PRAME expression by immunohistochemistry and reverse transcription quantitative PCR in conjunctival melanocytic lesions-a comprehensive clinicopathologic study of 202 cases and correlation of cytogenetics with PRAME expression in challenging conjunctival melanocytic lesions.

This study examined PRAME (preferentially expressed antigen in melanoma) expression by immunohistochemistry and reverse transcription quantitative PCR (RT-qPCR) in 202 histologically unequivocal conjunctival melanocytic lesions: 76 nevi, 29 benign melanoses, 25 low-grade conjunctival intraepithelial melanocytic lesions (LGCMIL), 26 high-grade conjunctival melanocytic intraepithelial lesions/in-situ melanoma (HGCMIL), and 46 invasive melanomas. PRAME score 0 was seen in 96% of nevi (73/76), 96% of benign melanoses (28/29), and 88% of LGCMIL (22/25). PRAME score 4 was seen in 50% HGCMIL (13/26) and 76% invasive melanomas (35/46). PRAME score 4 had a sensitivity of 50% and specificity of 100% in differentiating between HGCMIL and benign melanosis/LGCMIL. PRAME score 4 had a sensitivity of 76% and specificity of 100% in differentiating between melanoma and nevi. Relative quantification of PRAME mRNA expression by RT-qPCR was performed on 49 cases (24%): 17 nevi, 3 benign melanoses, 5 LGCMIL, 9 HGCMIL, and 15 invasive melanomas. The analysis generated two distinct groupings with 'high' relative PRAME expression for the HGCMIL and invasive melanoma and 'low/zero' expression for nevi, benign melanosis, and LGCMIL. Thirty-three challenging conjunctival melanocytic lesions that had previous fluorescence in situ hybridization (FISH) analysis were studied: 18 nevi, 12 melanomas in a nevus, 2 nevoid melanomas, and 1 in-situ melanoma. All nevi (100%) showed concordance between negative FISH and PRAME (scores 0-3). Four of 13 melanomas (31%; in-situ, invasive, isolated, and in association with nevus) showed concordance between positive FISH and PRAME score 4. In conclusion, PRAME score 4 has 100% specificity for the diagnosis of HGCMIL and melanoma. PRAME is limited in its sensitivity in the evaluation of challenging melanocytic lesions.

Multiple Genetically Distinct Uveal Melanomas Arise in the Same Eye of Two Patients with Melanosis Oculi.

PURPOSE: To determine whether unilateral multifocal uveal melanomas (UM) in the setting of ocular melanosis (melanosis oculi) represent genetically independent tumors. DESIGN: Clinical case series. METHODS: Two patients with unilateral multifocal UM in the setting of melanosis oculi were included. Tumors were evaluated for gene expression profile (GEP) and next generation sequencing (NGS) for uveal melanoma-associated mutations. Histopathologic analysis of enucleated specimens was also performed when available. RESULTS: Patients were both female, ages 73 and 83 years. In Patient #1, the tumors both exhibited Class 2 GEP but each harbored a unique BAP1 mutation. In Patient #2, one tumor was Class 1 and harbored an SF3B1 mutation, whereas the other tumor was Class 2 and harbored a BAP1 mutation. CONCLUSIONS: Unilateral multifocal UM in the setting of melanosis oculi can arise due to the development of genetically independent primary tumors, which is detectable based on the mutation profile of each tumor. This is the first report of genetically-confirmed independent primary tumors in the setting of unilateral multifocal UM.

Neurocutaneous Melanocytosis and Leptomeningeal Melanoma.

Neurocutaneous melanocytosis (NCM) is a disorder characterized by multiple or large congenital nevi and excessive proliferation of melanocytes in the leptomeninges and brain parenchyma. The majority of NCM is a result of somatic mosaicism due to a single postzygotic mutation in codon 61 of NRAS. Patients with NCM are at high risk of developing leptomeningeal melanoma. The prognosis for leptomeningeal melanoma is poor with no known effective treatment options. We describe the clinical features, treatment, and outcome of 4 children with NCM and leptomeningeal melanoma and discuss the latest molecular findings and treatment options for this rare condition.

