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3.
Br J Dermatol ; 172(6): 1498-1506, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25524463

RESUMO

Women with BRCA1/2 mutations have an elevated risk of breast and ovarian cancer. These patients and their clinicians are often concerned about their risk for other cancers, including skin cancer. Research evaluating the association between BRCA1/2 mutations and skin cancer is limited and has produced inconsistent results. Herein, we review the current literature on the risk of melanoma and nonmelanoma skin cancers in BRCA1/2 mutation carriers. No studies have shown a statistically significant risk of melanoma in BRCA1 families. BRCA2 mutations have been linked to melanoma in large breast and ovarian cancer families, though a statistically significant elevated risk was reported in only one study. Five additional studies have shown some association between BRCA2 mutations and melanoma, while four studies did not find any association. With respect to nonmelanoma skin cancers, studies have produced conflicting results. Given the current state of medical knowledge, there is insufficient evidence to warrant increased skin cancer surveillance of patients with a confirmed BRCA1/2 mutation or a family history of a BRCA1/2 mutation, in the absence of standard risk factors. Nonetheless, suspected BRCA1/2 mutation carriers should be counselled about skin cancer risks and may benefit from yearly full skin examinations.


Assuntos
Genes BRCA1/fisiologia , Genes BRCA2/fisiologia , Melanoma/genética , Mutação/genética , Neoplasias Cutâneas/genética , Neoplasias da Mama/genética , Feminino , Heterozigoto , Humanos , Masculino , Neoplasias Ovarianas/genética , Fatores de Risco
4.
Dermatology ; 224(1): 51-8, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22433231

RESUMO

BACKGROUND: The 'gold standard' for the diagnosis of melanocytic lesions is dermatopathology. Although most of the diagnostic criteria are clearly defined, the interpretation of histopathology slides may be subject to interobserver variability. OBJECTIVES: The aim of this study was to determine the variability among dermatopathologists in the interpretation of clinically difficult melanocytic lesions. METHODS: This study used the database of MelaFind®, a computer-vision system for the diagnosis of melanoma. All lesions were surgically removed and sent for independent evaluation by four dermatopathologists. Agreement was calculated using kappa statistics. RESULTS: A total of 1,249 pigmented melanocytic lesions were included. There was a substantial agreement among expert dermatopathologists: two-category kappa was 0.80 (melanoma vs. non-melanoma) and three-category kappa was 0.62 (malignant vs. borderline vs. benign melanocytic lesions). The agreement was significantly greater for patients ≥40 years (three-category kappa = 0.67) than for younger patients (kappa = 0.49). In addition, the agreement was significantly lower for patients with atypical mole syndrome (AMS) (kappa = 0.31) than for patients without AMS (kappa = 0.76). LIMITATIONS: The data were limited by the inclusion/exclusion criteria of the MelaFind® study. This might represent a selection bias. The agreement was evaluated using kappa statistics. This is a standard method for evaluating agreement among pathologists, but might be considered controversial by some statisticians. CONCLUSIONS: Expert dermatopathologists have a high level of agreement when diagnosing clinically difficult melanocytic lesions. However, even among expert dermatopathologists, the current 'gold standard' is not perfect. Our results indicate that lesions from younger patients and patients with AMS may be more problematic for the dermatopathologists, suggesting that improved diagnostic criteria are needed for such patients.


Assuntos
Melanoma/patologia , Neoplasias Cutâneas/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estatística como Assunto , Adulto Jovem
5.
Br J Dermatol ; 164(4): 797-806, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21294715

RESUMO

BACKGROUND: Early detection and treatment of melanoma is important for optimal clinical outcome, leading to biopsy of pigmented lesions deemed suspicious for the disease. The vast majority of such lesions are benign. Thus, a more objective and accurate means for detection of melanoma is needed to identify lesions for excision. OBJECTIVES: To provide proof-of-principle that epidermal genetic information retrieval (EGIR™; DermTech International, La Jolla, CA, U.S.A.), a method that noninvasively samples cells from stratum corneum by means of adhesive tape stripping, can be used to discern melanomas from naevi. METHODS: Skin overlying pigmented lesions clinically suspicious for melanoma was harvested using EGIR. RNA isolated from the tapes was amplified and gene expression profiled. All lesions were removed for histopathological evaluation. RESULTS: Supervised analysis of the microarray data identified 312 genes differentially expressed between melanomas, naevi and normal skin specimens (P<0·001, false discovery rate q<0·05). Surprisingly, many of these genes are known to have a role in melanocyte development and physiology, melanoma, cancer, and cell growth control. Subsequent class prediction modelling of a training dataset, consisting of 37 melanomas and 37 naevi, discovered a 17-gene classifier that discriminates these skin lesions. Upon testing with an independent dataset, this classifier discerned in situ and invasive melanomas from naevi with 100% sensitivity and 88% specificity, with an area under the curve for the receiver operating characteristic of 0·955. CONCLUSIONS: These results demonstrate that EGIR-harvested specimens can be used to detect melanoma accurately by means of a 17-gene genomic biomarker.


