Aberrant expression of embryonic epithelial-mesenchymal transition-inducing transcription factors (EMT-TFs) in epithelial cells triggers EMT, neoplastic transformation, stemness, and metastatic dissemination. We found that regulation and functions of EMT-TFs are different in malignant melanoma. SNAIL2 and ZEB2 transcription factors are expressed in normal melanocytes and behave as tumor-suppressor proteins by activating an MITF-dependent melanocyte differentiation program. In response to NRAS/BRAF activation, EMT-TF network undergoes a profound reorganization in favor of TWIST1 and ZEB1. This reversible switch cooperates with BRAF in promoting dedifferentiation and neoplastic transformation of melanocytes. We detected EMT-TF reprogramming in late-stage melanoma in association with enhanced phospho-ERK levels. This switch results in E-cadherin loss, enhanced invasion, and constitutes an independent factor of poor prognosis in melanoma patients.

Cellular senescence is a terminal differentiation state that has been proposed to have a role in both tumour suppression and ageing. This view is supported by the fact that accumulation of senescent cells can be observed in response to oncogenic stress as well as a result of normal organismal ageing. Thus, identifying senescent cells in in vivo and in vitro has an important diagnostic and therapeutic potential. The molecular pathways involved in triggering and/or maintaining the senescent phenotype are not fully understood. As a consequence, the markers currently utilized to detect senescent cells are limited and lack specificity. In order to address this issue, we screened for plasma membrane-associated proteins that are preferentially expressed in senescent cells. We identified 107 proteins that could be potential markers of senescence and validated 10 of them (DEP1, NTAL, EBP50, STX4, VAMP3, ARMX3, B2MG, LANCL1, VPS26A and PLD3). We demonstrated that a combination of these proteins can be used to specifically recognize senescent cells in culture and in tissue samples and we developed a straightforward fluorescence-activated cell sorting-based detection approach using two of them (DEP1 and B2MG). Of note, we found that expression of several of these markers correlated with increased survival in different tumours, especially in breast cancer. Thus, our results could facilitate the study of senescence, define potential new effectors and modulators of this cellular mechanism and provide potential diagnostic and prognostic tools to be used clinically.

The ideal classification of basal cell carcinoma (BCC) should be able to identify subtypes which correlate with clinical behaviour and treatment requirements. Unfortunately, however, such a classification has yet to be defined. In the interim, the currently most favoured classification is one based predominantly on histological growth pattern. This classification contributes to the useful concept of low- and high-risk histological subtypes of BCC. The latter are characterized by an increased probability of subclinical extension and/or incomplete excision and/or aggressive local invasive behaviour and/or local recurrence. The Royal College of Pathologists has published a minimum dataset for the histopathological reporting of BCC and this has been written to be compatible with the British Association of Dermatologists' management guidelines. Growth patterns to be reported include nodular, superficial, infiltrative/morphoeic and micronodular types, together with differentiation when of severely atypical or malignant squamous type (basosquamous carcinoma). Deep and peripheral excision margins will be reported to be either involved or clear. The latter will include a comment of a clearance of less than 1 mm for close margins and a measured distance in whole millimetres for other excisions. Clinical assessment and histology remain the 'gold standard' for evaluating BCC and cancers in general. However, in the postgenomic era emphasis is changing from the gathering and archiving of genomic data to its analysis and use in guiding clinical practice. In this context, a current goal is to define cancer phenotype in terms of molecular abnormalities and use this as a new gold standard. One way to assess whether this goal is being achieved for BCC is to determine whether our knowledge of its molecular pathology has any relevance to the minimum dataset for histological reporting. Knowledge of BCC molecular pathology has been fuelled by the recent discovery that deregulation of the Hedgehog (Hh) signalling pathway, a key player in embryonic patterning, appears to be fundamental to tumour growth. But despite accrual of a large amount of data concerning Hh pathway molecular alterations in neoplasia, little is known about the functional consequences of these changes in BCC, how they lead to tumour development, or how they relate to non-Hh pathway alterations such as TP53 mutation. Recent work suggests that the cellular localization of beta-catenin gives a degree of credence to the growth pattern classification of BCC. Furthermore, it is possible that beta-catenin may have a pathogenetic role in the invasive behaviour of BCC. This review draws on current evidence to discuss these issues and assess whether they are relevant to the minimum dataset.

