Expression of p53 protein in advanced head and neck squamous cell carcinoma before and after chemotherapy

Background: The expression of p53 protein has been reported to be in the range of 35% to 67% in head and neck squamous cell carcinoma (HNSCC). Mutations of the gene for p53 protein have been associated with rapidly proliferating tumors, and p53 protein expression has been shown to be a significant predictor of worse survival in surgically resected HNSCC. To determine whether p53 protein expression in advanced (stages III and IV) HNSCC has any impact on tumor response to 2 to 3 courses of paclitaxel (Taxol) and carboplatin, we prospectively studied prechemotherapy specimens from patients with previously untreated, advanced-stage HNSCC. We also attempted to study residual tumors after chemo therapy to determine if the p53 status of the tumor changed. Design: The expression of p53 protein was evaluated by immunohistochemical analysis (clone BP53-12-1; Bio-Genex, San Ramon, Calif). Setting: Tertiary university medical center. Intervention: Two to 3 courses of chemotherapy with paclitaxel and carboplatin. Main Outcome Measures: Pathologic complete remission or residual tumor. Results: The results of p53 immunostaining were positive in 24 (67%) of 36 HNSCC specimens before chemotherapy. After chemotherapy, 8 patients achieved pathologic complete remission. Before chemotherapy, the tumor was p53 negative in 2 patients and positive in 6 patients. Conclusions: No correlation of p53 protein expression with response to chemotherapy was noted. The expression of p53 protein converted from positive to negative in 5 (42%) of 12 specimens from patients with residual tumor after chemotherapy, with no impact on clinical outcome.