Purpose: It has been proposed that melanoma cells shift from E-cadherin to N-cadherin expression during tumor development, and recent gene profiling has shown increased expression of Wnt5a/Frizzled in aggressive melanomas possibly by interactions with h-catenin. We therefore wanted to investigate the role of cadherin subtypes, h-catenin, andWnt5a/Frizzled in melanocytic tumors, with focus on prognosis in nodular melanomas. Experimental Design: The immunohistochemical expression of E-cadherin, N-cadherin, P-cadherin, h-catenin, andWnt5a/Frizzled was examined using tissue microarrays of 312 melanocytic tumors. Results: Cytoplasmic expression of P-cadherin was associated with increasing tumor thickness (P = 0.005) and level of invasion (P = 0.019), whereas membranous staining was associated with thinner (P = 0.012) and more superficial (P = 0.018) tumors. Increased cytoplasmic P-cadherin was associated with reduced survival (P = 0.047). Lack of nuclear h-catenin expression was related to increased tumor thickness (P = 0.002) and poor patient survival in univariate (P = 0.0072) and multivariate (P = 0.004) analyses. Membranous expression of N-cadherin was significantly increased from primary tumors to metastatic lesions, whereas E-cadherin staining tended to be decreased. Wnt5a and its receptor Frizzled were highly coexpressed, and nuclear expression of both markers was significantly reduced from benign nevi to melanomas, with a shift from nuclear to cytoplasmic expression in malignant tumors. In addition, Wnt5a expression was significantly associated with nuclear h-catenin expression. Conclusions: Alterations in the expression and subcellular localization of cell adhesion markers are important in the development and progression of melanocytic tumors, and strong cytoplasmic P-cadherin expression and loss of nuclear h-catenin staining were associated with aggressive melanoma behavior and reduced patient survival.

BackgroundCDKN2A and CDK4 are high risk susceptibility genes for cutaneous malignant melanoma. Melanoma families with CDKN2A germline mutations have been extensively characterised, whereas CDK4 families are rare and lack a systematic investigation of their phenotype.MethodsAll known families with CDK4 germline mutations (n=17) were recruited for the study by contacting the authors of published papers or by requests via the Melanoma Genetics Consortium (GenoMEL). Phenotypic data related to primary melanoma and pigmentation characteristics were collected. The CDK4 exon 2 and the complete coding region of the MC1R gene were sequenced.ResultsEleven families carried the CDK4 R24H mutation whereas six families had the R24C mutation. The total number of subjects with verified melanoma was 103, with a median age at first melanoma diagnosis of 39 years. Forty-three (41.7%) subjects had developed multiple primary melanomas (MPM). A CDK4 mutation was found in 89 (including 62 melanoma cases) of 209 tested subjects. CDK4 positive family members (both melanoma cases and unaffected subjects) were more likely to have clinically atypical nevi than CDK4 negative family members (p<0.001). MPM subjects had a higher frequency of MC1R red hair colour variants compared with subjects with one tumour (p=0.010).ConclusionOur study shows that families with CDK4 germline mutations cannot be distinguished phenotypically from CDKN2A melanoma families, which are characterised by early onset of disease, increased occurrence of clinically atypical nevi, and development of MPM. In a clinical setting, the CDK4 gene should therefore always be examined when a melanoma family tests negative for CDKN2A mutation.

Background:Around 50% of primary melanomas harbour BRAF mutations, but their prognostic impact has not been clear. Recently, a BRAF-V600E mutation-specific antibody has become available for immunohistochemistry. Here, we investigated for the first time the prognostic impact of BRAF-V600E protein expression in primary melanoma.Methods:In a patient series of 248 nodular melanomas, BRAF-V600E and total BRAF expression were assessed by immunohistochemistry using tissue microarray sections of paraffin-embedded archival tissue. Mutation status was assessed by real-time PCR in cases with sufficient tumour tissue (n=191).Results:Positive BRAF-V600E expression was present in 86 (35%) of the cases, and was significantly associated with increased tumour thickness, presence of tumour ulceration and reduced survival. Further, BRAF-V600E expression was an independent prognostic factor by multivariate analysis, whereas BRAF mutation status was not significant. There was 88% concordance between BRAF-V600E expression and mutation status.Conclusions:Our findings indicate that BRAF-V600E expression is a novel prognostic marker in primary melanoma.

Earlier studies have shown frequent mutations in the BRAF and NRAS genes in cutaneous melanoma, but these alterations have not been examined in the rare category of melanoma from black Africans. Moreover, the frequency of epidermal growth factor receptor (EGFR) mutations in melanocytic tumors is not known. We therefore examined 165 benign and malignant melanocytic lesions (including 118 invasive melanomas and 18 metastases collected as consecutive cases from various time periods and from two different pathology departments; the 51 nodular melanomas were randomly selected from a larger, consecutive, population-based series of nodular melanomas) with respect to alterations in the EGFR, BRAF and NRAS genes. Mutations in EGFR (exons 18-21) were not detected. EGFR protein expression was observed in a subgroup of melanomas, but without associations with clinicopathologic phenotype or prognosis. Cytoplasmic EGFR expression was, however, significantly increased from benign nevi to melanomas. Mutations in BRAF and NRAS were detected in superficial melanoma (25 and 29%, respectively), nodular melanoma (29 and 28%, respectively) and lentigo maligna melanoma (15 and 16%, respectively). In a series of melanomas from black Africans (n=26), only two BRAF mutations (8%) were found, both being different from the common T1799A substitution. Moreover, melanomas from black Africans exhibited mutations in NRAS exon 1 only (12%), whereas NRAS exon 2 mutations were predominant in melanomas from Caucasians. Thus, the frequencies of BRAF and NRAS mutations were particularly low in melanomas from black Africans, supporting a different pathogenesis of these tumors.

BackgroundVEGF driven angiogenesis plays a key role in cancer progression. We determined the clinical efficacy of bevacizumab monotherapy in patients with metastatic melanoma.Methods and FindingsThirty-five patients with metastatic melanoma in progression were enrolled in this phase II, single arm clinical trial. Each patient received bevacizumab monotherapy 10 mg/kg q14 d until intolerable toxicity or disease progression occurred. Clinical efficacy was evaluated as objective response, disease control (DC), and survival. We observed one complete (3%) and 5 partial (14%) responses. In addition, 5 patients experienced stable disease >6 months (14%) while 24 patients had progressive disease (PD, 69%), corresponding to a total DC at 6 months in 11 out of 35 patients (31%). Median progression free survival (PFS) was 2.14 months and median overall survival (OS) was 9 months (1.12–49). Seven of the 11 patients experiencing DC developed early hypertension (<2 months) compared to 3/24 of patients with PD (P = 0.001), and hypertension was associated with PFS (P = 0.005) and OS (P = 0.013).ConclusionBevacizumab monotherapy demonstrated promising clinical efficacy in patients with metastatic melanoma with disease control in 31% of the patients. Induced early hypertension was a marker for clinical efficacy of bevacizumab.Trial RegistrationClinicalTrials.gov NCT00139360.