Protective effect of latent Toxoplasma infection against breast cancer risk: a comparative cross-sectional study in Iran

Some evidence suggested that Toxoplasma gondii, an obligate intracellular protozoan parasite, might have an inhibitory effect on cancers development.

We performed a matched case-control study of incident breast cancer (BC) cases versus healthy control subjects to evaluate the association between Toxoplasma infection and BC. We enrolled 161 newly diagnosed cases and 91 healthy controls, and anti-Toxoplasma serum antibodies were examined using ELISA kits. Chi-squared test was used to calculate the odds ratios (OR) and 95% confidence intervals (CIs).

Only one BC patient was seropositive for IgM while all healthy controls were seronegative. Moreover, the prevalence of anti-Toxoplasma IgG serum antibodies in the case and control groups was 70.8% (95% CI, 63.1–77.7%; 114/161) and 95.6% (95% CI, 89.1–98.7%; 87/91), respectively, indicating a significant protective association (OR, 0.11; 95% CI, 0.03–0.35%) for Toxoplasma infection in relation to BC development.

Latent Toxoplasma infection might have a protective role against the development of BC. More studies are needed to confirm our findings.