Decreased IL-10R-expressing B Cells in breast cancer patients: a potential biomarker for early cancer detection.

IL-10 plays a crucial role in regulating B cell function and differentiation, but its effects on B cells depend on its activation state. The frequency of IL-10R⁺ B cells and how it changes during breast cancer progression have not been studied. This study aimed to evaluate the expression of IL-10R on B cells in the peripheral blood of 50 patients with breast cancer compared to 29 healthy controls. After isolating mononuclear cells, we stained them using anti-CD19 and anti-IL-10R antibodies. We used Flow cytometry to analyze the expression of IL-10R on B cells. We found that over 50% of B cells in both patients with breast cancer and healthy controls expressed IL-10R. However, patients had a significantly lower frequency of IL-10R⁺ B cells compared to healthy individuals (64±16.0% of patients compared to 78.5±6.6% for healthy individuals, P<0.0001). This decrease was not associated with lymph node involvement or tumor size. Phenotypic analysis revealed that IL-10R-expressing B cells consist of both naive and memory B cells, with the majority of peripheral memory B cells expressing IL-10R. The decrease in IL-10R-expressing B cells in breast cancer patients may be due to apoptosis induced by IL-10 in naive or recently activated B cells, or their migration to lymph nodes to combat tumor cells. Our study suggests that IL-10R could be a potential biomarker for detecting breast cancer in its early stages.