Metastatic Melanoma Negative for 5 Melanocytic Markers, Complete Regressed Primary Cutaneous Melanoma, and Melanoma-Associated Leukoderma in the Same Patient.

Melanomas with complete histological regression have been seen very infrequently. On the other hand, the diagnosis of metastatic melanoma is based on the histopathology and positivity of markers such as S100, Melan-A, and HMB-45 whose sensitivity is 99%, 82%, and 76%, respectively. It is very rare that metastatic melanomas and even more primary melanoma are negative for all of these markers. In these rare cases, there is usually a known primary. We present the case of a 82-year-old woman with a erythematous mass in the left groin and a 1-cm black-bluish irregular nodule on the skin of the ipsilateral foot. This lesion was clinical and dermoscopically compatible with primary melanoma. In the histological evaluation of the skin, a dermis full of melanophages and hemosiderophages were found in a background of fibrosis, scarce lymphocytic infiltrate, and neovascularization. Any cells expressing melanocytic markers were observed. It was diagnosed as tumoral melanosis. Lymph nodes showed a proliferation of atypical epithelioid cells with eosinophilic cytoplasm. Mitosis was conspicuous. Tumoral cells were vimentin and CD99 positive, and S100, CD34, HMB-45, Melan-A, SOX 10, tyrosinase, C-KIT, CD45, and CKAE1/AE3 negative, and BRAF-V600 mutated was detected. During follow-up, atypical vitiligo-like lesions were discovered, suggesting the diagnosis of metastatic melanoma totally regressed in our patient.

Melanogenic Properties and Expression Profiles of Melanogenic Paracrine Molecules in Riehl's Melanosis.

Riehl's melanosis is a hyperpigmentary disorder that occurs predominantly on the face and neck. To date, the pathogenesis of Riehl's melanosis with regards to the melanogenic properties and paracrine melanogenic molecules has not well been studied. This study was aimed to provide a novel perspective on the pathogenesis of Riehl's melanosis by identifying the relevant paracrine melanogenic molecules in Riehl's melanosis. Skin biopsies were performed on lesional and normal-appearing perilesional skin of 12 patients with Riehl's melanosis and 12 age- and sex-matched healthy controls. Histopathological and immunohistochemical staining for paracrine melanogenic molecules was analyzed. The major histopathological findings of Riehl's melanosis were basal hyperpigmentation, melanocyte proliferation, interface change, dermal pigmentary incontinence, vascular proliferation, and dermal inflammation. Dermal expression intensities of stem cell factor (SCF) and c-kit were increased in the lesional skin of Riehl's melanosis. In addition, increased expression of epidermal and dermal ET-1 was also observed in the lesional skin of Riehl's melanosis. Increased tissue expressions of SCF, c-kit, and ET-1 in Riehl's melanosis support the role of these paracrine melanogenic molecules in the pathogenesis of Riehl's melanosis. The findings from this study might present useful information on the pathogenetic mechanism of Riehl's melanosis.

Genomic evolution of uveal melanoma arising in ocular melanocytosis.

Ocular melanocytosis is the most important predisposing condition for the eye cancer uveal melanoma (UM). Here, we present a patient who developed UM arising within ocular melanocytosis who was treated with enucleation (eye removal), which provided an invaluable opportunity to interrogate both the UM and adjacent uveal tissue containing the melanocytosis using whole-exome and deep-targeted sequencing. This analysis revealed a clonal PLCB4 mutation in the melanocytosis, confirming that this is indeed a neoplastic condition and explaining why it predisposes to UM. This mutation was present in 100% of analyzed UM cells, indicating that a PLCB4-mutant cell gave rise to the UM. The earliest aberrations specific to the tumor were loss of Chromosomes 1p, 3, and 9p, which were present in virtually all tumor cells. A mutation in BAP1 arose later on the other copy of Chromosome 3 in a tumor subclone, followed by a gain of Chromosome 8q. These findings provide a mechanistic explanation for the well-known clinical association between ocular melanocytosis and UM by showing that this predisposing condition introduces the first "hit" and thereby increases the stochastic likelihood of acquiring further aberrations leading to UM.

