A retrospective study of diameter and Breslow thickness in invasive melanomas

INTRODUCTION

A diameter larger than 6 millimeters is included in the criteria used in public health messages to detect a cutaneous melanoma. We aim to investigate the independent association of Breslow thickness with the melanoma diameter.

METHODS

A retrospective study was performed in patients with invasive melanomas of the nodular melanoma or superficial spreading melanoma subtype. The quartiles of the diameter (lower, median, upper) were studied in non-parametric quantile regression model.

RESULTS

In total, 537 cases of invasive melanomas were included and 60% had Breslow thickness ≤ 1.0 mm. There were 429 SSM (79.9%) and 108 NM (20.1%). Although NMs were significantly thicker (median Breslow thickness: 2.7 mm versus 0.7 mm respectively, p<0.0001), they were not associated with larger diameter compared to SSMs (p:0.71). After adjustment for age and sex, melanoma location and subtype, having Breslow thickness ≤ 1.0 mm was not significantly associated with the lower quartile, median and upper quartile of the diameter (p-values: 0.063, 0.083, and 0.791, respectively).

CONCLUSION

In our study including melanomas of the NM or SSM subtype, Breslow thickness was not associated with the diameter, adding evidence to support the limitations of using diameter larger than 6 mm for the detection of invasive melanomas and indicating the potential of smaller melanomas to be thicker tumors.

A Comprehensive Analysis of Cutaneous Melanoma Patients in Greece Based on Multi-Omic Data

Cutaneous melanoma (CM) is the most aggressive type of skin cancer, and it is characterised by high mutational load and heterogeneity. In this study, we aimed to analyse the genomic and transcriptomic profile of primary melanomas from forty-six Formalin-Fixed, Paraffin-Embedded (FFPE) tissues from Greek patients. Molecular analysis for both germline and somatic variations was performed in genomic DNA from peripheral blood and melanoma samples, respectively, exploiting whole exome and targeted sequencing, and transcriptomic analysis. Detailed clinicopathological data were also included in our analyses and previously reported associations with specific mutations were recognised. Most analysed samples (43/46) were found to harbour at least one clinically actionable somatic variant. A subset of samples was profiled at the transcriptomic level, and it was shown that specific melanoma phenotypic states could be inferred from bulk RNA isolated from FFPE primary melanoma tissue. Integrative bioinformatics analyses, including variant prioritisation, differential gene expression analysis, and functional and gene set enrichment analysis by group and per sample, were conducted and molecular circuits that are implicated in melanoma cell programmes were highlighted. Integration of mutational and transcriptomic data in CM characterisation could shed light on genes and pathways that support the maintenance of phenotypic states encrypted into heterogeneous primary tumours.

Cutaneous melanoma metastases: Clinical and dermoscopic findings

BACKGROUND

About 2%-20% of melanoma patients will develop cutaneous melanoma metastases (CMM). Their clinical diagnosis still remains challenging because of the variation of clinical and dermoscopic characteristics. Until today, few studies exist concerning the dermoscopic image of CMM but no one has focused on its possible association with clinicopathological melanoma characteristics.

METHODS

Between 2002 and 2019, 42 patients diagnosed with melanoma at Andreas Syggros Hospital developed CMM. We studied the dermoscopic presentation of these metastases and its possible association with the clinical and histologic characteristics of the underlying melanoma.

RESULTS

There were 20 male and 22 female patients with a mean age of 64.02 years. Nineteen patients developed satellites and 23 in transit metastases. Mean Breslow index was estimated at 2.93 mm and ulceration was observed in half of the tumours (50%). Almost half of the patients developed cutaneous metastases on the lower limbs (45.24%). We identified 5 dermoscopic patterns of CMM: saccular, amelanotic, homogenous, vascular and polymorphic. Homogenous (30.95%) and amelanotic (28.57%) were the most common patterns. Homogenous pattern was the most common in satellite metastases while amelanotic was mostly observed in in-transit metastases. Homogenous pattern was more frequent among superficial spreading melanomas. Patients with thin (<1 mm) and medium depth (1-2 mm) melanomas mostly developed metastases with saccular pattern. Vascular pattern was only present in metastases of tumours with Breslow index 2-4 mm. Homogenous and amelanotic were the only patterns found in tumours with Breslow index >4 mm.

CONCLUSIONS

We observed that vascular structures were more frequent in metastases of deeper tumours while nevus-like structures were more common in metastases of thinner tumours. CMM occasionally may constitute the first clinical sign of melanoma disease. Therefore, it is important for clinicians to recognize their dermoscopic patterns which seem to be associated with some of the clinical and histological characteristics of cutaneous melanomas.

A Web-based database of genetic association studies in cutaneous melanoma enhanced with network-driven data exploration tools

The publicly available online database MelGene provides a comprehensive, regularly updated, collection of data from genetic association studies in cutaneous melanoma (CM), including random-effects meta-analysis results of all eligible polymorphisms. The updated database version includes data from 192 publications with information on 1114 significantly associated polymorphisms across 280 genes, along with new front-end and back-end capabilities. Various types of relationships between data are calculated and visualized as networks. We constructed 13 different networks containing the polymorphisms and the genes included in MelGene. We explored the derived network representations under the following questions: (i) are there nodes that deserve consideration regarding their network connectivity characteristics? (ii) What is the relation of either the genome-wide or nominally significant CM polymorphisms/genes with the ones highlighted by the network representation? We show that our network approach using the MelGene data reveals connections between statistically significant genes/ polymorphisms and other genes/polymorphisms acting as 'hubs' in the reconstructed networks. To the best of our knowledge, this is the first database containing data from a comprehensive field synopsis and systematic meta-analyses of genetic polymorphisms in CM that provides user-friendly tools for in-depth molecular network visualization and exploration. The proposed network connections highlight potentially new loci requiring further investigation of their relation to melanoma risk. Database URL: http://www.melgene.org.

