p16INK4A in Oral Squamous Cell Carcinomas—A Correlation With Biological Behaviors: Immunohistochemical and FISH Analysis
Purpose
The p16INK4A gene and Rb gene are key tumor suppressor genes in a cell cycle regulatory pathway that is commonly inactivated in various cancers. The disruption of p16INK4A expression has been reported in several types of carcinoma but sparse in the area of oral oncology.
Materials and Methods
The study included 66 cases who were diagnosed as oral squamous cell carcinoma. Immunohistochemical p16INK4A and pRb expression, fluorescence in situ hybridization analysis were performed to the resected materials.
Results
p16INK4A protein expressions were detected in 14 cases without lymph node metastasis versus in 4 cases with metastasis (P = .04). As to histopathological grading of the effect of chemotherapy, almost all the p16INK4A-positive cases (9 cases out of 10) exhibited the histological feature of being rather sensitive to chemotherapy (2B and better response according to Ohboshi and Shimosato’s criteria) versus 17 of 33 negative cases (P = .02). Survival curves showed that the survival rate of patients with loss of p16INK4A expression was significantly worse than those with amplification and normal genetic dosage of p16INK4A (P < .0001).
Conclusions
The expressions of p16INK4A were significantly correlated with biological behavior of OSCCs. These results indicate we can use p16INK4A as a marker of a prognostic prediction of oral cancer and it is useful for management of OSCCs.
⁎Assistant Professor, Department of Oral and Maxillofacial Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.
†Professor, First Department of Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan.
‡Professor, Department of Oral and Maxillofacial Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Address correspondence and reprint requests to Dr Suzuki: Department of Oral and Maxillofacial Surgery, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu 431-3192, Japan
ABSTRACT