This promoter activity was decreased by more than 50% when 2.3 and 3.3 kb KIAA1199 5′-flanking regions were examined in COS-1 cells as well as in MCF-7 and MDA-MB-231 breast cancer cells, suggesting the presence of negative regulatory cis-acting elements in the upstream region between −1425 and −2341. Here, CEMIP is linked to breast cancer.