Assuntos
Melanoma/diagnóstico , Neoplasias Cutâneas/diagnóstico , Fita Cirúrgica , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Diagnóstico Diferencial , Diagnóstico Precoce , Feminino , Perfilação da Expressão Gênica/métodos , Humanos , Masculino , Melanoma/genética , Análise em Microsséries , Pessoa de Meia-Idade , Nevo/diagnóstico , Nevo/genética , RNA/genética , Sensibilidade e Especificidade , Neoplasias Cutâneas/genética
6.
Histol Histopathol ; 21(7): 743-52, 2006 07.
Artigo em Inglês | MEDLINE | ID: mdl-16598673

RESUMO

BACKGROUND: Function of the retinoblastoma tumor suppressor protein (pRB) may be compromised at a genetic level by gene loss or mutation or at a post-translational level by hyperphosphorylation. In this study, we examined adult soft tissue sarcomas (ASTS) to determine if alterations of pRB were associated with distinct patterns of pRB expression and clinical outcome. DESIGN: We investigated 86 ASTS patients using monoclonal antibodies that distinguish between hyperphosphorylated and underphosphorylated pRB products. We also used microsatellite analysis to investigate the genetic status of the RB locus. We correlated pRB alterations with proliferative activity, and with clinicopathological outcomes. RESULTS: Altered patterns of pRB expression are common in ASTS occurring in 84% of cases, and it is significantly associated with proliferative activity (p<0.001). Patients whose tumors either lack expression of pRB, or express hyperphosphorylated forms of pRB, have poor survivals compared to patients whose tumors exhibit a normal, underphosphorylated pattern of pRB expression (p=0.03). In addition, 63% of cases lacking expression of pRB showed loss-of-heterozygosity at the locus. CONCLUSIONS: Inactivation of pRB is common in adult STS, which may be due to either gene loss or post-translational modification, namely hyper-phosphorylation. Both mechanisms are associated with tumor cell proliferation and poor survival.


Assuntos
Regulação Neoplásica da Expressão Gênica , Proteína do Retinoblastoma/metabolismo , Sarcoma/metabolismo , Neoplasias de Tecidos Moles/metabolismo , Biomarcadores Tumorais/metabolismo , Proliferação de Células , Humanos , Técnicas Imunoenzimáticas , Perda de Heterozigosidade , Repetições de Microssatélites , Fosforilação , Estudos Prospectivos , Sarcoma/genética , Sarcoma/mortalidade , Sarcoma/patologia , Neoplasias de Tecidos Moles/genética , Neoplasias de Tecidos Moles/mortalidade , Neoplasias de Tecidos Moles/patologia , Taxa de Sobrevida
7.
Br J Dermatol ; 152(3): 512-7, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15787820

RESUMO

BACKGROUND: Large congenital melanocytic naevi (LCMN), which develop in utero and are present in approximately one in 20,000 newborns, are associated with markedly increased risks of cutaneous melanoma, leptomeningeal melanoma and neurocutaneous melanocytosis (NCM). OBJECTIVES: This study examined clinical characteristics associated with melanoma and NCM among patients with LCMN, and estimated the risk of developing melanoma and NCM in these patients. METHODS: Two hundred and five LCMN patients enrolled in the New York University registry were studied. One hundred and seventy of these patients were followed prospectively. The remaining 35 patients had either melanoma at the time of entry into the registry (n = 6), or had insufficient follow-up information (n = 29). The outcome measures were the occurrence of melanoma and NCM. The associations between these outcomes and the clinical covariates (anatomical location of the LCMN, size of the LCMN, number of satellite lesions, family history of melanoma, patient sex and treatment) were assessed. RESULTS: Four of 170 (2.3%) prospectively followed patients developed melanomas, representing a standardized morbidity ratio of 324. Among the entire cohort (n = 205), there were associations between increasing numbers of satellite naevi and the occurrence of melanoma (P = 0.04), and the presence of NCM (P = 0.06). Compared with patients who did not develop these diseases, median LCMN diameters were larger among patients who developed melanoma (49 vs. 39 cm) and NCM (55 vs. 46 cm). CONCLUSIONS: In LCMN patients, increasing numbers of satellite lesions and larger LCMN diameters are associated with melanoma and NCM.


