Correlation between p33ING1b Cytoplasmic Transfer and Lymph Node Metastasis in Oral Squamous Cell Carcinoma

Background: Oral squamous cell carcinoma is the sixth most common malignancy in the world today.  ING1b/p33 is a newly-discovered tumor suppressor which enhances p53 activity. Transfer of p33 protein from nucleus to cytoplasmic compartment has been previously reported in leukemias. The objective of this study was to determine the correlation between p33ing1b cytoplasmic transfer and lymph node metastasis in oral squamous cell carcinoma. Methods: Fifty seven patients treated with surgery alone or surgery and adjuvant radiotherapy for primary oral squamous cell carcinoma were enrolled into this study. Immunohistochemical expression of all of the above-mentioned markers was studied. Results: Analysis of the sections demonstrated that p53 and MDM2 were expressed in 45.6% and 68.4% of patients, respectively. p33ING1b nuclear expression was completely absent while cytoplasmic translocation was noted in 78.9% of cases. Positive cytoplasmic expression of p33ING1b correlated with increased risk of lymphatic metastasis (p=0.04).  No further correlation with overall disease recurrence or survival was noted. Conclusion: Apparently, p33ING1b cytoplasmic transfer correlates with lymph node metastasis in oral squamous cell carcinoma.