RARB and lung cancer: The investigated genes have been identified as epigenetically silenced in lung cancer based on previous evidence: RASSF1A, Ras-association domain family 10 (RASSF10), Wnt inhibitory factor-1 (WIF-1), adenomatous polyposis coli (APC), breast cancer metastasis suppressor 1 (BRMS1), DNA/RNA helicase Schlafen-11 (SLFN11), shisa family member 3 (SHISA3), retinoic acid receptor-beta (RARβ), and forkhead box protein A1 (FOXA1).