MGMT表达指导下的复发恶性胶质瘤挽救性化疗疗效分析（附30例报告）

O6-甲基鸟嘌呤-DNA甲基转移酶（O6-methylguanine-DNA methyltransferase,MGMT）是与恶性胶质瘤对替莫唑胺（temozolomide,TMZ）等烷化剂耐药相关的重要指标。本文总结根据MGMT表达状态选择不同的化疗方案,对复发恶性胶质瘤患者进行挽救性化疗的临床疗效。方法:经手术后病理确诊的复发恶性胶质瘤患者30例,均有可评价病灶。应用免疫组化法检测肿瘤MGMT表达状态,分为阳性组和阴性组。阳性组患者应用非TMZ常规5天方案或非烷化剂药物进行化疗,阴性组患者不限制化疗方案。结果:全组患者客观有效率为20%,中位无进展生存时间为8个月（95%CI:4.3～11.7）,中位生存时间为16个月（95%CI:7.4～24.6）。其中MGMT阳性组16例,阴性组14例。阳性组和阴性组患者的客观有效率分别为18.8%和21.4%,中位无进展生存时间分别为7个月（95%CI:3.1～10.9）和8个月（95%CI:3.9～12.1）,中位生存时间分别为16个月（95%CI:5.4～26.6）和16个月（95%CI:7.3～24.7）,差异均无统计学意义（P>0.05）。结论:复发恶性胶质瘤挽救性化疗具有良好的临床获益,根据肿瘤MGMT表达进行个体化化疗,特别是对于MGMT阳性复发恶性胶质瘤患者,能够避免耐药,得到与MGMT阴性患者相当的临床疗效。      

选择性化疗方案治疗恶性胶质瘤的疗效和生存情况分析

背景与目的：O^6-甲基鸟嘌呤-DNA甲基转移酶（O^6-methylguanine-DNA methyhransferase,MGMT）表达与胶质瘤患者的化疗耐药相关。本研究总结MGMT高表达和低表达恶性胶质瘤患者的化疗方案、近期疗效和生存情况．分析选择性化疗是否对MGMT高表达患者有益。方法：自2000年8月至2006年1月,中山大学肿瘤防治中心神经肿瘤科收治的经手术后病理确诊的成人恶性脑胶质瘤患者57例．所有病例化疗前均有可评价病灶。化疗前用免疫组化方法检测肿瘤组织MGMT表达情况．对MGMT高表达者．尽量避免使用亚硝脲类或替莫唑胺单药化疗,采用不含亚硝脲类或替莫唑胺方案,或由替莫唑胺（temozolomide,TMZ）和顺铂组成联合化疗方案;或亚硝脲类药物、替莫唑胺分别与其他细胞毒药物组成联合化疗方案（VM-26、DDP、CBP、IFO、VP16）;对MGMT低表达者,不限制亚硝脲类药物或替莫唑胺的应用。结果：35例患者MGMT高表达,22例MGMT低表达,MGMT低表达组的客观有效率（objective response,OR）和疾病控制率（response rate,RR）高于MGMT高表达组（40．9％：22．9％和72．7％：60.0%．但差异无统计学意义（P〉0．05）。57例中位随访时间11．7个月（0．7～53．4）。MGMT低表达组和高表达组中位无疾病进展时间（Drogressive-free survival,PFS）分别是8．5个月（95％CI 4．8—19．3）和6．7（95％CI 3．7—9．3）,中位生存时间（overail survival,OS）分别是20．3（95％CI 14．3～）和16．105％CI 11．1～26．2）,中位PFS和0S在MGMT低表达组和高表达组差异无统计学意义（P〉0．05）。结论：在化疗前检测恶性胶质瘤MGMT表达情况,对MGMT高表达患者选用有助于克服耐药的化疗方案进行选择性化疗。可使MGMT高表达患者的近期疗效（客观有效率和疾病控制率）和生存时间（无疾病进展生存和总生存）达到MGMT低表达患者水平。     

