Identification of Melanoma Susceptibility Gene at 1p22

描述（由申请人提供）：尽管经过数十年的研究，转移性皮肤恶性黑色素瘤（CMM）仍然是一种无法治愈的疾病，显示中位生存时间为9个月，5年生存率低于5%。此外，在过去的20年里，CMM的发病率在世界范围内急剧增加。对这项研究至关重要的是，阳性家族史是CMM最确定的危险因素之一；10%的CMM病例是由遗传易感性引起的。虽然CDKN2A和CDK4这两个基因的突变会增加CMM的风险，但它们只占CMM多发病例家庭的20% - 25%。我们假设存在额外的cmm易感基因，该应用程序提供了一种基于经验的、技术创新的方法来识别这样的基因。我们对82种不涉及CDKN2A或CDK4的CMM进行了全基因组连锁扫描，并在1号染色体上发现了一个新的CMM易感位点（1p22）。为了确定该位点的黑色素瘤易感基因（Aim 1），我们正在整合多种实验方法，旨在对候选基因进行突变筛选。具体而言，我们将：(a)进行高分辨率snp分型，寻找CMM家族之间单倍型共享的证据，以进一步缩小关键区域；(b)设计一个定制的寡核苷酸微阵列，代表1p22关键区域内所有潜在的编码序列，以鉴定新基因并表征组织特异性基因表达，以确定候选基因的优先级；(c)设计一个定制的1p22寡核苷酸微阵列，用于比较基因组杂交（CGH），并在患者淋巴细胞和1p22半合子缺失的黑色素瘤细胞系的DNA中寻找部分或全部基因缺失。基于这些数据，我们将优先考虑我们的候选基因和(d)使用DNA测序筛选突变基因。在确定1p22黑色素瘤易感基因后，我们将确定1p22基因突变/丢失（Aim 2）在一组黑色素瘤细胞系、肿瘤和痣中的患病率，并提出一种实验方法来了解其作用机制。最后，我们将验证黑素皮质素受体（MCIR）的低外显率易感等位基因改变1p22易感基因突变（Aim 3）的外显率的假设，以及这些等位基因在1p22突变阳性家族中受影响和未受影响成员的基因型。

DESCRIPTION (provided by applicant): Despite decades of research, metastatic cutaneous malignant melanoma (CMM) remains an incurable disease, demonstrating a median survival time of 9 months, with a 5-year survival rate of less than 5 percent. Further, over the past 20 years, the incidence of CMM has increased dramatically worldwide. Critical to this study, a positive family history of the disease is among the most established risk factors for CMM; 10% of CMM cases result from an inherited predisposition. Although mutations in two genes, CDKN2A and CDK4, confer an increased risk of CMM, they account for only 20% - 25% of families with multiple cases of CMM. We hypothesize that that there are additional CMM-predisposition genes, and this application provides an empirically based, technologically innovative approach to identify one such gene. We have performed a genome-wide linkage scan of 82 CMM kindreds with no involvement of CDKN2A or CDK4, and have identified a novel CMM susceptibility locus on chromosome 1 (1p22). To identify the melanoma susceptibility gene at this locus (Aim 1), we are integrating multiple experimental methods aimed at prioritizing candidate genes for mutation screening. Specifically, we will: (a) perform high-resolution SNP-typing and look for evidence of haplotype sharing between CMM families in order to further narrow the critical region; (b) design a custom oligonucleotide microarray representing all potential coding sequences within the 1p22 critical region in order to identify novel genes and to characterize tissue-specific gene expression for the purpose of candidate gene prioritization; and (c) design a custom 1p22 oligonucleotide microarray for comparative genomic hybridization (CGH) and look for partial- or whole-gene deletions in DNA from patient lymphocytes as well as melanoma cell lines with hemizygous loss at 1p22. Based on these data, we will prioritize our gene candidates and (d) screen genes for mutations using DNA sequencing. Following the identification of the 1p22 melanoma susceptibility gene, we will determine the prevalence of 1p22 gene mutation/loss (Aim 2) in a panel of melanoma cell lines, tumors, and nevi, and propose an experimental approach to understand its mechanism of action. Lastly, we will test the hypothesis that Iow-penetrance susceptibility alleles of the melanocortin receptor (MCIR) modify the penetrance of 1p22 susceptibility gene mutations (Aim 3) and genotype both affected and unaffected members of our 1p22-mutation positive families for these alleles.