Assuntos
Melanoma/etiologia , Melanose/etiologia , Síndromes Neurocutâneas/etiologia , Nevo Pigmentado/congênito , Neoplasias Cutâneas/congênito , Adolescente , Adulto , Criança , Pré-Escolar , Métodos Epidemiológicos , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Nevo Pigmentado/complicações , Neoplasias Cutâneas/complicações
8.
Clin Exp Dermatol ; 30(1): 68-70, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15663508

RESUMO

Atypical mole syndrome is a sporadic or an inherited condition with an increased risk of melanoma. Germline mutations in the CDKN2A, ARF, CDK4 and somatic mutations in the PTEN and BRAF genes have been associated with melanoma. In this study, we evaluated genes associated with familial and sporadic melanoma for mutations in 28 probands with the atypical mole syndrome. No sequence alterations in the coding regions or in the splice junctions of CDKN2A, ARF, CDK4, PTEN or BRAF were identified. These data suggest that genes evaluated in this study are unlikely to be candidate genes for atypical mole syndrome and support the notion that unknown susceptibility gene/s for this disease exist.


Assuntos
Síndrome do Nevo Displásico/genética , Mutação em Linhagem Germinativa/genética , Melanoma/genética , Pessoa de Meia-Idade , Neoplasias Cutâneas/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Pré-Escolar , Estudos de Coortes , Quinase 4 Dependente de Ciclina , Quinases Ciclina-Dependentes/genética , Feminino , Genes p16 , Humanos , Masculino , PTEN Fosfo-Hidrolase , Linhagem , Monoéster Fosfórico Hidrolases/genética , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas B-raf/genética , Proteína Supressora de Tumor p14ARF/genética , Proteínas Supressoras de Tumor/genética
9.
Cancer Res ; 61(20): 7642-6, 2001 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-11606406

RESUMO

We investigated the role of alterations of HDM2, the human homologue of murine mdm2, in the tumorigenesis and progression of cutaneous melanoma. A well-characterized cohort of 172 cases representing different points in the spectrum of melanocyte transformation (16 dysplastic nevi, 11 melanomas in situ, 107 invasive primaries, and 38 metastatic lesions), as well as 11 human melanoma cell lines were examined by immunohistochemistry and Western blotting for HDM2 protein expression, and by either Southern blotting (SB) or fluorescence in situ hybridization for HDM2 gene amplification. HDM2 overexpression, defined as >20% tumor cells showing nuclear immunoreactivity, was observed in 1 of 16 (6%) dysplastic nevi, 3 of 11 (27%) melanomas in situ, and 81 of 145 (56%) invasive primary and metastatic melanomas. Comparable frequencies of HDM2 overexpression were observed among invasive primary cases with differing tumor thicknesses as well as among the metastatic cases: 21 of 40 (53%) at < or =1.5 mm; 31 of 50 (62%) at 1.6-3.9 mm; 10 of 17 (58%) at >4 mm; and 19 of 38 (50%) metastases. HDM2 amplification was observed in 1 of 88 (1%) primary cases using fluorescence in situ hybridization, and in 0 of 12 (0%) metastatic cases that overexpressed HDM2 using SB. Melanoma cell lines expressed HDM2 protein, but there was no evidence of amplification by SB. Our data suggest that HDM2 protein overexpression is common in invasive and metastatic melanoma. Observing HDM2 overexpression in noninvasive melanoma suggests that expression of this oncogene may play an early role in melanocyte transformation. HDM2 amplification occurs infrequently, and other mechanisms that up-regulate HDM2 expression are under investigation.