替莫唑胺联合生物疗法预防晚期黑色素瘤脑转移临床分析

目的 评价接受替莫唑胺+铂类+生物治疗及传统药物达卡巴嗪+铂类+生物治疗不同方案治疗晚期黑色素瘤1年中脑转移情况; 探讨O6－甲基鸟嘌呤－DNA甲基转移酶(MGMT)表达与替莫唑胺疗效的关系。方法 88例晚期黑色素瘤患者中52例接受替莫唑胺+顺铂化疗6周期,36例患者接受达卡巴嗪+顺铂化疗6周期,观察治疗1年后两组脑转移发生率及MGMT表达与替莫唑胺疗效的关系。结果 替莫唑胺组治疗1年后仅有2名患者发生脑转移,发生率为3.85%;达卡巴嗪组6名患者发生脑转移,发生率为16.67%。MGMT (-)组疾病控制率为80％,MGMT（+～++）组40.91％。结论 替莫唑胺治疗组脑转移率明显下降。MGMT表达与替莫唑胺药效有关,MGMT表达阴性治疗有效率更高。治疗前检测MGMT的表达情况,可预测化疗敏感性,制定个体化治疗方案,克服耐药,提高治疗效果。     

MGMT的表达在预测乳腺癌化疗效果中的应用

目的：探讨O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）在乳腺癌组织中的表达及其与乳腺癌化疗预后的关系。方法选取行手术治疗，术后接受常规化疗的乳腺癌患者81例为研究对象，采用免疫组化法检测患者病理组织MGMT水平，分析其与患者临床指标及预后的关系。结果81例患者病理组织中，MGMT阳性表达58例，占71.6%；阳性表达患者雌激素受体阳性率低于阴性表达患者，差异有统计学意义（P﹤0.05）；MGMT阳性患者化疗总有效率低于阴性患者，差异有统计学意义（P﹤0.05）；MGMT阳性患者与阴性患者总生存期对比，差异无统计学意义（P﹥0.05）。结论 MGMT对预测乳腺癌化疗患者近期疗效有一定价值，但对患者总生存期缺乏预测价值。     

骨肉瘤组织中MGMT的表达与顺铂治疗后瘤组织坏死程度的关系

目的：探讨骨肉瘤组织中O(6)甲基鸟嘌呤DNA甲基转移酶\[O(6)methylguanineDNA methyltransferase,MGMT\]的表达与顺铂（cisplatin,DDP）治疗后瘤组织坏死程度的关系。方法：选取2001年1月至2008年4月北京307医院骨科收治的骨肉瘤患者76例,全部患者均以标准的DDP方案治疗3个疗程以上,然后手术切除肿瘤。以免疫组化法检测顺铂治疗前活检标本中MGMT的表达,以HE染色观察手术切除骨肉瘤组织的坏死程度,分析MGMT表达和肿瘤坏死程度的关系。结果：本组患者骨肉瘤组织中MGMT蛋白的表达率为68% （52/76）,其毛细胞血管扩张型、成骨细胞型、成软骨细胞型、成纤维细胞瘤型间的MGMT表达率无差异。MGMT阴性的肿瘤经DDP化疗后的组织坏死率高,反之肿瘤坏死率低（P<0.01）。结论：MGMT蛋白表达与DDP化疗后骨肉瘤组织的坏死程度呈负相关,该指标部分地反映肿瘤的耐药性和DDP的疗效。     

