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1.
Am J Dermatopathol ; 41(4): 264-272, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30211730

RESUMEN

Telomerase reverse transcriptase (TERT) promoter mutations are commonly found in malignant melanomas but rare in melanocytic nevi. To assess its potential diagnostic utility for the distinction of melanoma from nevus, we determined the TERT promoter mutation status of 86 primary melanomas, 72 melanocytic nevi, and 40 diagnostically problematic melanocytic proliferations. Of the 86 melanomas, 67 (77.9%) were TERT-positive, defined as harboring a hotspot TERT promoter mutation at positions -124C>T, -124_125CC>TT, -138_139CC>TT, or -146C>T. Of the 72 nevi, only 1 (1.4%) was TERT-positive. Of the 40 diagnostically uncertain melanocytic proliferations, 2 (5.0%) were TERT-positive. TERT positivity as a test for melanoma versus nevus had an accuracy of 87.3% [95% confidence interval (CI), 81.1-92.1], a sensitivity of 77.9% (95% CI, 68.9-85.4), a specificity of 98.6% (95% CI, 95.8-100), a positive predictive value of 98.5% (95% CI, 95.6-100), and a negative predictive value of 78.9% (95% CI, 72.6-85.4). Our results indicate that hotspot TERT promoter mutation status may be a useful ancillary parameter for the diagnosis of melanoma. In particular, the high specificity of these mutations for melanoma indicates the presence of a TERT promoter mutation in a melanocytic neoplasm associated with diagnostic controversy, or uncertainty should increase concern for a melanoma.


Asunto(s)
Melanoma/diagnóstico , Melanoma/genética , Regiones Promotoras Genéticas/genética , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/genética , Telomerasa/genética , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mutación , Nevo Pigmentado/diagnóstico , Nevo Pigmentado/genética , Melanoma Cutáneo Maligno
2.
Pediatr Dermatol ; 33(2): e106-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27001331

RESUMEN

Hair follicle nevi are rare, benign, congenital hamartomas that usually occur in the distribution of the first brachial arch. Histopathologically, the distinction between hair follicle nevus, trichofolliculoma, and accessory tragus has recently come into question, and it may be that they are all on a spectrum of the same condition. We report the case of a 7-day-old boy who presented with a "tag"-like lesion on his midline chin that had been present since birth. Biopsy of the lesion proved it to be a hair follicle nevus.


Asunto(s)
Enfermedades del Cabello/patología , Folículo Piloso/patología , Nevo/patología , Neoplasias Cutáneas/patología , Mentón/patología , Diagnóstico Diferencial , Humanos , Lactante , Recién Nacido , Masculino
3.
Cutis ; 95(6): 349-51, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26125212

RESUMEN

Imiquimod is a topical immunomodulator used to treat genital warts and cutaneous malignancies that exerts its effects via induction of proinflammatory cytokines through activation of toll-like receptor (TLR) 7. Although subacute cutaneous lupus erythematosus (SCLE) has been reported in association with multiple systemic medications, SCLE in patients treated with topical agents has not been widely reported. We report the case of a 50-year-old woman with local induction of lesions that clinically and histologically resembled SCLE following treatment with topical imiquimod.


Asunto(s)
Aminoquinolinas/efectos adversos , Factores Inmunológicos/efectos adversos , Lupus Eritematoso Cutáneo/inducido químicamente , Femenino , Humanos , Imiquimod , Lupus Eritematoso Cutáneo/patología , Persona de Mediana Edad
4.
J Cutan Pathol ; 41(9): 724-32, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24917033