Assuntos
Melanoma/metabolismo , Proteínas Nucleares , Proteínas Proto-Oncogênicas/genética , Neoplasias Cutâneas/genética , Transformação Celular Neoplásica/genética , Estudos de Coortes , Síndrome do Nevo Displásico/genética , Síndrome do Nevo Displásico/metabolismo , Amplificação de Genes , Humanos , Imuno-Histoquímica , Melanócitos/metabolismo , Melanócitos/patologia , Melanoma/genética , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas c-mdm2 , Neoplasias Cutâneas/metabolismo , Células Tumorais Cultivadas
10.
Cancer ; 92(4): 869-74, 2001 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-11550160

RESUMO

BACKGROUND: Soft tissue sarcomas (STSs) are heterogeneous neoplasms that have variable clinical outcome. Several clinical parameters and few molecular markers, including Ki-67 proliferative index, have been shown to correlate with patient prognosis. To the authors' knowledge, no definitive report exists to identify one molecular marker that can be analyzed easily in a clinical setting and that predicts survival in a cohort of patients with high-risk STS of identical clinical characteristics but variable outcome. METHODS: The influence of clinical prognostic factors was eliminated by selecting two patient groups with identical high-risk characteristics: large (> 10 cm), high-grade, deep, completely resected primary extremity STS (n = 47). Patients in the first group remained disease free (no evidence of disease [NED]) after primary tumor treatment (n = 19), whereas patients in the second group subsequently died of disease (DOD; n = 28). Triplicate 0.6-mm core biopsies from defined morphologic areas of paraffin embedded primary tumors were assembled on a tissue microarray and analyzed by immunohistochemistry with the MIB-1 antibody, and Ki-67 proliferative indices were correlated with patient outcome. RESULTS: High Ki-67 proliferative index, defined as greater than 30% tumor cells showing nuclear immunoreactivity, was significantly more frequent in the DOD group than in the NED group and was associated with tumor-related mortality (P = 0.02). This marker identifies an especially aggressive malignant phenotype within a cohort of high-risk tumors that is based on well established clinical and pathologic parameters alone and is easy to use in a clinical setting. CONCLUSIONS: On the basis of these data and previous reports, high Ki-67 proliferative index is suggested as a significant factor for predicting the prognosis of patients with high-risk STS and should be evaluated prospectively based on clinical trials.


Assuntos
Antígeno Ki-67/metabolismo , Sarcoma/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Prognóstico , Sarcoma/mortalidade , Sarcoma/patologia , Análise de Sobrevida
11.
Cancer Res ; 61(16): 6008-11, 2001 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-11507043

RESUMO

The helix-loop-helix transcription factor Id1 coordinates cell growth and differentiation pathways within mammalian cells and has been implicated in regulating G(1)-S phase cell cycle transitions. Recently Id1 has been shown to repress Ets- and E-protein-mediated transactivation of p16/Ink4a. Because the p16/Ink4a protein has been demonstrated to be inactivated in subsets of familial and sporadic melanomas, we sought to determine whether Id1 regulation of p16/Ink4a expression might be involved in the development of this human tumor. Here we evaluate 21 melanocytic lesions at various stages of malignant progression from common melanocytic nevi to metastatic melanomas and examine these lesions for Id1 and p16/Ink4a expression. We demonstrate that Id1 expression correlates with loss of p16/Ink4a expression in melanoma in situ; however, more advanced stages of melanoma do not express Id1 except within perivascular regions, despite overall decreased p16/Ink4a expression in these lesions. Microdissected lesions were evaluated for p16/Ink4a sequence, and invasive melanomas that did not express Id1 were found to have sustained inactivating p16/ink4a mutations. These data suggest a role for Id1 in regulating p16/Ink4a expression in early melanomas and demonstrate that later genetic changes may provide for irreversible loss of p16 expression in advanced stages of this tumor.


Assuntos
Proteínas de Ligação a DNA/fisiologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Genes p16/genética , Melanoma/genética , Proteínas Repressoras , Fatores de Transcrição/fisiologia , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Inibidor p16 de Quinase Dependente de Ciclina/genética , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Humanos , Proteína 1 Inibidora de Diferenciação , Melanoma/metabolismo , Melanoma/patologia , Estadiamento de Neoplasias , Análise de Sequência de DNA , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Regulação para Cima
12.
J Am Acad Dermatol ; 44(5): 767-74, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11312422

