✓ An inverse correlation between methylated CpGs of EGFR and mRNA/protein expression was observed.✓ Promoter hypermethylation was found to be associated with immune cell infiltration and increased IFN-γ signature, while the opposite was found for methylation of the gene body region.✓ Hypermethylation of cg02316066 and cg03046247 was strongly associated with lung adenocarcinoma prognosis. The gene discussed is IFNG; the disease is lung adenocarcinoma.