CONGENITAL EXPRESSION OF mdr-1 GENE IN FRESH CANCER TISSUES FROM SEVERAL HIGH-INCIDENCE NEOPLASMS WITHOUT PREOPERATIVE CHEMOTHERAPY

Objective: The purpose of the present study is to detect characteristics of primary expression of mdr 1 gene in several neoplasms which has high morbidity in clinic. Methods: 151 resected samples, which are pathologically malignant and clinically untreated before operation, were obtained from Anyang Cancer Hospital. All of them were investigated with RT PCR for the expression of mdr 1 gene and correlated each other. Besides, we evaluated the advantages of RT PCR in this study. Results: The mdr 1 gene expression rate of these 151 samples, including cancers of stomach and gastric cardia (n=51), esophagus (n=46), colorectum (n=16), breast (n=15), thyroid (n=10), lung (n=9), uterine cervix (n=4), was 33.3%, 37%, 31.3%, 13.2%, 40%, 55%, 0%, respectively. Conclusion: Compared with other methods, RT PCR for studying mdr 1 gene expression had certain advantages in simplicity, reliability, and accuracy. Overexpression of mdr 1 gene in these neoplasms suggested that cases should be distinguished before treatment according to MDR of tumor and to choose effective drugs for individual cancer patient.

Congenital expression of mdr-1 gene in tissues of carcinoma and its relation with patho morphology and prognosis

AIM To detect the congenital expression patterns of mdr 1 gene in commonly encountered malignant tumors in clinic, and the relationship between the expression of mdr 1 gene and the prognostic morphology in esophageal carcinomas. METHODS A total of 151 resected samples of malignant tumors without preoperative treatment were taken from Anyang City Tumor Hospital. The congenital expression of their mdr 1 gene was detected with reverse transcription polymerase chain reaction (RT PCR) and was compared with each other. The positive incidence of mdr 1 gene in 46 samples of esophageal carcinoma was compared with their differentiated grades, TNM stages and macroscopic types, and the precautions and advantages of RT PCR were evaluated. RESULTS All the 151 samples were confirmed to be malignant histopathologically, including cancers of stomach and gastric cardia (n =51), esophagus ( n =46), colorectum ( n =16), breast ( n =15), thyroid ( n =10), lung ( n =9), uterine cervix ( n =24). The positive expression rate of their mdr 1 gene was 33 3%, 37%, 31 3%, 13 2%, 40%, 55%, and 0% respectively. All the 46 samples of esophageal carcinoma were pathologically confirmed to be squamous cell carcinoma. The total expression rate of their mdr 1 gene was 37% (17/46), 35% (6/17), 40% (8/20), and 33% (3/9) for differentiation grade Ⅰ, Ⅱ and Ⅲ respectively. The expression rate of TNM classification was 33% (6/18), 40% (5/12) and 37% (6/16) in stage Ⅱa, Ⅱb and Ⅲ. The expression rate was 33% (3/9) in ulcerous type, 37% (3/8) in constrictive one, 33% (5/15) in fungoid one, and 40% (6/14) in medullary one. No statistically significant difference was found. CONCLUSION Compared with other methods, RT PCR is more simple, reliable and accurate in detecting mdr 1 gene expression in tissues of tumor. The overexpression of mdr 1 gene in these neoplasms suggested that cases should be handled differently for chemotherapy with rational use of drugs. Excision is the chief treatment for carcinoma of esophagus. The expression of mdr 1 gene in tissues of esophageal cancer is correlated with the parameters of tumor molecular biology which are independent of histopathological morphology.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells

In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparti- cles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDRl-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope （TEM）. MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration （IC50） ofpaclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control （P〈0.05）. MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC_50 （0.197±0.003, 0.144±0.001, 0.120±0.004） were decreased with difference being significant when compared with that in A2780/TS （0.269±0.003） cells control （P〈0.05）. It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

PRELIMINARY STUDY OF RETROVIRAL MEDIATED TRANSFER OF THE HUMAN mdr-1 GENE INTO MURINE AND HUMAN HEMATOPOIETIC STEM/PROGENITOR CELLS

