The relationship between the epidermal growth factor (EGF) 5'UTR variant A61G and melanoma/nevus susceptibility

The inheritance of a G allele in position 61 in the 5'UTR of the epidermal growth factor (EGF) gene has been reported to increase melanoma susceptibility, a finding we have investigated in this study. The most potent phenotypic risk factor for melanoma is the atypical mole syndrome (AMS) phenotype. Our hypothesis is that the AMS is genetically determined and that nevus genes are also low penetrance melanoma susceptibility genes. We report that the G allele frequencies were the same in 697 healthy women and 380 melanoma cases (OR 0.97, 95% CI 0.8-1.2 p=0.76). We therefore found no evidence that this polymorphism is a melanoma susceptibility gene. Furthermore, we found no evidence that the polymorphism controls the nevus phenotype (nevus number, number atypical nevi or AMS phenotype). We did find some evidence that the G allele may be associated with decreased tumor Breslow thickness (OR 0.5, 95% CI 0.3-0.9) for the A/A genotype versus A/G and G/G combined in tumors of thickness >3.5 vs < or =3.5 mm and may therefore act as a predictor of survival, although this finding is not in accord with the original report. This is the second study to find no association between EGF +61 and melanoma susceptibility.     

BRAF polymorphisms and risk of melanocytic neoplasia

Somatic mutations of the BRAF gene are common in melanomas and nevi but the contribution of polymorphisms in this gene to melanoma or nevus susceptibility remains unclear. An Australian melanoma case-control sample was typed for 16 single nucleotide polymorphisms (SNP) within the BRAF gene, and five SNP in three neighboring genes. The sample comprised 755 melanoma cases from 740 families stratified by family history of melanoma and controls from 635 unselected twin families (2,239 individuals). Ancestry of the cases and controls was recorded, and the twins had undergone skin examination to assess total body nevus count, degree of freckling, and pigmentation phenotype. Genotyping was carried out via primer extension followed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. SNP in the BRAF gene were found to be weakly associated with melanoma status but not with development of nevi or freckles. The estimated proportion of attributable risk of melanoma due to variants in BRAF is 1.6%. This study shows that BRAF polymorphisms predispose to melanoma but the causal variant has yet to be determined. The burden of disease associated with this variant is greater than that associated with the major melanoma susceptibility locus CDKN2A, which has an estimated attributable risk of 0.2%.     

An assessment of the CDKN2A variant Ala148Thr as a nevus/melanoma susceptibility allele

Melanocytic nevi are the most potent risk factors for melanoma yet identified. Variation in the nevus phenotype within a population is predominantly genetically determined. Genes that determine nevus expression may therefore act as low penetrance melanoma susceptibility genes. Rare germline mutations in CDKN2A predispose to melanoma and appear to be nevogenic, although the correlation between nevus phenotype and mutation status is poor. It is plausible that more common CDKN2A variants may influence both melanoma susceptibility and nevus susceptibility. Ala148Thr is a G to A missense polymorphism of CDKN2A, which is found in 4%-6% of the general population. We have investigated the role of Ala148Thr as a low penetrance melanoma or nevus susceptibility allele in two separate groups of individuals. The first was a sample of 488 adults recruited from 179 families of patients with the atypical nevus phenotype and/or a family history of melanoma, and the second was a population-based sample of 599 women. Similar prevalences of Ala148Thr (4.9% and 5.2%) were found in both samples but significant variation in the prevalence of the polymorphism was seen across geographic areas within England. There was no association between Ala148Thr status and nevus number or history of melanoma, and therefore the results did not support the hypothesis that the Ala148Thr variant is a low penetrance melanoma or nevus susceptibility allele. A significant protective role of Ala148Thr on the number of atypical nevi was observed in the family sample (mean of 1 atypical nevus in those with the allele and 3.5 nevi in those without, p = 0.02). After allowing for potential confounders this was not evident in the population-based sample.     

