Gómez L, Rubio M P, Martin M T, Vázquez J J, Idoate M, Pastorfide G, Pestaña A, Seizinger B R, Barnhill R L, Castresana J S
Instituto de Investigaciones Biomedicas, C.S.I.C., Arturo Duperier 4, Madrid, Spain.
J Invest Dermatol. 1996 Mar;106(3):432-6. doi: 10.1111/1523-1747.ep12343578.
Allelic loss in human cutaneous melanoma has been detected on chromosomes 1p, 6q, 9p, 10q, and 11q. Chromosome 17 contains important tumor suppressor genes such as p53, NM23, and neurofibromatosis type 1 (NF1), which have been implicated in melanoma tumorigenesis. The role of p53 has already been studied by a number of laboratories, showing contrasting results. In the present study, two restriction fragment length polymorphism (RFLP) probes for the NM23 and NF1 genes, together with five other RFLP and four variable number of tandem repeat chromosome 17 probes, were investigated at the loss of heterozygosity (LOH) level in a Southern blot-based assay. The NF1 gene was also tested for LOH by a polymerase chain reaction (PCR)-based approach in two different experiments, using a dinucleotide repeat polymorphic probe at locus D17S250 (17q11.2-q12), and an Alu probe intragenic to the NF1 gene (17q11.2). A PCR single-strand conformation polymorphism assay was included in the study for mutation detection at the NF1-GTPase-activating protein-related domain (GRD). A total of 68 melanocytic tumors were analyzed. LOH was detected in 9 of 87 informative cases (10%). LEW301 (17p11.2-pcen) presented the highest LOH frequency (22%). NM23 showed LOH in 17% of the informative cases, while NF1 did not show either LOH in the Southern blot- and PCR-based experiments or mutations at the NF1-GRD. These results are in concordance with those of previous smaller studies, but when compared with higher LOH frequencies obtained from other chromosomes, these findings indicate that the LOH values found in our study can most likely be attributed to background effect. Thus, chromosome 17 LOH is likely to play and unimportant role as a genetic event in melanoma tumorigenesis. Nevertheless, NF1 merits further study, since homozygous deletions have been detected at this locus in melanoma cell lines.
在人类皮肤黑色素瘤中已检测到1号染色体短臂、6号染色体长臂、9号染色体短臂、10号染色体长臂和11号染色体长臂存在等位基因缺失。17号染色体包含重要的肿瘤抑制基因，如p53、NM23和1型神经纤维瘤病（NF1）基因，这些基因与黑色素瘤的肿瘤发生有关。许多实验室已对p53的作用进行了研究，但结果相互矛盾。在本研究中，采用基于Southern印迹的分析方法，研究了用于NM23和NF1基因的两种限制性片段长度多态性（RFLP）探针，以及其他五种RFLP和四种17号染色体串联重复可变数目探针在杂合性缺失（LOH）水平的情况。在两项不同实验中，还采用基于聚合酶链反应（PCR）的方法，使用位于D17S250位点（17q11.2-q12）的二核苷酸重复多态性探针和NF1基因内部的Alu探针（17q11.2），检测NF1基因的LOH。本研究还采用PCR单链构象多态性分析方法检测NF1-鸟苷三磷酸酶激活蛋白相关结构域（GRD）的突变。共分析了68例黑素细胞肿瘤。在87例信息充分的病例中有9例检测到LOH（10%）。LEW301（17p11.2-pcen）的LOH频率最高（22%）。在17%的信息充分病例中检测到NM23存在LOH，而在基于Southern印迹和PCR的实验中，NF1既未显示LOH，也未在NF1-GRD处检测到突变。这些结果与之前规模较小的研究结果一致，但与从其他染色体获得的较高LOH频率相比，这些发现表明本研究中发现的LOH值很可能归因于背景效应。因此，17号染色体LOH作为黑色素瘤肿瘤发生中的一个遗传事件可能起不重要的作用。然而，NF1值得进一步研究，因为在黑色素瘤细胞系中已在该位点检测到纯合缺失。
