Refining the application of PRAME-a useful marker in high CSD and acral melanoma subtypes.

Pathologic discordance affecting patient management may approach 20% in melanocytic cases following specialist review. The diagnostic utility of PRAME has been highlighted in several studies but interpretative challenges exist including its use in severely dysplastic compound nevi showing progression to melanoma in situ, nevoid melanoma, and coexisting nevi with melanoma. We examine the PRAME status of a broad spectrum of melanocytic lesions including challenging, dysplastic nevi with severe atypia from a large Irish patient cohort. Retrospective review of the dermatopathology database was conducted to evaluate the PRAME staining characteristics of two hundred and twenty-one melanocytic lesions using a commercially available PRAME antibody (EPR20330). The proportion of nuclear labeling and intensity of staining was recorded. The sensitivity and specificity of PRAME for in situ and malignant melanocytic lesions was 77% and 100%, respectively. Virtually all of our melanoma in situ from high-cumulative sun damaged (CSD) skin (22/23) and all acral lentiginous melanoma (5/5) were PRAME positive while 80% (8/10) of our lentigo maligna melanoma showed diffuse expression. None of our benign subgroup showed diffuse immunoexpression (0/82), including thirty-seven moderate or severely dysplastic nevi. In all cases of melanoma in situ arising in association with a dysplastic compound nevus (0/10), no immunoexpression was observed in the nevic component while in five cases of melanoma in situ with coexistent, intradermal nevus immunostaining was confined to the in situ component. A total of 100% (2/2) of desmoplastic melanomas and 50% (4/8) of nodular melanomas were PRAME positive. PRAME is a sensitive and highly specific immunostain in the diagnosis of in situ and invasive melanoma and we emphasize its application in the evaluation of high CSD and acral melanoma subtypes as well as in challenging threshold cases.

The lupus band test: A review of the sensitivity and specificity in the diagnosis of lupus erythematosus.

Background: The lupus band test (LBT) is a direct immunofluorescence (DIF) technique which shows a band of localised immunoglobulins at the dermo-epidermal junction in lesional, non-sun-exposed skin of patients with both systemic and cutaneous lupus erythematosus (LE), and in perilesional skin of patients with systemic LE. However, low sensitivity and poor concordance between histological and clinical diagnoses warrant a review of the application of the LBT in the diagnosis of LE. Objectives: To assess the sensitivity and specificity of the LBT in diagnosing LE following clinico-pathological correlation (CPC). Methods: All cases sent to our pathology department between 2011 and 2018 for DIF with a clinical query of LE were reviewed. Data collection included demographic details, pathology requests, histology and DIF reports, clinical reports and diagnoses, and serology. Results: Of 256 histology requests, 9% (n = 23) had a positive LBT. This was discordant with the prevalence of LE diagnosis, as 46.3% were diagnosed with LE following CPC. The sensitivity and specificity of the LBT for LE was 17.6% and 98.8% respectively, with a positive predictive value of 92.9% and negative predictive value of 58.2%. Conclusion: The LBT is not a sensitive diagnostic test for LE, but is highly specific, and should be considered as a supportive diagnostic tool for LE. This is the largest reported case series evaluating the efficacy of the LBT in the diagnosis of LE.

The effect of calcium electroporation on viability, phenotype and function of melanoma conditioned macrophages.

Electroporation in combination with chemotherapy is an established treatment used on solid malignancies that results in enhanced chemotherapeutic uptake. Recent advances have begun to transition to the use of non-toxic compounds, such as calcium, in lieu of chemotherapy, which can also induce tumour cell death. While the effect of treatment on tumour cell death has been well characterized and has been shown to induce an immunogenic form of cell death, the effect of treatment on intratumoural immune cells has not been investigated. Here we present data showing the effect of calcium electroporation on immune cells, using melanoma-conditioned bone marrow-derived macrophages. Similar to tumour cells, macrophage cell membranes are susceptible to poration following treatment and subsequently reseal. Macrophages are less susceptible to calcium electroporation induced cell death in comparison to B16F10 melanoma cells. However treatment with electroporation with or without bleomycin or calcium was shown to affect macrophage phenotype and function. Coculture of calcium electroporated macrophages revealed that both the capacity of macrophages to stimulate and direct T cell responses are affected following exposure to treatment. We conclude that calcium electroporation has the potential to boost the immunogenic capacity of exposed tumour associated macrophages, and further research is warranted to determine if calcium electroporation can be optimised to generate systemic anti-cancer immune responses.

Differential association of CD68+ and CD163+ macrophages with macrophage enzymes, whole tumour gene expression and overall survival in advanced melanoma.

