GAB2 induces tumor angiogenesis in NRAS-driven melanoma.

GAB2 is a scaffold protein with diverse upstream and downstream effectors. MAPK and PI3K signaling pathways are known effectors of GAB2. It is amplified and overexpressed in a variety of human tumors including melanoma. Here we show a previously undescribed role for GAB2 in NRAS-driven melanoma. Specifically, we found that GAB2 is co-expressed with mutant NRAS in melanoma cell lines and tumor samples and its expression correlated with metastatic potential. Co-expression of GAB2(WT) and NRAS(G12D) in melanocytes and in melanoma cells increased anchorage-independent growth by providing GAB2-expressing cells a survival advantage through upregulation of BCL-2 family of anti-apoptotic factors. Of note, collaboration of GAB2 with mutant NRAS enhanced tumorigenesis in vivo and led to an increased vessel density with strong CD34 and VEGFR2 activity. We found that GAB2 facilitiated an angiogenic switch by upregulating HIF-1α and VEGF levels. This angiogenic response was significantly suppressed with the MEK inhibitor PD325901. These data suggest that GAB2-mediated signaling cascades collaborate with NRAS-driven downstream activation for conferring an aggressive phenotype in melanoma. Second, we show that GAB2/NRAS signaling axis is non-linear and non-redundant in melanocytes and melanoma, and thus are acting independent of each other. Finally, we establish a link between GAB2 and angiogenesis in melanoma for the first time. In conclusion, our findings provide evidence that GAB2 is a novel regulator of tumor angiogenesis in NRAS-driven melanoma through regulation of HIF-1α and VEGF expressions mediated by RAS-RAF-MEK-ERK signaling.

Are dark-skinned people really protected from ultraviolet radiation?

BACKGROUND: Premature ageing of the skin (photoageing) results from the action of ultraviolet radiation (UVR) on skin. One of the histopathological findings of photoageing is the presence of solar elastosis in the dermis. Skin pigmentation is protective against UVR. AIM: To evaluate the presence of solar elastosis in dark-skinned people. METHODS: Normal facial skin biopsies of 147 dark-skinned and 140 light-skinned people were examined histopathologically for solar elastosis. The degree of solar elastosis was graded on a five-point scale by a panel of dermatopathologists blinded to patient demographics. RESULTS: There were 112 of 140 (80%) light-skinned and 50 of 147 (34%) dark-skinned patients with high-grade solar elastosis. In the dark-skinned patient group, high-grade solar elastosis was seen in 29 of 61 (47.5%) Hispanic and 5 of 49 (10.2%) African American subjects. CONCLUSIONS: Dark-skinned people are not completely protected from the effects of UVR.

Daclizumab, a humanised monoclonal antibody to the interleukin 2 receptor (CD25), for the treatment of moderately to severely active ulcerative colitis: a randomised, double blind, placebo controlled, dose ranging trial.

BACKGROUND: An uncontrolled pilot study demonstrated that daclizumab, a humanised monoclonal antibody to the interleukin 2 receptor (CD25), might be effective for the treatment of active ulcerative colitis. METHODS: A randomised, double blind, placebo controlled trial was conducted to evaluate the efficacy of daclizumab induction therapy in patients with active ulcerative colitis. A total of 159 patients with moderate ulcerative colitis were randomised to receive induction therapy with daclizumab 1 mg/kg intravenously at weeks 0 and 4, or 2 mg/kg intravenously at weeks 0, 2, 4, and 6, or placebo. The primary end point was induction of remission at week 8. Remission was defined as a Mayo score of 0 on both endoscopy and rectal bleeding components and a score of 0 or 1 on stool frequency and physician's global assessment components. Response was defined as a decrease from baseline in the Mayo score of at least 3 points. RESULTS: Two per cent of patients receiving daclizumab 1 mg/kg (p = 0.11 v placebo) and 7% of patients receiving 2 mg/kg (p = 0.73) were in remission at week 8, compared with 10% of those who received placebo. Response occurred at week 8 in 25% of patients receiving daclizumab 1 mg/kg (p = 0.04) and in 33% of patients receiving 2 mg/kg (p = 0.30) versus 44% of those receiving placebo. Daclizumab was well tolerated. The most frequently reported adverse events in daclizumab treated patients compared with placebo treated patients were nasopharyngitis (14.6%) and pyrexia (10.7%). CONCLUSION: Patients with moderate ulcerative colitis who are treated with daclizumab are not more likely to be in remission or response at eight weeks than patients treated with placebo.

