CD4 and breast carcinoma: The results of our study on the effects of breast cancer cells on the cytokine production profile of CD4+ and CD8+ lymphocytes are reflected in research conducted recently in animal models by da Cunha et al. Both research teams demonstrated that the presence of breast cancer cells did not affect the frequency of IL-10-producing CD4+ T cells, but instead significantly reduced IL-10-positive CD8+ T cells.