IL10 and neoplasm: In contrast to the conflicting results regarding significance of general tumor infiltration with CD20+ B cells and CD138+ plasma cells in humans, the majority of studies examining infiltration of tumors with B cells that have an established regulatory phenotype (CD38hiCD24hi, CD5 + CD1dhi, CD24hiCD27+, IL-10+) have demonstrated that Breg infiltration is associated with impaired anti-tumor immunity and more aggressive disease [13–22].