Abstract 1158: Clinical significance of p53 codon 72 polymorphism in hepatocellular carcinomas

Abstract

Abstract Purpose: We recently demonstrated that, in colorectal carcinomas, the presence of a single nucleotide polymorphism (SNP) at codon 72 of the p53 gene was associated with a poor outcome for African American (AA) patients. Since such studies have not been performed for hepatocellular carcinomas (HCCs), we determined, for AAs and non-Hispanic Caucasians (NHCAs), the prevalence of p53 SNPs in codon 72 of HCCs and its association with adverse clinical and pathological features. Methods: DNA samples extracted from 48 archived, formalin-fixed, paraffin-embedded HCC tissues and from matching, uninvolved liver were analyzed for the mutational status of the p53 gene by sequencing exon 4 through exon 9. The results obtained were correlated with the demographic and clinicopathological features of the HCCs and with patient survival. Results: Overall, the frequency of missense point mutations in p53 of HCCs was low (6 of 48, 12%). Missense point mutations, however, were common in NHCAs (4 of 6). Genotyping of codon 72 of p53 demonstrated that the Arg/Arg phenotype had the highest frequency (27 of 48; 56%), followed by Arg/Pro (16 of 48; 33%) and Pro/Pro (5 of 48; 11%). Four of five patients with the Pro/Pro phenotype were AAs (χ2 p = 0.028). Of these, three of the four tumors had high proliferative (ki67) indices; two of the four were poorly differentiated. In contrast, poorly differentiated tumors were few in Arg/Arg (1 of 27, 4%) and Arg/Pro (1 of 16; 6%) (χ2p = 0.016) phenotype groups. For all patients, the Pro/Pro phenotype were associated with hepatitis C virus (HCV) infection (χ2 p = 0.048). Furthermore, AAs with the Pro/Pro phenotype had lower median survival (15.5 months) compared to those with the Arg/Arg and Arg/Pro (32 months) phenotypes. NHCA patients with missense point mutations had shorter median survival (22.5 months) relative to NHCAs with wild-type p53 (34 months).Conclusion: These preliminary findings suggest that, in AAs, the Pro/Pro phenotype at codon 72 of the p53 gene is associated with aggressive tumor behavior, shorter median survival, and HCV infection. These pilot studies were supported jointly by a Charles Barkley Award through the UAB Minority Health Disparities Research Center (MHRC) and the UAB Center for Clinical and Translational Science (5UL1 RR025777-04). 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 1158. doi:1538-7445.AM2012-1158