The Possible Involvement of Protozoans in Causing Cancer in Human

protozoans have also been found to cause cancer in humans and animals. They are eukaryotic, unicellular, anthropozoonotic microorganisms causing several life-threatening diseases and cancer in humans. While a plethora of good pieces of information was gathered while documenting the role of several protozoans causing cancer in humans, only Plasmodium falciparum has been categorized by the IARC as Group 2A carcinogen. However, certain other protozoan parasites have also got their ability to cause cancer in humans via the integration of protozoan DNA sequences in the host cells. Protozoans cause the stimulation of cell division and proliferation of the host cells by the release of reactive oxygen and nitrogen radicals, DNA damage and the p53 gene inhibition. The present review discusses some cancer-causing protozoan parasites like Leishmania donovani, Trypanosoma brucie, Toxoplasma gondii, Trichomonas vaginalis, Blastocystis hominis, Theileria microti and Cryptosporidium parvum including Plasmodium falciparum in the light of recent researches done so far in the field of microbial origin of cancer.