Purpose: Wnt ligands play a major role in development and are important in cancer. Expression microarray analysis correlates one member of this family, WNT5A, to a subclass of melanomas with increased motility and invasion. There are no large studies of clinical samples primarily addressing the importance of WNT5A in melanoma progression or outcome.Therefore, this study aimed to assess the protein expression of WNT5A during melanoma progression and its effect on outcome. Experimental Design: Expression of WNT5A was determined in a series of 59 primary melanomas with matched metastases. To provide a benchmark of progression against which to assess WNT5A, expression of p16 ink4a was analyzed, as this has been previously well documented in melanoma. The effect of WNT5A protein expression on outcome was assessed in 102 melanomas. Results: Cytoplasmic WNT5A showed a trend of increasing expression with melanoma progression (P = 0.013), whereas there was diminishing p16 ink4a expression (P = 0.006). Nevi showed relatively strong WNT5A expression. Strong cytoplasmic WNT5A was an independent risk factor for reduced metastasis-free and overall survival in multivariate analysis (P = 0.001and 0.003, respectively). Conclusion: Cytoplasmic WNT5A increases with melanoma progression and strong expression is associated with poor outcome.

Cutaneous melanoma (CM) is the most lethal form of skin cancer. Along with some benign melanocytic tumors, the majority shows BRAF or NRAS mutation, but it is not known whether these are essential to all forms of melanocytic neoplasia. We screened 79 melanocytic tumors of different types for BRAF and NRAS mutations and looked at MAPK pathway activity using immunohistochemistry in a subset. Significant differences in BRAF exon 15 mutation frequency were found: 14/16 (87.5%) in common acquired naevi (CANs), 9/12 (75%) in CMs, 0/26 in Spitz naevi and 3/25 (12%) in blue naevi (p < 0.01). We looked at whether Spitz and blue naevi showed a compensatory increase in BRAF exon 11 and/or NRAS exons 1 and 2 mutations to account for the low BRAF exon 15 mutation frequency. NRAS mutations were found in only 1/16 (6.3%) Spitz naevi and 0/15 blue naevi. In addition, NRAS mutations were found in 2/11 (18.2%) CANs and 3/12 (25%) CMs. None of the tumors showed BRAF exon 11 mutations. Despite their low combined BRAF and NRAS mutation frequency, Spitz naevi showed strong MAPK pathway activation as measured by cytoplasmic expression of dually phosphorylated ERK1/2, while blue naevi had weak pathway activation. We conclude that BRAF and NRAS mutations are not necessary for melanocytic tumor development and that some types of tumor must arise by alternative mechanisms. Cutaneous melanoma (CM) is the most lethal form of skin cancer and incidence in the Western world is rising. Recently, it was found that 66% of CMs and 82% of benign melanocytic tumors (comprising congenital, common acquired and dysplastic naevi) showed BRAF mutations, 1,2 while NRAS mutations are common in the remainder. 2 Both genes encode proteins of the MAPK pathway, which is therefore deregulated in the vast majority of melanocytic tumors. Congenital, common acquired and dysplastic naevi appear to be melanoma precursors based on histologic similarities and apparent development of melanomas from contiguous naevi. 3,4 This suggests that BRAF and NRAS mutations may be early events in melanoma progression, although this issue remains uncertain. A key question now is whether the very high combined frequency of these mutations is common to all melanocytic neoplasia. The answer is important because the relationship of Spitz and blue naevi to melanoma is poorly documented. This may be partly because these tumors occur less frequently than common acquired naevi (CANs) and would therefore be expected to have a less frequent association with melanoma, although large congenital naevi are rarer than Spitz naevi and yet have a significant association with melanoma. In addition, Spitz naevus and melanoma have many histologic similarities, so contiguous Spitz and melanoma would be hard to identify. 5 Malignant blue naevi have been reported, 6 but their relationship to benign blue naevus is unknown. To address whether these mutations are common in all types of melanocytic tumor, we screened for mutation hot-spot alterations in BRAF and examined a subset of mutant and wild-type case...