Akt/mTOR通路在胃肠胰神经内分泌肿瘤中的表达及其意义

目的探讨胃肠胰神经内分泌肿瘤中Akt/mTOR信号通路的作用及意义。方法选取60例胃肠胰神经内分泌肿瘤作为实验研究对象,同时纳入胃肠胰腺炎症患者30例作为对照组,ELISA法检测入组患者血液中Akt、mTOR水平,免疫组织化学法检测组织中Akt、mTOR的表达,分析AKt、mTOR表达水平与胃肠胰神经内分泌肿瘤临床病理特征的关系。结果实验组血清AKt、mTOR水平较对照组升高,差异有统计学意义(P<0.05);实验组瘤组织中AKt、mTOR阳性率均较瘤旁组织、对照组升高,差异有统计学意义(P<0.05);AKt、mTOR表达水平与胃肠胰神经内分泌肿瘤的分化程度、肿瘤大小、肿瘤数目、远处转移、患者生存时间有关(P<0.05)。结论在胃肠胰神经内分泌肿瘤患者的血清及组织中均存在AKt、mTOR的高度表达,表达水平与胃肠胰神经内分泌肿瘤的分化程度、肿瘤大小、肿瘤数目、远处转移、患者生存时间有关。     

评价替莫唑胺对脑胶质瘤治疗敏感性的新方法

背景与目的：替莫唑胺（temozolomide,TMZ）是治疗胶质母细胞瘤的唯一化疗药。O⁶-甲基鸟嘌呤DNA甲基转移酶（O⁶-methylguanine-DNA methyltransferase,MGMT）基因启动子甲基化是评价TMZ敏感性的唯一指标。但通过检测MGMT的甲基化程度来评估TMZ的敏感性是不够的,因为目前MGMT检测只是定性检测,而且这种检测只能反映DNA损伤修复的一条通路,而另两条通路的修复情况却没有反映出来。方法：该研究一方面是应用高分辨率熔解曲线（high resolution melting,HRM）,对MGMT的甲基化进行定量检测,同时应用实时荧光定量聚合酶链反应（real-time fluorescent quantitative polymerase chain reaction,RTFQPCR）来探讨另外两条修复通路蛋白N-甲基化嘌呤DNA糖基化酶（N-methylpurine DNA glycosylase,MPG）和人类烷烃羟化酶基因同系物2（alkane hydroxylase gene homolog 2,ALKBH2）的mRNA表达。将MPG和ALKBH2的表达分为高表达和低表达。结果：结合MGMT的甲基化（阳性）和非甲基化（阴性）程度,再把MPG和ALKBH2结合起来评估患者对TMZ的敏感性。三阳性（MGMT非甲基化,MPG阳性和ALKBH2阳性）为化疗抵抗,两阳性为不感,两阴性为次敏感,三阴性（MGMT甲基化,MPG阴性和ALKBH2阴性）为最敏感。结合8例胶质母细胞瘤患者的检测和生存期,结果与我们的判断结果相吻合,三阴性的患者生存时间最长,三阳性的患者的生存时间最短。结论：通过定量检测MGMT同时结合MPG和ALKBH2可以更精准地判断TMZ的敏感性。     

脑胶质瘤O6-甲基鸟嘌呤-DNA甲基转移酶启动区甲基化及其表达异质性的研究

目的研究脑胶质瘤组织不同部位O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）启动区甲基化状态及其表达的差异性。方法在54例脑胶质瘤组织的中心和周边部位分别获取标本,共获得92份标本,采用巢式甲基化特异性PCR（MSP）进行MGMT启动区甲基化状态的检测,同时采用免疫组织化学方法进行MGMT蛋白表达的检测。结果 38例胶质瘤中获得了肿瘤两个不同部位MG-MT启动区甲基化的状态,其中24例胶质瘤MGMT启动区甲基化的状态是一致的,占总数的63.2%（24/38）。在29例胶质瘤患者中获得了肿瘤两个不同部位MGMT蛋白表达的情况,其中10例胶质瘤MGMT蛋白表达是一致的,占总数的34.5%（10/29）。两总体一致性概率间差值的95%置信区间为（5.6%和51.8%）,两者的差异有统计学意义。巢式MSP和免疫组化都获得检测结果的标本有77份,在61份MGMT启动区甲基化标本中,25份MGMT蛋白表达阴性,14份蛋白表达可疑阳性,18份蛋白表达阳性,4份蛋白表达强阳性。在16份MGMT启动区非甲基化标本中,2份MGMT蛋白表达阴性,2份蛋白表达可疑阳性,9份蛋白表达阳性,3份蛋白表达强阳性,MGMT启动区甲基化状态与蛋白表达呈负相关（r=-0.318,P=0.005）。结论脑胶质瘤MGMT蛋白表达在同一肿瘤的不同部位存在明显的异质性。虽然脑胶质瘤MGMT启动区甲基化的状态在同一肿瘤的不同部位存在一定的异质性,但是大多数脑胶质瘤MGMT启动区甲基化的状态在同一肿瘤的不同部位是一致的。脑胶质瘤MGMT启动区甲基化状态的一致性优于蛋白表达的一致性。脑胶质瘤MGMT启动区甲基化,MGMT蛋白表达较少,MGMT启动区非甲基化,MGMT蛋白表达较多。     