RESUMO

BACKGROUND: The public has long been instructed to wear protective clothing against ultraviolet (UV) damage. OBJECTIVE: Our purpose was to determine the UV protection factor (UPF) of two cotton fabrics used in the manufacture of summer T-shirts and to explore methods that could improve the UPF of these fabrics. METHODS: Each of the two types of white cotton fabrics (cotton T-shirt and mercerized cotton print cloth) used in this study was divided into 4 treatment groups: (1) water-only (machine washed with water), (2) detergent-only (washed with detergent), (3) detergent-UV absorber (washed with detergent and a UV absorber), and (4) dyes (dyed fabrics). Ultraviolet transmission through the fabrics was measured with a spectrophotometer before and after laundry and dyeing treatments. Based on UV transmission through these fabrics, the UPF values were calculated. RESULTS: Before any treatments, the mean UPFs were 4.94 for the T-shirt fabric and 3.13 for the print cloth. There was greater UVA (320-400 nm) than UVB (280-320 nm) transmission through these fabrics. After 5 washings with water alone and with detergent alone, UPF increased by 51% and 17%, respectively, for the cotton T-shirt fabric. Washing the T-shirt fabrics with detergent plus the UV-absorbing agent increased the UPF by 407% after 5 treatments. Dyeing the fabric blue or yellow increased the UPF by 544% and 212%, respectively. Similar changes in UPFs were observed for the print cloth fabric. CONCLUSION: The two cotton fabrics used in this study offered limited protection against UV radiation as determined by spectrophotometric analysis. Laundering with detergent and water improves UPF slightly by causing fabric shrinkage. Dyeing fabrics or adding a UV-absorbing agent during laundering substantially reduces UV transmission and increases UPF. More UVA is transmitted through the fabrics than UVB.


Assuntos
Roupa de Proteção , Queimadura Solar/prevenção & controle , Raios Ultravioleta , Corantes , Detergentes , Gossypium , Humanos
13.
J Am Acad Dermatol ; 44(5): 837-46, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11312434

RESUMO

The incidence and mortality rates of melanoma have risen for many decades in the United States. Increased exposure to ultraviolet (UV) radiation is generally considered to be responsible. Sunburns, a measure of excess sun exposure, have been identified as a risk factor for the development of melanoma. Because sunburns are primarily due to UVB (280-320 nm) radiation, UVB has been implicated as a potential contributing factor to the pathogenesis of melanoma. The adverse role of UVA (320-400 nm) in this regard is less well studied, and currently there is a great deal of controversy regarding the relationship between UVA exposure and the development of melanoma. This article reviews evidence in the English-language literature that surrounds the controversy concerning a possible role for UVA in the origin of melanoma. Our search found that UVA causes DNA damage via photosensitized reactions that result in the production of oxygen radical species. UVA can induce mutations in various cultured cell lines. Furthermore, in two animal models, the hybrid Xiphophorus fish and the opossum (Mondelphis domestica), melanomas and melanoma precursors can be induced with UVA. UVA radiation has been reported to produce immunosuppression in laboratory animals and in humans. Some epidemiologic studies have reported an increase in melanomas in users of sunbeds and sunscreens and in patients exposed to psoralen and UVA (PUVA) therapy. There is basic scientific evidence of the harmful effects of UVA on DNA, cells and animals. Collectively, these data suggest a potential role for UVA in the pathogenesis of melanoma. To date evidence from epidemiologic studies and clinical observations are inconclusive but seem to be consistent with this hypothesis. Additional research on the possible role of UVA in the pathogenesis of melanoma is required.


Assuntos
Melanoma/etiologia , Neoplasias Cutâneas/etiologia , Raios Ultravioleta/efeitos adversos , Animais , Modelos Animais de Doenças , Humanos , Incidência , Melanoma/epidemiologia , Neoplasias Cutâneas/epidemiologia , Estados Unidos/epidemiologia
14.
Nature ; 409(6817): 207-11, 2001 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-11196646

RESUMO

Metastatic melanoma is a deadly cancer that fails to respond to conventional chemotherapy and is poorly understood at the molecular level. p53 mutations often occur in aggressive and chemoresistant cancers but are rarely observed in melanoma. Here we show that metastatic melanomas often lose Apaf-1, a cell-death effector that acts with cytochrome c and caspase-9 to mediate p53-dependent apoptosis. Loss of Apaf-1 expression is accompanied by allelic loss in metastatic melanomas, but can be recovered in melanoma cell lines by treatment with the methylation inhibitor 5-aza-2'-deoxycytidine (5aza2dC). Apaf-1-negative melanomas are invariably chemoresistant and are unable to execute a typical apoptotic programme in response to p53 activation. Restoring physiological levels of Apaf-1 through gene transfer or 5aza2dC treatment markedly enhances chemosensitivity and rescues the apoptotic defects associated with Apaf-1 loss. We conclude that Apaf-1 is inactivated in metastatic melanomas, which leads to defects in the execution of apoptotic cell death. Apaf-1 loss may contribute to the low frequency of p53 mutations observed in this highly chemoresistant tumour type.


