Melanocytic nevi and melanoma: unraveling a complex relationship. Oncogene. 2017;36:5771-5792. [PMID: 28604751 DOI: 10.1038/onc.2017.189]

Evaluation of tubulin β-3 and 5 hydroxy-methyl cytosine as diagnostic and prognostic markers in malignant melanoma

Tubulin β-3 staining pattern and staining intensity of 5-hydroxymethyl cytosine (5-hmC) are potential diagnostic and prognostic markers in melanocytic lesions that need further evaluation. Melanocytic nevi and primary cutaneous melanomas were immunohistochemically stained for tubulin-β-3 and 5-hmC. Immunoreactivity and staining patterns were correlated with Breslow-thickness, clinical and pathological characteristics, and progression-free survival. Melanocytes showed positive tubulin β-3 staining. However, in most nevi, tubulin β-3 staining appeared as a gradient with intense cytoplasmic staining in cells of the superficial part of the lesion that faded to weak staining in the deep dermal part, while no gradient was found in deep penetrating nevi and melanomas. In 53 % of the melanomas, areas with loss of tubulin β-3 staining were found. 5-hmC staining intensity was significantly higher in melanocytic nevi compared to melanomas. Breslow thickness in combination with low 5-hmC score and loss of tubulin-β-3 staining was predictive for poor prognosis. As single markers, tubulin-β-3 and 5-hmC can be useful to distinguish between melanocytic nevi and melanoma, but staining variability limits the use of 5-hmC. In melanomas measuring >1.5 mm, combination of low 5-hmC score and loss of tubulin-β-3 staining may have prognostic value.

Nevi and Melanoma

Cutaneous melanoma is an aggressive form of skin cancer derived from skin melanocytes and is associated with significant morbidity and mortality. A significant fraction of melanomas are associated with precursor lesions, benign clonal proliferations of melanocytes called nevi. Nevi can be either congenital or acquired later in life. Identical oncogenic driver mutations are found in benign nevi and melanoma. While much progress has been made in our understanding of nevus formation and the molecular steps required for transformation of nevi into melanoma, the clinical diagnosis of benign versus malignant lesions remains challenging.

An in vitro nevus explant model for studying the effects of ultraviolet radiation

Ultraviolet radiation (UVR) has been recognized as a potential trigger for the transformation of benign melanocytic nevi into melanoma. However, the mechanisms governing the formation and progression of melanocytic nevi remain poorly understood. This lack of understanding is partly due to the difficulty in isolating and culturing nevus tissues in vitro, resulting in a dearth of robust ex vivo models for nevi. Therefore, the establishment of a reliable melanocytic nevus model is imperative. Such a model is essential for elucidating nevus pathogenesis and facilitating the development of effective therapeutic interventions. Therefore, we have sought to establish an ex vivo nevus explant model to study UVR stimulation. And the structural integrity and tissue activity of the ex vivo nevi explant model was evaluated. We then observed melanogenesis and proliferation activity of the explants after UVR stimulation. There was less blister formation after Day 3 in nevi explants under our modified medium conditions. The nevi explant was able to maintain almost the same morphological structure and tissue activity as in vivo tissue within 24 h. Following UVR stimulation, we observed increased melanogenesis and proliferation activity in nevi explants. Nevi explants could serve as an ex vivo model for UVR-induced nevi stimulation research.

Review of the comparative pathological and immunohistochemical features of human and canine cutaneous melanocytic neoplasms

Melanocytic neoplasms originate from melanocytes and melanoma, the malignant form, is a common canine neoplasm and the most aggressive human skin cancer. Despite many similarities between these neoplasms in both species, only a limited number of studies have approached these entities in a comparative manner. Therefore, this review compares benign and malignant melanocytic neoplasms in dogs and humans, exclusively those arising in the haired skin, with regard to their clinicopathological, immunohistochemical and molecular aspects. Shared features include spontaneous occurrence, macroscopic features and microscopic findings when comparing human skin melanoma in the advanced/invasive stage and canine cutaneous melanoma, immunohistochemical markers and several histopathological prognostic factors. Differences include the apparent absence of active mutations in the BRAF gene in canine cutaneous melanoma and less aggressive clinical behaviour in dogs than in humans. Further studies are required to elucidate the aetiology and genetic development pathways of canine cutaneous melanocytic neoplasms. Evaluation of the applicability of histopathological prognostic parameters commonly used in humans for dogs are also needed. The similarities between the species and the recent findings regarding genetic mutations in canine cutaneous melanomas suggest the potential utility of dogs as a natural model for human melanomas that are not related to ultraviolet radiation.

Review: Are moles senescent?

Melanocytic nevi (skin moles) have been regarded as a valuable example of cell senescence occurring in vivo. However, a study of induced nevi in a mouse model reported that the nevi were arrested by cell interactions rather than a cell-autonomous process like senescence, and that size distributions of cell nests within nevi could not be accounted for by a stochastic model of oncogene-induced senescence. Moreover, others reported that some molecular markers used to identify cell senescence in human nevi are also found in melanoma cells-not senescent. It has thus been questioned whether nevi really are senescent, with potential implications for melanoma diagnosis and therapy. Here I review these areas, along with the genetic, biological, and molecular evidence supporting senescence in nevi. In conclusion, there is strong evidence that cells of acquired human benign (banal) nevi are very largely senescent, though some must contain a minor non-senescent cell subpopulation. There is also persuasive evidence that this senescence is primarily induced by dysfunctional telomeres rather than directly oncogene-induced.

A phase II study of efficacy and safety of the MEK inhibitor tunlametinib in patients with advanced NRAS-mutant melanoma

BACKGROUND

NRAS-mutant melanoma is an aggressive subtype with poor prognosis; however, there is no approved targeted therapy to date worldwide.

