TMEM220 and gastric cancer: Besides, due to the specific low expression and high methylation of TMEM220 in gastric cancer tissues [46], some scholars speculate that CTC-297N7.9 that located upstream of the protein-coding gene TMEM220, may be able to regulate the methylation of TMEM220 or participate in autophagy through its functional proteins, which in turn affects the prognosis of HCC patients [32].