About STC / Stanniocalcin:
Stanniocalcin (STC) is a type of hormone that regulates phosphate and calcium in the body. It gets its name because it was first discovered in fish and isolated from special organs called corpuscles of Stannius. This family of hormones is made up from 250 amino acids and exists in molecular pairs.
Stanniocalcin is often found in bony fishes, where it is used to regulate calcium levels. Although calcitonin is also present and acts as a calcium regulator, these fish are exposed to high levels of calcium through their gills, so Stanniocalcin is required. Unlike calcitonin, it also regulates phosphate levels at the same time.
STC has also been detected in mammals and in 1995, it was detected in the human kidney. In mammals, there are two variant forms; STC1 and STC2. Fish and mammalian STC1 are similar in structure and are around 50% similar. However, STC2 only shows 34% similarity and is unique to mammals.
Stanniocalcin is a glycoprotein that exists inside a homodimer. Each single molecule contains 179 different amino acids, however, the specific amino acid sequence and total length vary depending on the species of animal. For example, in Salmon it is around 2 kilobases in length and the primary translation product contains 256 different amino acids.
STC is important because it is known to be linked to certain cancers. In ovarian cancer and breast cancer, STC1 and STC2 are produced in large amounts in tumour locations. High levels of STC1 have also been linked to leukemia, colorectal cancer, carcinoma and lung cancer. STC2 has been linked to cervical cancer and ovarian cancer.