METHODS

We conducted a multicenter, single-arm, phase II, pivotal registrational study that evaluated the efficacy and safety of the MEK inhibitor tunlametinib in patients with unresectable, stage III/IV, NRAS-mutant melanoma (NCT05217303). The primary endpoint was objective response rate (ORR) assessed by independent radiological review committee (IRRC) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. The secondary endpoints included progression-free survival (PFS), disease control rate (DCR), duration of response(DOR), overall survival (OS) and safety.

FINDINGS

Between November 2, 2020 and February 11, 2022, a total of 100 patients were enrolled. All (n = 100) patients received at least one dose of tunlametinib (safety analysis set [SAS]) and 95 had central laboratory-confirmed NRAS mutations (full analysis set [FAS]). In the FAS, NRAS mutations were observed at Q61 (78.9%), G12 (15.8%) and G13 (5.3%). The IRRC-assessed ORR was 35.8%, with a median DOR of 6.1 months. The median PFS was 4.2 months, DCR was 72.6% and median OS was 13.7 months. Subgroup analysis showed that in patients who had previously received immunotherapy, the ORR was 40.6%. No treatment-related deaths occurred.

INTERPRETATION

Tunlametinib showed promising antitumor activity with a manageable safety profile in patients with advanced NRAS-mutant melanoma, including those who had prior exposure to immunotherapy. The findings warrant further validation in a randomized clinical trial.

Erbium: YAG laser treatment efficacy and association with histologic features for giant congenital melanocytic nevi management

BACKGROUND

Limited research exists on laser treatment of giant congenital melanocytic nevus (GCMN).

OBJECTIVE

We sought to elucidate the efficacy of the Erbium: YAG laser on GCMN and the histologic factors associated with a positive clinical response.

METHODS AND MATERIALS

Between 2019 and 2022, we enrolled 30 medium-to-giant CMN patients who underwent Er: YAG laser treatment. All patients received biopsies before and after laser treatments. Clinical efficacy outcomes were evaluated by the investigator's global assessment (IGA), 5-point scale of depigmentation, and Vancouver Scar Scale (VSS) scores at least 6 months after treatment.

RESULTS

Of the 30 cases, 18 (60.0%) showed improvement (IGA score ≥3). Eight (26.7%) patients showed repigmentation. Eight (26.7%) patients developed hypertrophic scars. The average IGA, depigmentation, and VSS scores were 2.93, 3.57, and 3.20. The IGA score was higher (3.24 ± 1.18 vs. 2.22 ± 0.97, p = 0.031) and a lower repigmentation rate (14.3% vs. 55.6%, p = 0.032) was observed in the cases with Grenz zone. The IGA score was higher (3.33 ± 1.24 vs. 2.13 ± 0.89, p = 0.023) and the repigmentation rate was lower (11.1% vs. 50.0%, p = 0.034) also in the cases with the melanocytes nests with aggregation of melanin. Lesions with superficial ablation resulted in less hypertrophic scar formation than those with deep ablation (5.9% vs. 53.8%, p < 0.05).

CONCLUSION

The Er: YAG laser demonstrated effective clinical results for GCMNs. The grenz zone and the melanocytes nests with aggregation of melanin are promising predictors of laser efficacy.

Integrated in vivo functional screens and multi-omics analyses identify α-2,3-sialylation as essential for melanoma maintenance

Glycosylation is a hallmark of cancer biology, and altered glycosylation influences multiple facets of melanoma growth and progression. To identify glycosyltransferases, glycans, and glycoproteins essential for melanoma maintenance, we conducted an in vivo growth screen with a pooled shRNA library of glycosyltransferases, lectin microarray profiling of benign nevi and melanoma patient samples, and mass spectrometry-based glycoproteomics. We found that α-2,3 sialyltransferases ST3GAL1 and ST3GAL2 and corresponding α-2,3-linked sialosides are upregulated in melanoma compared to nevi and are essential for melanoma growth in vivo and in vitro. Glycoproteomics revealed that glycoprotein targets of ST3GAL1 and ST3GAL2 are enriched in transmembrane proteins involved in growth signaling, including the amino acid transporter Solute Carrier Family 3 Member 2 (SLC3A2/CD98hc). CD98hc suppression mimicked the effect of ST3GAL1 and ST3GAL2 silencing, inhibiting melanoma cell proliferation. We found that both CD98hc protein stability and its pro-survival effect in melanoma are dependent upon α-2,3 sialylation mediated by ST3GAL1 and ST3GAL2. In summary, our studies reveal that α-2,3-sialosides functionally contribute to melanoma maintenance, supporting ST3GAL1 and ST3GAL2 as novel therapeutic targets in these tumors.

Histopathologic Characterization of Incidental Lesions Encountered During Mohs Micrographic Surgery With MART-1 Immunohistochemistry

BACKGROUND

As the use of melanoma antigen recognized by T cells (MART-1) immunohistochemistry (IHC) with Mohs surgery increases for the treatment of melanoma in situ and invasive melanoma, surgeons should be aware of MART-1 staining patterns of incidental lesions often encountered on frozen sections. Lack of this knowledge can lead to unnecessary additional surgery, increased health care costs, and loss of valuable laboratory staff time and resources.

OBJECTIVE

To characterize the histopathologic features of incidental lesions encountered during Mohs surgery for melanoma. To review key diagnostic and differentiating features on hematoxylin and eosin staining (H&E) and MART-1 IHC of these lesions.

METHODS

A comprehensive review of frozen-section histopathology slides from Mohs cases with MART-1 IHC at our institution was conducted from 2021 to 2023.

