1 The Criteria of Inclusion of Infectious Agents in the List of Biological Carcinogens
2 General Mechanisms of Biological Carcinogenesis
2.1 Metabolic mechanisms
2.2 Immune mechanisms
2.3 Mechanisms mediated by the carcinogenic activity of the bacterial and protozoan toxins
3 The Role of Bacteria in Cancer Development
3.1 The Role of Bacteria in Cancer of the Digestive Tract
3.2 The Role of Bacteria in Cancer of the Respiratory
3.3 The Role of Bacteria in Cancer of the Genitourinary Tract
3.4 The Role of Bacteria in Cancer of the Hematolymphopoietic Tract
3.5 Additional Bacteria Anecdotally Associated with Cancer
4 The Role of Protozoa in Cancer Development
4.1 Toxoplasma gondii
4.2 Cryptosporidium parvum
4.3 Trichomonas vaginalis
5 The Role of Helminths and Fungi in Cancer Development
5.1 Taenia spp
5.2 Strongyloides stercoralis.
5.3 Fasciola hepatica, Trichostrongylus colubriformis, Paracoccidioides brasiliensis.
6 Organ Microbiota in Cancer Development: the Holy Grail of Biological Carcinogenesis
6.1 The Role of Oral Microbiota in Cancer Development
6.2 The Role of Gut Microbiota in Colorectal Cancer Development
7 Conclusions: Are We There Yet?