RESUMO
Cancer is the main cause of death in developed countries. However, in underdeveloped countries infections and parasitic diseases are the main causes of death. There are raising scientific evidences indicating that parasitic infections induce antitumor activity against certain types of cancers. In this study, the effects of Toxoplasma gondii and Toxocara canis egg antigens in comparison with Bacillus Calmette Guerin (BCG) (known to have anticancer distinctive) on WEHI-164 fibosarcoma transplanted to BALB/c mice was investigated. Groups of 6 male BALB/c mice injected with T. gondii antigen, BCG, or T. canis egg antigen as case groups and alum alone as control groups. All mice were then challenged with WEHI-164 fibrosarcoma cells. The mice were examined for growth of the solid tumor and the tumor sizes were measured every other day up to 4 wk. The mean tumor area in T. gondii, BCG, or alum alone injected mice in 4 different days of measurements was 25 mm2, 23 mm2, and 186 mm2 respectively. Also the mean tumor area in T. canis injected mice in 4 different days was 25.5 mm2 compared to the control group (alum treated) which was 155 mm2. T. gondii parasites and T. canis egg antigens induced inhibition of the tumor growth in the fibrosarcoma mouse model. We need further study to clarify the mechanisms of anti-cancer effects.