Not all melanomas are created equal: a review and call for more research into nodular melanoma.

Among the histogenic subtypes of melanoma, nodular melanoma (NM) is the major contributor for thicker and fatal melanomas and it has been associated with melanoma-specific death in thin tumours, highlighting an important subgroup of 'aggressive thin' melanomas. This review provides a synthesis of the distinct characteristics of NM, with respect to epidemiology and risk factors, clinical presentation, histopathology, molecular and dermoscopic aspects, and screening practices. The real challenges are to find better biomarkers of aggressiveness and to know whether the control of such aggressive melanomas can be influenced by targeted interventions such as early detection, drug interventions and preventive strategies.

Desmoplastic melanoma: a review of its pathology and clinical behaviour, and of management recommendations in published guidelines.

Desmoplastic melanomas are uncommon. Their behaviour differs from that of other melanoma subtypes; therefore, management guidelines for non-desmoplastic melanomas may not be applicable. This review sought to examine all available evidence relating to the behaviour and management of desmoplastic melanomas, based on review of all relevant English-language publications, and to critically assess the recommendations for their management in current published melanoma management guidelines. Compared with other melanoma subtypes, patients with 'pure' desmoplastic melanomas (where ≥90% of the invasive melanoma is of desmoplastic melanoma subtype) have much lower rates of sentinel node positivity and distant metastasis. Local recurrence rates are higher for desmoplastic melanomas, but resection margins wider than those recommended for non-desmoplastic melanomas have not been shown to be of benefit. Adjuvant radiotherapy reduces the risk of local recurrence when a satisfactory histological clearance (≥8 mm) cannot be achieved. Of 29 published melanoma management guidelines identified, only 11 specified management for desmoplastic melanomas, while seven simply stated that the feature should be reported. Desmoplastic melanoma is a unique melanoma subtype with biology that differs from that of other melanoma subtypes. It requires specific management strategies but few current guidelines address these.

Differences between pure desmoplastic melanoma and superficial spreading melanoma in terms of survival, distribution and other clinicopathologic features.

BACKGROUND: Pure desmoplastic melanoma (pDM) is an uncommon subtype of malignant melanoma with comparative high rates of local recurrence and low rates of sentinel lymph node positivity. The melanoma-specific survival (MSS) of pDM compared to other melanoma subtypes is unclear, with conflicting reports and lack of multivariable analyses. OBJECTIVES: We aimed to describe clinicopathological characteristics of a cohort of patients with pDM and to compare the MSS of pDM with superficial spreading melanoma (SSM). METHODS: A prospective cohort study was performed of all primary invasive cutaneous pDM with known tumour location and thickness reviewed at a tertiary referral centre over 21 years. RESULTS: A total of 119 primary cutaneous invasive pDMs from 3570 total invasive cutaneous melanomas were included. Compared to 2272 SSMs, and due largely to their greater average thickness, patients with pDM had worse MSS (unadjusted hazard ratio, HR, 2.56, 95% confidence interval, CI, 1.56-4.22). After adjustment for clinicopathologic factors (including thickness, ulceration, mitotic rate, age and sex), there was evidence that patients with pDM had an improved MSS (adjusted HR, 0.49; 95% CI, 0.28-0.87). Median thickness of head and neck pDM was greater than non-head and neck pDM (P < 0.001). There was reduced univariable MSS in head and neck pDM compared to the rest of the body. CONCLUSIONS: Decreased univariable MSS of patients with pDM compared to SSM was explained by the increased frequency of adverse clinicopathologic features at diagnosis, in particular the greater Breslow thickness of pDM. After adjustment, patients with pDM had half the chance of melanoma-specific death compared to SSM. Head and neck pDM were thicker at diagnosis compared to the rest of the body, which may account for its poorer survival compared to the rest of the body.

Current and future treatment of amyloid diseases.