BACKGROUND: The density and phenotype of tumour-associated macrophages have been linked with prognosis in a range of solid tumours. While there is strong preclinical evidence that tumour-associated macrophages promote aspects of tumour progression, it can be challenging to infer clinical activity from surface markers and ex vivo behaviour. We investigated the association of macrophage infiltration with prognosis and functional changes in the tumour microenvironment in primary human melanoma. METHODS: Fifty-seven formalin-fixed, paraffin-embedded primary melanomas were analysed by immunohistochemical analysis of CD68, CD163, inducible nitric oxide synthase (iNOS) and arginase expression. RNA sequencing was performed on serial sections of 20 of the stained tumours to determine the influence of macrophage infiltration on gene expression. RESULTS: CD68+ cells are a functionally active subset of macrophages that are associated with increased iNOS and arginase staining and altered gene expression. In comparison, while there is a greater accumulation of CD163+ macrophages in larger tumours, these cells are comparatively inactive, with no association with the level of iNOS or arginase staining, and no effect on gene expression within the tumour. The infiltration of either subset of macrophages did not correlate to overall survival. CONCLUSIONS: Thus, melanomas contain distinct macrophage populations with diverse phenotypes, but with no observable prognostic role.

Should We Always Biopsy in Clinically Evident Lichen Sclerosus?

The aims of the study were to review cases of clinically diagnosed lichen sclerosus (LS) and to compare the histological features found on biopsy to clinical features seen on examination. METHODS: A retrospective chart review was undertaken of patients attending a specialist vulval service between 2013 and 2015 with a clinical diagnosis of LS. Patients in whom there was clinical diagnostic uncertainty or those with features of lichen planus or lichen planus/LS overlap were excluded. We determined the proportion of these patients who underwent vulval biopsy and reviewed their histology. RESULTS: One hundred fifteen charts were reviewed. Sixty-nine (69/115, 60%) had a firm diagnosis of established LS, and of these, 39 (39/69, 56.5%) had a biopsy performed in the previous 5 years. Thirteen (13/39, 33.3%) of these biopsies fell short of a diagnosis of LS histologically with some suggestive but nondiagnostic and some showing nonspecific features. CONCLUSIONS: Reliance on biopsies solely to establish or exclude the diagnosis of LS is inadvisable. A good level of knowledge of the characteristic clinical features is imperative among gynecologists, dermatologists, and general practitioners.

High concordance of BRAF mutational status in matched primary and metastatic melanoma.

BACKGROUND: Techniques for the accurate identification of activating mutations of BRAF in metastatic melanoma are of great clinical importance, due to the availability of targeted therapies for these tumors. There is uncertainty regarding the frequency with which BRAF status differs between primary and metastatic sites. METHODS: Between 2011 and 2016, 219 melanoma cases underwent BRAF testing in our institution. In 53 of these cases, paired primary and metastatic specimens were available for polymerase chain reaction (PCR) and immunohistochemical evaluation. RESULTS: Fifty-two out of 53 cases (98%) showed concordant BRAF status between primary and metastatic site by immunohistochemistry (IHC). In one case, a metastasis and its matched primary were positive by IHC, but the metastasis was negative on PCR. On further investigation, PCR was positive in the primary, and repeat PCR in the metastasis was positive, following macrodissection. CONCLUSIONS: Our results suggest that discordance of BRAF mutational status between primaries and metastases is a rare occurrence. In one case, IHC provided strong evidence that initial PCR testing had provided a false-negative result due to low tumor volume. Thus, in cases where tissue is difficult to obtain from a metastasis or unavailable, the primary tumor can be used with confidence.

Sampling of wide local excision specimens in cutaneous malignant melanoma.

BACKGROUND: Wide local excisions (WLEs) are frequently undertaken in the management of cutaneous melanoma; however, there is a considerable variability in their macroscopic sampling. The aim of our study was to establish evidence-based guidelines for the macroscopic handling of these specimens with a subsequent review of the impact on our service. METHODS: The study group of 128 cases with initial biopsy and subsequent WLE in our institution in 2010 were identified by a computer-generated search. From analysis of this group, guidelines for macroscopic sampling were derived with a repeat search performed in 2012. RESULTS: Residual melanoma was detected only in those cases in which the original specimen had clear margins of ≤1 mm or with a pigmented lesion. A 32% increase in case numbers was noted over this period with a reduction of 6.2% in block numbers. Average block numbers per case were reduced by 2.3 (30.7%). CONCLUSIONS: We have shown that for WLE specimens with no evidence of a macroscopic lesion and clear margins on original biopsy, little is to be gained from extensive sampling. In these cases we recommend a maximum of 3 blocks per case. Reduction in sampling based on this evidence would result in saving valuable laboratory resources.

BRAF V600 mutation detection in melanoma: a comparison of two laboratory testing methods.

AIMS: The assessment of B-raf proto-oncogene, serine/threonine kinase (BRAF) gene status is now standard practice in patients diagnosed with metastatic melanoma with its presence predicting a clinical response to treatment with BRAF inhibitors. The gold standard in determining BRAF status is currently by DNA-based methods. More recently, a BRAF V600E antibody has been developed. We aim to investigate whether immunohistochemical detection of BRAF mutation is a suitable alternative to molecular testing by polymerase chain reaction (PCR). METHODS: We assessed the incidence of BRAF mutation in our cohort of 132 patients, as determined by PCR, as well as examining clinical and histopathological features. We investigated the sensitivity and specificity of the anti-BRAF V600E VE1 clone antibody in detecting the presence of the BRAF V600E mutation in 122 cases deemed suitable for testing. RESULTS: The incidence of BRAF mutation in our cohort was 28.8% (38/132). Patients with the BRAF mutation were found to be significantly younger at age of diagnosis. BRAF-mutated melanomas tended to be thinner and more mitotically active. The antibody showed a sensitivity of 86.1% with a specificity of 96.9%. The positive predictive value was 96.9%; the negative predictive value was 94.4%. The concordance rate between PCR and immunohistochemical BRAF status was 95.1% (116/122). CONCLUSIONS: The rate of BRAF mutation in our cohort (28.8%) was lower than international published rates of 40%-60%. This may reflect ethnic or geographic differences within population cohorts. The high concordance rate of PCR and immunohistochemical methods in determining BRAF status suggests that immunohistochemistry is potentially a viable, cost-effective alternative to PCR testing and suitable as a screening test for the BRAF mutation.

