The role of bacteria in cancer etiology and pathogenesis

The review presents the data on the importance of microorganisms in cancer development. Intestinal autoflora has been found to play an important role not only in the host protection from pathogenic microorganisms and to take part in maintenance of immunologic reactivity of the organism but also may have a defined value in etiology and pathogenesis of cancer. Pathogenetic importance of bacteria in carcinogenesis is determined by participation of bacteria in metabolism of exogenic carcinogens and in the ability to generate carcinogens or co-carcinogens from foodstuffs and intestinal secretions. Series of experimental researches on bacteria-free animals and the efficacy of anti-bacterial therapy for some malignant tumors such as MALT-lymphomas indicate that bacteria can take immediate participation in tumor cell transformation.