An assessment of a variant of the DNA repair gene XRCC3 as a possible nevus or melanoma susceptibility genotype

Inheritance of the T allele in exon 7 (position 18067) of the DNA repair gene XRCC3 has been reported to be associated with susceptibility to melanoma in a study from Oxford. We report a study in which an attempt was made to confirm this association in a similar population. The most potent risk factor for melanoma in the general population is a phenotype characterized by the presence of multiple melanocytic nevi: the atypical mole syndrome. Our hypothesis is that the atypical mole syndrome may be a marker of genetic susceptibility to melanoma. We have therefore investigated whether the XRCC3 polymorphism influences the nevus phenotype. The XRCC3 genotype was investigated using PCR in a general-practice-based sample of 565 women and 475 patients from a cohort enriched for the atypical mole syndrome, of whom 140 had had melanoma. Allele frequencies were the same in the healthy women, the melanoma cases from this study, and the melanoma cases reported in the Oxford study, but were different from those in the Oxford control group. We found no evidence therefore that the T allele of this XRCC3 polymorphism is indicative of susceptibility to melanoma. There was a marginal relationship with nevus phenotype, but this was no longer statistically significant in multivariate analysis. The previous association between XRCC3 and melanoma may be a result of the choice of control group and we emphasize the need for appropriate choice of controls.     

Preliminary evidence for involvement of the tumour suppressor gene CHD5 in a family with cutaneous melanoma

Background Cutaneous melanoma is rapidly increasing in incidence worldwide and approximately 5% of melanomas are hereditary. Deletions in chromosome 1p36 have been detected in melanoma but no candidate melanoma tumour suppressor gene has yet been found in this area. Recently, strong evidence has been reported that CHD5 is a tumour suppressor gene in this region. Objectives To investigate CHD5 involvement in familial melanoma. Methods Peripheral blood DNA from 47 melanoma families who do not carry mutations in any of the three currently recognized melanoma genes, 398 patients with sporadic melanoma and 398 geographically matched nonmelanoma‐bearing controls were studied. Linkage investigation, single nucleotide polymorphism (SNP) genotyping and mutation screening studies were carried out on the CHD5 locus. Results The CHD5 gene was not excluded by linkage analysis in any of the families. On SNP genotyping, the CHD5 rs7513548 SNP was found to be significantly associated with sporadic melanoma (odds ratio 1·53, 95% confidence interval 1·13–2·06). The AG genotype was found in 208 cases and 169 controls (cf. 141 and 175 cases and controls, respectively, for the AA genotype). On CHD5 mutation screening, a total of 50 single‐base substitutions were detected. Of these, 39 were intronic and 11 were exonic. While 32 were previously recognized variants, 18 were newly identified. Three, in exons 4, 31 and 32, led to nonsynonymous substitutions. A p.Met1576Ile substitution was identified in a mother and daughter, both with invasive cutaneous melanoma. Conclusions This study appears to be the first report of CHD5 variants in familial cutaneous melanoma. Such CHD5 variants could block or alter the ability of CHD5 to regulate the cell cycle pathway and to effect cellular control. As only one of the 47 families studied has this variant, it appears to be a rare event and further screening of melanoma families is required to confirm whether or not CHD5 is involved in melanoma pathogenesis.     

The EGF A61G polymorphism is associated with disease-free period and survival in malignant melanoma

An earlier study reported that a common polymorphism in the 5' untranslated region of the epidermal growth factor (EGF) gene is associated with increased risk for cutaneous malignant melanoma (MM) and Breslow thickness. Since then, several independent studies have reported conflicting results that have challenged this hypothesis. However, none of the previous studies examined survival as the primary outcome. We therefore sought to study the association between this polymorphism and survival. One hundred and thirty patients diagnosed with MM with a Breslow thickness of >1.5 mm were included in this study. In our collective, the G/G genotype represented a significant risk factor for both shorter disease-free period (hazard ratio of 2.246, 95% CI: 1.06-4.78, P=0.036) and overall MM-specific survival (hazard ratio of 3.8, 95% CI: 1.5-9.5, P=0.004) compared with the A/A genotype, while the heterozygous A/G genotype showed an intermediate risk. In the present study, we demonstrate for the first time that the EGF A61G polymorphism is associated with survival. Our data suggest that this polymorphism is a potential marker for disease severity that predicts earlier progression of MM.     

