CD4 and neoplasm: Looking at Tregs frequency, as expected from the literature, an increase of splenic CD4+CD25+ T cells expressing Foxp3 was detected, from 8.75 ± 0.80% in tumor-free control mice to 14.80 ± 1.17% in MCA203 TB mice (Figure 3A and B), connecting with one of the proposed mechanisms for MDSCs mediated-suppression (i.e. the expansion of Tregs that reinforce the suppression of tumor-specific responses) [16,17].