Value Of Measuring HER-2 Extracellular Domain In The Serum Of Breast Cancer Patients

Background and ObjectiveBreast cancer is the most common malignancy in women, options for treatment of breast cancers are complex and varied, there is a need for biological prognostic indicators that would be sufficient to predict disease recurrence and choose proper thrapy. Determination of HER-2 tumor status offers clinically useful information, as it selects patients who may benefit from treatment with trastuzumab, the monoclonal antibody against HER-2. Currently approved methods for HER-2 testing include immunohistochemistry or fluorescent in situ hybridization using tumor tissue. A fragment of HER-2 composed of its extracellular domain (ECD) can also be detected in the serum of some patients with breast cancer. As an easily accessible tumor marker, it could offer additional useful prognostic or predictive information. We also explored the correlation between serum human epidermal growth factor receptor-2 (HER-2) extracellular domain (ECD) and tissue HER-2 status, their relationship with clinicopathological parameters and evaluated the clinical response to chemotherapy in advanced breast cancer patients.Materials and MethodsThe serum HER-2 protein levels of 40 advanced breast cancer patients pre and post chemotherapy, and 30 primary breast cancer patients post surgery in the oncology department of Chang Hai hospital were detected in ELISA method. The relationship between the protein level and patients'clinical features,therapeutic response and prognosis were analyzed retrospectively. Immunohistochemical staining was performed to determine the expression status of HER-2. Besidesthe consistency of expression in serum and tissue was also analyzed. The serum HER-2 ECD level≥15ng/ml was positive group and < 15ng/ml was negative group.ResultsIn advanced breast cancer, the mean serum HER-2 concentrations of advanced breast cancer patients pre therapy was 28.09 ng/ml (0.41ng/ml-178.35ng/ml),the level of serum HER-2 was concordance with strong expression of HER-2 in tumor tissue ,the number and site of metastasis. There was no correlation between pre therapy serum HER-2 levels and therapeutic.The majority of patients demonstrate a decrease in HER-2 ECD regardless of response, but HER-2 ECD decreases to a greater degree among responders than nonresponders.The difference was of statific significance.In primary breast cancer patients, the mean serum HER-2 concentrations post surgery was 7.66ng/ml (0.47ng/ml-24.32ng/ml), expression of HER-2 in tumor tissue was not concordance with the level of serum HER-2. There was significant difference between serum HER-2 ECD levels of advanced breast cancer and the levels of primary breast cancer patients.Conclusion1. In primary breast cancer patients, expression of HER-2 in tumor tissue was not concordance with the level of serum HER-2. The level of serum HER-2 was in concordance with strong expression of HER-2 in tumor tissue in advanced breast cancer.2. Serum HER-2 level of advanced breast cancer patients is concerned with numbers and locations of metastasis, but not with age, menstrual status, hormone receptor, pathological subtype and relapse-free survival.3. The rate of positive HER-2 ECD among advanced breast cancer is higher than primary breast cancer, so the serum HER-2 maybe is a biological prognostic indicator to predict disease recurrence.4. There was no correlation between pre thrapy serum HER-2 levels and therapeutic response in advanced breast cancer.5. The majority of patients demonstrate a decrease in HER-2 ECD regardless of response, but HER-2 ECD decreases to a greater degree among responders than nonresponders.