Carcinogenicity and Anti-tumoral Effect of Parasites: A Review Study

In endemic areas, some parasitic infections may be related to cancer induction or induction of immune responses against cancer. In some cases, parasites cause disease in their host, and in other cases, they reach a biological balance with them. Parasite invasion of the host depends on some factors such as parasite species, life cycle, enzyme production, and host immunity. The results of various studies in different parts of the world have shown that some parasites such as Schistosoma, Opisthorchis, Clonorchis, Strongyloides, Leishmania, Blastocystis, and Cryptosporidium could induce cancer in their host under certain conditions. However, others like Toxocara, Hydatid cyst, Mesocestoides, Taenia crassiceps, Fasciola, and Plasmodium initiate an anti-tumor immune response in the host. Some others, such as Trichomonas, Trypanosoma, and Toxoplasma, have both tumoral and anti-tumoral activity. A better and more complete understanding of these interactions could lead us to a clear future in the treatment of cancer, therefore, in this study, the role of parasites in the induction and prevention of cancer has been investigated.