CDKN2A mutations in melanoma families from Uruguay

Background  Familial melanoma, a cluster of several cases within a single family, accounts for approximately 10% of cases of melanoma. Hereditary melanoma is defined as two or more first-degree relatives having melanoma. A member of a melanoma-prone family has a 35–70-fold increased relative risk of developing a melanoma. Genetic susceptibility is linked to the major susceptibility genes CDKN2A and CDK4 , and the minor susceptibility gene MC1R .
Objectives  To determine the clinical and genetic characteristics of cutaneous melanoma in melanoma-prone families from Uruguay.
Methods  We studied 13 individuals from six melanoma-prone families living in Uruguay. Phenotype, familial and personal history were recorded. Molecular screening of CDKN2A and CDK4 was done by polymerase chain reaction–single strand conformational polymorphism analysis. The MC1R gene was sequenced.
Results  Mutations in CDKN2A were detected in five of six families: c.−34G>T, p.G101W and p.E88X. A novel germline mutation p.E88X, associated with hereditary melanoma in two unrelated families, is described. We hypothesize that a founder effect occurred probably in the Mediterranean region. No mutations in CDK4 were detected. Six different MC1R variants, all previously reported, were present in Uruguayan families.
Conclusions  The overall rate of deleterious CDKN2A mutations in our familial melanoma pedigrees, even though the sample size is small, was considerably higher (83%) than the often quoted range.     

Melanoma within naevus spilus: 5 cases

BACKGROUND: Nevus spilus is defined as café-au-lait macules with dark maculopapular speckles. Histologically, it has the aspect of lentigo associated with nevocellular nevus. There are 3 types of nevus spilus: small or medium-sized (<20 cm), giant and zosteriform. Malignant transformation of nevus spilus is rare. PATIENTS AND METHODS: We analyzed the cases of 5 patients presenting melanoma within nevus spilus as well as 20 published cases. The evaluation criteria were: for nevus spilus: size, type, topography, age of onset and presence of dysplastic nevi within the nevus spilus; for melanoma: clinical aspect, histological type, thickness, level and age at diagnosis. The presence of other risk factors for melanoma was noted. RESULTS: The 14 women and 11 men had a mean age of 49 years at melanoma diagnosis. Type of nevus spilus was: small or medium-sized (15 cases), zosteriform (6 cases) and giant (4 cases). Only 3 nevi spili were<4 cm in diameter. Nevus spilus was present since birth (11 cases), childhood (7 cases), after the age of 20 years (3 cases) and was unspecified in 4 cases. Three of our five patients had other risk factors for melanoma. Two patients were presenting 2 melanomas within nevus spilus. The histological type of melanoma was not specified in 8 cases but SSM was the most common type (13 cases). Median Breslow thickness was 1.25 mm (0.27 to 8 mm) for the 19 cases in which it was specified. CONCLUSION: The following criteria appeared to be associated with risk of developing melanoma in nevus spilus patients: nevus spilus present since birth, nevus spilus over 4 cm in diameter, and giant or zosteriform nevus spilus. Development of melanoma within nevus spilus is a rare event. Consequently, guidelines for follow-up of nevus spilus cannot be defined. However, follow-up is recommended, and in particular, self-examination.     

SPRR2E基因编码区单核苷酸多态性与银屑病

目的通过测定32个中国汉族人寻常性银屑病家系共157人SPRR2E基因的外显子编码区序列,研究SPRR2E基因与银屑病发病的关系。方法提取基因组DNA,对32个银屑病家系DNA进行扩增,产物经377DNA测序电泳仪电泳,用自动测序的方法测定SPRR2E基因的外显子编码区序列,并以ETDT及GENEHUNTER软件进行统计处理。结果SPRR2E基因编码区第156核苷酸( 156bp)处存在A或G二态性,可表现为AA纯合、GG纯合和AG杂合三种基因型,虽然该SNP不改变蛋白质编码,但它与银屑病存在传递不平衡,等位基因A优先传递给患病子代(P<0.05)。结论SPRR2E基因的外显子编码区中的一个核苷酸多态性与中国汉族人寻常性银屑病的发病相关联。     

