Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 15 4 2020 12 06 466 474 Maha Mustafa ASSIM Department of Biology, College of Sciences, University of Baghdad, Baghdad, Iraq Entsar Jabbar SAHEB Department of Biology, College of Sciences, University of Baghdad, Baghdad, Iraq 2020 12 06 Background: The possible risk factor of Toxoplasma infection and its possible correlation with Interleukin-12 (IL-12) and Interleukin-23 (IL-23) in breast cancer patients was investigated. Methods: Overall, 190 female patients referred to the Oncology Teaching Hospital in the Medical City Hospital, Baghdad, Iraq were enrolled from 2017-2018. All serum samples were tested for T. gondii immunoglobulins (IgG and IgM (antibodies and IL-12, IL-23 levels. Results: In patients with breast cancer, the results revealed a high positivity percentage for anti- Toxoplasma IgG. In breast cancer patients infected with T. gondii, the IL-12 level was lower than the controls while the mean level of IL-23 was higher than the controls. According to the cancer grade in breast cancer patients infected with T. gondii, the higher mean titer of IgG and IL-23 was in grade 3 in contrast the highest mean titer of IL-12 was in grade 1. Concerning the tumor stages in breast cancer patients infected with T. gondii, the higher mean titer of IgG, IL-12 and IL-23 was in stage (III). According to the tumor size in breast cancer patients infected with T. gondii, the highest mean titer of IgG, IL-12 and IL-23 was in size >3cm. Conclusion: The levels of IL-23 could be a candidate as a non-invasive primitive marker for earlier prediction of breast cancer stage. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/3166 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/3166/1082