PTCH mutations in squamous cell carcinoma of the skin.

Ultraviolet light exposure is the major risk factor for the development of squamous cell carcinoma in Caucasians. Mutations in the tumor suppressor gene p53 have been identified in both squamous cell carcinomas and basal cell carcinomas. The human homolog of the Drosophila patched gene, has been shown to be mutated in sporadic basal cell carcinomas; however, mutations in the patched gene have not been found in squamous cell carcinoma. In this study, we screened a total of 20 squamous cell carcinoma samples for mutations in the patched gene. Using polymerase chain reaction-single strand conformation polymorphism as an initial screening method, we identified one non-sense mutation, two mis-sense mutations and three silent mutations in five squamous cell carcinoma samples. In one squamous cell carcinoma sample, we identified a tandem GG-->AA transitional change at nucleotide 3152 in exon 18 of the patched gene that resulted in a premature stop codon at codon 1051. The three squamous cell carcinoma samples containing non-sense and mis-sense mutations were isolated from individuals with histories of multiple basal cell carcinoma. Sequence analysis of the p53 gene in these five squamous cell carcinoma samples identified one CC-->TT and three C-->T ultraviolet-specific nucleotide changes. Our study provides evidence that the patched gene is mutated in squamous cell carcinoma from individuals with a history of multiple basal cell carcinoma. The identification of ultraviolet-specific nucleotide changes in both tumor suppressor genes supports the notion that ultraviolet exposure plays an important part in the development of squamous cell carcinoma.

Role of PTCH and p53 genes in early-onset basal cell carcinoma.

Basal cell carcinoma (BCC) is the most common skin cancer in the Western world. Ultraviolet (UV) exposure, race, age, gender, and decreased DNA repair capacity are known risk factors for the development of BCC. Of these, UVB irradiation from sunlight is the most significant risk factor. The incidence of sporadic BCC increases in individuals older than age 55, with the greatest incidence reported in individuals who are older than 70, and is rare in individuals who are younger than 30. In this study, we analyzed 24 BCC samples from individuals who had BCC diagnosed by the age of 30. Fifteen single-stranded conformation polymorphism variants in the PTCH gene were identified in 13 BCC samples. Sequence analysis of these single-stranded conformation polymorphism variants revealed 13 single nucleotide changes, one AT insertion, and one 15-bp deletion. Most of these nucleotide changes (nine of 15) were predicted to result in truncated PTCH proteins. Fifteen p53 mutations were also found in 11 of the 24 BCC samples. Thirty-three percent (five of 15) and 60% (nine of 15) of the nucleotide changes in the PTCH and p53 genes, respectively, were UV-specific C-->T and CC-->TT nucleotide changes. Our data demonstrate that the p53 and PTCH genes are both implicated in the development of early-onset BCC. The identification of UV-specific nucleotide changes in both tumor suppressor genes suggests that UV exposure is an important risk factor in early onset of BCC.

Identification of PTEN mutations in metastatic melanoma specimens.

CONTEXT: PTEN, a tumour suppressor gene located on chromosome 10q23, develops somatic mutations in various tumours and tumour cell lines including brain, endometrium, prostate, breast, kidney, thyroid, liver, and melanoma. OBJECTIVES: To investigate the mutational profile of this gene further, as well as its role in tumour progression in melanoma. DESIGN, SETTINGS: We examined 21 metastatic melanoma samples for 10q23 allelic losses and PTEN sequence alterations. Additionally, we screened these samples for mutations in CDKN2A, a gene in which alterations are well documented in primary melanoma as well as in the germline of familial melanoma. RESULTS: Loss of heterozygosity (LOH) at 10q23 was observed in 33% (7/21) of the samples tested. We identified four sequence alterations in PTEN (19%) and two in CDKN2A (9.5%). Of interest, only one case showed mutations in both genes. CONCLUSIONS: These data support the notion that PTEN alterations occur in some metastatic melanomas, and that mutation of this gene plays a role in the progression of some forms of melanoma.

Varicella-zoster virus proteins in skin lesions: implications for a novel role of ORF29p in chickenpox.

Skin biopsy samples from varicella-zoster virus (VZV)-infected patients examined by immunohistochemistry demonstrated VZV replication in nonepithelial cell types. ORF29p, a nonstructural nuclear protein, was found in nerves of two of six patients with chickenpox. In tissue culture, ORF29p was secreted by VZV-infected fibroblasts. Extracellular ORF29p can be taken up through endocytosis by human neurons, implying a novel role for this protein in pathogenesis.