Human beta-defensin 1 circulating level and gene polymorphism in non-segmental vitiligo Egyptian patients

BackgroundVitiligo is an acquired depigmented skin disorder. It has a genetic and autoimmune background. Human beta defensin-1(HBD-1) plus its gene polymorphism were linked to some autoimmune disorders.ObjectiveTo elucidate the possible role of HBD-1 in the pathogenesis of non-segmental vitiligo (NSV) through evaluation of HBD-1 serum levels and its single nucleotide polymorphism (SNP) in patients having NSV, in addition, to correlating the results with the extent of vitiligo in those patients.MethodsA current case-control study included 50 patients having NSV and 50 controls. The authors used Vitiligo Area Scoring Index (VASI) score to assess vitiligo severity and laboratory investigations to assess serum HBD-1 level using ELISA and defensin-beta1 (DEFB1) SNP using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).ResultsThere were significantly lower HBD-1 serum levels in NSV cases than in controls (p < 0.001). There was a significant predominance of GG DEFB1 genotype and G allele in NSV patients in comparison to controls (p < 0.001). The levels of serum HBD-1 and DEFB1 genotypes were not associated or correlated significantly with any of the personal and clinical parameters of vitiligo patients.Study limitationThe small sample size.ConclusionsDEFB1 gene polymorphism (GG genotype and G allele) may modulate vitiligo risk and contribute to vitiligo development in Egyptian populations. Decreased circulating HBD-1 levels might have an active role in vitiligo etiopathogenesis that could be mediated through its possible anti-inflammatory effects.     

Benign melanocytic lesions: Risk markers or precursors of cutaneous melanoma?

Background: The role of benign melanocytic lesions as precursors and not only as risk markers for the development of cutaneous melanoma is controversial.Objective: The purpose of the study was to assess the frequency of the histologic association of benign melanocytic lesions with cutaneous melanoma of a maximum thickness of 1.00 mm. The possibility that the spatial association of benign lesions with melanoma may be co-incidental was also investigated.Methods: The study subjects representing 289 cases of cutaneous melanoma of maximum thickness 1.00 mm (or less) were examined histologically for the presence of an associated benign melanocytic lesion(s), including lentiginous melanocytic proliferation; junctional, compound, or intradermal nevus; dysplastic nevus; and congenital nevus contiguous with or adjacent to the melanoma. The effects of age, tumor thickness, level of invasion, histologic type, and anatomic site on the association of benign melanocytic lesions with melanoma were assessed. In the control subjects 40 basal cell carcinomas and 38 compound nevi (not dysplastic) randomly chosen and matched for age (±1 year) and site (head/neck, trunk, upper and lower limbs) with a melanoma case were examined to assess the proportion of these cases associated with benign lesions compared with the matched melanoma cases.Results: A nevus was associated with melanoma in 51% of cases (n = 147). Of these, 82 (56%) were dysplastic nevi, 61 (41%) were common acquired nevi, and 4 (3%) were congenital nevi. Lentiginous melanocytic proliferation was present in the epidermis adjacent to 219 melanomas (75%) and in 44% of these cases (n = 97) a coexisting nevus was also present.Conclusion: The results of this study lend further support to the concept of common acquired nevi and dysplastic nevi as precursors of cutaneous melanoma. In addition, lesions diagnosed clinically as simple lentigo and solar lentigo may be important as potential precursors of melanoma, particularly in the elderly.     