To investigate the characteristics of multidrugresistance and transplantation of modified stem/ progenitor cells by multidrugresistant gene (mdr1 gene), we established PA317/MDR1 cell line which producing retroviruses by transfecting the retroviral vector PHaMDR1/A into packging cell line PA317 by Lipofectin. The virus titer of the supernatants was 1.2×105 cfu/ml. We transfected the murine hematopietic cells collected from 5FU pretreated mice and they showed the ability to reconstitute the longterm hematopoiesis of preirradiated mice. After 4 months, both of bone marrow cells and peripheral blood cells of transplanted mice still contained mdr1 gene. We also transfered mdr1 gene into human bone marrow CD34+ cells selected by using magnetic cell sorting system. PCR analysis showed that transduced CD34+ cells maintained the mdr1 cDNA. A fraction of CFUGM originated from transfected CD34+ cells had the charactor of resistance to Taxol. It is indicated that mdr1 gene can be transduced into murine and human stem/proginitor cells through retroviral mediated gene transfer and it protects the transfected cells from cytotoxic drugs.

EXPRESSION OF mdr-1 GENE IN CANCER TISSUE AND ITS ASSOCIATION WITH MORPHOLOGICAL INDEXES OF ESOPHAGEAL CARCINOMA IN ANYANG

Objective: Overexpression of mdr-1 gene is associated with multidrug resistance (MDR) and aggressive characteristics of malignance. Our purposewas to detect the levels of P-gp expression in fresh untreated esophageal carcinomas, and to correlate these levels to current prognostic indicators of morphology.Methods: Reverse transcription polymerase chain reaction (RT-PCR) was used to investigate mdr-1 gene expression of 46 samples from untreated esophageal carcinoma, and compared the positive incidences among differentiated grades, TNM stages and macroscopic types.Results: All 46 samples were pathologically squamous cell carcinoma. The positive' incidences of mdr-1 gene expression were 37% (17/46) in whole group,35% (6/17), 40% (8/20), 33% (3/9), for Ⅰ,Ⅱ and Ⅲdifferentiated grades, respectively. The expression rates of 33% (6/18), 40% (5/12), and 37% (6/16), were found in Ⅱa, Ⅱ, and Ⅲ stage of TNM, respectively. In macroscopic type view, the positive incidence was 37%(3/8) in constrictive, 33% (5/15) in fungating, 40% (6/14)in marrowlike, 33% (319) in ulcerative type. There were no statistically significant differences among each category system of morphology.Conclusion: The result, high level expression of mdr-1 gene in untreated esophageal carcinoma, suggested the poor efficacy of chemotherapy for some esophageal carcinoma patients. And we should cautiously choose cases who will receive chemotherapy. Surgery is still the best treatment for carcinoma of esophagus. Besides, the data also revealed that the expression of mdr-1 gene in untreated esophageal cancer was independent of morphologic prognostic indexes, and that there were no correlation between mdr-1 gene expression and morphological indexes.

荧光定量RT-PCR检测mdr-1基因表达

目的 :建立荧光定量RT PCR检测肿瘤细胞mdr 1基因表达的方法 ,了解肺癌组织中mdr 1的表达水平。方法 :建立荧光定量RT PCR方法 ,在PE770 0型检测仪上定量检测K5 6 2 /ADM耐药株和K5 6 2不耐药株细胞mdr 1基因表达水平 ,同时检测 45例初治肺部肿瘤病人组织标本。结果 :荧光定量RT PCR检测K5 6 2 /ADM耐药株和K5 6 2不耐药株细胞mdr 1基因表达 ,重复 10次实验所得结果平均分别为 (6 86± 0 6 5 )× 10 7拷贝 /μgRNA和 (8 49± 0 6 7)× 10 5拷贝 /μgRNA ,两者相差 80 8倍 ,变异系数分别为 9 5 %和 7 9%。 45例肺部肿瘤中 ,有 12例检出有mdr 1基因不同程度的表达。结论 :荧光定量RT PCR检测mdr 1基因表达方法 ,检测结果用绝对拷贝数来表示 ,定量准确可靠 ,并有利于标准的统一。有 1/4未经化疗的肺癌病人有一定水平mdr

