Tumor SPARC microenvironment signature (SMS) and plasma levels in a phase II trial of unresectable stage IV melanoma treated with nab-paclitaxel and carboplatin: A translational study of NCCTG trial N057E.

8578 Background: Tumor overexpression of the albumin-binding protein SPARC (secreted protein acidic and rich in cysteine) is associated with poor prognosis in multiple cancers. SPARC in the tumor microenvironment may be associated with tumor cells and stromal components. While previous studies examined SPARC only in tumor cells and/or fibroblasts, it remains unclear which tumor SPARC components may be associated with poor prognosis in different tumors. Recently we have found that plasma SPARC may contribute to poor outcomes in tumor models. Herein, we examined all tumor microenvironment components as well as plasma SPARC levels to develop a SPARC signature that may be correlated to outcomes. Methods: 76 chemo naive and pretreated patients (pts) with unresectable stage IV melanoma were treated with nab-paclitaxel (nab-P, 100 mg/m2) and carboplatin (C, AUC 2) on d 1, 8, and 15 of a 28 day cycle until disease progression. SPARC in tumor biopsies was measured using a validated SPARC IHC. IHC data were analyze...