Topaloglu Ozlem, Hoque Mohammad Obaidul, Tokumaru Yutaka, Lee Juna, Ratovitski Edward, Sidransky David, Moon Chul-so
Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA.
Clin Cancer Res. 2004 Apr 1;10(7):2284-8. doi: 10.1158/1078-0432.ccr-1111-3.
Aberrant promoter hypermethylation of several known or putative tumor suppressor genes occurs frequently during the pathogenesis of lung cancers and is a promising marker for cancer detection. We investigated the feasibility of detecting aberrant DNA methylation in the bronchoalveolar lavage (BAL) samples of lung cancer patients.
We examined the tumor and the matched BAL DNA for aberrant methylation of eight gene promoters (CDH1, APC, MGMT, RASSF1A, GSTP1, p16, RAR-beta 2, and ARF) from 31 patients with primary lung tumors by quantitative fluorogenic real-time PCR. BAL from 10 age-matched noncancer patients was used as a control.
Promoter hypermethylation of at least one of the genes studied was detected in all 31 lung primary tumors; 27 (87%) CDH1, 17 (55%) APC, 14 (45%) RASSF1A, 12 (39%) MGMT, 7 (23%) p16, 3 (10%) GSTP1, 3 (10%) RAR-beta 2, and 0 (0%) ARF. Methylation was detected in CDH1 (48%), APC (29%), RASSF1A (29%), MGMT (58%), p16 (14%), GSTP1 (33%), RAR-beta 2 (0%), and ARF (0%) of BAL samples from matched methylation-positive primary tumors, and in every case, aberrant methylation in BAL DNA was accompanied by methylation in the matched tumor samples. BAL samples from 10 controls without evidence of cancer revealed no methylation of the MGMT, GSTP1, p16, ARF, or RAR-beta 2 genes whereas methylation of RASSF1, CDH1, and APC was detected at low levels. Overall, 21 (68%) of 31 BAL samples from cancer patients were positive for aberrant methylation.
Our findings suggest that promoter hypermethylation in BAL can be detected in the majority of lung cancer patients. This approach needs to be evaluated in large early detection and surveillance studies of lung cancer.
在肺癌发病过程中，几种已知或推测的肿瘤抑制基因启动子异常高甲基化频繁发生，是一种很有前景的癌症检测标志物。我们研究了检测肺癌患者支气管肺泡灌洗（BAL）样本中异常DNA甲基化的可行性。
我们通过定量荧光实时PCR检测了31例原发性肺癌患者肿瘤及配对的BAL DNA中8个基因启动子（CDH1、APC、MGMT、RASSF1A、GSTP1、p16、RAR-β2和ARF）的异常甲基化情况。10例年龄匹配的非癌症患者的BAL用作对照。
在所有31例原发性肺癌肿瘤中均检测到至少一个研究基因的启动子高甲基化；CDH1为27例（87%），APC为17例（55%），RASSF1A为14例（45%），MGMT为12例（39%），p16为7例（23%），GSTP1为3例（10%），RAR-β2为3例（10%），ARF为0例（0%）。在配对的甲基化阳性原发性肿瘤的BAL样本中，CDH1（48%）、APC（29%）、RASSF1A（29%）、MGMT（58%）、p16（14%）、GSTP1（33%）、RAR-β2（0%）和ARF（0%）检测到甲基化，且在每种情况下，BAL DNA中的异常甲基化均伴有配对肿瘤样本中的甲基化。10例无癌症证据的对照患者的BAL样本中未检测到MGMT、GSTP1、p16、ARF或RAR-β2基因的甲基化，而RASSF1、CDH1和APC的甲基化检测到的水平较低。总体而言，31例癌症患者的BAL样本中有21例（68%）异常甲基化呈阳性。
我们的研究结果表明，大多数肺癌患者的BAL中可检测到启动子高甲基化。这种方法需要在肺癌的大型早期检测和监测研究中进行评估。
