Abstract 21P
Background
Syndecan-1 (Sdc1) as a transmembrane heparin sulfate proteoglycan, an extracellular matrix receptor, which involved in intercellular communication, proliferation, angiogenesis, and metastasis. Previously, we found that higher SDC1 expression indicated worse survival in breast cancer in TCGA dataset. Immunohistochemistry microarray indicated that protein expression of SDC1 in tumor cell and cancer-associated fibroblasts (CAFs) was much higher in tumor sections than in Para cancerous tissues. The aim of the current study was to investigate whether SDC1 expressed in different part for breast cancer tissue, tumor cell cytoplasm and CAFs, indicated for the different survival in breast cancer patients.
Methods
protein SDC1 expressed in tumor cell cytoplasm or CAFs was evaluated in a tissue microarray of 708 breast tumors. The association between SDC1 expression in cell cytoplasm and OS (overall survival), EFS (event free survival) was analyzed, as well as in CAFs and OS, EFS. Furthermore, we checked the association of SDC1 expression in cell cytoplasm and OS for the different molecular subtype in breast cancer tissues.
Results
The mean followed up time was 6.64 (6.62,6.92) years. We found that SDC1 expressed in cell cytoplasm was associated with lower tumor survival, HR: 1.54 (1.01, 2.35), P=0.044; and with lower EFS, HR: 1.80 (1.29, 2.53) P=0.0006 when adjust for age, menstruation, Tumor, Nodal, TNM stage, vascular invasion, chemotherapy and radiotherapy; However, SDC1 expressed in CAFs was not associated with patient OS and EFS; In molecular subtype analysis, we found that SDC1 expressed in cell cytoplasm was associated with patient OS HR: 1.82 (1.02, 3.25) P=0.044 and EFS HR: 2.11 (1.35, 3.29) P=0.001 in luminal subtype but not in HER2-positive and triple-negative subtype. However, SDC1 expressed in CAFs was associated with patient OS and EFS in HER2-positive subtype but not in luminal and triple-negative subtype.
Conclusions
This study found that higher SDC1 expressed in cell cytoplasm of breast cancer is associated with a higher patient death, especially in Luminal molecular subtype. Hence, a higher expression of SDC1 in cell cytoplasm is a bad prognosis factor, which might become a therapy target for breast cancer, especially in Luminal molecular subtype.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.