The 'enriched PCR' method by Behn et al. (39) was used to sequence codon 273 mutation of p53 exon 8 from sample CT20 and wild-type samples. In addition, a second method [Amplification via Primer-Ligation At The Mutation (40, 41) ] was used to distinguish mutant and wild-type samples by virtue of the de novo Nla-III site generated in the mutant sample by the p53 codon 273 G4A mutation.