There are more than 30 human proteins whose aggregation appears to cause degenerative maladies referred to as amyloid diseases or amyloidoses. These disorders are named after the characteristic cross-ß-sheet amyloid fibrils that accumulate systemically or are localized to specific organs. In most cases, current treatment is limited to symptomatic approaches and thus disease-modifying therapies are needed. Alzheimer's disease is a neurodegenerative disorder with extracellular amyloid ß-peptide (Aß) fibrils and intracellular tau neurofibrillary tangles as pathological hallmarks. Numerous clinical trials have been conducted with passive and active immunotherapy, and small molecules to inhibit Aß formation and aggregation or to enhance Aß clearance; so far such clinical trials have been unsuccessful. Novel strategies are therefore required and here we will discuss the possibility of utilizing the chaperone BRICHOS to prevent Aß aggregation and toxicity. Type 2 diabetes mellitus is symptomatically treated with insulin. However, the underlying pathology is linked to the aggregation and progressive accumulation of islet amyloid polypeptide as fibrils and oligomers, which are cytotoxic. Several compounds have been shown to inhibit islet amyloid aggregation and cytotoxicity in vitro. Future animal studies and clinical trials have to be conducted to determine their efficacy in vivo. The transthyretin (TTR) amyloidoses are a group of systemic degenerative diseases compromising multiple organ systems, caused by TTR aggregation. Liver transplantation decreases the generation of misfolded TTR and improves the quality of life for a subgroup of this patient population. Compounds that stabilize the natively folded, nonamyloidogenic, tetrameric conformation of TTR have been developed and the drug tafamidis is available as a promising treatment.

The role of BRAF mutations in primary melanoma growth rate and survival.

BACKGROUND: The clinical behaviour and prognosis of primary melanomas harbouring BRAF mutations is not fully understood. OBJECTIVES: To investigate the effect of mutation status on primary melanoma growth rate and melanoma-specific survival (MSS). METHODS: A prospective cohort of 196 patients with stage I-III primary cutaneous melanoma were followed for a median of 92 months, pre-dating the institution of BRAF inhibitor therapy. Clinicopathological variables were correlated with mutation status and hazard ratios (HRs) estimated for MSS. RESULTS: Of 196 tumours, 77 (39.2%) were BRAF V600E, 10 (5.1%) BRAF V600K and 33 (16.8%) were NRAS mutant. BRAF V600E mutant melanomas were associated with favourable clinical characteristics and tended to be slower growing compared with BRAF V600K, NRAS mutant or BRAF/NRAS wild-type tumours (0.12 mm per month, 0.61 mm per month, 0.36 mm per month and 0.23 mm per month, respectively; P = 0.05). There were 39 melanoma deaths, and BRAF mutant melanomas were associated with poorer MSS in stage I-III disease [HR 2.60, 95% confidence interval (CI) 1.20-5.63; P = 0.02] and stage I-II disease (HR 3.39, 95% CI 1.12-10.22; P = 0.03) after adjusting for other prognostic variables. Considered separately, BRAF V600E mutant melanomas were strongly associated with MSS independently of thickness and nodal status (HR 3.89, 95% CI 1.67-9.09; P < 0.01) but BRAF V600K mutant tumours were not (HR 1.19, 95% CI 0.36-3.92; P = 0.77). CONCLUSIONS: The presence of a BRAF mutation does not necessarily 'drive' more rapid tumour growth but is associated with poorer MSS in patients with early-stage disease.

Postexcisional melanocytic regrowth extending beyond the initial scar: a novel clinical sign of melanoma.

BACKGROUND: Recurrent naevi are widely recognized to occur commonly following incomplete removal of melanocytic lesions. These lesions have been generally understood as representing benign imitators of melanoma. OBJECTIVES: To provide a formal description of the clinical findings of postexcisional melanocytic regrowth. METHODS: We examined all cases of recurrent pigmentation adjacent to scars from previous excisional biopsies of melanocytic naevi treated at a private dermatology practice from 1995 to 2012. RESULTS: We report nine cases of recurrence of melanocytic lesions that were melanomas. The most suspicious clinical feature for melanoma in these cases was the growth of the lesion beyond the confines of the initial scar, into the surrounding normal skin. CONCLUSIONS: This pattern of recurrence of a melanocytic lesion represents a little recognized and distinctive clinical presenting sign of melanoma.

Clinical and dermoscopic characteristics of Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with a high mortality rate. Diagnosis is often delayed. OBJECTIVES: To characterize the dermoscopic features of MCC. METHODS: Clinical and dermoscopic images of 12 biopsy-proven MCCs were analysed in a retrospective manner, with existing dermoscopic criteria being scored independently by three dermatologists. RESULTS: The four most frequent clinical features were cherry red colour, shiny surface, sharp circumscription and nodular morphology. Significant dermoscopic features included linear irregular and polymorphous vessels, poorly focused vessels, milky pink areas, white areas, structureless areas and architectural disorder. Pigmented structures were absent from all lesions. CONCLUSIONS: The dermoscopic features described herein help the clinician to distinguish MCC from other benign and malignant red nodules. Increasing recognition of the presenting features will facilitate earlier diagnosis of MCC and reduced mortality.

