CD6 and cancer: Preincubation with triple-negative breast cancer MDA-MB-231 cells with mAb 3a11 (mouse anti–human CD318) enhanced killing and inhibited survival of cancer cells compared with the control antibodies (anti-vWF and anti–LFA-1), but UMCD6 (anti-CD6) was more effective than anti-CD318 in augmenting cancer cell killing by PBMCs (Figure 2, A and B).