Likes other ER-resident chaperones, the expression of CALU can be triggered in response to ER stress and the unfolded protein response (UPR) caused by the physiological and pathologic stimuli such as metabolic disturbance, DNA damage, accumulation of misfolded proteins, calcium depletion, oxidative stress, and etc., which are directly associated with cancer initiation and development [48]. Here, CALU is linked to cancer.