背景资料：The protein encoded by this gene is localized in the endoplasmic reticulum (ER) and golgi, and is also secreted. Reducing expression of this gene increases susceptibility to ER stress-induced death and promotes cell proliferation. The protein was initially thought to be longer at the N-terminus and to contain an arginine-rich region but transcribed evidence indicates a smaller open reading frame that does not encode the arginine tract. The presence of polymorphisms in the arginine-rich region, including a specific mutation that changes the previously numbered codon 50 from ATG to AGG, have been reported in a variety of solid tumors; however, these polymorphisms were later shown to exist in normal tissues and are thus not tumor-related.