Abstract P3-07-60: Impact of high SPARC expression of a primary tumor as a strong risk factor for disease recurrence and overall survival in patients with triple-negative breast cancer

Abstract

Abstract Background: SPARC (secreted protein acidic and rich in cystein) is a secreted glycoprotein that interacts with extracellular matrix protein and acts as a regulator of critical cellular functions such as proliferation and cell migration. An increasing number of studies have shown altered expression of SPARC in several malignancies. However, the role of this potential biomarker in breast cancer development and progression is controversial. Triple-negative breast cancer (TNBC) is known for its poor prognosis and high recurrence probability. There is a need for prognostic biomarkers to guide treatment decisions for this subtype. Objective: To explore the association between SPARC and the prognosis of triple-negative breast cancer. Methods: In this study, a total of 211 samples of triple-negative breast lesions from 2004 to 2008 were collected in Cancer Hospital, Chinese Academy of Medical Sciences. SPARC expression was evaluated by immunohistochemistry using an immunoreactive score (IRS) from patients with up to 10 years clinical follow-up data. The current study set out to examine both the expression of SPARC in primary tumor tissue and to demonstrate if a link existed between the levels of SPARC and the clinical outcome. Cox proportional hazards model was used to estimate HRs and 95%CI, stratified on tumor grade, TNM stage, lymph node status and vascular invasion. Results: High SPARC expression (IRS≥3) was observed in 52.1% of all primary tumors. Patients expressing low levels of SPARC had better disease-free survival (DFS) (HR=0.632, 95%CI:0.405-0.987, P = 0.044) as well as overall survival(OS)(HR=0.576, 95%CI:0.351-0.946, P = 0.029) compared to those with high SPARC expression levels.Furthermore, the presence of high SPARC expression was an independent prognostic factor for both DFS (HR=1.67, 95%CI:1.04-2.69, P=0.034) and OS(HR=1.77, 95%CI:1.04-3.01, P=0.037) of triple-negative breast cancer patients, stratified on tumor grade, TNM stage, lymph node metastasis and vascular invasion, with adjustment for age, hormonal status, tumor size, adjuvant radiotherapy and adjuvant chemotherapy. Conclusion: Our results suggest that the presence of higher SPARC expression could be an indicator of high aggressiveness and may be a strong prognostic factor for triple-negative breast cancer. Citation Format: Zhu A, Yuan P, Du F, Ding X, Xu B. Impact of high SPARC expression of a primary tumor as a strong risk factor for disease recurrence and overall survival in patients with triple-negative breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-07-60.