替莫唑胺联合干扰素α/β治疗胶质瘤移植瘤的实验研究

背景与目的:6-氧甲基鸟嘌呤-DNA甲基转移酶(06-methylguanine-DNA-methyl transferase,MGMT)是肿瘤对甲基化类药物耐药的重要原因之一.替莫唑胺(temozolomide,TMZ)常规方案对MGMT阳性胶质瘤的化疗效果不理想.本实验在动物体内观察干扰素α/β(interfero...     

MGMT在神经胶质瘤中表达的临床意义及联合应用STZ对愈后的影响

目的:通过观察神经胶质瘤中O6甲基鸟嘌呤DNA甲基转移酶(O6methylguanineDNAmethyltransferaseMGMT)的表达状态,探讨MGMT在胶质瘤中的表达与亚硝脲(ACNU/BCNU)耐药之间的关系;同时对于部分MGMT阳性患者给予链脲菌素(STZ)联合ACNU/BCNU治疗,观察疗效。方法:采用免疫组化法对神经胶质瘤石蜡标本检测MGMT,并与临床亚硝脲的随访结果进行比较;对8例MGMT阳性率高且对亚硝脲治疗无效的难治性脑瘤患者,开展STZ联合ACNU治疗。结果:68例神经胶质瘤,MGMT表达的总阳性率为55.9%。在使用亚硝脲治疗的患者中,除8例加用STZ联合治疗外,余60例中,27例MGMT(-)者,使用ACNU治疗绝大部分有效;30例MGMT( ～ )者,使用ACNU治疗后绝大部分复发或死亡,表明MGMT表达与亚硝脲化疗呈负相关;另外8例MGMT阳性患者在进行了STZ联合ACNU治疗后,1例可测肿瘤全部消失,2例肿瘤体积缩小在50%以上,4例肿瘤体积消退<50%,1例无效。结论:MGMT阳性的胶质瘤患者比MGMT阴性的患者明显耐药,且耐药程度与MGMT表达强度无关,仅与其是否阳性有关。对于MGMT阳性患者,可选择ACNU/BCNU联合STZ使用,以提高亚硝脲的疗效。因此,化疗前检测胶质瘤MGMT的表达情况,预测化疗敏感性,对指导临床化疗具有重要意义。     

乳腺癌Survivin表达意义及苦参临床疗效分析

目的:探讨乳腺癌（breast cancer，BC）Survivin表达与以紫杉醇为主的化疗疗效之间的关系，并进一步研究复方苦参注射液对化疗疗效的影响。方法:筛选119例乳腺癌患者，通过回顾性分析，依据既往用药情况分为:含紫杉醇化疗组（A组）和化疗联合复方苦参注射液组（B组）。应用免疫组化法检测患者肿瘤组织中Survivin表达水平，再分为阳性表达组和阴性表达组。分别以χ2检验和Kaplan-Meier方法分析有效率和生存时间的差异。结果:A组阴性表达患者化疗有效率为83.3%，明显高于阳性表达组（P=0.031）；且PFS、OS均较阳性组延长，但仅PFS差异具有统计学意义（P=0.046）。B组阳性表达与阴性表达者在化疗有效率、PFS、OS方面均无明显差异。两组之间比较发现:联合苦参B组阳性表达患者有效率较单纯化疗A组阳性表达者有明显升高趋势(P=0.026)。阳性表达者PFS在联合苦参后由12.761月提高到16.197月，具有统计学差异（P=0.027）。OS由30.789月提高到36.570月，但差异并没有统计学意义（P>0.05）。结论:对Survivin表达水平的检测有望成为乳腺癌含紫杉醇化疗方案的预测指标，且针对Survivin高表达患者联合复方苦参注射液可能提高化疗的有效率，甚至延长PFS。     

