tokens: p53 cDNA from SK - N - AS cells for cloning was obtained from RT - PCR using F1 and reverse primer i9 + : 5 ' - GCAAAGTCATAGAACCATTTTCAT - 3 ' ( nucleotide position 14989 , GenBank accession no . X54156 ) primers which encompass from exon 1 to exon i9 + first identified by Flaman et al .