骨髓增生异常综合征降钙素基因甲基化的定量研究

目的：探讨降钙素（ＣＴ）基因高甲基化能否作为骨髓增生异常综合征（ＭＤＳ）向白血病转化的分子标志。方法：采用设有内、外参照的多聚酶链反应（ＰＣＲ），结合限制性内切酶和激光扫描技术，检测２７例ＭＤＳ和６例由ＭＤＳ转化的急性髓细胞白血病（ＡＭＬ）患者骨髓细胞的ＣＴ基因５′端甲基化率（ＣＴＭＲ）。结果：ＭＤＳ患者ＣＴＭＲ为３３．６５％±２３．３７％，显著高于对照组（８．０１％±４．２５％，Ｐ＜０．００１），其中ＲＡＥＢｔ组显著高于对照组和ＲＡ组，已随访３～１０年的ＲＡ患者５例均在正常范围，且无白血病转化。９例ＲＡＥＢｔ的ＣＴＭＲ均＞３０％，随访８例中７例于２个月内转化为ＡＭＬ。结论：ＣＴＭＲ对早期预测ＭＤＳ向白血病转化可能是一个有用的指标。

Quantitative study of calcitonin gene methylation in myelodysplastic syndromes

OBJECTIVE: To investigate the role of calcitonin gene hypermethylation in the transformation from myelodysplastic syndromes (MDS) to acute myeloid leukemias (AML). METHODS: The methylation rate of calcitonin gene (CTMR) in the genomic DNA extracted from bone marrow cell of 27 MDS patients and 6 AML patients with antecedent MDS were studied by PCR amplification of Hpa I digested DNA, with external reference of undigested and Msp I digested DNA and internal reference of 112bp fragment containing N-ras-61. Intensity of silver-stained PCR products was measured by densitometer and analysed using the computer program. RESULTS: The CTMR was significantly higher in MDS (33.65% +/- 23.37%) than in control group (P<0.001), in 9 RAEB(T) (58.35% +/- 17.44%) than in the control and RA groups. Five RA patients who have survived three to ten years without leukemia, have a normal CTMR. Seven of 8 RAEB(T) patients who had a high CTMR of more than 30% evolved into AML in two months. CONCLUSION: CTMR might be a useful marker for predicting the evolution of MDS into AML.