Detection of promoter hypermethylation of multiple genes in the tumor and bronchoalveolar lavage of patients with lung cancer.
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Topaloglu
Ozlem
O
Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA.
Hoque
Mohammad Obaidul
MO
Tokumaru
Yutaka
Y
Lee
Juna
J
Ratovitski
Edward
E
Sidransky
David
D
Moon
Chul-so
CS
D018893:Bronchoalveolar Lavage; D001992:Bronchoalveolar Lavage Fluid; D045744:Cell Line, Tumor; D018899:CpG Islands; D004247:DNA / Q000737:chemistry; D019175:DNA Methylation; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D013447:Sulfites / Q000494:pharmacology; D013997:Time Factors
D013447:Sulfites; D004247:DNA