To understand the possible mechanisms through which CBX7 represses p16 transcription, we established CBX7 overexpression models by transfecting wildtype CBX7 expression vector to MGC803 and BGC823 cells and found both transiently and stably upregulated CBX7 could repress p16 expression in these gastric cancer cell lines, increase levels of H3K9me3 within the p16 promoter and RD regions. This evidence concerns the gene CBX7 and gastric cancer.