初发及复发转移大肠癌患者外周血MDR-1基因表达的研究

目的 :检测初发及复发转移大肠癌患者外周血中多药耐药基因 (MDR 1)的表达 ,探讨其与病理类型及化疗疗效的关系。方法 :应用逆转录多聚酶链反应 (RT -PCR)法对 5 6例初发大肠癌及 4 0例经术后辅助化疗后复发、转移大肠癌患者的外周血进行检测 ,并与其病理类型及化疗疗效作对比研究。结果 :5 6例初发大肠癌患者外周血中MDR 1阳性表达率为2 7 2 % ,与病理类型无显著相关 (P >0 0 5 ) ;但与肠系膜淋巴结转移密切相关 ,有淋巴结转移者阳性表达率显著高于无淋巴结转移者 (P <0 0 5 ) ;4 0例化疗后复发、转移患者外周血MDR 1阳性表达率为 72 5 % ,与初发大肠癌患者的MDR 1阳性表达率相比差异有显著性 (P <0 0 5 ) ,且MDR 1的表达与化疗疗效呈负相关 ,MDR 1阳性表达者化疗疗效明显低于阴性表达者(P <0 0 5 )。结论 :大肠癌存在先天性和获得性多药耐药性 ;检测外周血MDR 1表达情况可以帮助预测化疗疗效 ,对制定临床化疗方案有指导意义。

急性白血病患者bcl-2和bax基因表达的临床意义及其与mdr-1基因表达的关系

细胞凋亡受抑作为肿瘤细胞的耐药机制 ,是急性白血病 (AL)预后不良的原因之一。bcl 2家族是目前最受重视的调控细胞凋亡的基因家族 ,本研究为探讨bcl 2和bax基因在急性白血病表达的意义 ,应用逆转录 聚合酶链反应 (RT PCR)方法测定 70例初治AL患者及 2 0例正常人的bcl 2 ,bax ,mdr 1基因mRNA水平的表达 ,用流式细胞术检测其蛋白表达。结果表明 ,bcl 2和bax基因在AL患者广泛表达 ,bcl 2mRNA平均表达水平明显高于正常对照 (1.4 6vs 0 .71,P <0 .0 5 )。bcl 2和bax基因表达及bax bcl 2比值与AL患者的年龄、性别、血小板计数、血红蛋白水平、骨髓原始细胞百分率、FAB分型和S +G2 M %均未发现相关。Bcl 2蛋白表达 (34.6 %vs 6 9.2 %,P <0 .0 5 ) ,bax bcl 2mRNA比值 (37.1%vs 82 .9%,P <0 .0 1)决定AL对化疗的敏感性 ,与ALCR率密切相关。bax bcl 2mRNA比值还是影响总生存期的因素。bcl 2与bax基因表达和mdr 1表达两者无相关关系。

选择性COX-2抑制剂塞来昔布抑制B细胞淋巴瘤细胞株MDR-1及Bcl-2的mRNA表达并增强表柔比星的抗肿瘤作用

背景与目的:部分非霍奇金淋巴瘤(non-Hodgkin’s lymphoma,NHL)具有高表达环氧合酶-2(cyclooxygenase-2,COX-2)的特征,而后者与P-糖蛋白及Bcl-2表达相关,可能导致NHL对化疗耐药。本研究旨在探讨B细胞淋巴瘤细胞株中COX-2的表达以及选择性COX-2抑制剂塞来昔布增强淋巴瘤细胞对表柔比星抗肿瘤效应的敏感性及其可能机制。方法:用荧光定量PCR(q RT-PCR)及蛋白[质]印迹法(Western blot)分别检测Raji、Jeko-1和Namalwa等淋巴瘤细胞株以及正常人外周血B细胞的COX-2表达;以梯度浓度的塞来昔布作用于淋巴瘤细胞株,CCK-8方法检测细胞增殖的抑制程度,q RT-PCR检测各细胞株MDR-1 mRNA及Bcl-2 mRNA表达的变化;表柔比星单独或联合不同浓度的塞来昔布处理Raji细胞株72 h后,CCK-8方法分析塞来昔布对表柔比星的增敏作用。结果:各淋巴瘤细胞株及正常对照外周血B细胞均不表达COX-2。塞来昔布单药即可对各淋巴瘤细胞株产生程度不同的抗增殖效应;随着塞来昔布作用浓度的增加,除Jeko-1细胞不表达MDR-1外,其余细胞株MDR-1 mRNA及Bcl-2 mRNA表达水平逐渐下降;塞来昔布明显增强表柔比星对Raji细胞的抗肿瘤活性,两者之间具有协同作用。结论:选择性COX-2抑制剂塞来昔布下调B细胞淋巴瘤细胞株的MDR-1 mRNA及Bcl-2 mRNA水平,并且增强表柔比星对淋巴瘤细胞的抗肿瘤效应。