High naevus count and MC1R red hair alleles contribute synergistically to increased melanoma risk.

BACKGROUND: A high total body naevus count is the highest risk factor for melanoma; the phenotype of red hair colour, freckling and pale skin that burns easily, produced by MC1R R alleles, also predisposes to melanoma. OBJECTIVES: To determine whether the known melanoma risk factors of high naevus count and red hair or MC1R R alleles act synergistically to increase melanoma risk. METHODS: The Brisbane Naevus Morphology Study involved 1267 participants from volunteers presenting at a melanoma unit, dermatology outpatient clinic, private dermatology clinics, the Brisbane Longitudinal Twin Study and the QSkin Study. We examined pigmentation characteristics, total body naevus ≥ 5 mm count, and MC1R, ASIP and CDKN2A genotype in participants with and without a personal history of melanoma, living in Queensland, Australia, which is an area of high ultraviolet radiation. RESULTS: Cases were older than controls (median 57 vs. 33 years). Compared with individuals with dark brown hair and zero to four naevi, individuals with red hair and ≥ 20 naevi had a melanoma odds ratio of 10·0 (95% confidence interval 4·2-24·3). Individuals with MC1R R/R genotype and ≥ 20 naevi (≥ 5 mm diameter) had a melanoma odds ratio of 25·1 (95% confidence interval 8·4-82·7) compared with wild-type (WT)/WT individuals with zero to four naevi. The highest risk group is Australian men with the MC1R R/R genotype and ≥ 20 moles, who have an absolute risk of melanoma to age 75 years of 23·3%, compared with 0·8% for men with the WT/WT genotype and zero to four naevi. CONCLUSIONS: Patients who live in areas of high ultraviolet radiation, and have many large naevi and the red hair colour phenotype, particularly those with the MC1R R/R genotype, have a high risk of melanoma above the threshold recommended for screening in other cancers. Therefore, they should undergo intensive physician-led surveillance. What's already known about this topic? A high number of acquired melanocytic naevi, the red hair phenotype and MC1R R alleles all independently increase melanoma risk. Women with atypical naevi have an increasing melanoma risk gradient from darker hair to lighter hair. Women with many naevi have an increasing melanoma risk gradient from those with no elements of the red hair phenotype, to those with freckles but not red hair, to those with red hair. What does this study add? In Queensland, Australia, people with ≥ 20 naevi (≥ 5 mm diameter) and MC1R R/R genotype have a 25-fold increased melanoma risk, relative to people with zero to four naevi and the MC1R WT/WT genotype. In Queensland, individuals with ≥ 20 naevi and the MC1R R/R genotype have an absolute melanoma risk to age 75 years of 23·3% for men and 19·3% for women. This effect is independent of CDKN2A genotype. Further research is required to determine the effect of areas of lower ultraviolet radiation, as this study took place in the Queensland, Australia, which is an area of high ultraviolet radiation. MC1R R/r genotype is associated with increased total body naevus count but this is not the case for R/R. What is the translational message? Patients with many large naevi and the red hair colour phenotype, particularly those with an MC1R R/R genotype, have an unusually high risk of melanoma. In a high ultraviolet environment, this risk exceeds the threshold recommended for screening in other cancers, and such individuals should undergo intensive, regular, physician-led surveillance. Patients with many large naevi but with non-red colour hair may benefit further from clinical MC1R genotyping.

Identification of candidate biomarkers associated with apoptosis in melanosis coli: GNG5, LPAR3, MAPK8, and PSMC6.