O(6) -methylguanine-DNA methyltransferase (MGMT) promoter methylation and low MGMT-encoded protein expression as prognostic markers in glioblastoma patients treated with biodegradable carmustine wafer implants after initial surgery followed by radiotherapy with concomitant and adjuvant temozolomide

BACKGROUND:

O⁶‐methylguanine‐DNA methyltransferase (MGMT) promoter methylation status was proposed as a prognostic biomarker for patients with glioblastoma. However, the prognostic impact of MGMT in patients with newly diagnosed glioblastoma who receive carmustine‐releasing wafers (Gliadel) along with temozolomide (TMZ) is still unknown.

METHODS:

MGMT promoter methylation status and protein expression were analyzed in formalin‐fixed, paraffin‐embedded tumor specimens obtained from 111 French patients with newly diagnosed glioblastoma. Patients received the Gliadel wafers followed by radiotherapy plus concomitant and adjuvant TMZ chemotherapy while they were enrolled in a French multicenter prospective study.

RESULTS:

For the whole cohort, the median overall survival (OS) was 17.5 months, and the progression‐free survival was 10.3 months. Patients with tumors that harbored MGMT methylation had a significantly longer OS compared with patients who had wild‐type MGMT (21.7 months vs 15.1 months; P = .025). Similarly, patients who had low MGMT protein expression (≤15%) had a significantly improved OS compared with patients who had high MGMT expression (27.0 months vs 15.1 months; P = .021). The extent of resection was the strongest clinical predictor of outcome. In multivariate Cox models that were adjusted for sex, performance status, and extent of surgery, both MGMT methylation and protein expression were identified as independent prognosticators, and the finding was validated internally using a bootstrap resampling technique. Discrepancies were identified between protein expression and MGMT methylation status, thus suggesting that the 2 assays probably assess different biologic features.

CONCLUSIONS:

MGMT promoter methylation status and low MGMT expression both were identified as positive prognosticators in patients with newly diagnosed glioblastoma who underwent surgical resection and received Gliadel wafer implants followed by adjuvant radiotherapy and concomitant oral TMZ chemotherapy (the Stupp protocol). Cancer 2012. © 2012 American Cancer Society.     

肿瘤原位液中肿瘤来源DNA实时监测脑胶质母细胞瘤术后替莫唑胺诱导超突变的临床应用价值

目的:探讨脑肿瘤原位液（tumor in situ fluid,TISF）来源的肿瘤DNA（tumor-derived DNA）测序实时监测脑胶质母细胞瘤（GBM）术后替莫唑胺（temozolomide,TMZ）诱导超突变的临床应用价值。方法:收集2019年3月至2021年6月于我院神经外科接受诊治的21例GBM患者的肿瘤组织标本及术后TMZ辅助治疗期间的TISF标本和CSF标本,共50个样本（4个CSF、19个组织标本、27个TISF）,从TISF和CSF中提取无细胞DNA（cell-free DNA,cfDNA）进行肿瘤来源DNA靶向测序,表征脑胶质母细胞瘤术后基因组景观,并与肿瘤组织标本测序结果对比,鉴定出在术后TMZ辅助化疗期间基因组发生超突变的GBM患者。结果:21例GBM患者平均年龄（53.2±13.5）岁,18例为IDH野生型,3例为IDH突变型,初始MGMT甲基化均阳性。共检测到67个不同基因的785个突变,每个个体平均突变数为15.7,最常见的改变基因为TP53（35%）、NF1（33%）、TSC2（29%）、PTEN（27%）、PTCH1（23%）,最常见的突变类型是错义突变（65%）,其次是多重突变（13%）和移码突变（12%）。与初始肿瘤组织标本测序结果对比,共有2例患者经TISF 肿瘤来源DNA测序检测出在用药期间发生基因组超突变,并证实为TMZ诱导产生的超突变。结论:通过TISF 肿瘤来源DNA在体动态监测,可实时在体表征脑胶质母细胞瘤术后肿瘤基因景观及监测替莫唑胺诱导的超突变,通过基因组分析,早期发现肿瘤耐药,提示临床调整后续治疗方案。     

