Overexpression in metastatic breast cancer supports Syndecan-1 as a marker of invasiveness and poor prognosis

Compartmental Syndecan-1 (CD138) expression as a novel prognostic marker in triple-negative metaplastic breast cancer

BACKGROUND

Metaplastic breast cancer (MpBC) is rare, aggressive, and mostly triple-negative (TN) subtype of BC. We aimed to investigate the potential prognostic significance of Syndecan-1 (SDC1/CD138) expression in this unique tumor.

METHODS

Archived charts of 50 TNBC patients [21 MpBC and 29 invasive ductal carcinoma (IDC)] were retrospectively evaluated. Corresponding paraffin blocks were used for immunohistochemical (IHC) staining of SDC1. Compartmental (epithelial membranous, stromal, and cytoplasmic) staining scores were expressed in quartiles (Q) and correlated with disease-free survival (DFS) and overall survival (OS).

RESULTS

The median follow-up period was 54.6 months (range: 2.2-112.7). MpBC patients showed significantly worse DFS and OS than IDC (p = 0.007 and 0.004, respectively). MpBC demonstrated significantly higher Q4 stromal and membranous SDC1 compared to IDC (p = 0.016 and 0.021, respectively), whereas IDC exhibited significantly higher cytoplasmic Q4 SDC1 than MpBC (p = 0.015). Stromal Q4 SDC1 expression was found to be an independent factor associated with MpBC relative to IDC (OR: 6.7, 95% CI: 1.24-36.90; p = 0.028). Stromal Q4 SDC1 expression was also an independent prognostic parameter for worse DFS and OS compared to Q1-3 in the whole cohort (HR: 4.2, 95% CI: 1.6-10.5; p = 0.003 and HR: 5.8; 95% CI: 2.2-15.3; p < 0.001, respectively). In MpBC, cytoplasmic Q1-3 SDC1 expression was an independent prognostic indicator for worse OS compared with their IDC counterparts (HR: 2.837, 95% CI: 1.048-7.682; p = 0.04).

CONCLUSION

This study suggests, for the first time, that differential expression and localization of SDC1 may contribute to the pathogenesis and prognosis of TN-MpBC. Therefore, targeting SDC1 (CD138) could emerge as a novel therapeutic approach for this devastating disease.

Clinical/prognostic significance of Syndecan-1 expression in invasive breast carcinoma with distant metastasis and its correlation with tumor immunity

OBJECTIVE

Breast Cancer (BC) is the most common malignant tumor for women in the world. 90% of BC-associated deaths are attributed to distant metastasis (DM). Therefore, there is an urgent need for a novel molecular target for the treatment of distant metastatic breast cancer (DMBC). Syndecan-1 (SDC-1) is a cell surface heparan sulfate proteoglycan (HSPG). This study aims to study the expression patterns of SDC-1 in invasive breast carcinoma (IBC) with DM and to analyze its relationship with different clinicopathologic features, stromal tumor infiltrating lymphocytes (sTILs) status and the clinical outcomes.

METHODS

A total of 50 DM breast cancer and 100 non-distant metastasis (non-DM) breast cancer patients in West China Hospital, Sichuan University from January 1, 2011 to December 31, 2011 were collected. Immunohistochemical (IHC) method was used to detect the expression of SDC-1, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), and Ki-67 in 150 specimens of patients with IBC. STILs were used to evaluate immune cells in the stromal tissue within the tumor. Various clinicopathologic characteristics were retrospectively analyzed, and follow-up information were collected for prognosis analyses. The expression pattern difference of SDC-1 in the DM group and the non-DM group and its correlation with clinicopathologic characteristics of IBC were analyzed.

RESULTS

Compared with the non-DM group, SDC-1 had higher cytoplasmic (90.0%) and stromal diffuse (70.0%) expressions and lower stromal peritumoral (18.0%) expression in the DM group. SDC-1 cytoplasmic expression was significantly associated with HER2-positive and high Ki-67 index in DM group, and with high histological grade and lymph node (LN) metastasis in non-DM group (P < 0.05). Compared with the non-DM group, the membranous expression of SDC-1 in the DM group was related to higher histological grade and T stage, higher frequency of LN involvement. Meanwhile, the expression pattern of SDC-1 in tumor stroma was associated with sTILs status (P < 0.05). The different combinations of SDC-1 staining patterns were correlated with clinicopathological features, biomarkers and sTILs status between DM group and non-DM group.There was no significant difference in overall survival between DMBC with different expression patterns of SDC-1.

CONCLUSION

The cytoplasmic and stromal expressions of SDC-1 in the primary lesion of IBC are closely associated with DM, and the stromal expression of SDC-1 is correlated with tumor immune microenvironment. SDC-1 is expected to be a potential new marker for predicting the risk of DM in IBC.

Revisiting the Syndecans: Master Signaling Regulators with Prognostic and Targetable Therapeutic Values in Breast Carcinoma

Syndecans (SDC1 to 4), a family of cell surface heparan sulfate proteoglycans, are frequently expressed in mammalian tissues. SDCs are aberrantly expressed either on tumor or stromal cells, influencing cancer initiation and progression through their pleiotropic role in different signaling pathways relevant to proliferation, cell-matrix adhesion, migration, invasion, metastasis, cancer stemness, and angiogenesis. In this review, we discuss the key roles of SDCs in the pathogenesis of breast cancer, the most common malignancy in females worldwide, focusing on the prognostic significance and molecular regulators of SDC expression and localization in either breast tumor tissue or its microenvironmental cells and the SDC-dependent epithelial–mesenchymal transition program. This review also highlights the molecular mechanisms underlying the roles of SDCs in regulating breast cancer cell behavior via modulation of nuclear hormone receptor signaling, microRNA expression, and exosome biogenesis and functions, as well as summarizing the potential of SDCs as promising candidate targets for therapeutic strategies against breast cancer.