Ductal carcinoma in situ on stereotactic biopsy of suspicious breast microcalcifications: Expression of SPARC (Secreted Protein, Acidic and Rich in Cysteine) can predict postoperative invasion.

BACKGROUND AND OBJECTIVES: Secreted protein, acidic and rich in cysteine (SPARC) is able to play an important role in cancer invasion due to de-adhesive properties and impact on stromal remodeling. The aim of study was to investigate SPARC expression in preoperatively diagnosed breast DCIS and to assess its predictive value for the final invasion. METHODS: A total of 209 patients with DCIS found on stereotactic vacuum-assisted biopsy of suspicious microcalcifications were studied prospectively. RESULTS: SPARC staining was positive in luminal epithelial cells, stromal fibroblasts, and myoepithelial cells in 38%, 62%, and 61% of tumors, respectively. Neither patient age nor pattern of microcalcifications were related to SPARC expression. High nuclear grade and comedonecrosis were associated with strong immunoreactivity of SPARC in stromal fibroblasts and myoepithelial cells while not in luminal epithelial cells. Rate of postoperative invasion was significantly increased in DCIS with strong SPARC staining with regard to all investigated cells. None of standard parameters significantly influenced the upgrading risk. In multivariate analysis most significant and independent predictive factors were strong SPARC expression in luminal epithelial cells, and stromal fibroblasts. CONCLUSIONS: SPARC can be a new biomarker helpful to identify more aggressive DCIS and for prediction of invasive disease on final pathology. J. Surg. Oncol. 2016;114:548-556. © 2016 Wiley Periodicals, Inc.