Determination of p53 genotypes in oral cancer patients from India

The p53 tumour suppressor gene is inactivated in various types of human can cers, and has been implicated as an early event in several cancers. A p53 P ro/Arg polymorphism at exon 4 codon 72, has been suggested to be involved i n susceptibility to cancers as well. Hence, in the current study, we invest igated p53 exon 4 codon 72 polymorphism using Proline or Arginine specific primers from the peripheral blood cells (PBC) representing constitutional D NA from 72 oral cancer patients. PBC from 153 normal healthy individuals we re used to determine the frequency of the p53 genotypes, Pro/Pro, Arg/Arg a nd Pro/Arg, in the Indian population. The frequency of distribution of geno types in the normal healthy individuals was, Pro/Pro - 0.20 (31/153), Arg/A rg - 0.14 (22/153) and Pro/Arg - 0.65 (100/153); and in the oral cancer pat ients was, Pro/Pro - 0.19 (14/72), Arg/Arg - 0.08 (6/72) and Pro/Arg - 0.72 (52/72). Thus, we observed an equidistribution of the genotypes in normal control and oral cancer patients (chi (2) = 1.77, df = 2, 0.3 < P < 0.5). F urther, DNA from corresponding tumours from the 72 oral cancer patients wer e examined for loss of heterozygosity in the p53 gene. Allelic loss was obs erved in 8 of 52 (15%) heterozygous informative oral cancer patients. Our d ata indicates an equidistribution of the genotypes and absence of over-repr esentation of either Pro/Pro or Arg/Arg genotypes in the oral cancer patien ts as compared to the normal healthy controls. Hence, association of the p5 3 genotypes with susceptibility to oral cancer, was not observed. (C) 2001 Cancer Research Campaign http://www.bjcancer.com.