The perturbation of granulocyte-macrophage colony-stimulating factor (GM-CSF) in breast cancer tissue (Figure 1F and Figure S1A) is particularly interesting as GM-CSF secretion from orthotopic primary breast tumor models was previously found to depend on carbonic anhydrase activity and lead to recruitment of granulocytic myeloid-derived suppressor cells to pre-metastatic niches in the lung [51]. Here, CSF2 is linked to breast cancer.