RESUMEN

BACKGROUND: BRAF mutation status, and therefore eligibility for BRAF inhibitors, is currently determined by sequencing methods. We assessed the validity of VE1, a monoclonal antibody against the BRAF V600E mutant protein, in the detection of mutant BRAF V600E melanomas as classified by DNA pyrosequencing. METHODS: The cases were 76 metastatic melanoma patients with only one known primary melanoma who had had BRAF codon 600 pyrosequencing of either their primary (n = 19), metastatic (n = 57) melanoma, or both (n = 17). All melanomas (n = 93) were immunostained with the BRAF VE1 antibody using a red detection system. The staining intensity of these specimens was scored from 0 to 3+ by a dermatopathologist. Scores of 0 and 1+ were considered as negative staining while scores of 2+ and 3+ were considered positive. RESULTS: The VE1 antibody showed a sensitivity of 85% and a specificity of 100% as compared to DNA pyrosequencing results. There was 100% concordance between VE1 immunostaining of primary and metastatic melanomas from the same patient. V600K, V600Q, and V600R BRAF melanomas did not positively stain with VE1. CONCLUSIONS: This hospital-based study finds high sensitivity and specificity for the BRAF VE1 immunostain in comparison to pyrosequencing in detection of BRAF V600E in melanomas.


Asunto(s)
Anticuerpos Monoclonales , Inmunohistoquímica , Melanoma/diagnóstico , Proteínas Proto-Oncogénicas B-raf/metabolismo , Neoplasias Cutáneas/diagnóstico , Biomarcadores de Tumor/metabolismo , Humanos , Melanoma/genética , Melanoma/metabolismo , Mutación , Proteínas Proto-Oncogénicas B-raf/genética , Sensibilidad y Especificidad , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo
5.
Pediatr Dermatol ; 30(5): 608-13, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24016284

RESUMEN

Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe drug-induced hypersensitivity syndrome that presents with diffuse cutaneous eruptions, fever, and multiorgan involvement. Here we present a pediatric case of DRESS complicated by human herpesvirus (HHV)-6 reactivation. After 1 week of sulfasalazine, our patient developed a diffuse morbilliform eruption. Sulfasalazine was discontinued. The patient presented to the emergency department soon thereafter with worsening eruption, fever, rigors, facial edema, and lymphadenopathy. Methylprednisolone was initiated. Peripheral smear did not demonstrate eosinophilia but showed toxic granulation with atypical lymphocytes. Transaminase levels and white blood cell count quickly became elevated, with increased eosinophils, suggesting DRESS. During the methylprednisolone taper, our patient experienced symptom exacerbation, acute hepatitis, and HHV-6 seroconversion, indicating HHV-6 reactivation as the cause. As demonstrated by our patient, a decelerated methylprednisone taper is important because of potential symptom flaring during taper. Additionally, in the care of individuals with DRESS, HHV-6 is often tested for upon admission and not repeated. Delay in the rise of titers necessitates repeat testing.


Asunto(s)
Síndrome de Hipersensibilidad a Medicamentos/patología , Síndrome de Hipersensibilidad a Medicamentos/virología , Eosinofilia/virología , Exantema Súbito/patología , Herpesvirus Humano 6/fisiología , Activación Viral , Adolescente , Eosinofilia/patología , Humanos , Masculino
7.
Pediatr Dermatol ; 29(2): 169-76, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22066977

RESUMEN

Lupus erythematosus panniculitis (LEP) is a rare finding in children, with only 12 fully reported prior cases in the English literature. We describe three cases of LEP in children younger than 18 and compare them to previous cases reported in the literature. We examine laboratory tests performed, biopsy results, age at onset and diagnosis, presence or absence of systemic symptoms, and outcomes after treatment. It is unknown what the risk is of these patients developing future systemic lupus erythematosus. We also discuss the relevance of subcutaneous panniculitis-like T-cell lymphoma, because the clinical and pathologic pictures are similar in presentation.