RESULTS

Incidental benign and malignant lesions were identified and characterized on H&E frozen sections and MART-1 IHC. Although such entities can share MART-1 staining characteristics with melanoma in situ or melanoma, distinguishing characteristics on H&E and lack of histopathologic criteria for melanoma on MART-1 IHC can be used to distinguish these incidental lesions from melanoma.

CONCLUSION

Staining of frozen sections for Mohs micrographic surgery with H&E and MART-1 IHC together can differentiate common incidental benign and malignant cutaneous lesions from melanoma.

Risk Factors and Innovations in Risk Assessment for Melanoma, Basal Cell Carcinoma, and Squamous Cell Carcinoma

Skin cancer is the most frequently diagnosed cancer globally and is preventable. Various risk factors contribute to different types of skin cancer, including melanoma, basal cell carcinoma, and squamous cell carcinoma. These risk factors encompass both extrinsic, such as UV exposure and behavioral components, and intrinsic factors, especially involving genetic predisposition. However, the specific risk factors vary among the skin cancer types, highlighting the importance of precise knowledge to facilitate appropriate early diagnosis and treatment for at-risk individuals. Better understanding of the individual risk factors has led to the development of risk scores, allowing the identification of individuals at particularly high risk. These advances contribute to improved prevention strategies, emphasizing the commitment to mitigating the impact of skin cancer.

Assessment of RAS-RAF-MAPK Pathway Mutation Status in Healthy Skin, Benign Nevi, and Cutaneous Melanomas: Pilot Study Using Droplet Digital PCR

In the present study, we employed the ddPCR and IHC techniques to assess the prevalence and roles of RAS and RAF mutations in a small batch of melanoma (n = 22), benign moles (n = 15), and normal skin samples (n = 15). Mutational screening revealed the coexistence of BRAF and NRAS mutations in melanomas and nevi and the occurrence of NRAS G12/G13 variants in healthy skin. All investigated nevi had driver mutations in the BRAF or NRAS genes and elevated p16 protein expression, indicating cell cycle arrest despite an increased mutational burden. BRAF V600 mutations were identified in 54% of melanomas, and NRAS G12/G13 mutations in 50%. The BRAF mutations were associated with the Breslow index (BI) (p = 0.029) and TIL infiltration (p = 0.027), whereas the NRAS mutations correlated with the BI (p = 0.01) and the mitotic index (p = 0.04). Here, we demonstrate that the "young" ddPCR technology is as effective as a CE-IVD marked real-time PCR method for detecting BRAF V600 hotspot mutations in tumor biopsies and recommend it for extended use in clinical settings. Moreover, ddPCR was able to detect low-frequency hotspot mutations, such as NRAS G12/G13, in our tissue specimens, which makes it a promising tool for investigating the mutational landscape of sun-damaged skin, benign nevi, and melanomas in more extensive clinical studies.

Clinical features and management of eyelid margin nevi

PURPOSE

Acquired melanocytic nevi are common eyelid lesions; however, their clinical presentation is not well documented.

METHODS

In this retrospective study, clinical records were reviewed in patients evaluated between 2005 and 2022.

RESULTS

Eyelid margin nevi (n = 150) were more commonly excised in female (78%) and Caucasian (86%) patients. Change in appearance/size were frequent presenting complaints, and 17% experienced ocular symptoms. Referring diagnosis included other benign lesions (11.3%), and concern for malignancy (16.7%). Many individuals (38.7%) noted their lesion for ≤5 years. Nevi were distributed across the 4 margins (9% peripunctal), and 88% had a regular base. Visible pigmentation was more common in non-Caucasians (95.2%) than Caucasians (41.1%). Lashes grew through 60.7% of nevi and were often misdirected.Nevi were treated with superficial excision and cauterization. Histologic subtypes included: dermal (86.6%), compound (9.4%), blue (2.7%), junctional (0.7%), lentiginous dysplastic (0.7%). An irregular base (p=0.042) and pigmentation (p=0.056) were more common in compound than dermal nevi. Lash line quality and appearance were improved in the majority of patients returning for follow-up, although postoperative trichiasis, marginal erythema, and residual pigmentation were observed.

CONCLUSIONS

Melanocytic nevi commonly involve the eyelid margins and have a variety of presentations and appearances. Existing nevi can change, and new lesions appear throughout adulthood. Stable, benign appearing nevi can be observed. Shave excision provides a diagnosis and improved appearance for symptomatic or suspicious lesions, with few serious complications. Malignant transformation is rare, although evidence for recurrence warrants further evaluation.

A Narrative Review of Current Knowledge on Cutaneous Melanoma

Cutaneous melanoma is a public health problem. Efforts to reduce its incidence have failed, as it continues to increase. In recent years, many risk factors have been identified. Numerous diagnostic systems exist that greatly assist in early clinical diagnosis. The histopathological aspect illustrates the grim nature of these cancers. Currently, pathogenic pathways and the tumor microclimate are key to the development of therapeutic methods. Revolutionary therapies like targeted therapy and immune checkpoint inhibitors are starting to replace traditional therapeutic methods. Targeted therapy aims at a specific molecule in the pathogenic chain to block it, stopping cell growth and dissemination. The main function of immune checkpoint inhibitors is to boost cellular immunity in order to combat cancer cells. Unfortunately, these therapies have different rates of effectiveness and side effects, and cannot be applied to all patients. These shortcomings are the basis of increased incidence and mortality rates. This study covers all stages of the evolutionary sequence of melanoma. With all these data in front of us, we see the need for new research efforts directed at therapies that will bring greater benefits in terms of patient survival and prognosis, with fewer adverse effects.

