Genome-wide methylation profiling has been used to identify altered methylation patterns in lung cancer tissue (including genes such as CDKN2A, RASSF1A, ARHI, MGMT and RARβ) [56,57], but so far only one larger scale study has shown the possibilities of identifying methylation biomarkers for the diagnostic or screening setting in noninvasive biospecimens utilizing microarray-based technologies. This evidence concerns the gene RARB and lung carcinoma.