Abstract
Since long, it has been known that many types of mammalian cancer relates to exogenous causes and thus should be susceptible to intervention and prevention. Among these exogenous sources, microbes and microbial products have turned out to be of key importance. These microbial influence (s) upon tumorigenesis can be investigated either by comparative analysis of the composition of the microbial flora in individuals belonging to high- and low-risk populations, by investigating spontaneous tumor development in germfree (GF), ex-germfree (EX-GF) and conventional (CONV) animals and by investigation of fat and function of carcinogens and procarcinogens in GF, EX-GF and CONV animals. These three major routes of investigations are examplified. In the future, it is reasonable to assume that gnotobiotic and transgenic technology will contribute substantially to a better understanding of the complex interplay between a host and its micrioflora in tumorigenesis.