Asunto(s)
Paniculitis de Lupus Eritematoso/diagnóstico , Paniculitis de Lupus Eritematoso/tratamiento farmacológico , Adolescente , Biopsia , Preescolar , Fármacos Dermatológicos/uso terapéutico , Quimioterapia Combinada , Femenino , Humanos , Hidroxicloroquina/uso terapéutico , Paniculitis de Lupus Eritematoso/patología , Prednisolona/uso terapéutico , Resultado del Tratamiento
9.
J Am Acad Dermatol ; 62(2): 257-61, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19962786

RESUMEN

BACKGROUND: Accurate clinicopathologic correlation can be crucial to arriving at the correct microscopic diagnosis. OBJECTIVE: We reviewed the clinical information provided on the dermatopathology requisition forms for melanocytic lesions submitted by community dermatologists. METHODS: The clinical information provided and the microscopic diagnoses rendered were recorded in a retrospective, unblinded fashion for 100 consecutive melanocytic lesions submitted as wet tissue to our dermatopathology department. RESULTS: Biopsy specimens were received from 60 community dermatologists and 5 nurse practitioners/physician assistants. Clinical morphology (ie, papule) was provided in 33% of cases. With respect to the ABCDE criteria, 55% of cases had none, 12% had one criterion, 21% had two criteria, 10% had 3 criteria, 2% had 4 criteria, and none had all 5 criteria. No forms stated whether the biopsy specimen was a partial or complete sampling of the lesion. Asymmetry was provided 4% of the time, border irregularity 8%, color 39%, diameter 22%, and evolution 10%. A family or personal history of melanoma was provided in 8% of cases. No requisition forms mentioned the "ugly duckling" sign. Dermatoscopy information and a clinical photograph were provided once each. In 19 cases, the only information on the requisition form was one of the phrases: "r/o atypia," "r/o atypical nevus," "r/o Clark's," or "r/o dysplastic nevus." In 10 cases, the only information was "r/o nevus." LIMITATIONS: Only 100 consecutive melanocytic lesions were studied in a retrospective, unblinded fashion. CONCLUSION: Important clinical information regarding pigmented lesions is often not provided on the requisition form. Potential reasons for this deficit and suggestions for improvement are discussed.


Asunto(s)
Dermatología , Registros Médicos/normas , Melanoma/patología , Derivación y Consulta/normas , Enfermedades de la Piel/patología , Neoplasias Cutáneas/patología , Biopsia , Humanos , Patología Clínica , Piel/patología , Enfermedades de la Piel/diagnóstico , Neoplasias Cutáneas/diagnóstico
10.
J Cutan Pathol ; 37(2): 292-6, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19614999

RESUMEN

Dermal mucinoses are a heterogeneous group of disorders characterized by abnormal deposition of dermal mucin, an amorphous substance composed of hyaluronic acid and sulfated glycosaminoglycans. We describe two cases of dermal mucinosis in the setting of chronic venous insufficiency. Both patients presented with painful, edematous lower extremity plaques. Biopsies of all lesions showed striking dermal mucin deposition, a slight increase in small blood vessel density, slightly thickened vessel walls and no inflammation. Neither patient showed laboratory or clinical findings consistent with a secondary mucinosis such as thyroid dysfunction, lupus erythematosus, dermatomyositis, scleroderma, granuloma annulare, graft-vs.-host disease or mucin deposition post-ultraviolet or photochemotherapy treatment. Both patients were diagnosed with localized cutaneous mucinosis secondary to venous insufficiency. The clinicopathological features of this entity are described, and a pathogenic mechanism is proposed.


Asunto(s)
Pierna/patología , Mucinosis/patología , Piel/patología , Muslo/patología , Insuficiencia Venosa/patología , Anciano , Humanos , Masculino , Persona de Mediana Edad , Mucinosis/complicaciones , Insuficiencia Venosa/complicaciones
11.
J Cutan Pathol ; 36(11): 1185-90, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19469877