Desmoplastic melanocytic nevi with lymphocytic aggregates

Desmoplastic melanocytic nevi can be difficult to distinguish from desmoplastic melanoma. The presence of lymphocytic aggregates in association with a sclerosing melanocytic proliferation is commonly regarded as a feature in support of a diagnosis of desmoplastic melanoma. However, the finding is not specific for melanoma. Herein we report six cases of sclerosing melanocytic nevi with associated lymphocytic aggregates. They occurred in five women and one man, ranging in age from 11 to 61 years. Three lesions were sclerosing Spitz nevi; one was an amelanotic sclerosing blue nevus, one an acquired intradermal sclerosing nevus, and one was a congenital compound melanocytic nevus with sclerosis of its dermal component. The lesions were interpreted as benign, i.e. melanocytic nevi, because of their histopathologic attributes (symmetric silhouette, benign cytologic features) and results from immunohistochemical studies (all lesions strongly expressed Melan-A and p16) and fluorescence in situ hybridization (FISH). Three lesions tested by FISH lacked copy number changes of 11p, 6q or 6p. None of the lesions recurred. The cases highlight that contextual information is essential for the diagnosis of desmoplastic melanoma and sclerosing nevus. The presence of lymphocytic aggregates per se does not prove that a sclerosing melanocytic proliferation is malignant.     

Eotaxin gene single nucleotide polymorphisms in the promoter and exon regions are not associated with susceptibility to atopic dermatitis,but two of them in the promoter region are associated with serum IgE levels in patients with atopic dermatitis

Eotaxin is believed to play an important role in atopic dermatitis (AD) as a potent chemoattractant and activator of eosinophils and Th2 lymphocytes. The eotaxin gene is located at chromosome 17q21.1-q21.2, and linkage findings of AD on chromosome 17 were reported. Recently we have identified single nucleotide polymorphisms (SNPs) of eotaxin gene (-426C > T, -384A > G, 67G > A). To learn whether eotaxin gene SNPs are associated with susceptibility to AD or phenotypes of AD, we investigated the genotype frequencies at each SNP of the gene in AD patients and in controls. We examined 140 Japanese AD patients and 140 healthy Japanese individuals. Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. No significant difference was observed in allele or genotype frequencies of any SNP between AD patients and controls. Serum immunoglobulin E (IgE) levels were significantly lower in CT and TT genotype than in CC (P = 0.038) in -426C > T SNP, and lower in GG than in AA and AG with borderline significance (P = 0.053) in -384A > G SNP in AD patients. Eotaxin gene SNPs in the promoter and exon regions are not associated with susceptibility to AD, but two of them in the promoter region are associated with phenotype of AD.     

BRAF mutations are common somatic events in melanocytic nevi

We determined mutations in the BRAF, N-ras, and CDKN2A genes in 27 histologically diverse melanocytic nevi and corresponding surrounding tissues from 17 individuals. Mutations in the BRAF and N-ras gene were found in 22 nevi (81%) from 16 individuals (94%). The predominant BRAF mutation T1799A (V600E) was detected in 18 nevi; 1 nevus had a novel A1781G (D594V) mutation in the same gene and 3 nevi had mutations in codon 61 of the N-ras gene. In 4 individuals both nevi carried a BRAF mutation, whereas in 2 other individuals 1 nevus showed a BRAF mutation and the second nevus had an N-ras mutation. In 2 individuals normal skin distant from nevi showed a BRAF mutation. No mutations were detected in the CDKN2A gene. The mutations in the BRAF and N-ras genes, in this study, were not associated with histologic type, location, skin type, size, or numbers of nevi. Our results suggest that mutations in the BRAF gene and to some extent in the N-ras gene represent early somatic events that occur in melanocytic nevi. We hypothesize the dual effect of solar ultraviolet irradiation on melanoma, through mutagenesis and by increasing the number of melanocytic nevi, many of which carry a BRAF or N-ras mutation.     

Investigation of the eotaxin gene -426C-->T, -384A-->G and 67G-->a single-nucleotide polymorphisms and atopic dermatitis in Italian children using family-based association methods.

