title: Aberrant promoter methylation of multiple genes in non-small cell lung cancers.
abstract: Aberrant methylation of CpG islands acquired in tumor cells in promoter regions is one method for loss of gene function. We determined the frequency of aberrant promoter methylation (referred to as methylation) of the genes retinoic acid receptor beta-2 (RARbeta), tissue inhibitor of metalloproteinase 3 (TIMP-3), p16INK4a, O6-methylguanine-DNA-methyltransferase (MGMT), death-associated protein kinase (DAPK), E-cadherin (ECAD), p14ARF, and glutathione S-transferase P1 (GSTP1) in 107 resected primary non-small cell lung cancers (NSCLCs) and in 104 corresponding nonmalignant lung tissues by methylation-specific PCR. Methylation in the tumor samples was detected in 40% for RARbeta, 26% for TIMP-3, 25% for p16INK4a, 21% for MGMT, 19% for DAPK, 18% for ECAD, 8% for p14ARF, and 7% for GSTP1, whereas it was not seen in the vast majority of the corresponding nonmalignant tissues. Moreover, p16INK4a methylation was correlated with loss of p16INK4a expression by immunohistochemistry. A total of 82% of the NSCLCs had methylation of at least one of these genes; 37% of the NSCLCs had one gene methylated, 22% of the NSCLCs had two genes methylated, 13% of the NSCLCs had three genes methylated, 8% of the NSCLCs had four genes methylated, and 2% of the NSCLCs had five genes methylated. Methylation of these genes was correlated with some clinicopathological characteristics of the patients. In comparing the methylation patterns of tumors and nonmalignant lung tissues from the same patients, there were many discordancies where the genes methylated in nonmalignant tissues were not methylated in the corresponding tumors. This suggests that the methylation was occurring as a preneoplastic change. We conclude that these findings confirm in a large sample that methylation is a frequent event in NSCLC, can also occur in smoking-damaged nonmalignant lung tissues, and may be the most common mechanism to inactivate cancer-related genes in NSCLC.
authors.affiliation: Hamon Center for Therapeutic Oncology Research, The University of Texas, Southwestern Medical Center at Dallas, 75390-8593, USA.
authors.forename: S
authors.initials: S
authors.lastname: Zöchbauer-Müller
authors.forename: K M
authors.initials: KM
authors.lastname: Fong
authors.forename: A K
authors.initials: AK
authors.lastname: Virmani
authors.forename: J
authors.initials: J
authors.lastname: Geradts
authors.forename: A F
authors.initials: AF
authors.lastname: Gazdar
authors.forename: J D
authors.initials: JD
authors.lastname: Minna
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051017:Apoptosis Regulatory Proteins; D015820:Cadherins / Q000235:genetics; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000096:biosynthesis; D019175:DNA Methylation; D064550:Death-Associated Protein Kinases; D005260:Female; D019942:Genes, p16 / Q000235:genetics; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000235:genetics; D019656:Loss of Heterozygosity; D008175:Lung Neoplasms / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011506:Proteins / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D012307:Risk Factors; D015996:Survival Rate; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics; D025803:Tumor Suppressor Protein p14ARF
chemical_list: D051017:Apoptosis Regulatory Proteins; D015820:Cadherins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D007527:Isoenzymes; D011506:Proteins; D018168:Receptors, Retinoic Acid; D019717:Tissue Inhibitor of Metalloproteinase-3; D025803:Tumor Suppressor Protein p14ARF; C082925:retinoic acid receptor beta; D019853:O(6)-Methylguanine-DNA Methyltransferase; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases