Toxoplasma gondii infection may increase the risk of glioma

Toxoplasma gondii infection appeared to increase risk for glioma in adults, according to study results published in International Journal of Cancer.

“That idea T. gondii which may have been a risk factor for glioma proliferation in studies that suggested higher rates of brain tumors in areas where the parasite was endemic. This has been followed by a few epidemiologic studies that appear to support attachment, ” Caitlin M. Egan, ScD, a researcher in the department of cancer epidemiology at the Moffitt Cancer Center, told Healio. “Researchers have been interested in the issue because the parasite is tropical to the brain and disease has been linked to brain problems, all of which raise concerns about exposure to brain tumors. Our study is the first to show a link between T. gondii antibodies in the blood – which indicate pre-infection – and subsequent glioma development. ”

T. gondii it is a parasitic disease usually acquired from undercooked meat, and has the potential to cause cysts in the brain. Previous research has shown a link between the risk for glioma and an increased frequency of T. gondii infection; however, a lack of data is imminent.

Caitlin M. Egan

For this reason, Egan and colleagues investigated a prediagnostic connection T. gondii antibodies with glioma risk among participants in the American Cancer Society Study-II Consortium Consortium (cases, n = 37; controls, n = 74) and Janus Serum Bank at the Norwegian Cancer Register (cases, n = 323; controls , n = 323).

Approximately 54% of patients with glioma in the American Cancer Society cohort were women. The average age at blood draw was 70 years among all cases and controls, and the average year of blood draw was 2000. In the Norwegian group, approximately 68% of patients with male glioma, the average age of a blood draw was 40 years and 1983 was the average year of a blood draw.

Researchers analyzed blood samples collected prior to glioma diagnosis to assess the presence of antibodies to two T. gondii surface antigens and considered those with antibodies to antigen as seropositive. They used retrieval of logistic conditions to measure ORs.

Results showed an increased risk for glioma among those with T. gondii infectivity both in the American Cancer Society cohort (OR = 2.7; 95% CI, 0.96–7.62) and in the Norwegian cohort (OR = 1.32; 95% CI, 0.85–2.07). Those with high levels of antibody titers specific to the sag-1 antigen showed the highest risk (American Cancer Society cohort, OR = 3.35; 95% CI, 0.99-11.38; Norwegian cohort, OR = 1.79; 95% CI, 1.02- 3.14).

Researchers saw similar positive connections between T. gondii overall seroprevalence and glioblastoma among all cohorts (American Cancer Society, OR = 2.31; 95% CI, 0.71–7.47; Norway, OR = 1.5 95% CI, 0.83–2.72).

The limitations of the study included that it was not possible to make a reliable assessment T. gondii associations specific to glioma subtype, exposure latency and antibody titer in the American Cancer Society cohort due to small sample size. Researchers were unable to assess associations by race and ethnicity because the majority of patients in both groups were white. In some cases, blood samples were collected years before a serologic test was performed for T. gondii, and long storage time could affect results, according to the researchers.

“If our decisions are proven, avoid being open to people T. gondii offering a way to reduce the risk for glioma. This is important because there are few ways to reduce the risk for these invasive tumors. There is a need for more prospective studies to confirm our findings, ”said Egan.

For more information:

Caitlin M. Egan, ScD, can be reached at Moffitt Cancer Center, 12902 Magnolia Drive, Tampa, FL 33612; e-mail: [email protected].