初发及复发转移大肠癌组织与外周血MDR-1基因表达相关性研究

目的 探讨初发及复发转移大肠癌组织与外周血MDR 1基因表达的相关性。方法 采用RT PCR方法分别检测了 5 6例初发大肠癌组织及外周血和 4 0例术后化疗的复发转移大肠癌病灶组织及外周血的MDR 1表达情况。结果 无论是组织中 ,还是外周血中经过化疗的大肠癌患者MDR 1的阳性表达率均明显高于初发大肠癌患者 ,统计学上有显著性差异 (P <0 .0 5 )。结论 可以用外周血代替癌组织来检测MDR

儿童急性白血病Bcl-2基因MDR1基因表达及意义(英文)

目的 研究Bcl 2 ,MDR1基因与儿童急性白血病耐药的关系及其临床意义。方法 采用逆转录多聚酶链式反应 (RT PCR)技术 ,对 36例急性白血病患儿及 10例血小板减少性紫癜患儿 (对照 )骨髓单个核细胞中Bcl 2和MDR1基因的表达进行检测。结果 ①初治组、复发组Bcl 2基因表达明显高于对照组 ,差异均有显著性(P <0 .0 5 )。初治组、完全缓解组Bcl 2基因表达明显低于复发组 ,差异均有显著性 (P <0 .0 1)。复发组MDR1基因的表达明显高于对照组、初治组、完全缓解组 (P <0 .0 1或 0 .0 5 )。初治组与对照组间及完全缓解组与对照组间的MDR1表达差异无显著性 (P >0 .0 5 )。②Bcl 2和MDR1基因的表达与白血病临床特征如性别、年龄、初诊时白细胞数、骨髓中幼稚细胞百分数及肝、脾、淋巴结肿大程度均无显著相关性 (P >0 .0 5 )。③Bcl 2与MDR1基因之间无显著相关性 (rs=0 .30 8,P>0 .0 5 )。结论 Bcl 2和MDR1基因可能通过不同的机制导致白血病的耐药。

麂属(Muntiacus)动物MDR-1基因序列分析及其分子进化关系

对麂属（Muntiacus）中的3种动物:赤麂（M.muntjak）（2n=6 ,7 ）小麂（M.reevesi）（2n=46）,黑麂（M.crinifrons）（2n=8 ,9 ）MDR-1基因（multidrug resistance,多药耐药基因）726bP左右的片段进行了序列分析,并根据序列信息建立分子系统树,同时探讨了这3种动物的起源、分类地位及进化关系。

RNAi对白血病细胞mdr-1基因和多药耐药表型的影响

目的:探讨RNA干扰技术(RNAi)对慢性粒细胞白血病急变细胞系K562/AO2细胞mdr1基因的抑制和耐药表型的逆转作用。方法:选择合成封闭mdr-1基因的小干扰序列(si-MDR1),以1个碱基突变的si-MDR1-mut为对照序列,在脂质体介导下转染至K562/AO2细胞系。RT-PCR和Western blot检测mdr1 mRNA及P-gp蛋白水平,流式细胞术分析细胞内柔红霉素(daunorubicin,DNR)积累量,并以四甲基唑蓝快速比色法(MTT)反映K562/AO2对阿霉素、长春新碱、足叶乙甙药物敏感性的变化。结果:实验证实该序列能高效封闭K562/AO2细胞内mdr-1基因表达,增加细胞内化疗药物DNR积累量,增强K562/AO2细胞对阿霉素、长春新碱、足叶乙甙的敏感性。结论:RNAi可以通过抑制mdr1基因表达,逆转K562/AO2细胞耐药表型。