Hamartomas, choristomas, and teratomas of the oral cavity: A 49-years cross-sectional study in an oral diagnostic service

BACKGROUND

To investigate the incidence and demographic profile of hamartomatous, choristomatous, and teratoid lesions in a Brazilian population over a 49 years-period.

METHODS

A retrospective cross-sectional study was performed, and data regarding demographic and clinical aspects were obtained from the medical records of a [removed for blind peer review] referral center (1970-2019). The collected data were submitted to descriptive analysis and Pearson's chi-square, Fisher's exact, and Kruskal-Wallis tests (p ≤ 0.05).

RESULTS

In a total of 16,412 medical records analyzed, 300 (1.83 %) were hamartomatous, 2 (0.01 %) choristomatous, and 1 (0.01 %) teratoid lesions. Hamartomas were most diagnosed in females and adults. Statistical significance was observed between hamartoma and age group (p < 0.001). Odontoma was the most frequent hamartomatous lesion. In choristomatous and teratoid lesions, there was no occurrence in males. The jaws were the most affected anatomical site by hamartoma. Choristomas were observed on the mandible and tongue, while a teratoid lesion was seen on the floor of the mouth.

CONCLUSIONS

Low occurrence of choristomatous and teratoid lesions over hamartomatous lesions and a heterogeneous occurrence profile regarding sex, age group, and anatomic site were observed. Hamartomas are relatively common and benign conditions that may cause damage and require special care during dental treatment. Thus, the dentist needs to be able to identify and treat them appropriately. Likewise, although choristomas and teratomas present no risk to patients and have a lower occurrence than hamartomas, they also require treatment.

Analysing the causal relationship between potentially protective and risk factors and cutaneous melanoma: A Mendelian randomization study

BACKGROUND

Previous observational studies reported altered melanoma risks in relation to many potential factors, such as coffee intake, smoking habits and photodamage-related conditions. Considering the susceptibility of epidemiological studies to residual confounders, there remains uncertainty about the actual causal roles of these reported factors in melanoma aetiology.

OBJECTIVES

This study aims to investigate the causal association between cutaneous melanoma (CM) and previously reported factors: coffee intake, alcohol consumption, lifetime smoking, socioeconomic status (SES), ease of skin tanning, childhood sunburn and facial ageing, providing insight into its underlying aetiology and preventative strategies.

METHODS

We utilized a two-sample MR analysis on data from the largest meta-analysis summary statistics of confirmed cutaneous melanoma including 30,134 patients. Genetic instrumental variables were constructed by identifying single nucleotide polymorphisms (SNPs) that associate with corresponding factors. Inverse variance weighted (IVW) was the primary MR method. For sensitivity and heterogeneity, MR Egger, weighted median, simple mode, weighted mode and MR Egger intercept tests were examined.

RESULTS

Cutaneous melanoma risks were found to be elevated in association with a predisposition towards ease of skin tanning (IVW: OR = 2.842, 95% CI 2.468-3.274, p < 0.001) and with childhood sunburn history (IVW: OR = 6.317, 95% CI 4.479-8.909, p < 0.001). Repeated MR after removing potential confounders and outliers demonstrated resolved horizontal pleiotropy and statistically significant results that closely mirrored the initial findings. Other potential factors, such as coffee intake, alcohol consumption, smoking and socioeconomic status (SES), indicated insignificant effects on melanoma risk in the analysis, and therefore, our Mendelian randomization study does not support their roles in modifying melanoma risks.

CONCLUSIONS

Our extensive MR analysis provides strong evidence of the causative role of ease of skin tanning and childhood sunburn history in elevating melanoma risk. Curtailing ultraviolet radiation (UVR) exposure may be the single best preventative strategy to reduce melanoma risk.

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.

Telomere length is associated with increased risk of cutaneous melanoma: a Mendelian randomization study

RESULTS

The MR analysis using two TL GWAS datasets revealed strong and consistent evidence that long TL is causally associated with an increased risk of CM. The analysis of the Codd et al. dataset found that long TL significantly predicted an elevated risk of CM (IVW OR = 2.411, 95% CI 2.092-2.780, P = 8.05E-34). Similarly, the analysis of the Li et al. dataset yielded consistent positive results across all MR methods, providing further robustness to the causal relationship (IVW OR = 2.324, 95% CI 1.516-3.565, P = 1.11E-04). The study provides evidence for a causal association between TL and CM susceptibility, indicating that longer TL increases the risk of developing CM and providing insight into the unique telomere biology in melanoma pathogenesis. Telomere maintenance pathways may be a potential target for preventing and treating CM.

Neo-Darwinian Principles Exemplified in Cancer Genomics

Within the last two decades, the advent of next-generation sequencing accompanied by single-cell technologies has enabled cancer researchers to study in detail mutations and other genetic aberrations that transpire during transformation of cells to a neoplastic state. This article covers the insights gained through these extensive studies where neo-Darwinian principles can be inferred to play roles throughout neoplastic transformation. The cells promoted during cancer development exhibit cancer hallmarks combined with the related enabling characteristics as outlined by Hanahan and Weinberg, analogous to natural selection and survival of the fittest. Selection of driver mutations that inactivate proteins encoded by tumor suppressor genes differs in profound ways from mutations that activate tumor promoter proteins. In most cases, the later stages of cancer development are characterized by sudden, extensive damage to chromosomes in a process that is not Darwinian in nature. Nevertheless, cells that survive these cataclysmic events remain subject to Darwinian selection promoting clones exhibiting the greatest rates of progression. Duplications of chromosomal segments containing oncogenes, deletions of segments harboring tumor suppressor genes, or distinctive chromosomal rearrangements are often found in cells progressing into later stages of cancer. In summary, the technological developments in genome sequencing since the start of the century have given us clear insights into genomic alterations promoting tumor progression where neo-Darwinian mechanisms of clonal selection can be inferred to play a primary role.

