Value of pedigree/clinical data, immunohistochemistry and microsatellite instability analyses in reducing the cost of determining hMLH1 and hMSH2 gene mutations in patients with colorectal cancer $ T. Debniak a, *, G. Kurzawski a , B. Gorski a , J. Kladny b , W. Domagala c , J. Lubinski a a Department of Genetics and Pathology, Pomeranian Medical University, Szczecin 70-111, Al. Powstan Âco Âw Wlkp 72, Poland b III Department of Surgery, Pomeranian Medical University, Szczecin 70-111, Al. Powstan Âco Âw Wlkp 72, Poland c Department of Pathology, Pomeranian Medical University, Szczecin 70-111, Al. Powstan Âco Âw Wlkp 72, Poland Received 1 March 1999; accepted 5 July 1999 Abstract The aim of this study was to evaluate the signi®cance of pedigree/clinical data, immunohistochemistry (IHC) and microsatellite instability (MI) analyses in the reduction of costs of constitutional hMLH1 and hMSH2 gene mutation diagnosis in patients with colorectal cancers (CRC). Pedigree/clinical data were evaluated on a series of 168 patients with CRC, including 43 consecutive sporadic late-onset and 25 consecutive, de®nitive or suspected hereditary non-polyposis colorectal cancer (HNPCC) cases, exam- ined by IHC and MI analyses. In the latter group, 6/25 (24%) constitutional mutations were found. We detected no germline mutations in the sporadic late-onset patients. The lowest costs (880 Euro/mutation detected) were achieved by performing pedigree/ clinical data (for exclusion of late-onset sporadic CRC) in conjuction with IHC only. In this model 1/6 (17%) mutations was mis- sed. Additional preselection by IHC and MI analyses before sequencing was required to detect all mutations. In this approach, which seems to be the most eective in the search for hMLH1 and hMSH2 gene mutation, the cost was 1767 euro/mutation detected. # 2000 Elsevier Science Ltd. All rights reserved. Keywords: hMLH1; hMSH2; Mutation detection; Clinical criteria; Immunohistochemistry; Microsatellite instability 1. Introduction Hereditary non-polyposis colorectal cancer (HNPCC, Lynch syndrome) is an autosomal dominant disease comprising 0.5±10% of all colorectal cancers (CRCs) [1, 2]. The Amsterdam criteria used in the diagnosis of the syndrome are restrictive, identifying only a small proportion of patients being actually aected by this disease [3]. Unequivocal diagnosis of HNPCC can be established by ®nding constitutional mutations in one of the genes involved in the development of this disease such as hMLH1 [4], hMSH2 [5], hPMS1, hPMS2 [6], hMSH6 [7] and TGF type II [8]. Indeed, hMLH1 and hMSH2 show abnormalities in more than 90% of HNPCC families with identi®ed germline mutations [9]. The most sensitive technique to detect such mutations is DNA sequencing. However, this procedure is expensive and is not recommended for the examination of indivi- duals with a very low probability of carrying a muta- tion. In the routine diagnosis of Lynch syndrome it is thus essential to develop various methods of preselec- tion before sequencing, thus allowing a reduction of costs without a signi®cant loss of sensitivity in the identi®cation of alterations within hMLH1 and hMSH2 genes. Over the past few years, three such methods have 0959-8049/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S0959-8049(99)00208-7 European Journal of Cancer 36 (2000) 49±54 www.elsevier.com/locate/ejconline $ Data have been presented at the 2nd Joint Meeting Leeds Poly- posis Group and International Collaborative Group for Hereditary Non-polyposis Colorectal Cancer, 1±6 March 1999, Melbourne, Australia. * Corresponding author. E-mail address: debniak@friko6.onet.pl (T. Debniak).