Inventors analyzed the prognostic value of tumor and stromal-derived SPARC in a large series that included 148 non-metastatic TNBC patients with a long follow-up by immunohistochemistry. They show that SPARC expression was detected in cancer cells (42.4%), cancer-associated fibroblasts (CAFs) (88.1%), TAMs (77.1%), endothelial cells (75.2%) and TILs (9.8%). Recurrence-free survival (RFS) was significantly lower for patients with a positive expression of SPARC in CAFs (SPARC+ CAFs) with a median follow-up of 5.4 years. SPARC expression in CAFs was found to be an independent prognostic factor in multivariate analysis.
Accordingly, the present invention relates to a method for predicting the survival time of a subject suffering from triple-negative breast cancer (TNBC) comprising determining the expression level of Secreted Protein Acidic and Rich in Cysteine (SPARC) in cancer-associated fibroblasts (CAFs) in a biological sample obtained from the subject wherein said positive expression of SPARC in CAFs (SPARC+CAFs) correlates with a short survival time of the subject.