BACKGROUND: Eotaxin plays an important role in atopic dermatitis (AD) as a potent chemoattractant and activator of eosinophils and T-helper 2 lymphocytes. AIM: To investigate whether single-nucleotide polymorphisms of the eotaxin gene are associated with AD, we investigated the genotype and allelic frequencies of -426C-->T, -384A-->G, and 67G-->A SNPs in 130 Italian families. METHODS: In total, 130 children with either the extrinsic allergic or intrinsic nonallergic forms of AD (EAD and IAD) were recruited from 130 families. Genotyping was performed using PCR and restriction fragment length polymorphism analysis. RESULTS: A significant difference was observed in the genotype frequency of the -426C-->T SNP between children with EAD and those with IAD (P = 0.01), and between children with EAD and controls (P = 0.01). The allele frequencies of the -426C-->T SNP were significantly different between children with EAD and those with IAD (P < 0.01), and between children with EAD and controls (P < 0.01). For children with EAD, the genotype frequency of the -426C-->T SNP was no different between the groups with mild, moderate and severe SCORAD (P = NS). No significant association was observed between the -384A-->G and 67G-->A SNPs and the two groups of children with EAD and IAD compared with the control group. In 32 trios selected from 68 EAD families, the transmission disequilibrium test showed a preferential transmission of the -426T allele from the parents to affected offspring (P < 0.01). CONCLUSIONS: Our results suggest that in our group of children with AD, the eotaxin gene may play a crucial role in the development of extrinsic AD, probably with other genetic factors.     

组氨酸三聚体核苷结合蛋白1在黑素瘤组织中的表达及其基因启动子甲基化水平研究

目的：检测组氨酸三聚体核苷结合蛋白1（HINT1）在黑素瘤中的表达和HINT1基因启动子甲基化状态,探讨HINT1启动子甲基化与临床病理参数的关系。方法采用甲基化特异性PCR（MSP）法检测56例黑素瘤及瘤旁组织和51例色素痣组织中HINT1基因启动子区甲基化水平,免疫组化法检测56例黑素瘤和51例色素痣组织中HINT1蛋白的表达。结果 MSP显示,黑素瘤组织、瘤旁组织及色素痣组织中HINT1基因启动子区甲基化率分别为76.8%（43/56）、33.9%（19/56）和35.3%（18/51）,黑素瘤组HINT1基因启动子区甲基化率明显高于瘤旁组织组和色素痣组,且差异有统计学意义（χ2=20.810、18.749,均P<0.05）,瘤旁组织组与色素痣组间差异无统计学意义（χ2=0.022,P>0.05）。免疫组化显示,56例黑素瘤和51例色素痣组织中分别有12例（21.4%）和42例（82.4%）HINT1蛋白阳性表达,两组阳性率差异有统计学意义（χ2=39.633,P<0.01）。12例HINT1蛋白阳性的黑素瘤组织中,有6例HINT1基因启动子甲基化,而在44例HINT1蛋白阴性的癌组织中HINT1启动子甲基化率高达84.1%（37/44）,两组差异有统计学意义（χ2=6.147,P=0.013）。56例黑素瘤中,HINT1基因启动子区甲基化率在Clark分级Ⅰ~Ⅱ级组（59.1%,13/22）与Ⅲ~Ⅴ级组（88.2%,30/34）间差异有统计学意义（χ2=6.365,P=0.012）。结论 HINT1在黑素瘤组织中低表达,其机制可能与启动子区发生高甲基化有关;HINT1启动子区高甲基化可能参与黑素瘤的发生及发展。     

Analysis of N- and K-ras mutations in the distinctive tumor progression phases of melanoma