Targeting ferroptosis in melanoma: cancer therapeutics

Melanoma is an aggressive kind of skin cancer; its rate has risen rapidly over the past few decades. Melanoma reports for only about 1% of skin cancers but leads to a high majority of skin cancer deaths. Thus, new useful therapeutic approaches are currently required, to state effective treatments to consistently enhance the overall survival rate of melanoma patients. Ferroptosis is a recently identified cell death process, which is different from autophagy, apoptosis, necrosis, and pyroptosis in terms of biochemistry, genetics, and morphology which plays an important role in cancer treatment. Ferroptosis happens mostly by accumulating iron and lipid peroxides in the cell. Recently, studies have revealed that ferroptosis has a key role in the tumor's progression. Especially, inducing ferroptosis in cells can inhibit the tumor cells' growth, leading to back warding tumorigenesis. Here, we outline the ferroptosis characteristics from its basic role in melanoma cancer and mention its possible applications in melanoma cancer treatment. Video Abstract.

Reactivation of telomerase reverse transcriptase expression in cancer: the role of TERT promoter mutations

Telomerase activity and telomere elongation are essential conditions for the unlimited proliferation of neoplastic cells. Point mutations in the core promoter region of the telomerase reverse transcriptase (TERT) gene have been found to occur at high frequencies in several tumour types and considered a primary cause of telomerase reactivation in cancer cells. These mutations promote TERT gene expression by multiple mechanisms, including the generation of novel binding sites for nuclear transcription factors, displacement of negative regulators from DNA G-quadruplexes, recruitment of epigenetic activators and disruption of long-range interactions between TERT locus and telomeres. Furthermore, TERT promoter mutations cooperate with TPP1 promoter nucleotide changes to lengthen telomeres and with mutated BRAF and FGFR3 oncoproteins to enhance oncogenic signalling in cancer cells. TERT promoter mutations have been recognized as an early marker of tumour development or a major indicator of poor outcome and reduced patients survival in several cancer types. In this review, we summarize recent findings on the role of TERT promoter mutations, telomerase expression and telomeres elongation in cancer development, their clinical significance and therapeutic opportunities.

GREB1 isoform 4 is specifically transcribed by MITF and required for melanoma proliferation

Growth regulation by estrogen in breast cancer 1 (GREB1) is involved in hormone-dependent and -independent tumor development (e.g., hepatoblastoma). In this study, we found that a GREB1 splicing variant, isoform 4 (Is4), which encodes C-terminal half of full-length GREB1, is specifically expressed via microphthalmia-associated transcription factor (MITF) in melanocytic melanoma, and that two MITF-binding E-box CANNTG motifs at the 5'-upstream region of GREB1 exon 19 are necessary for GREB1 Is4 transcription. MITF and GREB1 Is4 were strongly co-expressed in approximately 20% of the melanoma specimens evaluated (17/89 cases) and their expression was associated with tumor thickness. GREB1 Is4 silencing reduced melanoma cell proliferation in association with altered expression of cell proliferation-related genes in vitro. In addition, GREB1 Is4 targeting by antisense oligonucleotide (ASO) decreased melanoma xenograft tumor formation and GREB1 Is4 expression in a BRAFV600E; PTENflox melanoma mouse model promoted melanoma formation, demonstrating the crucial role of GREB1 Is4 for melanoma proliferation in vivo. GREB1 Is4 bound to CAD, the rate-limiting enzyme of pyrimidine metabolism, and metabolic flux analysis revealed that GREBI Is4 is necessary for pyrimidine synthesis. These results suggest that MITF-dependent GREB1 Is4 expression leads to melanoma proliferation and GREB1 Is4 represents a new molecular target in melanoma.

Differentiating between early melanomas and melanocytic nevi: A state-of-the-art review

Clinicians and dermatologists are challenged by accurate diagnosis of melanocytic lesions, due to melanoma's resemblance to benign skin conditions. Several methodologies have been proposed to diagnose melanoma, and to differentiate between a cancerous and a benign skin condition. First, the ABCD rule and Menzies method use skin lesion characteristics to interpret the condition. The 7-point checklist, 3-point checklist, and CASH algorithm are score-based methods. Each of these methods attributes a score point to the features found on the skin lesion. Furthermore, reflectance confocal microscopy (RCM), an integrated clinical and dermoscopic risk scoring system (iDscore), and a deep convoluted neural network (DCNN) also aids in diagnosis. RCM optically sections live tissues to reveal morphological and cellular structures. The skin lesion's clinical parameters determine iDscore's score point system. The DCNN model is based on a detailed learning algorithm. Therefore, we discuss the conventional and new methodologies for the identification of skin diseases. Moreover, our review attempts to provide clinicians with a comprehensible summary of the wide range of techniques that can help differentiate between early melanomas and melanocytic nevi.

The E3/E4 ubiquitin ligase UFD-2 suppresses normal and oncogenic signaling mediated by a Raf ortholog in Caenorhabditis elegans

Signaling by the kinase cascade composed of Raf, MEK, and ERK is critical for animal development and is often inappropriately activated in human malignancies. We sought to identify factors that control signaling mediated by the Caenorhabditis elegans Raf ortholog LIN-45. A genetic screen showed that the degradation of LIN-45 required the E3/E4 ubiquitin ligase UFD-2. Both UFD-2 and its partner, the ATP-dependent segregase CDC-48, were required for the developmental regulation of LIN-45 protein abundance. We showed that UFD-2 acted in the same pathway as the E3 ubiquitin ligase SCFSEL-10 to decrease LIN-45 abundance in cells in which Raf-MEK-ERK signaling was most highly active. UFD-2 also reduced the protein abundance of activated LIN-45 carrying a mutation equivalent to the cancer-associated BRAF(V600E) variant. Our structure-function studies showed that the disruption of LIN-45 domains that mediate protein-protein interactions, including the conserved cysteine-rich domain and 14-3-3 binding motifs, were required for UFD-2-independent degradation of LIN-45. We propose a model in which UFD-2 and CDC-48 act downstream of SCFSEL-10 to remove LIN-45 from its protein interaction partners and facilitate proteasomal targeting and degradation. These findings imply that UFD-2 and CDC-48 may be important for Raf degradation during normal and oncogenic Ras and MAPK signaling in mammalian cells.

BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers

Melanoma is an aggressive form of skin cancer resulting from the malignant transformation of melanocytes. Recent therapeutic approaches, including targeted therapy and immunotherapy, have improved the prognosis and outcome of melanoma patients. BRAF is one of the most frequently mutated oncogenes recognised in melanoma. The most frequent oncogenic BRAF mutations consist of a single point mutation at codon 600 (mostly V600E) that leads to constitutive activation of the BRAF/MEK/ERK (MAPK) signalling pathway. Therefore, mutated BRAF has become a useful target for molecular therapy and the use of BRAF kinase inhibitors has shown promising results. However, several resistance mechanisms invariably develop leading to therapeutic failure. The aim of this manuscript is to review the role of BRAF mutational status in the pathogenesis of melanoma and its impact on differentiation and inflammation. Moreover, this review focuses on the mechanisms responsible for resistance to targeted therapies in BRAF-mutated melanoma and provides an overview of circulating biomarkers including circulating tumour cells, circulating tumour DNA, and non-coding RNAs.

Noncoding RNA circuitry in melanoma onset, plasticity, and therapeutic response

Melanoma, the cancer of the melanocyte, is the deadliest form of skin cancer with an aggressive nature, propensity to metastasize and tendency to resist therapeutic intervention. Studies have identified that the re-emergence of developmental pathways in melanoma contributes to melanoma onset, plasticity, and therapeutic response. Notably, it is well known that noncoding RNAs play a critical role in the development and stress response of tissues. In this review, we focus on the noncoding RNAs, including microRNAs, long non-coding RNAs, circular RNAs, and other small RNAs, for their functions in developmental mechanisms and plasticity, which drive onset, progression, therapeutic response and resistance in melanoma. Going forward, elucidation of noncoding RNA-mediated mechanisms may provide insights that accelerate development of novel melanoma therapies.

Leveraging Machine Learning for Accurate Detection and Diagnosis of Melanoma and Nevi: An Interdisciplinary Study in Dermatology

This study explores the application of machine learning and deep learning algorithms to facilitate the accurate diagnosis of melanoma, a type of malignant skin cancer, and benign nevi. Leveraging a dataset of 793 dermatological images from the Kaggle online platform (Google LLC, Mountain View, California, United States), we developed a model that can accurately differentiate between these lesions based on their distinctive features. The dataset was divided into training (80%), validation (10%), and testing (10%) sets to optimize model performance and ensure its generalizability. Our findings demonstrate the potential of machine learning algorithms in enhancing the efficiency and accuracy of melanoma and nevi detection, with the developed model exhibiting robust performance metrics. Nonetheless, limitations exist due to the potential lack of comprehensive representation of melanoma and nevi cases in the dataset, and variations in image quality and acquisition methods, which may influence the model's performance in real-world clinical settings. Therefore, further research, validation studies, and integration into clinical practice are necessary to ensure the reliability and generalizability of these models. This study underscores the promise of artificial intelligence in advancing dermatologic diagnostics, aiming to improve patient outcomes by supporting early detection and treatment initiation for melanoma.

Pirin is a prognostic marker of human melanoma that dampens the proliferation of malignant cells by downregulating JARID1B/KDM5B expression

Originally considered to act as a transcriptional co-factor, Pirin has recently been reported to play a role in tumorigenesis and the malignant progression of many tumors. Here, we have analyzed the diagnostic and prognostic value of Pirin expression in the early stages of melanoma, and its role in the biology of melanocytic cells. Pirin expression was analyzed in a total of 314 melanoma biopsies, correlating this feature with the patient's clinical course. Moreover, PIR downregulated primary melanocytes were analyzed by RNA sequencing, and the data obtained were validated in human melanoma cell lines overexpressing PIR by functional assays. The immunohistochemistry multivariate analysis revealed that early melanomas with stronger Pirin expression were more than twice as likely to develop metastases during the follow-up. Transcriptome analysis of PIR downregulated melanocytes showed a dampening of genes involved in the G1/S transition, cell proliferation, and cell migration. In addition, an in silico approach predicted that JARID1B as a potential transcriptional regulator that lies between PIR and its downstream modulated genes, which was corroborated by co-transfection experiments and functional analysis. Together, the data obtained indicated that Pirin could be a useful marker for the metastatic progression of melanoma and that it participates in the proliferation of melanoma cells by regulating the slow-cycling JARID1B gene.

Whole-Genome Doubling as a source of cancer: how, when, where, and why?

Chromosome instability is a well-known hallmark of cancer, leading to increased genetic plasticity of tumoral cells, which favors cancer aggressiveness, and poor prognosis. One of the main sources of chromosomal instability are events that lead to a Whole-Genome Duplication (WGD) and the subsequently generated cell polyploidy. In recent years, several studies showed that WGD occurs at the early stages of cell transformation, which allows cells to later become aneuploid, thus leading to cancer progression. On the other hand, other studies convey that polyploidy plays a tumor suppressor role, by inducing cell cycle arrest, cell senescence, apoptosis, and even prompting cell differentiation, depending on the tissue cell type. There is still a gap in understanding how cells that underwent WGD can overcome the deleterious effect on cell fitness and evolve to become tumoral. Some laboratories in the chromosomal instability field recently explored this paradox, finding biomarkers that modulate polyploid cells to become oncogenic. This review brings a historical view of how WGD and polyploidy impact cell fitness and cancer progression, and bring together the last studies that describe the genes helping cells to adapt to polyploidy.