Light interception efficiency explained by two simple variables: a test using a diversity of small- to medium-sized woody plants.

• Plant light interception efficiency is a crucial determinant of carbon uptake by individual plants and by vegetation. Our aim was to identify whole-plant variables that summarize complex crown architecture, which can be used to predict light interception efficiency. • We gathered the largest database of digitized plants to date (1831 plants of 124 species), and estimated a measure of light interception efficiency with a detailed three-dimensional model. Light interception efficiency was defined as the ratio of the hemispherically averaged displayed to total leaf area. A simple model was developed that uses only two variables, crown density (the ratio of leaf area to total crown surface area) and leaf dispersion (a measure of the degree of aggregation of leaves). • The model explained 85% of variation in the observed light interception efficiency across the digitized plants. Both whole-plant variables varied across species, with differences in leaf dispersion related to leaf size. Within species, light interception efficiency decreased with total leaf number. This was a result of changes in leaf dispersion, while crown density remained constant. • These results provide the basis for a more general understanding of the role of plant architecture in determining the efficiency of light harvesting.

Toward smarter BCIs: extending BCIs through hybridization and intelligent control.

This paper summarizes two novel ways to extend brain-computer interface (BCI) systems. One way involves hybrid BCIs. A hybrid BCI is a system that combines a BCI with another device to help people send information. Different types of hybrid BCIs are discussed, along with challenges and issues. BCIs are also being extended through intelligent systems. Software that allows high-level control, incorporates context and the environment and/or uses virtual reality can substantially improve BCI systems. Throughout the paper, we critically address the real benefits of these improvements relative to existing technology and practices. We also present new challenges that are likely to emerge as these novel BCI directions become more widespread.

Therapeutic strategies to ameliorate lysosomal storage disorders--a focus on Gaucher disease.

The lysosomal storage disorders encompass more than 40 distinct diseases, most of which are caused by the deficient activity of a lysosomal hydrolase leading to the progressive, intralysosomal accumulation of substrates such as sphingolipids, mucopolysaccharides, and oligosaccharides. Here, we primarily focus on Gaucher disease, one of the most prevalent lysosomal storage disorders, which is caused by an impaired activity of glucocerebrosidase, resulting in the accumulation of the glycosphingolipid glucosylceramide in the lysosomes. Enzyme replacement and substrate reduction therapies have proven effective for Gaucher disease cases without central nervous system involvement. We discuss the promise of chemical chaperone therapy to complement established therapeutic strategies for Gaucher disease. Chemical chaperones are small molecules that bind to the active site of glucocerebrosidase variants stabilizing their three-dimensional structure in the endoplasmic reticulum, likely preventing their endoplasmic reticulum-associated degradation and allowing their proper trafficking to the lysosome where they can degrade accumulated substrate to effectively ameliorate Gaucher disease.

The V122I cardiomyopathy variant of transthyretin increases the velocity of rate-limiting tetramer dissociation, resulting in accelerated amyloidosis.

The transthyretin (TTR) amyloid diseases are of keen interest, because there are >80 mutations that cause, and a few mutations that suppress, disease. The V122I variant is the most common amyloidogenic mutation worldwide, producing familial amyloidotic cardiomyopathy primarily in individuals of African descent. The substitution shifts the tetramer-folded monomer equilibrium toward monomer (lowers tetramer stability) and lowers the kinetic barrier associated with rate-limiting tetramer dissociation (pH 7; relative to wild-type TTR) required for amyloid fibril formation. Fibril formation is also accelerated because the folded monomer resulting from the tetramer-folded monomer equilibrium rapidly undergoes partial denaturation and self-assembles into amyloid (in vitro) when subjected to a mild denaturation stress (e.g., pH 4.8). Incorporation of the V122I mutation into a folded monomeric variant of transthyretin reveals that this mutation does not destabilize the tertiary structure or alter the rate of amyloidogenesis relative to the wild-type monomer. The increase in the velocity of rate-limiting tetramer dissociation coupled with the lowered tetramer stability (increasing the mol fraction of folded monomer present at equilibrium) may explain why V122I confers an apparent absolute anatomic risk for cardiac amyloid deposition.

