BACKGROUND: DNA methylation is one of major factors in cancer progression. We observed multiple genes involved in cancer-related signaling and focused on patients with advanced non-small cell lung cancer (NSCLC) and evaluated methylation in relation to various clinical parameters. PATIENTS AND METHODS: Thirty genes were examined in 121 NSCLC patients using the methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) method. Correlations to gender, smoking status, tumor subtype, disease stage and EGFR/KRAS mutation status were performed by chi-square test. RESULTS: 90% of tumors exhibited methylation of at least one gene. Most frequently methylated were cadherin-13 (CDH13), Ras associated domain-containing protein (RASSF1A), Wilms' tumor protein (WT1), adenomatous polyposis coli protein (APC), paired box protein Pax-5 (PAX5), estrogen receptor (ESR1), an inhibitor of cyclin-dependent kinase p15 (CDKN2B), paired box protein Pax-6 (PAX6), transcription factor GATA-5 (GATA5) and cell adhesion molecule 4 (IGSF4). Overall methylation (any gene) was increased in adenocarcinomas (p=0.0329), unrelated to gender or disease stage. Several genes exhibited variable methylation with gender (CDH13, p<0.001; GATA5, p=0.02; PAX6, p=0.01 and ESR1, p=0.03), smoking (CDH13, p=0.002), or epidermal growth factor receptor (EGFR) mutation status [Von Hippel-Lindau disease tumor supresor (VHL), p=0.001; CDKN2B, p=0.02; CDH13, p=0.02; APC, p=0.04 and ESR1, p=0.04]. CONCLUSION: Differences in gene methylation associated with gender, smoking and EGFR mutation suggest potential for prediction in relation to management of tyrosine kinase inhibitor therapy.

Center for Applied Genomics of Solid Tumors Genomac International Ltd Prague Czech Republic

Department of Pathology Faculty Hospital Pilsen Pilsen Czech Republic

Department of Pneumology Faculty Hospital Pilsen Pilsen Czech Republic

Laboratory for Molecular Genetics and Oncology Genomac International Ltd Prague