ERBB2 and cancer: The distinct effect of CA7 compared to other cytosolic carbonic anhydrase isoforms in HER2-enriched breast cancer is consistent with the expression of CA7 exclusively in cancer-associated fibroblasts and myeloid cells, whereas expression of the other cytosolic carbonic anhydrase isoforms (CA1, CA2, CA3, and CA13) is most prominent in cancer epithelial and endothelial cells (Fig. 2B).