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...

The association of Taq 1 and Fok 1 restriction fragment length polymorphisms of the vitamin D receptor with occurrence and outcome of malignant melanoma (MM), as predicted by tumour (Breslow) thickness, has been reported previously. We now report a novel adenine -guanine substitution À1012 bp relative to the exon 1a transcription start site (A-1012G), found following screening by single-stranded conformational polymorphism of this promoter region. There was a total of 191 MM cases , which were stratified according to conventional Breslow thickness groups, cases being randomly selected from each group to form a distribution corresponding to the known distribution of Breslow thickness in our area, and this population (n ¼ 176) was compared to 80 controls. The A allele was over-represented in MM patients and, with GG as reference, odds ratio (OR) for AG was 2.5, 95% confidence interval (CI) 1.1 -5.7, (P ¼ 0.03) and AA 3.3, CI 1.4 -8.1, (P ¼ 0.007). The outcome was known in 171 of 191 patients and the A allele was related to the development of metastasis, the Kaplan -Meier estimates of the probability of metastasis at 5 years being: GG 0%; AG 9%, CI 4 -16%; AA 21%, CI 12 -36%; (P ¼ 0.008), and to thicker Breslow thickness groups (P ¼ 0.04). The effect on metastasis was independent of tumour thickness and A-1012G may have predictive potential, additional to Breslow thickness. Neither the Fok 1 nor Taq 1 variants (f and t) were significantly related to the development of metastasis, although there was a strong relationship of fftt with the thickest Breslow thickness group (P ¼ 0.005). There was an interaction between the A-1012G and Fok 1 polymorphisms (P ¼ 0.025) and the Fok 1 variant enhanced the effect of the A allele of the A-1012G polymorphism on metastasis, the probability of metastasis for AAff at 5 years follow-up being 57%, CI 24 -92%.

First, the morphological similarity of spitzoid tumours reflects an underlying molecular similarity, namely a relative lack of dependence on BRAF/NRAS mutations. Second, Spitz naevi do not appear to progress into spitzoid melanoma, and consequently ambiguous spitzoid tumours are likely to be unclassifiable Spitz naevi or spitzoid melanoma rather than genuine entities. Third, HRAS mutation may be a marker of Spitz naevus, raising the possibility that other molecular markers for discriminating Spitz naevi from spitzoid melanoma can be discovered.

No abstract

An in situ hybridization technique has been developed for the detection of immunoglobulin light chain mRNA in routine pathology specimens. The method detects kappa or lambda constant region sequences using a cocktail of synthetic oligonucleotide probes labelled with biotin or fluorescein 5-isothiocyanate (FITC) reporter molecules. The probes were labelled at flanking sites chemically by primary amine directed acylation and by 'homopolymer tailing' with terminal deoxynucleotidyl transferase using non-radioactive nucleotide analogues. The mRNA was unmasked in the formalin-fixed tissue sections by digestion with varying concentrations of proteinase K, and the hybrids were demonstrated using alkaline phosphatase with either a streptavidin/biotin based four-stage system or an anti-FITC antibody based detection system. Alkaline phosphatase was visualized using a Fast Red naphthol-capture method and the sections were counterstained with haematoxylin. The results confirm that the method is specific for kappa or lambda mRNA and show that specific mRNAs can be detected in routine formalin-fixed sections using non-radioactive techniques with retention of good morphology. The method reliably detects light chain mRNA in cells expressing secretory immunoglobulin. The protocol can also be applied to tissue rich in endogenous biotin by using hapten-labelled probes.