Data from the CPTAC data set indicated that CUL5 total protein expression was lower in lung adenocarcinoma, colon cancer, breast cancer, and uterine corpus endometrial carcinoma than in normal tissues (P < 0.001, Figure 1(c)), whereas it did not differ significantly between normal tissues and clear renal cell carcinoma and ovarian cancer (P > 0.05, Figure 1(c)). Here, CUL5 is linked to breast cancer.