Comprehensive mutational analysis of CDKN2A and CDK4 in Greek patients with cutaneous melanoma

BACKGROUND

The penetrance of CDKN2A mutations is subject to geographical and latitudinal variation and is presumably dictated by ultraviolet radiation exposure and possibly other co-inherited genetic factors. The frequency of mutations increases with the number of family members affected and the number of primary tumours, and also fluctuates with geography. To date, little is known about the prevalence of CDKN2A mutations in patients with melanoma from Greece.

OBJECTIVE

To characterize the frequency of CDKN2A and CDK4 mutations in a hospital-based population of Greek patients with melanoma.

METHODS

Three hundred and four consecutive single primary melanoma (SPM), nine familial melanoma (FM) and seven multiple primary melanoma cases (MPM) were assessed for sequence variants in exons 1α, 1β and 2 of CDKN2A and exon 2 of CDK4.

RESULTS

Germline CDKN2A mutations were detected in 10 of 304 SPM (3·3%), in four of seven MPM (57%) and in two of nine FM (22%) cases. The most common mutation was a Northern European allele (p16 p.R24P) detected in eight individuals. Five previously unreported CDKN2A variants were also identified: -34G>C, c.41_43delins20bp, c.301G>C (p.G101R), c.301G>A (p.G101E) and c.296_297insGACC. We also describe the first report of a CDK4 p.R24H substitution in a Greek family.

CONCLUSIONS

The Greek population appears to harbour a higher prevalence of the CDKN2A mutation than other reported cohorts. This supports the notion that genetic susceptibility may play a stronger influence in a country with a relatively low incidence of melanoma. Furthermore, the identification of Northern European alleles suggests that gene migration may be responsible, in part, for the observed cases in Greece.

Comprehensive field synopsis and systematic meta-analyses of genetic association studies in cutaneous melanoma

BACKGROUND

Although genetic studies have reported a number of loci associated with cutaneous melanoma (CM) risk, a comprehensive synopsis of genetic association studies published in the field and systematic meta-analysis for all eligible polymorphisms have not been reported.

METHODS

We systematically annotated data from all genetic association studies published in the CM field (n = 145), including data from genome-wide association studies (GWAS), and performed random-effects meta-analyses across all eligible polymorphisms on the basis of four or more independent case-control datasets in the main analyses. Supplementary analyses of three available datasets derived from GWAS and GWAS-replication studies were also done. Nominally statistically significant associations between polymorphisms and CM were graded for the strength of epidemiological evidence on the basis of the Human Genome Epidemiology Network Venice criteria. All statistical tests were two-sided.

RESULTS

Forty-two polymorphisms across 18 independent loci evaluated in four or more datasets including candidate gene studies and available GWAS data were subjected to meta-analysis. Eight loci were identified in the main meta-analyses as being associated with a risk of CM (P < .05) of which four loci showed a genome-wide statistically significant association (P < 1 × 10(-7)), including 16q24.3 (MC1R), 20q11.22 (MYH7B/PIGU/ASIP), 11q14.3 (TYR), and 5p13.2 (SLC45A2). Grading of the cumulative evidence by the Venice criteria suggested strong epidemiological credibility for all four loci with genome-wide statistical significance and one additional gene at 9p23 (TYRP1). In the supplementary meta-analyses, a locus at 9p21.3 (CDKN2A/MTAP) reached genome-wide statistical significance with CM and had strong epidemiological credibility.

CONCLUSIONS

To the best of our knowledge, this is the first comprehensive field synopsis and systematic meta-analysis to identify genes associated with an increased susceptibility to CM.

ERp46 is reduced by high glucose and regulates insulin content in pancreatic beta-cells

Our studies focus on ERp46, an endoplasmic reticulum (ER) component, and analyze its involvement in glucose toxicity and in insulin production. Differences in pancreatic beta-TC-6 cell proteome under conditions of low vs. high glucose were examined by proteomic approaches, including two-dimensional gel electrophoresis, image analysis, and mass spectrometry. Among differentially expressed proteins, ERp46, a novel endoplasmic reticulum component, was examined further. The expression of ERp46 in pancreatic sections was analyzed by immunocytochemistry, and high glucose-induced alterations of expression were evaluated in cultured beta-cells, in isolated pancreatic islets, and in the pancreas of db/db diabetic animals. Inhibition of ERp46 expression by siRNA was performed to study its role in insulin production, in secretion, and in ER stress. Proteomic analysis led to identification of 46 differentially expressed spots corresponding to 23 proteins. Since ERp46 is a novel protein with a possible crucial role in secretory cells, we further analyzed its role in beta-cell function. ERp46 expression is reduced in high glucose concentration in beta-TC-6 cells and in isolated murine islets. Further analysis revealed high expression of ERp46 in pancreatic islets compared with exocrine tissue. Interestingly, a marked decrease in ERp46 expression was found in the pancreatic islets of db/db mice. Most importantly, siRNA-mediated knockdown of ERp46 in cultured beta-cells led to a significant decrease in the insulin content; however, no alterations in insulin mRNA levels were observed under these conditions. In addition, reduced expression of ERp46 by siRNA increased the expression of CHOP and peIF2a, indicating development of ER stress. We conclude that ERp46 may be an important component in the phenomenon of "glucose toxicity" involved in insulin production at the posttranslational level.