FOXP3 and neoplasm: Consistent with the results seen in the 4 T1 murine model, the depletion of B cells using α-CD20 mAb in mice inoculated with EMT-6 did not result in tumor rejection as expected, and was associated with a paradoxical increase of CD4+FoxP3+ Tregs in the spleens of treated mice, although a role for 4-1BBL was not investigated in the EMT-6 model [63].