A TP53 polymorphism is associated with increased risk of colorectal cancer and with reduced levels of TP53 mRNA Federica Gemignani 1,2,5 , Victor Moreno 3,5 , Stefano Landi 1,2,5 , Norman Moullan 1 , Ame´ lie Chabrier 1 , Sara Gutie´rrez-Enrı´quez 1 , Janet Hall 1 , Elisabeth Guino 3 , Miguel Angel Peinado 4 , Gabriel Capella 3 and Federico Canzian* ,1 1 International Agency for Research on Cancer (IARC), 150, Cours Albert Thomas, Lyon 69372, France; 2 Dipartimento di Scienze dell’Uomo e Ambiente, University of Pisa, 56100, Italy; 3 Institut Catala d’Oncologia, Hospitalet, Barcelona, Spain; 4 Institut de Recerca Oncologica, Hospitalet, Barcelona, Spain We undertook a case–control study to examine the possible associations of the TP53 variants Arg4Pro at codon 72 and p53PIN3, a 16 bp insertion/duplication in intron 3, with the risk of colorectal cancer (CRC). The p53PIN3 A2 allele (16 bp duplication) was associated with an increased risk (OR 1.55, 95% CI 1.102.18, P ¼ 0.012), of the same order of magnitude as that observed in previous studies for other types of cancer. The Pro72 allele was weakly associated with CRC (OR ¼ 1.34, 95% CI 0.981.84, P ¼ 0.066). The possible functional role of p53PIN3 was investigated by examining the TP53 mRNA transcripts in 15 lymphoblastoid cell lines with different genotypes. The possibility that the insertion/deletion could lead to alternatively spliced mRNAs was excluded. However, we found reduced levels of TP53 mRNA associated with the A2 allele. In conclusion, the epidemiological study suggests a role for p53PIN3 in tumorigenesis, supported by the in vitro characterization of this variant. Oncogene (2004) 23, 1954–1956. doi:10.1038/sj.onc.1207305 Published online 1 December 2003 Keywords: TP53; colorectal cancer; polymorphism; mRNA levels A total of 14 polymorphisms have been identified in the TP53 gene (http://www.iarc.fr/p53/Index.html), the most studied being Arg72Pro, p53PIN3 (where the A2 allele carries a duplication of 16bp in intron 3), and MspI (A4G, intron 6). Clues to their biological function have only been reported for the Arg72Pro variant. The wild-type form was found to be more susceptible than the variant Pro72 to degradation by the E6 onco-protein following human papillomavirus infec- tion (Storey et al., 1998), and more efficient in triggering cellular apoptosis due to a greater ability to localize to the mitochondria (Dumont et al., 2003). We performed a case–control study on 374 cases of colorectal cancer (CRC) and 322 controls, in order to examine possible associations between the Arg72Pro or the p53PIN3 A1/A2 alleles and the risk of cancer. Incident CRC cases (histologically confirmed) attending the Bellvitge Hospital (Barcelona, Spain) over the period 1996–1998 made up the case group. Controls were patients admitted to several departments of this hospital over the same period. Full details of the cohort are published elsewhere (Landi et al., 2003). The study was approved by the local Ethical Committees. All subjects gave written informed consent according to the Helsinki declaration. The p53PIN3 variant was genotyped as previously reported (Lazar et al., 1993), while the Arg72Pro variant was analysed using a primer extension approach (To˜nisson et al., 2002). The MspI intron 6 polymorphism was not investigated because it has been reported to be in complete linkage disequilibrium (LD) with the p53PIN3 variant (Weston et al., 1997). We found that the p53PIN3 genotypes A1/A2 and A2/A2 were statistically associated with an increased risk of CRC. The association of the Pro72 allele with CRC was weaker and statistically borderline (Table 1). Haplotype frequencies were reconstructed by use of the EM algorithm (Excoffier et al., 1995) and the Pro72 and A2 alleles were found in strong but not complete LD (r 2 ¼ 0.63, Po0.001), according to the Genotype Trans- poser software (Cox and Canzian, 2001). When the analysis was mutually adjusted for each polymorphism, the association of p53PIN3 remained significant (P trend ¼ 0.042), while the Pro72 variant was clearly unrelated to CRC (P trend ¼ 0.96). Previous studies have documented associations between these variants and cancer. In particular, the A2 allele has been found to be associated with increased risk of cancers of the lung (Wu et al., 2002), breast (Weston et al., 1997; Powell et al., 2002; Wang-Gohrke et al., 2002), and ovary (Runnebaum et al., 1995; Wang-Gohrke et al., 1999). Exon 3 and intron 3 of TP53 are only 21 and 112 bp, respectively, and it is possible that an increase of 15% in the length of the intron could alter mRNA splicing, thus affecting p53 function. However, publicly avail- able databases (http://www.ncbi.nih.gov/IEB/Research/ Acembly/) do not detail splicing variants affecting exon Received 18 June 2003; revised 21 July 2003; accepted 22 October 2003 *Correspondence: F Canzian,Genome Analysis Group, IARC; E-mail: canzian@iarc.fr 5 These authors contributed equally to the manuscript. Oncogene (2004) 23, 1954–1956 & 2004 Nature Publishing Group All rights reserved 0950-9232/04 $25.00 www.nature.com/onc