Assuntos
Apoptose , Melanoma/metabolismo , Proteínas/metabolismo , Antineoplásicos/farmacologia , Fator Apoptótico 1 Ativador de Proteases , Caspase 9 , Caspases/metabolismo , Cromossomos Humanos Par 12 , Clonagem Molecular , Metilação de DNA , DNA de Neoplasias/metabolismo , Doxorrubicina/farmacologia , Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Genes p53 , Humanos , Perda de Heterozigosidade , Melanoma/patologia , Melanoma/secundário , Mutação , Proteínas/genética , Células Tumorais Cultivadas
15.
Genes Dev ; 11(21): 2822-34, 1997 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-9353252

RESUMO

The familial melanoma gene (INK4a/MTS1/CDKN2) encodes potent tumor suppressor activity. Although mice null for the ink4a homolog develop a cancer-prone condition, a pathogenetic link to melanoma susceptibility has yet to be established. Here we report that mice with melanocyte-specific expression of activated H-rasG12V on an ink4a-deficient background develop spontaneous cutaneous melanomas after a short latency and with high penetrance. Consistent loss of the wild-type ink4a allele was observed in tumors arising in ink4a heterozygous transgenic mice. No homozygous deletion of the neighboring ink4b gene was detected. Moreover, as in human melanomas, the p53 gene remained in a wild-type configuration with no observed mutation or allelic loss. These results show that loss of ink4a and activation of Ras can cooperate to accelerate the development of melanoma and provide the first in vivo experimental evidence for a causal relationship between ink4a deficiency and the pathogenesis of melanoma. In addition, this mouse model affords a system in which to identify and analyze pathways involved in tumor progression against the backdrop of genetic alterations encountered in human melanomas.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/genética , Neoplasias Oculares/genética , Genes p16 , Genes ras , Melanoma/genética , Neoplasias Cutâneas/genética , Animais , Inibidor p16 de Quinase Dependente de Ciclina/biossíntese , Inibidor p16 de Quinase Dependente de Ciclina/deficiência , Primers do DNA , Suscetibilidade a Doenças , Éxons , Neoplasias Oculares/patologia , Humanos , Melanoma/patologia , Melanoma/fisiopatologia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Reação em Cadeia da Polimerase , Neoplasias Cutâneas/patologia
16.
Proc Natl Acad Sci U S A ; 88(20): 9243-7, 1991 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-1924388

RESUMO

Mice homozygous for the H-2d haplotype at the major histocompatibility complex are markedly more susceptible to erythroleukemia induction by the Friend isolate of murine leukemia retrovirus (FV) than are congenic mice homozygous for the H-2b haplotype. The resistance conferred by the H-2b haplotype is recessive in this cross, since heterozygous F1 mice are as susceptible as parental strain H-2d homozygotes. However, H-2b-associated resistance is not an intrinsically recessive trait, since H-2b/H-2dm1 heterozygotes resemble H-2b homozygotes in their relative resistance to FV; the mutant H-2dm1 haplotype lacks the entire D region of the parental haplotype except for a single class I gene formed by the fusion of its terminal D-region genes to produce a class I gene differing from both parental genes, and thus this finding indicates that one or more D-region genes of the H-2d haplotype can actively suppress H-2b-associated resistance. Unlike H-2dm1, the mutant H-2dm2 haplotype, which retains only the class IDd gene in the D region of the H-2d haplotype, strongly suppresses resistance in H-2b/H-2dm2 heterozygotes, and the presence of Dd as a transgene significantly reduces the resistance of H-2b homozygotes. Since H-2b-associated resistance to FV appears to be due mainly to the capacity of Lb (also called Db), the only class I molecule encoded in the D region of the H-2b haplotype, to present viral epitopes for recognition by FV-specific cytotoxic T lymphocytes, suppression of resistance to FV by the Dd molecule implies that the presence of one class I molecule of the major histocompatibility complex can interfere with either the presentation of viral epitopes by another class I molecule or the generation of T cells that recognize viral epitopes so presented.


Assuntos
Vírus da Leucemia Murina de Friend/patogenicidade , Genes MHC Classe I , Antígenos H-2/genética , Leucemia Experimental/imunologia , Animais , Deleção Cromossômica , Vírus da Leucemia Murina de Friend/imunologia , Predisposição Genética para Doença , Haplótipos , Leucemia Experimental/microbiologia , Camundongos , Camundongos Endogâmicos , Camundongos Mutantes , Especificidade da Espécie , Esplenomegalia/imunologia
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