PTPN11 and Epstein-Barr virus infection: SHP2 homologue SHP1 also interacts with Cag A, but SHP1 dampens the oncogenic function of Cag A. Saju et al. reported that EBV infection can induce promoter methylation of SHP1 and downregulate the expression of SHP1, which might increase the oncogenic function caused by the interaction of Cag A and SHP2 [57].