Late-Onset Friedreich's Ataxia Presenting as a Spastic Paraparesis.

A 55-year-old woman presented with a 10-yeai history of a progressive gait disorder. Her examination showed a spastic paraparesis with brisk deep tendon reflexes, but only minimal limb ataxia and no evidence for a sensory neuropathy The patient was found to be homozygous for the GAA trinucleotide repeal diagnostic of Friedreich's ataxia The presentation of Friedreich's ataxia as a spastic paraparesis reinforces the appreciation of the variable phenotype of this disease.

Invasive squamous cell carcinoma with sporotrichoid metastasis in a patient with cutaneous T cell lymphoma treated with chronic extracorporeal photopheresis.

An 83-year-old Caucasian man with cutaneous T-cell lymphoma developed an aggressive squamous cell carcinoma of the left forearm, which recurred and metastasized after Mohs micrographic surgery and systemic chemotherapy with cis-platin and 5-fluorouracil. He was treated with extracorporeal photopheresis, radiation therapy, PUVA photochemotherapy, and interferon therapy for cutaneous T-cell lymphoma. Aggressive squamous cell carcinoma can occur in the setting of extracorporeal photopheresis.

Cisapride 20 mg b.d. for preventing symptoms of GERD induced by a provocative meal. The CIS-USA-89 Study Group.

BACKGROUND: Cisapride is a substituted piperidinyl benzamide indicated for the symptomatic treatment of patients with nocturnal heartburn due to gastro-oesophageal reflux disease (GERD). The currently recommended dosing regimen for cisapride is 10 mg q.d.s., but the elimination half-life of 8-10 h supports b.d. dosing with 20 mg. METHODS: This multicentre, randomized, double-blind, placebo-controlled trial was undertaken to determine the efficacy and safety of cisapride 20 mg b.d. dosing in reducing or preventing heartburn and other meal-related symptoms after challenge with a provocative fatty meal. In phase 1 of the study, 137 patients with at least a 3-month history of symptoms suggestive of GERD and at least five episodes of GERD on 7-day diary were eligible to receive single-blind treatment with placebo for 7 (range +/- 3) days and then ingested a provocative meal. One hundred and twenty-two patients (45 men and 77 women, 22-65 years of age) who experienced heartburn during the 3 h after ingestion of the meal qualified for the double-blind phase of the study and were randomly assigned to either cisapride 20 mg or matching placebo b.d. for 7 (+/-3) days. At the end of this period, 118 patients again ate a fatty meal and were assessed for symptoms of GERD. RESULTS: Heartburn was prevented in a significantly higher percentage of cisapride-treated patients (40%; 24 out of 60) than placebo-treated patients (21%; 12 out of 58) after the repeat provocative meal at the end of the double-blind phase (P = 0.017). Cisapride was also significantly more effective in reducing the severity of postprandial heartburn, belching, and regurgitation (P < 0.05). Twice-daily dosing with cisapride 20 mg was well tolerated; the number of cisapride- and placebo-treated patients who experienced at least one adverse event was similar (31% and 22%, respectively). The most common adverse events were diarrhoea (cisapride, 18%; placebo, 0%) and rhinitis (cisapride, 2%; placebo, 5%). CONCLUSIONS: These results demonstrate that cisapride 20 mg b.d. is effective in preventing or reducing symptoms of heartburn in patients who developed heartburn after ingesting a provocative fatty meal. Cisapride was also effective in reducing the severity of heartburn-related symptoms such as belching and regurgitation.

A comparison of frozen and paraffin sections in dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a tumor with a high local reoccurrence rate. Mohs micrographic surgery offers the highest cure rate. However, differentiating minimal residual tumor from normal skin can be difficult during Mohs surgery. OBJECTIVE: To clarify the problem of determining when a tumor-free plane had been achieved during Mohs surgery for a DFSP. METHODS: In two patients with DFSPs, we compared frozen and paraffin-embedded sections extending from tumor to normal skin, using both H&E and CD34 stains. RESULTS: On frozen, but not paraffin-embedded, sections scattered dermal spindle cells were seen in normal skin. CONCLUSIONS: Scattered dermal spindle cells in the dermis of normal skin make it difficult to differentiate minimal residual tumor from normal dermis during Mohs surgery. A biopsy of normal skin can be useful as a control in this setting.

Invasive Trichophyton rubrum resembling blastomycosis infection in the immunocompromised host.

