Ion channels and transporters in cancer. 4. Remodeling of Ca2+ signaling in tumorigenesis: role of Ca2+ transport

The Ca(2+) signal has major roles in cellular processes important in tumorigenesis, including migration, invasion, proliferation, and apoptotic sensitivity. New evidence has revealed that, aside from altered expression and effects on global cytosolic free Ca(2+) levels via direct transport of Ca(2+), some Ca(2+) pumps and channels are able to contribute to tumorigenesis via mechanisms that are independent of their ability to transport Ca(2+) or effect global Ca(2+) homeostasis in the cytoplasm. Here, we review some of the most recent studies that present evidence of altered Ca(2+) channel or pump expression in tumorigenesis and discuss the importance and complexity of localized Ca(2+) signaling in events critical for tumor formation.