SPARC Expression Correlates with Tumor Response to Albumin-Bound Paclitaxel in Head and Neck Cancer Patients

TLDR

SPARC up‑regulation is a poor prognostic factor in head and neck cancer. The study hypothesizes that tumor SPARC facilitates albumin accumulation, enhancing the efficacy of albumin‑bound paclitaxel (nab‑paclitaxel). The hypothesis was examined by correlating nab‑paclitaxel response with SPARC expression in a retrospective analysis of 60 patients, with 16 tumor specimens available for analysis. Among 16 patients with available specimens, 10 of 12 SPARC‑positive patients responded (83%) versus 1 of 4 SPARC‑negative patients (25%), supporting the hypothesis that SPARC overexpression correlates with nab‑paclitaxel response.

Abstract

SPARC up-regulation is a poor prognostic factor in head and neck cancer. It was hypothesized that because of a SPARC-albumin interaction, tumoral SPARC facilitates the accumulation of albumin in the tumor and increases the effectiveness of albumin-bound paclitaxel (nab-paclitaxel). This hypothesis was tested by correlating the response to nab-paclitaxel and SPARC tumor expression in a retrospective analysis of a 60-patient clinical study of nab-paclitaxel as monotherapy against head and neck cancer. Sixteen tumor specimens were available for analysis. There were 11 responders (CR/PR) and 5 nonresponders (SD/PD) among the 16 nab-paclitaxel-treated patients (12/16 SPARC-positive, 75%). Response to nab-paclitaxel was higher for SPARC-positive patients (10/12, 83%) than SPARC-negative patients (1/4, 25%). The SPARC-negative patients exhibited significantly lower response than the overall response rate among all 60 patients (1/4, 25% vs 45/60, 75%). Although preliminary, data are supportive of the hypothesis that SPARC overexpression may correlate with response to nab-paclitaxel. If confirmed in larger studies, treatment with nab-paclitaxel may convert a poor prognosis SPARC-positive patient population into a group with better clinical outcomes.