"p53 mutation spectrum and its role in prognosis of oral cancer patients: A study from Gujarat, West India".

BACKGROUND AND AIM: p53 mutations are critical players in etiopathogenesis of oral cancer. Interestingly, they show differences in terms of type and codon specificity. These differences might be attributed to geographical variations in tobacco use. We aimed to analyze the frequency of p53 mutations in oral cancer patients from Gujarat, India and their effect on clinico-pathological features, local recurrence and survival. MATERIAL AND METHODS: p53 mutation analysis was performed on 46 paired tissue samples (adjacent normal and primary malignant) using PCR-SSCP and sequencing. RESULTS: Sequencing confirmed 51 p53 mutations in 46 paired tissues. Three novel mutations (frameshift deletion in exon 4; G>T transversion at codon 117 in exon 4 and G>A transition at codon 319 in exon 9) were identified. Distinct pattern of p53 mutations was observed: more common C>T transitions and recurring mutation sites at codon 90 and 116 in exon 4. Interestingly, the probability of developing recurrence was higher in small tumors (<4 cm) with p53 mutations and in cases with p53 mutations in both adjacent normal and malignant tissues. A significant low disease free survival and overall survival was observed in cases harboring truncating and transcriptionally non-active mutations. CONCLUSION: We report a very high frequency and a diverse pattern of p53 mutations in cases from this region. Interestingly, three distinct novel mutations in exons 4 and 9 were also observed. Analyzing p53 mutation status in tumor tissues at an early stage could serve as an important prognostic factor.