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

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.