PTGER4 and cancer: In previous studies, Lertpiriyapong et al. reported that colonization of male INS-GAS mice (INS-GAS transgenic mice overexpress pancreatic gastrin) with restricted microbiota consisting of Lactobacillus murinus ASF361, Clostridium ASF356, and Bacteroides ASF519, was sufficient to promote gastrointestinal intraepithelial neoplasia, which associated with robust expression of gastric inflammatory and cancer-associated genes, including TNF-α, Ptger4 and Tgf-β.