The absence of beta-catenin gene mutations indicate that the Hh pathway-directed Wnt signalling remains the most likely cause of nuclear beta-catenin accumulation in BCC. Additionally, the correlation with increased proliferation is the first evidence that nuclear beta-catenin may have a biological effect. However, a causal link between Hh pathway deregulation, Wnt ligand overexpression, nuclear beta-catenin accumulation and increased proliferation remains to be confirmed.

Purpose: BRAF mutations are present in two thirds of cutaneous melanomas and many of the rest have NRAS mutations. However, cutaneous melanoma is a heterogeneous disease with many clinicopathologic subtypes. Of these, the majority fits into four categories: superficial spreading, nodular, lentigo maligna, and acral lentiginous melanoma (ALM). Thus far, there is very limited data combining BRAF and NRAS mutation analysis to explore differences between cutaneous melanoma subtypes. The aim of this study was to address this issue. Experimental Design:The frequency of BRAF and NRAS hotspot mutations, in exons 15 and 2, respectively, was assessed in 59 cutaneous melanomas comprising superficial spreading, nodular, lentigo maligna, and ALM using single-strand conformational polymorphism and RFLP-PCR analysis. Results: Only 2 of 21 (9.5%) ALM showed BRAF exon 15 mutation compared with 9 of 14 (64.3%) superficial spreading malignant melanomas, 4 of 11 (36.4%) nodular melanomas, and 7 of 13 (53.4%) lentigo maligna melanomas (P < 0.01). However, our key finding is that the combined analysis of BRAF exon 15 and NRAS exon 2 showed that there were no significant differences in the overall mutation frequency between subtypes. In particular, 9 of 19 (47.4%) ALM without BRAF exon 15 mutation had an NRAS exon 2 mutation. Conclusions: We show that the overall BRAF/NRAS frequency in mutation hotspots is not significantly different among cutaneous melanoma subtypes. These data show that mitogenactivated protein kinase pathway activation may be important in all major subtypes of cutaneous melanoma, although the mechanism by which this is achieved varies.Cutaneous melanoma is the most serious form of skin cancer because it metastasizes so readily. Initially, it was regarded as a homogeneous entity with a uniformly poor prognosis, but the advent of specialized pigmented lesion clinics allowed detailed multidisciplinary study of cutaneous melanoma and, as a result, a number of different subtypes with distinct clinicopathologic features were described. The distinctions were based on the preferred site of origin, relative amount of UV light exposure, and duration of preinvasive growth, with four subtypes accounting for the vast majority of cutaneous melanomas. These are superficial spreading, nodular, lentigo maligna, and acral lentiginous melanoma (ALM), comprising f70% to 75%, 20% to 25%, 5% to 10%, and 5% of cutaneous melanoma cases, respectively, in White Caucasian populations, with acral melanomas being the most frequent in dark-skinned races (1). More recently, molecular differences between these subtypes have come to light, corroborating the clinicopathologic observations. Compelling evidence for differences comes from patterns of DNA alterations observed in cytogenic and comparative genomic hybridization studies, where distinct alterations have been identified. For example, acral melanomas tend to have frequent genetic loci showing amplifications, some of which are early events that can even be detected in adjacent histol...

Objective-This study aimed to determine the usefulness of sural nerve biopsy in neurological practice. Methods-The first prospective study of sural nerve biopsy in 50 consecutive patients was undertaken. The investigating neurologist declared the prebiopsy diagnosis and management plan and after 3 months an independent neurologist evaluated the contribution of the biopsy to diagnosis and management. An independent audit oYcer sought information from the patient about the adverse eVects and value of the biopsy after 6 weeks and 6 months. Results-In seven cases the nerve biopsy changed the diagnosis, in 35 cases the biopsy confirmed the suspected diagnosis, and in eight cases the biopsy was noncontributory. The biopsy either changed or was helpful in guiding patient management in 60%, especially those with demyelinating neuropathy and multiple mononeuropathy. Seven patients reported having had infection and 10 reported increased pain at the biopsy site 6 months later. Conclusion-In a consecutive series of 50 cases, sural nerve biopsy altered the diagnosis in 14%, aVected management in 60%, and caused persistent increased pain at the biopsy site in 33%. (J Neurol Neurosurg Psychiatry 2000;69:442-446)