A recent report indicates that CD303+ pDC accumulating in human breast cancer beds of patients with positive lymph nodes promote CXCR4 expression by cancer cells, suggesting that these tumor-associated pDC may participate to malignant cell metastasis to lymph nodes expressing SDF-1 through a CXCR4/SDF-1-dependent mechanism (130). This evidence concerns the gene CXCL12 and cancer.