供补充信息。