Furin initiates gelsolin familial amyloidosis in the Golgi through a defect in Ca(2+) stabilization.

Hereditary familial amyloidosis of Finnish type (FAF) leading to amyloid in the peripheral and central nervous systems stems from deposition of a 71 residue fragment generated from the D187N/Y variants of plasma gelsolin by two sequential endoproteolytic events. We identify the protease accomplishing the first cleavage as furin, a proprotein convertase. Endoproteolysis of plasma gelsolin occurs in the trans-Golgi network due to the inability of the FAF variants to bind and be stabilized by Ca(2+). Secretion and processing of the FAF variants by furin can be uncoupled by blocking the convergence of the exocytic pathway transporting plasma gelsolin and the endocytic recycling of furin. We propose that coincidence of membrane trafficking pathways contributes to the development of proteolysis-initiated amyloid disease.

Support for the multigenic hypothesis of amyloidosis: the binding stoichiometry of retinol-binding protein, vitamin A, and thyroid hormone influences transthyretin amyloidogenicity in vitro.

The amyloidoses are a large group of protein misfolding diseases. Genetic and biochemical evidence support the hypothesis that amyloid formation from wild-type or 1 of 80 sequence variants of transthyretin causes the human amyloid diseases senile systemic amyloidosis or familial amyloid polyneuropathy, respectively. The late onset and variable penetrance of these diseases has led to their designation as multigenic--implying that the expression levels and alleles of multiple gene products influence the course of pathology. Here we show that the binding stoichiometry of three interacting molecules, retinol-binding protein, vitamin A, and L-thyroxine, notably influenced transthyretin amyloidogenicity in vitro. At least 70 genes control retinol-binding protein, vitamin A, and L-thyroxine levels in plasma and have the potential to modulate the course of senile systemic amyloidosis or familial amyloid polyneuropathy.

Trans-suppression of misfolding in an amyloid disease.

The transthyretin (TTR) amyloid diseases, representative of numerous misfolding disorders, are of considerable interest because there are mutations that cause or suppress disease. The Val30 --> Met30 (V30M) TTR mutation is the most prevalent cause of familial amyloid polyneuropathy in heterozygotes, whereas a Thr119 --> Met119 (T119M) mutation on the second TTR allele protects V30M carriers from disease. Here, we show that the incorporation of one or more T119M TTR subunits into a predominantly V30M tetramer strongly stabilized the mixed tetramer against dissociation. Dissociation is required for amyloid formation, so these findings provide a molecular explanation for intragenic trans-suppression of amyloidosis. The data also suggest a potential therapeutic strategy, provide insight into tissue-specific deposition and amyloid composition, and support the validity of the amyloid hypothesis in human disease.

An engineered transthyretin monomer that is nonamyloidogenic, unless it is partially denatured.

Transthyretin (TTR) is a soluble human plasma protein that can be converted into amyloid by acid-mediated dissociation of the homotetramer into monomers. The pH required for disassembly also results in tertiary structural changes within the monomeric subunits. To understand whether these tertiary structural changes are required for amyloidogenicity, we created the Phe87Met/Leu110Met TTR variant (M-TTR) that is monomeric according to analytical ultracentrifugation and gel filtration analyses and nonamyloidogenic at neutral pH. Results from far- and near-UV circular dichroism spectroscopy, one-dimensional proton NMR spectroscopy, and X-ray crystallography, as well as the ability of M-TTR to form a complex with retinol binding protein, indicate that M-TTR forms a tertiary structure at pH 7 that is very similar if not identical to that found within the tetramer. Reducing the pH results in tertiary structural changes within the M-TTR monomer, rendering it amyloidogenic, demonstrating the requirement for partial denaturation. M-TTR exhibits stability toward acid and urea denaturation that is nearly identical to that characterizing wild-type (WT) TTR at low concentrations (0.01-0.1 mg/mL), where monomeric WT TTR is significantly populated at intermediate urea concentrations prior to the tertiary structural transition. However, the kinetics of denaturation and fibril formation are much faster for M-TTR than for tetrameric WT TTR, particularly at near-physiological concentrations, because of the barrier associated with the tetramer to folded monomer preequilibrium. These results demonstrate that the tetramer to folded monomer transition is insufficient for fibril formation; further tertiary structural changes within the monomer are required.