In summary, we found that G9a protein was overexpressed in a subgroup of NSCLC samples probably by gene amplification [14], hypoxia [51] and/or other unknown mechanisms; in collaboration with HP1α and DNMT1, G9a epigenetically regulates gene expression through H3K9-Me2 and DNA methylation. This evidence concerns the gene CBX5 and non-small cell lung carcinoma.