High-throughput oncogene mutation profiling shows demographic differences in BRAF mutation rates among melanoma patients.

Because of advances in targeted therapies, the clinical evaluation of cutaneous melanoma is increasingly based on a combination of traditional histopathology and molecular pathology. Therefore, it is necessary to expand our knowledge of the molecular events that accompany the development and progression of melanoma to optimize clinical management. The central objective of this study was to increase our knowledge of the mutational events that complement melanoma progression. High-throughput genotyping was adapted to query 159 known single nucleotide mutations in 33 cancer-related genes across two melanoma cohorts from Ireland (n=94) and Belgium (n=60). Results were correlated with various clinicopathological characteristics. A total of 23 mutations in 12 genes were identified, that is--BRAF, NRAS, MET, PHLPP2, PIK3R1, IDH1, KIT, STK11, CTNNB1, JAK2, ALK, and GNAS. Unexpectedly, we discovered significant differences in BRAF, MET, and PIK3R1 mutations between the cohorts. That is, cases from Ireland showed significantly lower (P<0.001) BRAF(V600E) mutation rates (19%) compared with the mutation frequency observed in Belgian patients (43%). Moreover, MET mutations were detected in 12% of Irish cases, whereas none of the Belgian patients harbored these mutations, and Irish patients significantly more often (P=0.027) had PIK3R1-mutant (33%) melanoma versus 17% of Belgian cases. The low incidence of BRAF(V600E)(-) mutant melanoma among Irish patients was confirmed in five independent Irish cohorts, and in total, only 165 of 689 (24%) Irish cases carried mutant BRAF(V600E). Together, our data show that melanoma-driving mutations vary by demographic area, which has important implications for the clinical management of this disease.

Global mRNA analysis to determine a transcriptome profile of cancer stemness in a mouse model.

BACKGROUND: Striking similarities between stem cells and cancer cells have led to the concept of the existence of a cancer stem cell, a concept that has since been documented in many tumours including breast, brain and prostate tumours. Teratocarcinomas are malignant tumours occurring predominantly in the testes composed of undifferentiated stem cells and mature tissues. Cancer stemness was studied using the teratocarcinoma model of tumourigenesis. MATERIALS AND METHODS: The gene expression profile of murine embryonic stem cell lines was compared to its malignant counterpart, murine teratocarcinoma cell lines. Validation was performed using real-time quantitative PCR. RESULTS: A list of 1170 differentially expressed genes was obtained. Significant pathways involved in cancer stemness included oxidative stress and angiogenesis. Transcription factors and extracellular matrix molecules appeared prominently. CONCLUSION: Novel molecules have been highlighted including decorin, an extracellular matrix protein, which may provide opportunities for the investigation of innovative strategies in the future treatment of cancer.

Quantitation of CDC6 and MCM5 mRNA in cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the cervix.

CDC6 and MCM5 play essential roles in eukaryotic DNA replication. Several studies have highlighted the potential of these proteins as molecular markers of dysplastic and malignant cells in histopathological diagnosis. The mode of expression of CDC6 and MCM5 mRNA and their significance in normal, dysplastic and malignant cervical cells remains to be elucidated. Using a quantitative real-time RT PCR assay, we compared CDC6 and MCM5 mRNA expression in normal cervical epithelium, cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the cervix. Our study cohort comprised 20 normal cervical biopsies, 20 CIN3 and eight invasive squamous cell carcinomas. All samples were formalin fixed and paraffin embedded. Total RNA was extracted and analysed for expression of GAPDH, CDC6 and MCM5 using real-time quantitative TaqMan RT-PCR. A linear increase in MCM5 and CDC6 mRNA expression is observed in normal cervix, CIN3 and invasive cervical carcinoma. The overall difference in MCM5 mRNA expression in the normal cervix, CIN3 and invasive cohort groups is highly statistically significant (P=0.001). An increase in CDC6 mRNA expression in CIN3 and invasive cervical squamous cell carcinoma was observed; however, the overall difference between cohort groups was not found to be statistically significant (P=0.104). Increased transcription of MCM5 and CDC6 occurs as a consequence of cervical neoplastic progression. This pattern of increased mRNA expression in CIN3 and invasive cervical carcinoma directly correlates with findings at the phenotypic protein expression level. This study further confirms the importance of MCM5 and CDC6 in malignant transformation and in the pathogenesis of cervical dysplasia.