TERF2IP and gastric cancer: On the basis of previous investigation, it has been validated that TRF2 promotes MDR of gastric cancer cells by interfering the activation of ATM-dependent DNA damage response.7 To further investigate how Rap1 affect TRF2-mediated resistance to etoposide in gastric cancer cells, overexpression of TRF2 in SGC7901 was firstly obtained after transfected with TRF2 eukaryotic expression vector.