Aspirin May Enhance Immunosurveillance Against Colorectal Cancer

MONDAY, April 22, 2024 (HealthDay News) -- Aspirin may promote an immune response against cancer, with fewer nodal metastases and higher infiltration of tumor-infiltrating lymphocytes among aspirin users with colorectal cancer (CRC), according to a study published online April 22 in Cancer.

Ottavia De Simoni, M.D., from Veneto Institute of Oncology IOV‐IRCCS in Padova, Italy, and colleagues conducted a retrospective analysis of 238 patients with a diagnosis of CRC operated on from 2015 to 2019 (METACCRE cohort) to analyze the effect of aspirin on the tumor microenvironment, systemic immunity, and the healthy mucosa surrounding cancer. mRNA expression of immune surveillance‐related genes (PD‐L1, CD80, CD86, HLA I, and HLA II) in CRC primary cells treated with aspirin was extracted; the experiment was repeated in cell lines. In a subgroup of patients, the mucosal immune microenvironment was analyzed with immunohistochemistry and flow cytometry.

Overall, 12 percent of the patients in the METACCRE cohort were aspirin users. The researchers found that aspirin users had nodal metastasis significantly less frequently and higher tumor-infiltrating lymphocyte infiltration. CD80 mRNA expression was increased following aspirin treatment in the CRC primary cells and selected cell lines. The ratio of CD8/CD3 and epithelial cells expressing CD80 was higher in aspirin users in the healthy mucosa surrounding rectal cancer.

"Our data suggested that aspirin use may be associated with a lower grading and nodal metastasis rate and a higher tumor-infiltrating lymphocytes infiltration in patients with CRC," the authors write. "These results are more evident in the right colon where, realistically, the bioavailability of aspirin is higher."

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