Original article 431 Genomic rearrangements of the CDKN2A locus are infrequent in Italian malignant melanoma families without evidence of CDKN2A/CDK4 point mutations Marina Vignoli a , Maria Chiara Scaini b , Paola Ghiorzo c , Roberta Sestini d , William Bruno c , Chiara Menin e , Francesca Gensini d , Mauro Piazzini d , Alessandro Testori f , Siranoush Manoukian g , Claudio Orlando h , Emma D’Andrea b,e , Giovanna Bianchi-Scarra ` c and Maurizio Genuardi a,d Predisposition to familial cutaneous malignant melanoma has been associated with mutations in the CDKN2A and CDK4 genes. However, only a small subgroup of melanoma pedigrees harbour CDKN2A or CDK4 germline mutations. It is possible that other types of CDKN2A rearrangements, not detectable by routine PCR-based approaches, are involved in a fraction of melanoma cases negative for point sequence changes. In order to gain insights on the possible role of CDKN2A large deletions or duplications in melanoma susceptibility in the Italian population, we screened a series of 124 cutaneous malignant melanoma families referred to five national medical/cancer genetics centres. All probands were negative for point mutations in CDKN2A and CDK4. All samples were tested by MLPA (multiplex ligation-dependent probe amplification), and the results were confirmed by real-time quantitative PCR in a subset of 53 cases. No genomic rearrangements were detected in this series, one of the largest so far investigated. These data suggest that large deletions/ duplications in the CDKN2A locus are infrequently involved in the development of familial melanoma in the Italian population. Based on these results, routine search for these rearrangements in CDKN2A- and CDK4-mutation negative melanoma families is not warranted, although it would be reasonable to pursue it in selected cases with very strong family history and/or showing linkage to 9p21. Melanoma Res 18:431–437  c 2008 Wolters Kluwer Health | Lippincott Williams & Wilkins. Melanoma Research 2008, 18:431–437 Keywords: CDKN2A, familial melanoma, large deletions, multiplex ligation-dependent probe amplification a Fiorgen Foundation for Pharmacogenomics, Sesto Fiorentino, b Department of Oncology and Surgical Sciences, Section of Oncology, University of Padova, c Department of Oncology, Biology and Genetics/Medical Genetics Service, University of Genoa, d Section of Medical Genetics, Department of Clinical Pathophysiology, University of Florence, e Molecular Immunology and Diagnostic Oncology, Istituto Oncologico Veneto (IOV), IRCCS, Padova, f European Institute of Oncology (IEO), g Medical Genetics Unit, Fondazione IRCCS Istituto Nazionale dei Tumori (INT), Milan and h Section of Clinical Biochemistry, Department of Clinical Pathophysiology, University of Florence, Italy Correspondence to Maurizio Genuardi, MD, Section of Medical Genetics, Department of Clinical Pathophysiology, University of Florence Medical School, Viale G. Pieraccini 6, 50139 Florence, Italy Tel: + 39 055 4271 421; fax: + 39 055 4271 413; e-mail: m.genuardi@dfc.unifi.it Received 14 March 2008 Accepted 15 September 2008 Introduction Familial cutaneous malignant melanoma (CMM) repre- sents 5–10% of all CMM cases. Genetic linkage analyses of CMM kindreds have identified the CDKN2A gene, located on human chromosome band 9p21, as the major melanoma susceptibility gene. CDKN2A encodes two cell cycle regulatory proteins, p16INK4a and p14ARF; the former is transcribed by exons 1a, 2, and 3, while the latter utilizes an alternative first exon, CDKN2A exon 1b, coupled with exons 2 and 3 in a different reading frame. p16INK4a is a cyclin-dependent kinase inhibitor redu- cing the level of phosphorylation of RB1 through inhibition of cyclinD/cdk4 complexes, whereas p14ARF acts as a p53 activator through its ability to inhibit MDM2-mediated p53 degradation [1]. So far CDKN2A is the major gene linked to hereditary malignant melanoma. Only a few families have been reported with germline mutations in the CDK4 gene, encoding cyclin dependent kinase 4 [2–4]. Germline CDKN2A mutations have been identified in 20–40% of melanoma-prone families [5–11]. The fractions of cases positive for CDKN2A mutations among familial CMM patients vary by geographic region, with higher frequen- cies occurring in regions of low incidence [11–13]. Most CDKN2A germline mutations identified to date are located within the coding sequence. Mutations in non coding regions, such as deep intronic regions and the promoter/5 0 UTR [14–17], and rare mutations in exon 1b have also been described, but they only account for a small subset of all 9p21-linked families [18,19]. Indeed, it is currently difficult to estimate how many families are 9p21-linked, given the difficulty of verifying segregation in small families. Methods used to screen for CDKN2A mutations are usually based on traditional PCR amplification and 0960-8931  c 2008 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/CMR.0b013e328319412f Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.