Purpose: Melanosis coli (MC) is a disorder of pigmentation of the wall of the colon, often identified at the time of colonoscopy. The aim of the present study is to identify candidate biomarkers for MC. Methods: The transcriptome data for MC (GSE78933) with five MC tissues and five corresponding normal tissues is obtained from the NCBI Gene Expression Omnibus (GEO) database. R/Bioconductor package limma was used to screen differently expressed genes (DEGs). ClueGO of cytoscape was applied for Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Based on STRING V10 database, protein-protein interaction (PPI) network was constructed. The pathological tissue and normal tissue from 23 MC patients and 23 controls were collected, respectively. The relative expression of hub nodes was detected by qRT-PCR and Western blot. For regulating the expression of these genes, overexpression vector was constructed or siRNA transfection was used. Finally, apoptosis was detected by flow cytometry. Results: Total 1342 DEGs were screened, including 786 up-regulated and 556 down-regulated genes. These genes were mainly enriched in stimulatory C-type lectin receptor signaling pathway, polysaccharide biosynthetic process, intracellular, and oxidative phosphorylation. PPI network was then constructed with 426 DEGs and 895 interactions. Thereinto, G-protein subunit γ 5 (GNG5), lysophosphatidic acid receptor 3 (LPAR3), mitogen-activated protein kinase 8 (MAPK8), NHP2L1, proteasome 26S subunit, ATPase 6 (PSMC6), and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit ß (PIK3CB) were hub nodes with higher degree. RT-PCR and Western blot results showed that GNG5, LPAR3, MAPK8, and PSMC6 were differently expressed with significance. The expression of these screened genes is also related with cell apoptosis. Conclusion: GNG5, LPAR3, MAPK8, and PSMC6 might be candidate biomarkers associated with apoptosis in MC.

NRASQ61K mutated diffuse leptomeningeal melanomatosis in an adult patient with a brief review of the so-called "forme fruste" of neurocutaneous melanosis.

Primary melanocytic tumors of central nervous system represent rare tumors arising from melanocytes of the leptomeninges. These neoplasms include focal forms like melanocytoma and primary malignant melanoma and diffuse forms like leptomeningeal melanocytosis and primary leptomeningeal melanomatosis. The clinical diagnosis remains challenging, with clinical and radiologic features overlapping with other more common diseases. Here we present a case of a 38 years old male with primary diffuse leptomeningeal melanomatosis with presence of a NRASQ61K mutation without features of neurocutaneous melanosis.

Anti-melanogenic effects of resorcinol are mediated by suppression of cAMP signaling and activation of p38 MAPK signaling.

In this study, we investigated the inhibitory mechanisms of resorcinol in B16F10 mouse melanoma cells. We found that resorcinol reduced both the melanin content and tyrosinase activity in these cells. In addition, resorcinol suppressed the expression of melanogenic gene microphthalmia-associated transcriptional factor (MITF) and its downstream target genes tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. In addition, we found that resorcinol reduced intracellular cAMP levels and protein kinase A (PKA) activity, and increased phosphorylation of the p38 mitogen-activated protein kinase (MAPK). Resorcinol was also found to directly inhibit tyrosinase activity. However, resorcinol-induced decrease in melanin content, tyrosinase activity, and tyrosinase protein levels were attenuated by SB203580, a p38 MAPK inhibitor. Taken together, these data indicate that anti-melanogenic activity of resorcinol is be mediated through the inhibition of cAMP signaling and activation of p38 MAPK, indicating that resorcinol may be a possible ameliorating agent in the treatment of hyperpigmentation skin disorders.

The clinicoaetiological, hormonal and histopathological characteristics of melasma in men.

BACKGROUND: Melasma is relatively uncommon in males, and there is a paucity of data on male melasma, including its clinical pattern, triggering factors, endocrine profile and histopathological findings. AIM: To characterize the clinical findings and aetiological factors, including hormonal and histopathological features, of male melasma. METHODS: Male patients with melasma and age- and sex-matched healthy controls (HCs) were recruited. Demographic profile, risk factors, clinical pattern and Wood lamp findings of patients were recorded. Sera were obtained from patients and HCs to determine hormone levels. Biopsy specimens were obtained from lesional and adjacent nonlesional skin. RESULTS: In total, 50 male patients with melasma and 20 HCs were recruited into the study. Mean age of patients was 27.58 ± 4.51 years. The most common clinical pattern of melasma was malar, which occurred in 52% of cases. Positive family history was present in 16% of patients, while 34% had disease aggravation with sun exposure and 62% used mustard oil for hair growth and/or as an emollient. Wood lamp examination revealed epidermal-type melasma in 54% of patients. There were no significant differences in hormone levels between patients and HCs. Histologically, epidermal melanin, elastotic degeneration, vascular proliferation and mast cells were more pronounced in lesional compared with nonlesional skin. Absent to weak expression of oestrogen receptors, progesterone receptors and stem cell factor was observed in lesional skin. CONCLUSION: Ultraviolet light and mustard oil are important causative factors in male melasma. Although stress and family history may contribute, hormonal factors possibly have no role. Quantitative analysis of immunohistochemical markers would provide insight in understanding the pathogenesis of melasma.