Mutations in the ras genes are key events in the process of carcinogenesis; in particular, point mutations in codon 61 of exon 2 of the N-ras gene occur frequently in cutaneous melanoma. To investigate whether these mutations occur in early or late tumor progression phases, we searched for point mutations in the N- and K-ras genes in 69 primary cutaneous melanoma, 35 metastases, and seven nevocellular nevi in association with cutaneous melanoma. Lesions were microdissected in order to procure pure tumor samples from the distinctive growth phases of the cutaneous melanoma; the very sensitive denaturing gradient gel electrophoresis technique was used to visualize the mutations, and was followed by sequencing. Point mutations in the N-ras gene but not in the K-ras gene were detected on denaturing gradient gel electrophoresis. Twenty-three primary (33%) and nine metastatic (26%) melanomas showed bandshifts for N-ras. In the majority of cases, mutations occurring in early growth phases (i.e., the "intraepidermal" radial growth phase), were preserved in later growth phases (i.e., the invasive radial growth phase, vertical growth phase, and metastatic phase), which proves the clonal relationship between the successive growth phases. In three cases, however, the mutations differed between the distinctive growth phases within the same cutaneous melanoma, due to the occurrence of an additional mutation (especially in codon 61) in a later tumor progression phase. Our approach also permitted us to analyze the mutational status of nevi, associated with cutaneous melanoma. Six out of seven associated nevi carried the same sequence (mutated or wild-type) as the primary cutaneous melanoma, whereas in one case the sequence for N-ras differed between the primary melanoma and the associated nevus. In conclusion, this approach allowed us to demonstrate the clonal relationship between subsequent growth phases of melanoma and associated nevi; our results suggest that N-ras exon 1 mutations preferentially occur during early stages of tumor progression and hence may be involved in melanoma initiation, whereas those in N-ras exon 2 are found preferentially during later stages and hence are more probably involved in metastatic spread of cutaneous melanoma.     

恶性黑素瘤Survivin和C-erbB-2的检测及其意义

目的检测恶性黑素瘤的Survivin和CerbB2及其与临床病理特征的关系。方法应用免疫组化SP法检测72例恶性黑素瘤、61例瘤旁组织、22例黑色素细胞痣和20例正常皮肤组织中Survivin和CerbB2蛋白。结果恶性黑素瘤Survivin蛋白阳性率为59.7%,明显高于瘤旁组织3.3%,黑色素细胞痣4.5%和正常皮肤组织0%(P均<0.01)。Survivin阳性与转移状况和组织学分级有显著相关性。恶性黑素瘤无转移组和Ⅰ级分别明显低于转移组和Ⅱ,Ⅲ,Ⅳ级(P均<0.05)。恶性黑素瘤CerbB2蛋白阳性率为68.1%,明显高于瘤旁组织8.3%,黑色素细胞痣5.6%和正常皮肤组织2.8%(P均<0.01),CerbB2阳性与临床病理特征无明显相关性。Survivin在CerbB2阳性和阴性患者中阳性率分别为69.4%和39.1%,两者间有显著性差异(P<0.05)。结论Survivin和CerbB2蛋白在恶性黑素瘤组织中水平上调,提示两者对恶性黑素瘤发生发展起重要作用。恶性黑素瘤中Survivin蛋白水平与肿瘤转移和组织学分级有关,Survivin可能为临床判断恶性黑素瘤转移和评估预后的有用指标。     

Genetic variations of patients with familial or multiple melanoma in Southern Brazil

Background Patients with familial melanoma or multiple primary melanoma represent a high‐risk population to hereditary melanoma. Mutations in susceptibility genes, such as CDKN2A, CDK4 and MC1R, have been associated with the development of melanoma. Objectives The purpose of this study was to determine the genotypic background of patients with familial and/or multiple melanoma in southern Brazil. Methods This study analysed 33 cases (5 patients with multiple primary melanoma and 28 patients from families with at least two well documented cases) and 29 controls. Genomic analysis of CDKN2A and CDK4 genes by PCR‐SSCP analysis and sequencing and direct sequencing of MC1R were performed in all individuals. Results No functional mutations in CDKN2A or CDK4 were detected in the 62 individuals. Infrequent variants in polymorphic loci of CDKN2A gene were identified in 15 participants (24.2%) and 24/33 (72.8%) cases and 19/27 (70.4%) controls reported at least one infrequent variant in MC1R (P = 0.372). Furthermore, a non‐significant tendency towards an association between melanoma risk and MC1R variants G274A and C451T and a non‐significant linear tendency to the number of infrequent high‐risk variants in MC1R were observed. Conclusions These results suggest that in southern Brazilian population, CDKN2A or CDK4 germinal alterations may have a weaker influence than previously thought and environmental risk factors may play a central role in melanoma susceptibility. However, considering the tendency observed for gene MC1R, low‐penetrance genes may be a relevant aetiological factor in southern Brazil with fair skin population and high sunlight exposure.