The CXCL16 expression levels varied, and not all TN breast tumours expressed CXCL16 in their fibroblasts, an observation that might be explained by the heterogeneity within the TN subgroup and indeed when analysed using the TCGA breast cancer RNAseq data, only the basal breast cancer subgroup showed a significantly higher expression level of CXCL16. We also found that CXCL16 could be expressed by the malignant cells of both luminal A and TN tumours, a finding that might explain why CD163+/GRN+ myeloid cells are located in the tumour nests of luminal A tumours4. Here, CXCL16 is linked to breast cancer.