细菌在致癌病因上应考虑如下四个方面:1.产生致癌物或副致癌物。亚硝胺——在正常 pH 值下,从次级胺类及硝酸盐制造亚硝胺是靠酶或是肠道菌的代谢产物来促进的。有人认为亚硝胺在膀胱中形成并吸收,这与胃癌的发生有关。类固醇代谢产物——不少的类固醇能致癌,胆道类固醇经细菌代谢后的产物可能与人类结 Bacteria on the cause of carcinogenesis should consider the following four aspects: 1. Produce carcinogens or carcinogens. Nitrosamines - At normal pH levels, the production of nitrosamines from secondary amines and nitrates is promoted by enzymes or metabolites from intestinal bacteria. Some people think that nitrosamines form and absorb in the bladder, which is related to the occurrence of gastric cancer. Steroid metabolites - many of the steroids are carcinogenic, and products of biliary steroids that are metabolized by bacteria may bind to humans