Immunohistochemical Expressions of p16 and p21 Proteins in Laryngeal Squamous Cell Carcinomas

Do, Nam Yong; Park, Sung Young; Yun, Hyuk Su; Cho, Sung Il; Choi, Seong Jun; Kim, Jong Hee; Lim, Sung Chul

Abstract

BACKGROUND AND OBJECTIVES
Cyclin-dependent kinase inhibitor (CDKI) is known to play an important role in oncogenesis, but its clinical effect in head and neck cancer has not been reported yet. This study was designed to investigate the prognostic relevance of p16 and p21 protein expressions by evaluating the correlation between the expression pattern of p16 and p21 proteins, and tumor progress in laryngeal squamous cell carcinoma. MATERIALS AND METHODS: Paraffin-embedded tissue specimens from 54 patients, who were diagnosed with laryngeal squamous cell carcinoma between 1993 and 2002, were immunohistochemically stained for p16 and p21 proteins. The clinical features from these patients were retrospectively evaluated. The percentages of positive nuclei that stained positive for tumor were determined. RESULTS: In p16 protein, the proportion of strong expression was higher than that of weak expression in early tumor stage (T1, T2) and clinical stages (stage I, II): the proportion of weak expression was higher in the advanced tumor stage (T3, T4) and the clinical stages (stage III, IV): the correlations between the expressions of p16 protein and tumor clinical stages were significant (p<0.05). In p21 protein, the proportion of weak expression was higher in early and advanced tumor stage clinical stage: the correlations between expression of p21 protein and tumor clinical stages were not significant, respectively (p>0.05). In p16 and p21 protein, the proportion of weak expression was higher in nodal stage with neck metastasis than in nodal stage without neck metastasis: but the correlation between expression of p16 or p21 protein and nodal stage was not significant, respectively (p>0.05). CONCLUSION: There was a significant correlation between weak expression of p16 protein and more advanced tumor clinical stages. The expression of p16 protein may have prognostic value restrictively in laryngeal squamous cell carcinoma. Further study will be needed to understand the role of p16 and p21 protein in oncogenesis of laryngeal squamous cell carcinoma.