RESUMO
BACKGROUND AND OBJECTIVES: The p16, cyclin D1, their partners Cdk4/Cdk6, and pRb constitute a G1 regulatory pathway commomly targeted in tumorigenesis. Genetical, immunochemical, and functional analyses show abnormalities of this pathway in various tumors including head and neck squmaous cell carcinoma. To investigate the clinicopathologic meanings of p16 protein and the relationship between p16 and cyclin D1 in head and neck squmous cell carcinoma. MATERIAL AND METHOD: Formalin-fixed paraffin-embeded tumor materials that were obtained from 37 patient with head and neck squmaous cell carcinoma were analyzed by immunohistochemical staining method using antiserum that were directed against p16 and cyclin D1. RESULTS: 1) Deletion of p16 was found in 67.6% (25/37) of the patients with head and neck squamous cell carcinoma. The deletion was not associated with the clinicopathologic parameters (eg. T and N stages, cell differentiation). 2) Deletion of p16 protein and overexpression of cyclin D1 were identified in 76% (28/37) of the patients with head and neck squmaous cell carcinoma. But deletion of p16 was not affected by the overexpression of cyclin D1 in head and neck squmaous cell carcinoma. CONCLUSION: Deletion of p16 and overexpression of cyclin D1 were identified in head and neck squmaous cell carcinoma. These may abrogate the G1 regulatory pathway. These data suggested that combination of these abnormalities may be important in head and neck turmorigenesis.
