Abstract 727: Homozygosity for Arg of p53 codon 72 correlates with poor prognosis in Puerto Rican patients with head and neck squamous cell carcinoma

Abstract

Abstract Objective: Genetic variations at codon 72 of p53 gene results in altered activities for p53 and are suggested as a potential cancer risk. However, epidemiologic findings have been inconsistent. The p53 gene has a polymorphic site at exon 4 codon 72, which, in an occurrence of a base substitution, can produce Proline or Arginine (Arg72Pro). This polymorphism is differentially dispersed among different ethnic populations. The objective of this study is to evaluate the association between p53 polymorphism and head and neck squamous cell carcinoma (HNSCC) in the Puerto Rican population. Methods: Genotyping of the p53 polymorphism at exon 4 codon 72 was performed using PCR-based restriction fragment polymorphism (PCR-RFLP) in a study with 72 HNSCC patients. Correlations between clinicopathological parameters and p53 polymorphism were analyzed by Fisher's exact test and chi-square when suitable. Survival analysis of HNSCC patients, with each type of p53 genotype, was performed using Mantel-Cox test. Results: The frequencies for homozygote Arg allele were 34.7% in HNSCC cases and 31.1% in controls. The Pro allele carriers (Arg/Pro or Pro/Pro) had a frequency of 65.3% in HNSCC cases and 68.9% in healthy controls. The OR of HNSCC cancer-associated with the Arg-Arg genotypes of codon 72 was 1.18 [95% confidence interval (CI): 0.53-2.61]. Survival analysis showed that HNSCC patients with the Arg/Arg allele had a poorer survival rate compared to patients with the Pro allele (Hazard Ratio = 2.40, 95% CI: 1.27-4.56, P=0.0074). Also, there were differences in survival based on patient's genotype and response to treatment. However, no statistically significant association was found between p53 polymorphic variants and gender, age, risk factors and staging. Conclusion: Our results suggest that homozygosity for Arg of p53 Arg72Pro may have a role in the progression of HNSCC in the Puerto Rican population. Detection of the p53 polymorphic variants may be used as an indicator of prognosis in HNSCC patients. Accurate prognosis in HNSCC will help clinicians to establish proper treatment and increase the survival of HNSCC patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 727. doi:1538-7445.AM2012-727