化疗对食管癌组织中mdr-1基因表达的影响及其意义

目的研究ｍｄｒ１基因过度表达与肿瘤化疗疗效的相关性，进一步研究食管癌组织ｍｄｒ１基因的表达与食管癌多药耐药及相关因素的关系。方法３０例未作治疗的食管癌患者，均行术前计划化疗，化疗前食管镜下取癌及癌旁活组织。术前化疗方案：丝裂霉素（ＭＭＣ）４～６ｍｇ／ｍ２静脉注射，第１、８、１５天；顺铂（ＤＤＰ）２０～３０ｍｇ／ｍ２静脉点滴，第２、３、４天；平阳霉素（ＰＹＭ）６ｍｇ／ｍ２肌肉注射，第１、３、８、１１、１６、１８天。２１天为一周期，２周期为一疗程，休息２周后手术。将切除标本及化疗前食管镜活检取材组织作匀浆，抽提总ＲＮＡ后用反转录多聚酶链反应技术（ＲＴＰＣＲ）检测ｍｄｒ１的表达，与化疗疗效及癌旁组织ｍｄｒ１之表达作对比。结果癌组织ｍｄｒ１的表达高于癌旁组织中ｍｄｒ１的表达（３３％与１０％，Ｐ＜００５）；化疗后癌组织中ｍｄｒ１的表达高于化疗前（３３％与８３％，Ｐ＜００５），而癌旁组织中ｍｄｒ１的表达则无差异（１０％与１０％，Ｐ＞００５）；化疗前癌组织ｍｄｒ１阳性表达者化疗疗效差于化疗前癌组织ｍｄｒ１阴性表达者（１０％与４５％，Ｐ＜００５）。结论食管癌存在先天性ＭＤＲ，癌组织ｍｄｒ１阳?

联合检测MDR_1/P-gp、C-erbB-2在乳腺癌中的表达及临床意义

目的 :联合检测乳腺癌患者中MDR1/P gp、及C erbB 2的表达 ,并探讨MDR1/P gp与C erbB 2的相关性。方法 :采用荧光定量RT PCR(FQ RT PCR)法检测 5 7例乳腺癌、2 0例对照组 (包括 10例乳腺良性疾病、10例癌旁正常组织 )中MDR1基因的表达 ,同时采用免疫组化法检测上述标本中P gp及C erbB 2蛋白的表达。 结果 :乳腺癌患者中MDR1基因扩增率及P gp蛋白阳性率分别为 5 0 .88% (2 9/ 5 7)和 4 2 .11% (2 4 / 5 7) ,与正常对照组相比均具有显著性差异 (P <0 .0 1)。MDR1基因扩增率高于P gp蛋白表达 ,二者呈高度相关 ,但并不完全相符 ;乳腺癌中C erbB 2过表达率为 2 8.0 7% (16 / 5 7) ,正常对照组中无C erbB 2蛋白过表达。MDR1/P gp阳性率与C erbB 2过表达呈正相关。结论 :乳腺癌中存在多药耐药基因MDR1及原癌基因C erbB 2的共表达 ,且其表达呈正相关。上述二种基因的表达 ,与乳腺癌的多药耐药有关。

MDR_1基因及P-gp在脑胶质瘤中定量表达的研究

目的检测脑胶质瘤中多药耐药基因ＭＤＲ１、ｍＲＮＡ和膜糖蛋白Ｐ－ｇｐ相对含量，确定胶质瘤的化疗敏感性。方法免疫组织化学和逆转录聚合酶链反应（ＲＴ－ＰＣＲ）。结果在非化疗组和短期化疗组ＭＤＲ１ｍＲＮＡ含量及Ｐ－ｇｐ表达无显著差别，但长期化疗组明显高于前两组。结论推测ＭＤＲ１基因过度表达可能是胶质瘤继发耐药的主要原因。