结肠癌中LZTS1和CDK1表达与术后辅助化疗敏感性的关系

目的:探讨结肠癌组织中亮氨酸拉链肿瘤抑制基因1（LZTS1）和细胞周期蛋白依赖性激酶1（CDK1）表达与术后辅助化疗敏感性之间的关系。方法:采用免疫组织化学法检测结肠癌组织和癌旁组织中LZTS1和CDK1表达，分析其表达与患者临床病理特征的关系。统计术后辅助化疗后复发转移或死亡患者及未转移患者人数无病生存期（DFS），分析LZTS1和CDK1表达与术后辅助化疗敏感性的关系。Kaplan-Meier法分析LZTS1和CDK1表达对结肠癌患者术后辅助化疗后DFS影响，Cox比例风险回归模型分析影响结肠癌患者术后辅助治疗敏感性的因素。结果:与癌旁组织相比，结肠癌组织中LZTS1阳性表达率显著降低（P＜0.05），CDK1阳性表达率显著提高（P＜0.05）。LZTS1和CDK1表达与结肠癌患者年龄、性别以及肿瘤直径大小无关（P＞0.05），与肿瘤分化程度和淋巴结转移相关（P＜0.05）。LZTS1阳性表达患者对术后辅助化疗敏感性高，而CDK1阴性表达患者对术后辅助化疗敏感性高。LZTS1阳性表达患者DFS较阴性表达患者升高（P＜0.05），中位生存时间延长。CDK1阳性表达患者DFS较阴性表达患者降低（P＜0.05），中位生存时间缩短。Cox 多因素分析结果显示，淋巴结转移、LZTS1和CDK1是结肠癌患者术后辅助化疗敏感性的预测指标。结论:结肠癌组织中LZTS1阳性表达降低，CDK1阳性表达升高，LZTS1阳性表达和CDK1阴性表达患者更能从辅助化疗中获益，均可作为术后化疗敏感性的参考指标。     

Relationship Between Hypermethylated MGMT Gene and Osteosarcoma Necrosis Rate After Chemotherapy

To investigate the relativity of MGMT(O-6-methylguanine-DNA methyltransferase) gene methylation from patients with protein expression and osteosarcoma necrosis rate after chemotherapy. Fifty-one oteosarcoma tissues were collected, Methylation of MGMT gene promoter was detected by methylation-specific PCR method, and protein expression of MGMT was examined by immunohistochemistry procedure, the relationship between methylated MGMT gene expression and patients response to chemotherapy was analyzed. The positive ratio of methylation MGMT gene promoter in 51 patients was 23.5% (12 in 51). Negative percentage of protein expression of MGMT was 27.5% (14 in 51). It seemed that methylation of MGMT gene in osteosarcoma tissues had no evident relationship with the patient’s age, sexuality, and the size and type of neoplasms, etc. The necrosis rates of methylated MGMT of osteosarcoma (tumor grade from I to IV) were 0 (0/51), 3.9% (2/51), 5.9% (3/51), 13.7% (7/51), respectively. In contrast, the necrosis rates of unmethylated MGMT of osteosarcoma (tumor grade from I to IV) were 45.1% (23/51), 25.5% (13/51), 3.9% (2/51), 2.0% (1/51), respectively. It suggest that methylated and unmethylated MGMT gene of osteosarcoma have significant difference in protein expression. The unmethylated MGMT gene has higher positive protein expression (u = −4.92, P < 0.001). Methylation of MGMT gene has higher tumor necrosis rate in osteosarcoma patients. Methylation in MGMT promoter may be important for judging the effect of chemotherapy in Osteosarcoma patients.     

