Hereditary melanoma: a five-year study of Brazilian patients in a cancer referral center - phenotypic characteristics of probands and pathological features of primary tumors

Familial Melanoma Phenotype With Xeroderma Pigmentosum Group C (XP-C) Genotype - The Putative Role of MC1R Polymorphism as Modifier

INTRODUCTION

Xeroderma pigmentosum (XP), a rare inherited condition, hallmarked by extreme sensitivity to sun exposure resulting in multiple skin cancers and non-malignant skin alterations is attributed to homozygous inactivating pathogenic variants (PVs) in DNA repair genes, predominantly the XPC gene.

OBJECTIVES

Report a unique phenotypic expression of mutant XPC allele that may be compatible with a putative modifier role for MC1R polymorphism.

METHODS

A family of 13 siblings, seven of whom were diagnosed with at least one cutaneous melanoma (N = 53) and non-melanoma skin cancers (N = 9) was studied. Of seven melanoma-affected cases, five consented for genetic analysis. CDKN2A revealed no PV in any case and subsequent whole-exome sequencing (WES) identified a rare homozygous missense PV (c.919C>T; p.Arg307Trp) in exon 8 of the XPC gene in all affected individuals. Notably, XPC PV carriers who co-harbored the p.I155T MC1R variant (N = 3) exhibited larger number of tumors, deeper Breslow indexes, higher rates of invasive melanomas and earlier age at diagnosis compared with non MC1R variant carriers (N = 2).

CONCLUSIONS

Familial malignant melanoma phenotype may, in fact, be an unusual clinical presentation of XPC, and MC1R may be a genetic modifier of penetrance and phenotype of mutant XPC alleles.

Antimelanoma effect of manool in 2D cell cultures and reconstructed human skin models

Melanoma is the most aggressive and lethal type of skin cancer, characterized by therapeutic resistance. In this context, the present study aimed to investigate the cytotoxic potential of manool, a diterpene from Salvia officinalis L., in human (A375) and murine (B16F10) melanoma cell lines. The analysis of cytotoxicity using the XTT assay showed the lowest IC₅₀ after 48 h of treatment with the manool, being 17.6 and 18.2 µg/ml for A375 and B16F10, respectively. A selective antiproliferative effect of manool was observed on the A375 cells based on the colony formation assay, showing an IC₅₀ equivalent to 5.6 µg/ml. The manool treatments led to 43.5% inhibition of the A375 cell migration at a concentration of 5.0 µg/ml. However, it did not affect cell migration in the B16F10 cells. Cell cycle analysis revealed that the manool interfered in the cell cycle of the A375 cells, blocking the G2/M phase. No changes in the cell cycle were observed in the B16F10 cells. Interestingly, manool did not induce apoptosis in the A375 cells, but apoptosis was observed after treatment of the B16F10 cells. Additionally, manool showed an antimelanoma effect in a reconstructed human skin model. Furthermore, in silico studies, showed that manool is stabilized in the active sites of the tubulin dimer with comparable energy concerning taxol, indicating that both structures can inhibit the proliferation of cancer cells. Altogether, it is concluded that manool, through the modulation of the cell cycle, presents a selective antiproliferative activity and a potential antimelanoma effect.

Study on Early Onset Melanoma and Germ-Line Mutation in CDKN2A among Patients in Imam Khomeini Hospital Complex

OBJECTIVE

Malignant melanoma is a highly lethal melanocytic neoplasia with different predisposing factors. The genetic background in familial cases is an important issue in finding at risk family members. CDKN2A is one of these predisposing genes which have been estimated to be involved in germ line mutation in approximately 5-10% of familial melanoma cases.

MATERIALS AND METHODS

An inclusion criteria for familial melanoma was prepared according to the literature, and the age of onset was considered as a single criteria for selection. A total number of 322 melanoma cases were investigated regarding the criteria, among which 20 patients were chosen (<40 years). DNA was extracted from Formalin Fixed Paraffin Embed of normal tissues and DNA sequencing was performed for all coding sequences of CDKN2A (p16).

RESULTS

One of the cases showed a pathogenic mutation in codon 108, exon 2(322G >C; Asp108His). Further analysis of his offspring indicated no mutation in the next generation.

CONCLUSION

As far as the authors of the present study are concerned, this was the first report on this germ-line mutation with mentioned amino acid alteration in the melanoma. Screening the CDKN2A gene for possible mutation could prevent the incidence of familial cases in at risk members.
.

Imaging of pediatric cutaneous melanoma

Melanoma accounts for 7% of all cancers in adolescents ages 15-19 years but is an unexpected malignancy in younger children. The prevalence of malignant melanoma is very rare in children ages 1-4 years, but certain non-modifiable risk factors such as xeroderma pigmentosum, congenital melanocytic nevus syndrome and other inherited traits increase the risk for its development in these young children. Recent genomic studies have identified characteristics of pediatric melanoma that differ from conventional melanoma seen in adults. In this review the authors inform on the types of melanoma seen in children and adolescents, discuss similarities and differences in melanoma between children and adults, and discuss the role of imaging in the care of these children.