Melasma, a photoaging disorder.

Melasma is a common hyperpigmentary disorder. The impact on the quality of life of affected individuals is well demonstrated, demanding new therapeutic strategies. However, the treatment of melasma remains highly challenging. Melasma is often considered as the main consequence of female hormone stimulation on a predisposed genetic background. Although these two factors do contribute to this acquired pigmentary disorder, the last decade has revealed several other key players and brought new pieces to the complex puzzle of the pathophysiology of melasma. Here, we summarize the latest evidence on the pathophysiology of melasma, and we suggest that melasma might be a photoaging skin disorder affecting genetically predisposed individuals. Such data must be taken into consideration by clinicians as they could have a profound impact on the treatment and the prevention of melasma.

Potential Causative Mutation for Melanism in Rats Identified in the Agouti Signaling Protein Gene (Asip) of the Rattus rattus Species Complex on Okinawa Island, Japan.

The occurrence of black fur, or melanism, in many mammalian species is known to be linked to DNA sequence variation in the agouti signaling protein (Asip) gene, which is a major determinant of eumelanin and pheomelanin pigments in coat color. We investigated 38 agouti (i.e., banded wildtype) and four melanistic Rattus rattus species complex (RrC) lineage II specimens from Okinawa Island, Ryukyu Islands, Japan, for genetic variation in three exons and associated flanking regions in the Asip gene. On Okinawa, a predicted loss-of-function mutation caused by a cysteine to serine amino acid change at p.124C>S (c.370T>A) in the highly conserved functional domain of Asip was found in melanistic rats, but was absent in agouti specimens, suggesting that the p.124C>S mutation is responsible for the observed melanism. Phylogeographic analysis found that Asip sequences from Okinawan RrC lineage II, including both agouti and melanistic specimens, differed from: 1) both agouti and melanistic RrC lineage I from Otaru, Hokkaido, Japan, and 2) agouti RrC lineages I and II from South Australia. This suggests the possibility of in-situ mutation of the Asip gene, either within the RrC lineage II population on Okinawa or in an unsampled RrC lineage II population with biogeographic links to Okinawa, although incomplete lineage sorting could not be ruled out.

Arginase-2, a miR-1299 target, enhances pigmentation in melasma by reducing melanosome degradation via senescence-induced autophagy inhibition.

Expression profiles revealed miR-1299 downregulation concomitant with arginase-2 (ARG2) upregulation in hyperpigmented skin of melasma patients. Opposite regulation of tyrosinase and PMEL17 by miR-1299 and inverse relationship between miR-1299 and ARG2 expression denoted a role of miR-1299 in pigmentation with ARG2 as a miR-1299 target. ARG2 overexpression or knock-down in keratinocytes, the main source of ARG2 in epidermis, positively regulated tyrosinase and PMEL17 protein levels, but not mRNA levels or melanosome transfer. ARG2 overexpression in keratinocytes reduced autophagy equivalent to 3-MA, an autophagy inhibitor which also increased tyrosinase and PMEL17 protein levels, whereas ARG2 knock-down induced opposite results. Autophagy inducer rapamycin reduced ARG2-increased tyrosinase and PMEL17 protein levels. Also, autophagy was reduced in late passage-induced senescent keratinocytes showing ARG2 upregulation. ARG2, but not 3-MA, stimulated keratinocyte senescence. These results suggest that ARG2 reduces autophagy in keratinocytes by stimulating cellular senescence, resulting in skin pigmentation by reducing degradation of transferred melanosomes.