O6‐methylguanine DNA methyltransferase immunoexpression in nonfunctioning pituitary adenomas

BACKGROUND:

Currently, no effective alternative treatment exists for progressive, regrowing, nonfunctioning pituitary adenomas (NFPA) that are resistant to conventional multimodality therapy. Temozolomide (TMZ) was proposed as a treatment option for pituitary carcinomas and aggressive pituitary adenomas. Recently, it was suggested that the responsiveness of pituitary tumors to TMZ depends on the immunoexpression of O⁶‐methylguanine DNA methyltransferase (MGMT). Therefore, the authors of this report assessed MGMT expression in a series of patients with progressive, regrowing NFPAs to evaluate whether TMZ may serve as alternative treatment option.

METHODS:

On the basis of postoperative magnetic resonance imaging, 45 patients with NFPAs were allocated to either a group with progressive, regrowing tumors (n = 24) or a tumor‐free group (n = 21), which served as a control. MGMT expression was assessed semiquantitatively by immunohistochemistry (low expression was defined as ≤50% immunostained adenoma cells, and high expression was defined as >50% immunostained adenoma cells) and was compared between the 2 groups.

RESULTS:

At the time of initial surgery, low MGMT expression was observed in 12 of 24 patients (50%) in the study group with progressive, regrowing NFPAs. In the control group of tumor‐free patients, only 5 of 21 patients (24%) exhibited low MGMT expression. A comparable distribution of MGMT expression was observed in the specimens from repeat surgeries. A shorter interval to second surgery was observed in patients who had low MGMT expression.

CONCLUSIONS:

The current data has suggested that half of the patients with progressive, regrowing NFPAs exhibit low MGMT expression and are potential candidates for treatment with TMZ. These findings provide a rationale for the use of TMZ as an alternative treatment approach in this subgroup if conventional therapy, including reoperation, radiosurgery, and radiotherapy, fails. Cancer 2009. © 2009 American Cancer Society.     

Prognostic significance of O6-methylguanine-DNA methyltransferase protein expression in patients with recurrent glioblastoma treated with temozolomide

BACKGROUND: Temozolomide (TMZ) is active against newly diagnosed glioblastoma (GBM), and O(6)-methylguanine-DNA methyltransferase (MGMT) is implicated in resistance to TMZ and nitrosoureas. We evaluated the efficacy and safety of the standard 5-day TMZ regimen in patients with recurrent GBM after initial therapy including nitrosourea-based chemotherapy, in conjunction with an analysis of the prognostic value of MGMT protein expression regarding response to TMZ and survival. METHODS: From September 2003 to January 2007, 30 patients having recurrent GBM received 150-200 mg/m(2)/day of TMZ for five consecutive days every 28 days. Tumor tissue from 19 patients was analysed for MGMT protein expression using western blotting, and 17 of them were assessable for a response. RESULTS: The overall response rate was 23.5% (one complete response and three partial responses). Six patients had stable disease (35.3%). Median progression-free survival (PFS) time was 2.2 months, and median overall survival (OS) time was 9.9 months from the initiation of TMZ therapy. Patients with low MGMT protein expression had a significantly improved PFS (P = 0.016) and OS (P = 0.019) compared to those with high expression. Both low MGMT expression (P = 0.040) and re-resection at relapse (P = 0.014) persisted as significant independent favorable prognostic factors for OS. The most common grade 3 and 4 hematological toxicity was lymphopenia (22.2%). CONCLUSIONS: The standard 5-day TMZ regimen resulted in moderate antitumor activity with an acceptable safety profile in patients with nitrosourea-pretreated recurrent GBM, and protein expression of MGMT is an important prognostic factor for patients treated with TMZ even after recurrence.