CUL2 and breast cancer: We went on to validate the gene expression of the ECV complex genes RBX1, CUL2, TCEB1, and TCEB2 in MCF7 and MDA-MB-231 breast cancer cell lines ectopically overexpressing ∆Np73, and found their downregulation to be consistent with the breast cancer patient data (Fig. 5b, c).