RESUMEN

BACKGROUND: Cellular neurothekeoma is a benign lesion most commonly found on the face and upper extremities in the first two decades of life. METHODS: Retrospective clinicopathologic review of 12 examples of cellular neurothekeoma typified by prominent stromal sclerosis, a distinctive variant that we refer to as desmoplastic cellular neurothekeoma. RESULTS: The mean age was 30 years (range, 3-55 years, 3 males, 9 females). The site was the head and neck in 3 cases, upper extremity in 4, lower extremity in 2, and trunk/abdomen in 3. All cases showed fascicles of slightly spindled and polygonal cells arrayed haphazardly in a prominent sclerotic background in the dermis and superficial subcutis. The cells displayed pale cytoplasm with indistinct membranes and vesicular nuclei with a single nucleolus. Lesional cells expressed NKI/C3, laminin, CD68, and CD10 and lacked expression of S-100 protein, EMA, and CD34. Clinical follow up was available on 10 cases with a mean duration of 24 months (range, 11-42 months) with no local recurrences or metastases. CONCLUSIONS: The immunohistochemical staining pattern, clinical findings, and benign nature are similar to "conventional" cellular neurothekeomas. The differential diagnosis includes desmoplastic melanocytic lesions, desmoplastic spindle cell carcinoma, dermatofibroma, "immature" scar, plexiform fibrohistiocytic tumor, perineurioma, and piloleiomyoma.


Asunto(s)
Neurotecoma/patología , Neoplasias Cutáneas/patología , Adolescente , Adulto , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neurotecoma/metabolismo , Neoplasias Cutáneas/metabolismo , Adulto Joven
12.
Dermatol Online J ; 15(10): 14, 2009 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-19951632

RESUMEN

Angiokeratomas are benign proliferations of dilated thin-walled blood vessels in the upper dermis with overlying epidermal hyperkeratosis. There are several clinical variants of angiokeratomas: 1. Fordyce: smooth reddish-purple papules on scrotum or vulva; 2. Mibelli: hyperkeratotic papules on fingers or toes, solitary, multiple, or circumscriptum (grouped papules usually on an extremity); 4. angiokeratoma corporis diffusum, widespread papules that are a manifestation of one of several inherited lysozomal storage diseases. Herein, we report a rare case of multiple angiokeratomas of Fordyce on the corona of the glans penis.


Asunto(s)
Angioqueratoma/patología , Neoplasias del Pene/patología , Neoplasias Cutáneas/patología , Humanos , Masculino , Persona de Mediana Edad
13.
J Invest Dermatol ; 139(6): 1349-1361, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30529013

RESUMEN

Early diagnosis improves melanoma survival, yet the histopathological diagnosis of cutaneous primary melanoma can be challenging, even for expert dermatopathologists. Analysis of epigenetic alterations, such as DNA methylation, that occur in melanoma can aid in its early diagnosis. Using a genome-wide methylation screening, we assessed CpG methylation in a diverse set of 89 primary invasive melanomas, 73 nevi, and 41 melanocytic proliferations of uncertain malignant potential, classified based on interobserver review by dermatopathologists. Melanomas and nevi were split into training and validation sets. Predictive modeling in the training set using ElasticNet identified a 40-CpG classifier distinguishing 60 melanomas from 48 nevi. High diagnostic accuracy (area under the receiver operator characteristic curve = 0.996, sensitivity = 96.6%, and specificity = 100.0%) was independently confirmed in the validation set (29 melanomas, 25 nevi) and other published sample sets. The 40-CpG melanoma classifier included homeobox transcription factors and genes with roles in stem cell pluripotency or the nervous system. Application of the 40-CpG melanoma classifier to the diagnostically uncertain samples assigned melanoma or nevus status, potentially offering a diagnostic tool to assist dermatopathologists. In summary, the robust, accurate 40-CpG melanoma classifier offers a promising assay for improving primary melanoma diagnosis.


