In lung cancer, the roles of molecular alterations in blood, sputum, bronchial brushing, and exhaled gas samples, which are relatively easy to obtain, have been evaluated for clinical availability. This study was based on the hypothesis that similar molecular alterations occur in the lung and oral cavity because both are exposed to the same environmental or tobacco-derived carcinogens. Because epigenetic alterations due to exposure to carcinogens are thought to play a major role in the development of lung cancer, the DNA methylation status of 11 genes in the oral epithelium was analyzed in lung cancer patients ( ) and control individuals without lung cancer ( ). DNA methylation profiling revealed that GDNF, RARB, and HS3ST2 were methylated more frequently in cancer patients than in the control participants ( , 0.0062, and 0.0193, resp.). Combined analysesindicatedthat 6 of 16 cancer patients (37.5%), but only 1 of 32 control individuals (3.1%) showed DNA methylation in 2-3 of these 3 genes ( ). These combined analyses showed the high specificity and positive predictive value in total and subgroup analyses. Our data suggest that DNA methylation profiling using oral epithelium may help in the identification of individuals with a high risk of lung cancer. 1. Introduction Lung cancer is the leading cause of cancer-related death in many countries [1]. A major factor contributing to this high mortality is that most tumors are not diagnosed until an advanced stage [2]. Although a variety of investigations and screening programs for early detection of lung cancer have been conducted, each approach has lacked diagnostic specificity [3, 4]. Recent reports indicated that screening using low-dose computed tomography (CT) showed encouraging results in reducing lung cancer mortality in patients with a history of cigarette smoking of at least 30 packs per year [5]. However, the frequency of lung cancer in that screening program was considerably low, although the participants were limited to individuals with a heavy smoking history. These results indicate that identification of individuals with a high risk of lung cancer is important for improving the specificity and reliability of lung cancer screening programs. Inhaled carcinogens from tobacco smoke, workplace agents, and other environmental factors such as air pollution are well known to be among the main etiological factors that cause molecular alterations in lung cancer pathogenesis [6], and the predisposition of smokers to epigenetic alterations has been characterized [7–9]. Because gene promoter methylation is a
References
[1]
R. T. Greenlee, M. B. Hill-Harmon, T. Murray, and M. Thun, “Cancer Statistics, 2001,” Ca-A Cancer Journal for Clinicians, vol. 51, no. 1, pp. 15–36, 2001.
[2]
P. A. Wingo, L. A. G. Ries, G. A. Giovino et al., “Annual report to the nation on the status of cancer, 1973–1996, with a special section on lung cancer and tobacco smoking,” Journal of the National Cancer Institute, vol. 91, no. 8, pp. 675–690, 1999.
[3]
T. Blanchon, J. M. Bréchot, P. A. Grenier et al., “Baseline results of the Depiscan study: a French randomized pilot trial of lung cancer screening comparing low dose CT scan (LDCT) and chest X-ray (CXR),” Lung Cancer, vol. 58, no. 1, pp. 50–58, 2007.
[4]
P. B. Bach, G. A. Silvestri, M. Hanger, and J. R. Jett, “Screening for lung cancer: ACCP evidence-based clinical practice guidelines,” Chest, vol. 132, no. 3, pp. S69–S77, 2007.
[5]
D. R. Aberle, A. M. Adams, C. D. Berg et al., “Reduced lung-cancer mortality with low-dose computed tomographic screening,” New England Journal of Medicine, vol. 365, no. 5, pp. 395–409, 2011.
[6]
A. J. Alberg, M. V. Brock, and J. M. Samet, “Epidemiology of lung cancer: looking to the future,” Journal of Clinical Oncology, vol. 23, no. 14, pp. 3175–3185, 2005.
[7]
H. E. Gabriel, J. W. Crott, H. Ghandour et al., “Chronic cigarette smoking is associated with diminished folate status, altered folate form distribution, and increased genetic damage in the buccal mucosa of healthy adults,” American Journal of Clinical Nutrition, vol. 83, no. 4, pp. 835–841, 2006.
[8]
H. W. Chang, G. S. Ling, W. I. Wei, and A. P. W. Yuen, “Smoking and drinking can induce p15 methylation in the upper aerodigestive tract of healthy individuals and patients with head and neck squamous cell carcinoma,” Cancer, vol. 101, no. 1, pp. 125–132, 2004.
[9]
C. V. Breton, H. M. Byun, M. Wenten, F. Pan, A. Yang, and F. D. Gilliland, “Prenatal tobacco smoke exposure affects global and gene-specific DNA methylation,” American Journal of Respiratory and Critical Care Medicine, vol. 180, no. 5, pp. 462–467, 2009.
[10]
J. G. Herman and S. B. Baylin, “silencing in cancer in association with promoter hypermethylation,” New England Journal of Medicine, vol. 349, no. 21, pp. 2042–2054, 2003.
[11]
T. A. Rauch, Z. Wang, X. Wu, K. H. Kernstine, A. D. Riggs, and G. P. Pfeifer, “DNA methylation biomarkers for lung cancer,” Tumor Biology, vol. 33, no. 2, pp. 287–296, 2012.
