Analysis of PDAC tissue revealed relatively few T-cell infiltrates as marked by CD3 and CD4 or CD8 staining compared with melanoma.9 This is certainly troublesome, since increased infiltration of CD4+ and CD8+ T cells in tumors is consistently associated with increased survival in patients.8 13–16 This observation parallels immune suppressive features of other tumors, including prostate and breast cancers. Here, CD4 is linked to breast carcinoma.