However, the very marked differences in expression of the various NBC isoforms across different cancers [52] suggests that the specific NBC isoform relevant is likely to differ, a notion substantiated by the recently reported role of another SLC4 family member, NBCe1 (SLC4A4), in proliferation of MDA-MB-231 cells as well as LS174 colon cancer cells [53]. Here, SLC4A4 is linked to malignant colon neoplasm.