A 55-year-old renal transplant recipient with onychomycosis and chronic tinea pedis presented with tender nodules on his left medial heel. He then developed papules and nodules on his right foot and calf. A skin biopsy demonstrated periodic acid-Schiff (PAS) positive, thick walled round cells, 2 to 6 microm in diameter, in the dermis. Skin biopsy culture grew Trichophyton rubrum. T. rubrum has been described as an invasive pathogen in immunocompromised hosts. The clinical presentation, histopathology, and early fungal culture growth suggested Blastomyces dermititidis in the differential diagnosis before the final identification of T. rubrum.

Skin resurfacing of the face with the Erbium:YAG laser.

BACKGROUND: Laser resurfacing of facial skin is a very popular method of rhytide and scar removal. Until recently, the most effective tool utilized for these purposes was the pulsed char-free carbon dioxide laser. These lasers, however, produce thermal damage related to prolonged wound healing. The Erbium (Er): YAG laser, with its 2940-nm wavelength and maximal water absorption, has been recently introduced for laser resurfacing of the facial skin. OBJECTIVE: In this study, specific parameters for Er:YAG laser treatment of rhytides were evaluated clinically and histologically. METHODS: Fifteen patients were treated with the Er:YAG laser. Perioral, periorbital, and total face rhytides were treated. All patients were treated with 0.8-1.0 J, 5-mm spot size, with the final fluences of 4-5 J/cm2. Patients were evaluated daily after treatment for 7 days and weekly for 2 months for erythema, healing time, improvement, and pigmentary changes. Histologic evaluation of preauricular human facial ex vivo skin was done to determine the penetration of multiple passes of Er:YAG laser in human facial skin. RESULTS: All patients showed some degree of improvement of their rhytides. Reepithelialization occurred between 3 and 8 days. All evidence of erythema resolved between 3 and 6 weeks after treatment. The level of tissue ablation was determined to be down to: the granular layer after one pass; to the basal cell layer after two passes, to the papillary dermis after three to four passes, and deeper into the papillary and superficial reticular dermis after five to six passes. CONCLUSION: The Er:YAG laser plays a significant role in the treatment of superficial and mid-depth rhytides.

Domperidone in the management of symptoms of diabetic gastroparesis: efficacy, tolerability, and quality-of-life outcomes in a multicenter controlled trial. DOM-USA-5 Study Group.

The purpose of this clinical study was to determine the efficacy, tolerability, and impact on quality of life of domperidone--a specific peripherally acting dopamine antagonist--in the management of symptoms of gastroparesis, a common and potentially debilitating condition in patients with diabetes mellitus. In the first phase of this multicenter, two-phase withdrawal study, 287 diabetic patients with symptoms of gastroparesis of at least 6 months' duration received domperidone 20 mg QID in a single-masked fashion for 4 weeks. Efficacy was evaluated using a four-point rating scale (0 = none, 1 = mild, 2 = moderate, 3 = severe) for each of the following symptoms: nausea, abdominal distention/bloating, early satiety, vomiting, and abdominal pain. At the end of the first phase, patients with sufficient improvement in their total symptom score (a score < or = 6 and a decrease in score of > or = 5 units from the baseline [selection] visit) were eligible for the 4-week, randomized, placebo-controlled, double-masked withdrawal phase of the study. The impact of domperidone on quality of life was determined using the Medical Outcomes Study Short Form-36 (SF-36). Of 269 patients with data from the single-masked phase, 208 (77%) qualified for entry into the double-masked phase based on a statistically significant improvement in total symptom score, from a mean score of 10.32 at baseline (initial visit) to 3.79 after 4 weeks of single-masked domperidone therapy. During the double-masked phase, patients in the placebo group had significantly greater deterioration in total symptom scores compared with patients in the domperidone group (mean changes of 1.84 and 0.85, respectively). Similar significant differences in favor of domperidone were seen in the secondary efficacy variables (i.e., patients' diary scores and global assessments of symptoms). The tolerability profile of domperidone was similar to that of placebo. Patients who responded to domperidone experienced significant improvements in quality of life, as indicated by the SF-36 physical and mental component summary scores. During the double-masked phase, patients who were randomized to placebo experienced a significant deterioration in the physical component summary score compared with patients in the domperidone group. The results of this study suggest that domperidone 20 mg QID provides significant improvement in the upper gastrointestinal symptoms of diabetic gastroparesis and is well tolerated in patients with this condition.