Asunto(s)
Biomarcadores de Tumor/genética , Metilación de ADN , Epigenómica/métodos , Melanoma/diagnóstico , Neoplasias Cutáneas/diagnóstico , Algoritmos , Islas de CpG/genética , Diagnóstico Diferencial , Epigénesis Genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Masculino , Melanoma/genética , Melanoma/patología , Persona de Mediana Edad , Nevo/diagnóstico , Nevo/genética , Nevo/patología , Curva ROC , Estudios Retrospectivos , Piel/patología , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología
14.
J Am Acad Dermatol ; 58(1): 49-55, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17919774

RESUMEN

BACKGROUND: Many complications have been reported after orf infection, including lymphadenopathy, secondary bacterial infection, and erythema multiforme. Rare associations with papulovesicular eruptions, including a bullous pemphigoid-like eruption, have also been described. OBJECTIVES: Our purpose was to clinically, histologically, and immunologically characterize two cases of orf-induced blistering disease, and to determine whether this condition represented a novel disease entity distinct from known immunobullous diseases. METHODS: Two patients were clinically described and skin biopsy specimens were collected for routine histology, direct immunofluorescence studies, and polymerase chain reaction analysis to detect orf viral DNA. Patients' sera were assessed for autoantibodies by indirect immunofluorescence studies using normal-appearing human salt-split skin, by Western blot analysis using keratinocyte extracts, dermal extracts, and recombinant type VII collagen, and immunoprecipitation studies of extracts from biosynthetically radiolabeled human keratinocytes. RESULTS: Two distinctive cases of severe, diffuse blistering eruptions after orf infection are described. In one patient, orf virus DNA was detected in the inciting orf lesion, but not in blistered skin, ruling out disseminated orf infection as a cause of the blisters. In both cases, histology revealed subepidermal blisters with mixed inflammatory cell infiltrates containing neutrophils and eosinophils, direct immunofluorescence microscopy studies demonstrated IgG and C3 deposited at the dermoepidermal junctions of perilesional skin, and indirect immunofluorescence studies demonstrated circulating antibasement membrane IgG that bound the dermal side of salt-split skin. Extensive immunoblot and immunoprecipitation studies failed to reveal a consistent, identifiable autoantigen. LIMITATIONS: We describe only two cases. The autoantigen recognized by circulating autoantibodies was not identified. CONCLUSIONS: Orf-induced immunobullous disease is a unique disease entity that is clinically and immunologically distinct from bullous pemphigoid, epidermolysis bullosa acquisita, and other known immunobullous conditions.


Asunto(s)
Enfermedades Autoinmunes/fisiopatología , Enfermedades Autoinmunes/virología , Ectima Contagioso/complicaciones , Enfermedades Cutáneas Vesiculoampollosas/fisiopatología , Enfermedades Cutáneas Vesiculoampollosas/virología , Piel/patología , Adulto , Enfermedades Autoinmunes/inmunología , Enfermedades Autoinmunes/patología , Membrana Basal/inmunología , Complemento C3/metabolismo , ADN Viral/análisis , Femenino , Técnica del Anticuerpo Fluorescente Directa , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Inmunoglobulina G/inmunología , Inmunoglobulina G/metabolismo , Masculino , Pruebas de Sensibilidad Microbiana , Microscopía Fluorescente , Persona de Mediana Edad , Virus del Orf/genética , Piel/metabolismo , Enfermedades Cutáneas Vesiculoampollosas/inmunología , Enfermedades Cutáneas Vesiculoampollosas/patología
15.
J Am Acad Dermatol ; 56(6): 1013-20, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17504718

RESUMEN

BACKGROUND: The clinical distribution and character of cutaneous lupus erythematosus lesions can simulate squamous neoplasms, leading physicians to submit a shave biopsy specimen with a differential diagnosis of squamous neoplasm. OBJECTIVE: Our aim was to describe histologic features of interface dermatitis that cause difficulty in distinguishing between cutaneous lupus erythematosus and squamous neoplasia in shave biopsy specimens and to identify distinguishing criteria. METHODS: Twenty-six biopsy specimens from 10 patients initially diagnosed with squamous neoplasia that ultimately proved to be cutaneous lupus erythematosus were identified. Comparisons were made of these to 38 control biopsies of chronic cutaneous lupus erythematosus and 34 control biopsies of keratoses/carcinomas without lupus. All biopsies were scored (0 or 1: absent or present) with respect to 11 histologic criteria. RESULTS: The criteria of perifollicular inflammation, follicular plugging, vacuolar interface change, compact orthokeratosis, and acrosyringeal inflammation were significantly more common in the lupus cases than in the keratoses/carcinomas controls. The mean lupus case score was 6.88, lupus control score 6.55, and keratoses/carcinomas control score 5.08. LIMITATIONS: A limited number of patients were studied. Microscopic observations and assumptions with inherent subjectivity were used in establishing the histologic scores. CONCLUSION: Use of the criteria presented, although not absolute, should alert one to the possibility of lupus in an atypical squamous proliferation, especially in suspected squamous neoplasms that worsen or recur after therapy.