食管癌、癌旁和淋巴结组织中mdr-1、mrp表达及其预后关系

目的 探讨食管癌、癌旁及淋巴结组织中多药耐药基因 (mdr 1)和多药耐药相关蛋白基因 (mrp)表达的相互关系及其对患者预后的影响。方法 采用逆转录 聚合酶链反应 (RT PCR)技术 ,检测了 5 1例食管癌、癌旁及 49枚手术切除淋巴结组织的mdr 1和mrp基因表达。结果 食管癌组织中mdr 1、mrp和两基因共表达的阳性率与癌旁组织比较具有显著性差异 (P <0 0 1) ;转移淋巴结组织 (N1 2 )高于非转移淋巴结 (N0 ) (P <0 0 1) ;而癌组织mdr 1、mrp阴性的转移和非转移淋巴结组织未发现mdr 1和mrp基因表达。随访发现 ,食管癌组织mdr 1和 (或 )mrp阳性患者的一、二、三年生存率 (72 4%、42 1%和 14 3% )低于mdr 1、mrp阴性者(88 9% ,6 3 6 %和 6 0 % )。结论 检测癌组织及其淋巴结中的mdr 1、mrp基因表达可能对指导食管癌的术后化疗。

mdr-1基因骨髓造血干细胞移植诱导大鼠肝移植免疫耐受

目的探讨mdr-1基因骨髓造血干细胞移植诱导肝移植术后免疫耐受的可行性及其可能机制。方法选用雄性Wistar大鼠30只为肝移植供体,另选雌性SD大鼠20只为异基因肝移植受体,随机分为mdr-1基因骨髓造血干细胞移植联合肝移植组(A组)和单纯肝移植组(B组)。雌性Wistar大鼠10只为同基因肝移植受体(C组)。比较A、B两组大鼠肝移植术后1周生存率、生存状况、生存时间,以及移植肝脏的病理变化。结果 C组大鼠生存时间均达60 d以上,A组为(31.2±4.9)d,明显高于B组[(12.1±4.7)d],差异有统计学意义(P<0.05)。B组病理组织切片可见中、重度急性排斥反应,肝内单核细胞浸润较为明显,主要集中在汇管区;A组移植肝内组织损伤程度明显减轻;C组基本无排斥反应,接近正常肝组织。结论 mdr-1基因骨髓造血干细胞可明显减轻大鼠肝移植后免疫排斥反应。

乳腺癌中c-erbB-2癌基因和mdr-1基因的检测及相关性研究

目的 检测原发性乳癌中c erbB 2扩增和mdr 1表达的情况 ,并探讨二者的相关性。方法 分别采用PCR和RT PCR法检测 47例乳癌中c erbB 2扩增和mdr 1表达。结果 ⑴c erbB 2扩增与组织学分级和腋淋巴结阳性数有关 ,有统计学意义。ER、PR阴性与阳性乳癌比较 ,非浸润性与浸润性乳癌比较 ,c erbB 2扩增均有显著性差异。⑵mdr 1表达与组织学分级有关 ,有统计学意义。⑶mdr 1表达与c erbB 2扩增之间无统计学意义。结论 c erbB 2扩增与乳癌的组织学分级、腋淋巴结阳性数、ER、PR状态、组织学类型有关 ,mdr 1表达只与组织学分级有关 ,c erbB 2扩增与mdr

荧光定量RT-PCR检测mdr_1在急性白血病中的表达及临床意义

采用荧光定量 RT- PCR法检测 36例不同类型白血病患者的多药耐药基因 (mdr1 m RNA)表达 ,同时检测 15例骨髓或外周血正常患者 ,以做对照。结果对照组均为阴性表达 ,初治患者组 m dr1 阳性基因拷贝数平均为 2 .7× 10 3拷贝 / μg RNA;复发难治患者组为 1.0× 10 4拷贝 / μg RNA(P<0 .0 5 )。表达阴性 m dr1 与 mdr1 阳性患者的完全缓解 (CR)率分别为 82 %和 2 1% (P<0 .0 5 )。提示荧光定量 RT- PCR检测 mdr1 基因表达结果用绝对拷贝数表示 ,其定量准确、可靠。临床急性白血病化疗耐药的发生主要与 mdr1 阳性高表达有关。