Assessing immuno-expression of p53 protein and TP 53 gene amplification in histologically negative surgical margins of oral squamous cell carcinoma patients and normal oral mucosa.

OBJECTIVE: To assess and compare the immuno-expression of p53 and TP 53 gene amplification and correlate local recurrence and survival in histologically negative surgical margins of oral squamous cell carcinoma (OSCC) with normal oral mucosa. METHODS: Forty formalin-fixed paraffin-embedded tissue blocks of HNMs of OSCC and 40 normal oral mucosa samples were analyzed for p53 immunostaining and TP 53 gene amplification by PCR. RESULTS: Significantly, higher positivity was noted with p53 immuno-expression, TP53 gene amplification, and combined p53 and TP53 expression in the study group compared to the control group (C0.05). Most cases that were positive for p53 immuno-expression, TP 53 gene amplification, and combined p53 and TP53 expression showed local recurrence and poor survival. Kaplan-Meier survival analysis showed that subjects with TP53 and combined p53 and TP53 positivity had decreased survival rate than their negative counterparts. CONCLUSION: Detection of p53 in HNMs of OSCC can be used as a biomarker to identify patients at a higher risk of developing local recurrence and to predict survival. CLINICAL RELEVANCE: Combined p53 and TP 53 assessment may be more reliable for predicting LR to help clinicians and surgeons in treatment planning.