Cellular senescence in skin-related research: Targeted signaling pathways and naturally occurring therapeutic agents

Despite the growing interest by researchers into cellular senescence, a hallmark of cellular aging, its role in human skin remains equivocal. The skin is the largest and most accessible human organ, reacting to the external and internal environment. Hence, it is an organ of choice to investigate cellular senescence and to target root-cause aging processes using senolytic and senomorphic agents, including naturally occurring plant-based derivatives. This review presents different aspects of skin cellular senescence, from physiology to pathology and signaling pathways. Cellular senescence can have both beneficial and detrimental effects on the skin, indicating that both prosenescent and antisenescent therapies may be desirable, based on the context. Knowledge of molecular mechanisms involved in skin cellular senescence may provide meaningful insights for developing effective therapeutics for senescence-related skin disorders, such as wound healing and cosmetic skin aging changes.

Localized immune surveillance of primary melanoma in the skin deciphered through executable modeling

While skin is a site of active immune surveillance, primary melanomas often escape detection. Here, we have developed an in silico model to determine the local cross-talk between melanomas and Langerhans cells (LCs), the primary antigen-presenting cells at the site of melanoma development. The model predicts that melanomas fail to activate LC migration to lymph nodes until tumors reach a critical size, which is determined by a positive TNF-α feedback loop within melanomas, in line with our observations of murine tumors. In silico drug screening, supported by subsequent experimental testing, shows that treatment of primary tumors with MAPK pathway inhibitors may further prevent LC migration. In addition, our in silico model predicts treatment combinations that bypass LC dysfunction. In conclusion, our combined approach of in silico and in vivo studies suggests a molecular mechanism that explains how early melanomas develop under the radar of immune surveillance by LC.

miRNAs as potential game-changers in melanoma: A comprehensive review

Melanoma is the sixth most frequent malignancy. It represents 1.7% of all cancer cases worldwide. Many risk factors are associated with melanoma including ultraviolet radiation skin phenotype, Pigmented Nevi, Pesticides, and genetic and epigenetic factors. Of the main epigenetic factors affecting melanoma are microribonucleic acids (miRNAs). They are short nucleic acid chains that have the potential to prevent the expression of a number of target genes. They could target a number of genes related to melanoma initiation, stemness, angiogenesis, apoptosis, proliferation, and potential resistance to treatment. Additionally, they can control several melanoma signaling pathways, including P53, WNT/-catenin, JAK/STAT, PI3K/AKT/mTOR axis, TGF- β, and EGFR. MiRNAs also play a role in the resistance of melanoma to essential treatment regimens. The stability and abundance of miRNAs might be important factors enhancing the use of miRNAs as markers of prognosis, diagnosis, stemness, survival, and metastasis in melanoma patients.

The Importance of Immunohistochemistry in the Evaluation of Tumor Depth of Primary Cutaneous Melanoma

Primary cutaneous melanoma (PCM) is the most aggressive skin malignancy, with an increasing incidence and significant mortality. Tumoral invasion, expressed as Breslow thickness, is routinely assessed on hematoxylin and eosin (HE), although this stain may sometimes underestimate the tumoral depth. The aim of this study was to compare the efficiency of the immunohistochemical (IHC) markers S-100, SOX10, Melan-A, and HMB-45 with HE for the evaluation of the Breslow thickness and staging of PCM. This retrospective study included 46 cases of PCM diagnosed between 2015 and 2022; for each case, the Breslow thickness using HE, S-100, SOX10, Melan-A, and HMB-45 was measured and the appropriate T category was recorded. The highest values of the Breslow thickness were observed for S-100. However, S-100, SOX10, and Melan-A provided statistically significant higher values of the Breslow thickness compared to HE, but no difference was noted between HMB-45 and HE. S-100 was most frequently involved in increasing the T category (26.1%), the majority of cases being upstaged from T1a to T1b. The IHC markers S-100, SOX10, and Melan-A contributed to better evaluation of the melanoma invasion, especially in thin melanomas, but their impact on staging and consecutive treatment remains to be confirmed by future studies.

Nursing care and management of adverse events for patients with BRAFV600E-mutant metastatic colorectal cancer receiving encorafenib in combination with cetuximab: a review

Encorafenib is a B-Raf proto-oncogene serine/threonine-protein kinase (BRAF) inhibitor, approved in the EU and USA, in combination with the epidermal growth factor receptor (EGFR) inhibitor cetuximab, for the treatment of patients with BRAF^V600E-mutant metastatic colorectal cancer (mCRC). In the pivotal BEACON CRC trial, patients achieved longer survival with encorafenib in combination with cetuximab vs. conventional chemotherapy. This targeted therapy regimen is also generally better tolerated than cytotoxic treatments. However, patients may present with adverse events unique to the regimen and characteristic of BRAF and EGFR inhibitors, which produce their own set of challenges. Nurses play an essential role in navigating the care of patients with BRAF^V600E-mutant mCRC and managing adverse events that patients may experience. This includes early and efficient identification of treatment-related adverse events, subsequent management of adverse events and education of patients and their caregivers around key adverse events. This manuscript aims to provide support to nurses managing patients with BRAF^V600E-mutant mCRC receiving encorafenib in combination with cetuximab, by summarising potential adverse events and providing guidance on how to manage them. Special attention will be paid to the presentation of key adverse events, dose modifications that may be required, practical recommendations and supportive care measures.

