User:Elena Lusi/sandbox/Oncogenic Retro-Giant microbes

Oncogenic Retro-Giants The Retro-Giants are ancestral microbes disclosed in 2017 [1]. They are transmissible agents acutely transforming that infect humans and other species, being also involved in contagious cancer in the wild [2].

These oncogenic microbial entities are tentatively named Retro Giants, but they should not be confused with giant Mimiviruses infecting amoeba. Distinct from amoeba Mimiviruses, that display a complete different tropism, the Retro Giants don’t require for their isolation amoeba co-culture, since amoeba is not their natural host. The Retro-Giants infect humans and animals.

The Retro Giants appear as a microbial system composed by a large particle of ~1- 1.5 micron and smaller satellite ~ 450 nm associated viral particles. Some particles can reach up to 2.0 μm. The genome contains roughly 1.5 million base pairs base and displays multiple cells-based oncogenes [3].

The morphology, biology and genetic features suggest that the Retro-Giants are halfway in between a classic oncogenic virus and an infectious cancer cell. They should be viewed as a small autonomous infectious microbial cell, a simplified version of its eukaryotic counterparts, specialized in carcinogenesis. The transforming nature of the Retro-Giants goes with their constant ability to induce tumours formation in mice, that develop multiple tumours three weeks post infection.

The striking features of mammalian Retro-Giants are the gag-akt fusion protein, related to feline retrovirus lineage, reverse transcriptase activity, cell-based oncogenes and kinases, all enclosed in a single microbial cell [4].

The discovery of these microbial entities with an acute transformation mechanism suggests that the number of cancer of infectious origin would be even greater than what is supposed.

The Retro-Giants might open the door to a preventive vaccine against cancer in humans and other species, since they give possibility to target an entire shuttling system of oncogenes, and not just a solitary molecule involved in carcinogenesis.