儿童急性白血病CDX2基因WT1基因表达及其临床意义对照研究

Gene expression and its clinical implications of CDX2 and WT1 gene in children with acute leukemia

目的将WT1基因作为同期对照基因,探讨尾型同源盒转录因子-2(CDX2)在儿童急性白血病(AL)中的表达特点、临床意义及潜力。方法应用RT-PCR技术同期检测儿童白血病患者骨髓(BM)、外周血(PM)单个核细胞(MNC)CDX2基因、WT1基因的表达。2009年1月至2011年1月西京医院收治儿童急性白血病患者共57例,未缓解组39例,其中初发35例(ALL25例,AML10例),复发4例;AL缓解组18例;25例健康体检者对照。结果未缓解组82.1%(32/39例)AL患儿CDX2基因不同程度高表达(0.6187±0.2170),其中ALL组和AML组阳性率(89.3%vs.63.6%)、表达水平(0.6181±0.2342vs.0.6230±0.2441)无统计学意义(P>0.05)。缓解组、对照组CDX2基因表达均阴性。9例初发白血病同期BM、PB中MNCsCDX2基因表达水平分别为(0.4083±0.2279)、(0.4124±0.1749),差异无统计学意义(P>0.05)。ALCDX2基因、WT1基因表达的比较:未缓解组阳性率(48.7%vs.82.1%)差异有统计学意义(P<0.05),其中ALL组(46.4%vs.89.3%)差异有统计学意义(P<0.05),AML组(54.5%vs.63.6%)差异无统计学意义(P>0.05)。CDX2基因表达阳性、阴性AL患儿WT1基因阳性率分别46.8%(15/32)和57.1%(4/7),统计分析CDX2基因与WT1基因在儿童AL中的表达无明显相关性(P>0.05)。初发儿童AL中,CDX2基因表达阳性、阴性者CR率比较两组差异无统计学意义(P>0.05)。CDX2基因、WT1基因表达双阳性组与双阴性组、双阳性组与单阳性组、单阳性组与双阴性组比较差异均无统计学意义。随访11例AL患儿8～14个月,初诊时CDX2表达阳性的9例患儿,5例于治疗第13～19d时转为阴性,余4例于诱导缓解治疗后转为阴性至今。而初诊时CDX2基因表达阴性的患儿,在骨髓CR时仍为阴性,此后持续阴性。结论与WT1基因比较,CDX2基因或为儿童AL更具潜力的泛白血病基因标志,能够一定程度反映疾病的状态和白血病负荷,于MRD监测有一定意义。

Objective To study the expression of caudal-related homeodomain transcription 2 （CDX2） gene in Children with acute leukemia （AL） and its clinical implications , and compare with those of Wilms＇ tumor 1 （WT1） gene. Methods Both of the genes were detected by semi-quantitative reverse transcriptase polymerase chain reaction （RT-PCR） in bone marrow（BM） and peripheral blood（PB） samples of 57 cases of children with acute leukemia---39 cases of non-remission acute leukemia （AL） consisting of 35 cases of the newly diagnosed （25 cases of ALL, 10 cases of AML） and 4 cases of the relapsed, 18 cases of the remission. In addition , 25 cases of healthy people were enrolled as control. Results The overexpression（0.6187±0.2170）of CDX2 was found in 82.1% （32/39） AL, with the positive rate being 89.3% （25/28） in ALL and 63.6% （7/11 ） in AML, which showed no statistical difference （P 〉 0.05） and so was the expression level （0.6181 ± 0.2342 VS 0.6230 ± 0.2441） （P 〉 0.05）. In addition, CDX2 was not detectable in both the remission group and the control. Detecting samples of BM and PB from the same period of 9 newly diagnosed AL patients by semi-quantitative RT-PCR, the average CDX2 expression level was （0.4083 ± 0.2279） and （0.4124 ± 0.1749） , which was of no statistical difference （P〉 0.05）. In compariing CDX2 with WT1 in children with AL, positive rates in non-remission group （48.7% VS 82.1% ） had statistical difference （P 〈 0.05）, and those in ALL group （46.4% VS 89.3% ） also showed statistically significant difference （P 〈 0.05）, while those in AML group（54.5% VS 63.6% ） were of no statistical difference （P 〉 0.05）.In CDX2 positively and negatively expressed patients, positive rates of WT1 were respectively 46.8% （15/32）and 57.1% （4/7）, which suggested no statistical correlation between the ex- pression of CDX2 and that of WT1 in AL children. In the newly diagnosed AL children, rates of complete remission （CR） in the C DX2 positively expressed patients and negatively expressed ones （96.4% VS 100%） showed no statistical difference （P 〉 0.05）.For CDX2 and WT1, the comparison of CR rates between the double positive group and the double negative group was of no statistical difference （P 〉 0.05）, and so were the positive group and the single positive group （P 〉 0.05）, as well as the single positive group and the double negative group （P 〉 0.05）. Nine newly diagnosed AL patients with positive CDX2 expression were followed up for 8 to 14 months. CDX2 in 5 patients gradually turned negative during day 13 - 19 and the remained four turned negative after induction. However, in CDX2 negatively expressed AL patients, CDX2 remained negative at CR till present. Conclusion CDX2 gene may be more potential in children with AL and the expression level of CDX2 may have correlation with the load of leukemia , which might be of better value than WT1 in MRD detection.