Among 43 BC plasma samples examined, HR-negative (n=20), HER2-positive (n=18), and P53-negative (n=22) phenotypes showed significantly higher levels of HE4 expression compared with HR-positive, HER2-negative, and P53-positive, respectively (P<0.01 for all three) (the results are available in Table 6). Here, ERBB2 is linked to breast cancer.