Purpose: The role of cytokine-producing B cells in antitumor immunity is mostly overlooked. In the present study, we investigated changes in B cell cytokine profiles in breast tumor-draining lymph nodes (TDLNs) during disease progression, and associations of these changes with prognostic indicators.
Methods: Flow cytometry was used to measure the expression of TNF-α, IL-10, TGF-β, IL-2 and IFN-γ in B cells from 42 axillary lymph nodes. The frequencies of IL-10+ and FoxP3+ T regulatory cells (Tregs) were also determined.
Results: No significant changes in B cell cytokine profiles were observed during breast cancer progression from stage I to III, but the percentage of B cells with high TNF-α expression (TNFhi) showed a negative relationship with lymph node involvement and Her2 expression (p < 0.05). The percentage of IL-10+ B cells was found to be significantly higher in non-metastatic lymph nodes in node-negative compared to node-positive patients (p = 0.001). The frequencies of IL-10+ and TNFhi B cells were found to be negatively correlated with the number of involved lymph nodes. The frequency of TNFhi B cells showed an inverse correlation with the frequency of FoxP3+ Tregs, which in turn was associated with indicators of a poor prognosis.
Conclusions: Our data indicate that the cytokine profiles of B cells in TDLNs of patients with breast cancer show associations with various disease parameters. TNFhi and IL-10+ B cells correlated positively with indicators of a good prognosis. Further functional studies are required to elucidate the role of cytokine production by B cells in immunity against breast cancer.
Keywords: B cells; B10 cells; Breast cancer; T regulatory cells; TNF-α; Tumor-draining lymph nodes.