PLK1 and cancer: Importantly, ERP29 is frequently deregulated in cancer and forms a feedback loop with microRNA-135a-5p to promote progression of colorectal cancer [69], while protein disulfide isomerase family A member 3 (alias ERP57) modulates folding of glycoproteins and stimulates cell proliferation via c-Myc, PLK1 and the AKT pathway [70].