Asunto(s)
Carcinoma de Células Escamosas/diagnóstico , Lupus Eritematoso Cutáneo/patología , Neoplasias Cutáneas/patología , Adulto , Anciano , Anciano de 80 o más Años , Biopsia , Carcinoma Basocelular/patología , Dermatitis/patología , Diagnóstico Diferencial , Epidermis/patología , Femenino , Humanos , Hiperplasia , Queratosis/patología , Masculino , Persona de Mediana Edad
16.
J Neuroimmunol ; 278: 108-11, 2015 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-25595259

RESUMEN

IMPORTANCE: This is the first report of neuromyelitis optica spectrum disorder (NMOSD) associated with dermatomyositis (DM). REPORT: A 40year-old Caucasian female presented with 6months of worsening fatigue, rash, acute weakness worse in her lower extremities, and urinary retention. She was found to have both NMOSD and anti-melanoma differentiation-associated gene (MDA)5 positive DM with interstitial lung disease (ILD). She was treated aggressively and she regained her ability to ambulate. CONCLUSION: We recommend considering NMOSD in the differential diagnosis of patients with DM and other autoimmune disorders that also present with clinical signs of myelopathy.


Asunto(s)
Dermatomiositis/diagnóstico , Neuromielitis Óptica/fisiopatología , Adulto , Anticuerpos/sangre , ARN Helicasas DEAD-box/inmunología , Dermatomiositis/sangre , Femenino , Humanos , Helicasa Inducida por Interferón IFIH1 , Imagen por Resonancia Magnética , Piel/patología , Médula Espinal/patología
17.
J Invest Dermatol ; 135(6): 1590-1597, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25695683

RESUMEN

There are two major clinical subsets of pemphigus vulgaris (PV)-mucosal PV (mPV) and mucocutaneous PV (mcPV). The mPV subset exhibits anti-human desmoglein (Dsg) 3 autoantibodies that fail to recognize murine Dsg3 (mDsg3); thus, passive transfer experiments of mPV IgG into wild-type (WT) mice have been unsuccessful at inducing disease. We therefore generated a fully humanized Dsg3 (hDSG3) murine model utilizing a hDsg3 transgenic animal crossed to the mDsg3 knockout line. Expression of hDsg3 in the mucosa rescues the mDsg3 knockout phenotype. Well-characterized mPV sera bind mucosal epithelia from the hDsg3 mice, but not mucosal tissues from WT mice, as detected by indirect immunofluorescence (IF). The majority of mPV sera preferentially recognize hDsg3 compared with mDsg3 by immunoprecipitation as well. Passive transfer of mPV IgG into adult hDsg3 mice, but not WT mice, induces suprabasilar acantholysis in mucosal tissues, thus confirming the pathogenicity of mPV anti-hDsg3 IgG in vivo. Human anti-hDsg3 antibodies are detected in perilesional mucosa as well as in sera of recipient mice by IF. These findings suggest that the Dsg3 epitopes targeted by pathogenic mPV IgG are human specific. This hDsg3 mouse model will be invaluable in studying the clinical transition from mPV to mcPV.


