CpG island hypermethylation as a biomarker for the early detection of lung cancer.

Lung cancer is the most frequent cause of cancer-related deaths and causes over one million deaths worldwide each year. Despite significant strides in the diagnosis and treatment of lung cancer, the prognosis is extremely poor, with the overall 5-year survival rates still remaining around 15 %. This is largely due to occult metastatic dissemination, which appears in approximately two-thirds of patients at the time of detection. Thus, the development of efficient diagnostic methods to enable the early detection of cancer for these patients is clearly imperative.One promising approach is the identification of lung cancer-specific biomarkers at an early stage. The de novo methylation of CpG islands within the promoters of tumor suppressor genes is one of the most frequently acquired epigenetic changes during the pathogenesis of lung cancer and usually associated with transcriptional downregulation of a gene. The analysis of DNA methylation patterns in sputum, bronchial fluid, plasma, or serum could become a powerful tool for the accurate and early diagnosis of lung cancer with unparalleled specificity and sensitivity.