Sequence at codon 337 of TP53 and at SNP 28 (rs9894946) in DNA extracted from patient's biopsies (S1, S2, S3G and S3M) and from the father's peripheral blood cells. Direct sequencing was performed as described in (http://www-p53.iarc.fr/Download/TP53_DirectSequencing_IARC.pdf) A) As indicated by arrows, metaplasia (S1) showed the wild-type sequence of codon 337 (G allele in homozygosis). The dysplastic (S2), the neoplastic (S3G) and the metastastic (S3M) tissues were heterozygous at codon 337, with a G to A transition corresponding to the p.R337H mutation. B) Sequencing for SNP28 showed the wild-type sequence (CCG) in S1 and the presence of T allele in S2, S3G and S3M. The mutant haplotype was detected in father's germline.