Asunto(s)
Desmogleína 3/genética , Inmunoglobulina G/química , Pénfigo/inmunología , Animales , Autoanticuerpos/química , Cromosomas Artificiales Bacterianos , Desmogleína 1/metabolismo , Desmogleína 3/metabolismo , Epitelio/metabolismo , Epítopos/química , Técnica del Anticuerpo Fluorescente Indirecta , Humanos , Inmunoprecipitación , Ratones , Ratones Noqueados , Ratones Transgénicos , Mucosa Bucal/metabolismo , Membrana Mucosa/metabolismo , Fenotipo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
19.
Cancer Discov ; 4(12): 1418-29, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25252692

RESUMEN

UNLABELLED: NRAS mutation at codons 12, 13, or 61 is associated with transformation; yet, in melanoma, such alterations are nearly exclusive to codon 61. Here, we compared the melanoma susceptibility of an NrasQ61R knock-in allele to similarly designed KrasG12D and NrasG12D alleles. With concomitant p16INK4a inactivation, KrasG12D or NrasQ61R expression efficiently promoted melanoma in vivo, whereas NrasG12D did not. In addition, NrasQ61R mutation potently cooperated with Lkb1/Stk11 loss to induce highly metastatic disease. Functional comparisons of NrasQ61R and NrasG12D revealed little difference in the ability of these proteins to engage PI3K or RAF. Instead, NrasQ61R showed enhanced nucleotide binding, decreased intrinsic GTPase activity, and increased stability when compared with NrasG12D. This work identifies a faithful model of human NRAS-mutant melanoma, and suggests that the increased melanomagenecity of NrasQ61R over NrasG12D is due to heightened abundance of the active, GTP-bound form rather than differences in the engagement of downstream effector pathways. SIGNIFICANCE: This work explains the curious predominance in human melanoma of mutations of codon 61 of NRAS over other oncogenic NRAS mutations. Using conditional "knock-in" mouse models, we show that physiologic expression of NRASQ61R, but not NRASG12D, drives melanoma formation.


Asunto(s)
Transformación Celular Neoplásica/genética , Codón , Genes ras , Melanoma/genética , Mutación , Quinasas de la Proteína-Quinasa Activada por el AMP , Alelos , Animales , Línea Celular Tumoral , Transformación Celular Neoplásica/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Eliminación de Gen , Orden Génico , Sitios Genéticos , Genotipo , Guanosina Trifosfato/metabolismo , Humanos , Melanoma/metabolismo , Melanoma/mortalidad , Melanoma/patología , Ratones , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Metástasis de la Neoplasia , Proteínas de Fusión Oncogénica/genética , Proteínas de Fusión Oncogénica/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Unión Proteica , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , Carga Tumoral
20.
Clin Lab Med ; 31(2): 311-20, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21549244

RESUMEN

Spitz nevi and melanoma represent benign and malignant counterparts commonly coupled in the same differential diagnosis. The precise distinction between the two entities remains an ongoing challenge in dermatopathology and surgical pathology. In past years, considerable work has been devoted to the assembly of criteria to permit exact diagnosis. Although diagnostic accuracy has improved, many lesions remain challenging to classify based solely upon conventional microscopic criteria. In this article, the clinical and histopathological attributes of Spitz nevi and spitzoid melanoma are reviewed. Lesions that cannot be definitively classified based solely upon conventional microscopic criteria are referred to as atypical spitzoid neoplasms, which the authors view as a provisional diagnostic category rather than as a formal disease entity. Molecular assessment by way of comparative genomic hybridization or fluorescence in situ hybridization is increasingly used to facilitate assessment of this challenging differential and is especially germane to the evaluation of ambiguous lesions.


Asunto(s)
Melanoma/patología , Nevo de Células Epitelioides y Fusiformes/patología , Neoplasias Cutáneas/patología , Adolescente , Adulto , Preescolar , Diagnóstico Diferencial , Histocitoquímica , Humanos , Hibridación Fluorescente in Situ , Masculino , Melanoma/diagnóstico , Nevo de Células Epitelioides y Fusiformes/diagnóstico , Pronóstico , Neoplasias Cutáneas/diagnóstico
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