[1] Univ Pittsburgh, Dept Otolaryngol, Pittsburgh, PA 15260 USA
[2] Univ Pittsburgh, Dept Med Pharmacol & Chem Biol, Pittsburgh, PA 15260 USA
[3] Univ Pittsburgh, Inst Canc, Dept Biostat, Pittsburgh, PA 15260 USA
[4] Univ Pittsburgh, Dept Med, Pittsburgh, PA 15260 USA
[5] Univ Pittsburgh, Dept Surg, Pittsburgh, PA 15260 USA
[6] Univ Colorado, Denver Vet Affairs Med Ctr, Dept Med, Denver, CO 80202 USA