EGFR and gastric cancer: Both wt and ΔhtrA strains activated transcription of the EREG and EPGN genes both of which contribute to stimulation of the epidermal growth factor receptor gene EGFR. Elevated epiregulin (EREG) expression predicts poor prognosis in gastric cancer (Xia et al., 2019), while epigen (EPGN) is suspected to play a role in the development of lung carcinomas (Fujimoto et al., 2005).