Meaningful interpretation of serum HER2 ECD levels requires clear patient clinical background, and serves several functions in the efficient management of breast cancer patients.
BACKGROUND
This study was initiated to evaluate the clinical significant of HER2 extracellular domain (ECD) in the real-time management of breast cancer patients.


METHODS
Five-hundred forty-six eligible breast cancer patients were divided according to their clinical background. The correlation between ECD, tissue HER2, and clinical outcome of the patients were analyzed.


RESULTS
Receiver operating characteristic analysis revealed that ECD measured before receiving neoadjuvant therapy yielded the highest area under the curve (0.9185; P<0.0001), indicating that ECD and tissue HER2 levels are consistent in untreated tumor-bearing patients. At cut-off of 15.0ng/ml, the prognostic value of ECD was demonstrated using univariate (HR=1.664, P<0.0001) and multivariate (HR=1.547, P=0.011) Cox regression analysis. Kaplan-Meier survival curves revealed that patients with elevated ECD had shorter progression-free survival (PFS) (4.0 vs. 6.1months, P<0.0001). Elevated ECD was also an adverse predictor for PFS in response to anti-HER2 therapy (4.3 vs. 10.2months, P=0.0155). In contrast, ≥20%, decreased ECD was associated with longer PFS in patients who received anti-HER2 therapy (10.9 vs. 2.4months, P=0.0164) and overall (10.7 vs. 2.8months, P=0.0034).


CONCLUSIONS
A patient's clinical history can help determine whether ECD could provide added value for breast cancer management.
Department of Breast Cancer, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Tao
T
Wang
Department of Breast Cancer, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Jinmei
J
Zhou
Department of Breast Cancer, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Shaohua
S
Zhang
Department of Breast Cancer, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Li
L
Bian
Translational Medicine Center, Laboratory of Oncology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Haixu
H
Hu
Translational Medicine Center, Laboratory of Oncology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Chunhong
C
Xu
Department of Breast Surgery, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Xiaopeng
X
Hao
Translational Medicine Center, Laboratory of Oncology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Bing
B
Liu
Department of Medical Molecular Biology, Institute of Beijing Biotechnology, Beijing, China.
Qinong
Q
Ye
Translational Medicine Center, Laboratory of Oncology, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China. Electronic address: liuyi790114@163.com.
Yi
Y
Liu
Department of Breast Cancer, Affiliated Hospital of Academy of Military Medical Sciences, Beijing, China.
Zefei
Z
Jiang
D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy*; D005260:Female; D006801:Humans; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood*
D018719:Erb-b2 Receptor Tyrosine Kinases
Breast cancer; Extracellular domain (ECD); Human epidermal growth factor receptor 2 (HER2); Real time HER2 status