检测降钙素基因鉴别难治性贫血和AA的研究

Quantitative Study of Calcitonin Gene Methylation as a Indicator for Differential Diagnosis of Refractory Anemia and Aplastic Anemia

目的：探讨降钙素（CT）基因高甲基化能否作为鉴别骨髓增生异常综合征-难治性贫血，（MDS－RA）和再生障碍性贫血（AA）的分子标志。方法：采用设有内、外参照的聚合酶链反应（PCR），结合限制性内切酶和激光扫描技术，检测25例MDS－RA和25例AA患者骨髓细胞CT基因5′端甲基化率（CTMR）。结果；25例MDS－RA患者CTMR为22．8±17．68％，显著高于对照组（P＜0．05），25例AA患者CTMR为9．46±14．84％，与对照组差异无显著性（P＞0．05）。25例MDS－RA中6例已随访3～10年未转化为白血病，CTMR正常，余19例中1例l．5个月后转化为原始细胞过多性难治性贫血（RAEB），3例2～9个月后转化为急性髓性白血病AML。25例再障中3例CTMR＞30％，其中2例2～4．5个月后转化为AML。结论：CTMR对鉴别MDS－RA或AA可能是一个有用的分子标志。

To explore the possibility of taking calcitonin gene hypermethylation as a molecular indicator for differential diagnosis of refractory anemia of myelodysplastic syndrome (MDS-RA)and aplastic anemia (AA). The methylation rate of calcitonin gene (CTMR)in the genomic DNA extracted from bone marrow cells of 25 cases of MDS-RA and 25 cases of AA were studied by PCR amplification of Hpa Ⅱ digested DNA,with external references 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-RA (22. 83% ± 17. 68% )than in control group (P <0. 05) there was no signficant difference between AA andcontrol group (P >0. 05),six of 25 MDS-RA patients who survived three to tenyears without leukemia had a normal CTMR. Four of other 19 MDS-RA patients evolved into RAEB or AML in 1. 5~9 months. Two of 3 AA patients who had high CTMR of more than 30% evolved into AML in 2~4. 5 months.