[12]
M. V. Brock, C. M. Hooker, E. Ota-Machida et al., “DNA methylation markers and early recurrence in stage I lung cancer,” New England Journal of Medicine, vol. 358, no. 11, pp. 1118–1128, 2008.
[13]
K. L. Ostrow, M. O. Hoque, M. Loyo et al., “Molecular analysis of plasma DNA for the early detection of lung cancer by quantitative methylation-specific PCR,” Clinical Cancer Research, vol. 16, no. 13, pp. 3463–3472, 2010.
[14]
O. Topaloglu, M. O. Hoque, Y. Tokumaru et al., “Detection of promoter hypermethylation of multiple genes in the tumor and bronchoalveolar lavage of patients with lung cancer,” Clinical Cancer Research, vol. 10, no. 7, pp. 2284–2288, 2004.
[15]
W. Han, T. Wang, A. A. Reilly, S. M. Keller, and S. D. Spivack, “Gene promoter methylation assayed in exhaled breath, with differences in smokers and lung cancer patients,” Respiratory Research, vol. 10, article no. 86, 2009.
[16]
Y. Watanabe, H. S. Kim, R. J. Castoro et al., “Sensitive and specific detection of early gastric cancer with DNA methylation analysis of gastric washes,” Gastroenterology, vol. 136, no. 7, pp. 2149–2158, 2009.
[17]
T. Maekita, K. Nakazawa, M. Mihara et al., “High levels of aberrant DNA methylation in Helicobacter pylori-infected gastric mucosae and its possible association with gastric cancer risk,” Clinical Cancer Research, vol. 12, no. 3, part 1, pp. 989–995, 2006.
[18]
K. Miyamoto, K. Asada, T. Fukutomi et al., “Methylation-associated silencing of heparan sulfate D-glucosaminyl 3-O-sulfotransferase-2 (3-OST-2) in human breast, colon, lung and pancreatic cancers,” Oncogene, vol. 22, no. 2, pp. 274–280, 2003.
[19]
J. G. Herman, J. R. Graff, S. Myohanen, B. D. Nelkin, and S. B. Baylin, “Methylation-specific PCR: a novel PCR assay for methylation status of CpG islands,” Proceedings of the National Academy of Sciences of the United States of America, vol. 93, no. 18, pp. 9821–9826, 1996.
[20]
K. Miyamoto, T. Fukutomi, S. Akashi-Tanaka et al., “Identification of 20 genes aberrantly methylated in human breast cancers,” International Journal of Cancer, vol. 116, no. 3, pp. 407–414, 2005.
[21]
J. Furuta, Y. Umebayashi, K. Miyamoto et al., “Promoter methylation profiling of 30 genes in human malignant melanoma,” Cancer Science, vol. 95, no. 12, pp. 962–968, 2004.
[22]
S. A. Belinsky, “Gene-promoter hypermethylation as a biomarker in lung cancer,” Nature Reviews Cancer, vol. 4, no. 9, pp. 707–717, 2004.
[23]
M. Bhutani, A. K. Pathak, Y. H. Fan et al., “Oral epithelium as a surrogate tissue for assessing smoking-induced molecular alterations in the lungs,” Cancer Prevention Research, vol. 1, no. 1, pp. 39–44, 2008.
[24]
X. Wu, T. A. Rauch, X. Zhong et al., “CpG Island hypermethylation in human astrocytomas,” Cancer Research, vol. 70, no. 7, pp. 2718–2727, 2010.
[25]
H. Funahashi, Y. Okada, H. Sawai et al., “The role of glial cell line-derived neurotrophic factor (GDNF) and integrins for invasion and metastasis in human pancreatic cancer cells,” Journal of Surgical Oncology, vol. 91, no. 1, pp. 77–83, 2005.
[26]
C. Garnis, J. J. Davies, T. P. H. Buys et al., “Chromosome 5p aberrations are early events in lung cancer: implication of glial cell line-derived neurotrophic factor in disease progression,” Oncogene, vol. 24, no. 30, pp. 4806–4812, 2005.
[27]
P. P. Anglim, J. S. Galler, M. N. Koss et al., “Identification of a panel of sensitive and specific DNA methylation markers for squamous cell lung cancer,” Molecular Cancer, vol. 7, article no. 62, 2008.
[28]
Q. Feng, S. E. Hawes, J. E. Stern et al., “DNA methylation in tumor and matched normal tissues from non-small cell lung cancer patients,” Cancer Epidemiology Biomarkers and Prevention, vol. 17, no. 3, pp. 645–654, 2008.
[29]
J. H. Chung, H. J. Lee, B. H. Kim, N. Y. Cho, and G. H. Kang, “DNA methylation profile during multistage progression of pulmonary adenocarcinomas,” Virchows Archiv, vol. 459, no. 2, pp. 1–11, 2011.
[30]
N. Shivapurkar, M. E. Sherman, V. Stastny et al., “Evaluation of candidate methylation markers to detect cervical neoplasia,” Gynecologic Oncology, vol. 107, no. 3, pp. 549–553, 2007.
[31]
W. A. Palmisano, K. K. Divine, G. Saccomanno et al., “Predicting lung cancer by detecting aberrant promoter methylation in sputum,” Cancer Research, vol. 60, no. 21, pp. 5954–5958, 2000.