p16 Immunohistochemical Expression as a Surrogate Assessment of CDKN2A Alteration in Gliomas Leading to Prognostic Significances

CDKN2A is a tumor suppressor gene encoding the p16 protein, a key regulator of the cell cycle. CDKN2A homozygous deletion is a central prognostic factor for numerous tumors and can be detected by several techniques. This study aims to evaluate the extent to which immunohistochemical levels of p16 expression may provide information about CDKN2A deletion. A retrospective study was conducted in 173 gliomas of all types, using p16 IHC and CDKN2A fluorescent in situ hybridization. Survival analyses were performed to assess the prognostic impact of p16 expression and CDKN2A deletion on patient outcomes. Three patterns of p16 expression were observed: absence of expression, focal expression, and overexpression. Absence of p16 expression was correlated with worse outcomes. p16 overexpression was associated with better prognoses in MAPK-induced tumors, but with worse survival in IDH-wt glioblastomas. CDKN2A homozygous deletion predicted worse outcomes in the overall patient population, particularly in IDH-mutant 1p/19q oligodendrogliomas (grade 3). Finally, we observed a significant correlation between p16 immunohistochemical loss of expression and CDKN2A homozygosity. IHC has strong sensitivity and high negative predictive value, suggesting that p16 IHC might be a pertinent test to detect cases most likely harboring CDKN2A homozygous deletion.

The Complex Interplay between Nevi and Melanoma: Risk Factors and Precursors

One effort to combat the rising incidence of malignant melanoma is focused on early detection by the clinical and dermoscopic screening of melanocytic nevi. However, the interaction between nevi, which are congenital or acquired benign melanocytic proliferations, and melanoma is still enigmatic. On the one hand, the majority of melanomas are thought to form de novo, as only a third of primary melanomas are associated with a histologically identifiable nevus precursor. On the other hand, an increased number of melanocytic nevi is a strong risk factor for developing melanoma, including melanomas that do not derive from nevi. The formation of nevi is modulated by diverse factors, including pigmentation, genetic risk factors, and environmental sun exposure. While the molecular alterations that occur during the progression of a nevus to melanoma have been well characterized, many unanswered questions remain surrounding the process of nevus to melanoma evolution. In this review, we discuss clinical, histological, molecular, and genetic factors that influence nevus formation and progression to melanoma.

The Many Roles of Dermoscopy in Melanoma Detection

Dermoscopy is a non-invasive method of examination that aids the clinician in many ways, especially in early skin cancer detection. Melanoma is one of the most aggressive forms of skin cancer that can affect individuals of any age, having an increasing incidence worldwide. The gold standard for melanoma diagnosis is histopathological examination, but dermoscopy is also very important for its detection. To highlight the many roles of dermoscopy, we analyzed 200 melanocytic lesions. The main objective of this study was to detect through dermoscopy hints of melanomagenesis in the studied lot. The most suspicious were 10 lesions which proved to be melanomas confirmed through histopathology. The second objective of this study was to establish if dermoscopy can aid in estimating the Breslow index (tumoral thickness) of the melanomas and to compare the results to the histopathological examination. We found that the tumoral thickness may be estimated through dermoscopy, but the histopathological examination is superior. To conclude, the aim of this study was to showcase the versatility and many roles of dermoscopy, besides being one of the most important tools for early melanoma diagnosis.

UV light-induced dual promoter mutations dismantle the telomeric guardrails in melanoma

Understanding how benign nevi can progress to invasive and metastatic Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USAelanoma is critical for developing interventions and therapeutics for this most deadly form of skin cancer. UV-induced mutations in the telomerase TERT gene promoter occur in the majority of melanomas but fail to prevent telomere shortening despite telomerase upregulation. This suggests additional "hits" are required to enable telomere maintenance. A new study in Science identified somatic variants in the promoter of the gene that encodes telomere shelterin protein TPP1 in human melanomas. These variants show mutational signatures of UV-induced DNA damage and upregulate TPP1 expression, which synergizes with telomerase to lengthen telomeres. This study provides evidence that TPP1 promoter variants are a critical second hit to prevent telomere shortening and promote immortalization of melanoma cells.

Review: The Key Factors to Melanomagenesis

Melanoma is the most dangerous form of skin cancer that develops from the malignant transformation of the melanocytes located in the basal layer of the epidermis (cutaneous melanoma). Melanocytes may also be found in the meninges, eyes, ears, gastrointestinal tract, genito-urinary system, or other mucosal surfaces (mucosal melanoma). Melanoma is caused by an uncontrolled proliferation of melanocytes, that at first may form a benign lesion (nevogenesis), but in time, it may transition to melanoma, determining what it is named, melanomagenesis. Some tumors may appear spontaneously (de novo melanoma) or on preexisting lesions (nevus-associated melanoma). The exact cause of melanoma may not be fully understood yet, but there are some factors that initiate and promote this malignant process. This study aims to provide a summary of the latest articles regarding the key factors that may lead to melanomagenesis. The secondary objectives are to reveal the relationship between nevi and melanoma, to understand the cause of "de novo" and "nevus-associated melanoma" and highlight the differences between these subtypes.

Intramucosal Melanocytic Nevi - A Rare Cause for Gingival Enlargement. Report of a Case and Review of Literature

Background

Oral melanocytic nevi are infrequent oral lesions derived from nevus cells of oral mucosa which causes focal hyperpigmentation. The most common site of occurrence of oral nevi is the hard palate followed by buccal mucosa and gingiva. The mean age group affected are in their 3rd and 4th decade of life and there seems to be a predilection for females. Clinically, oral nevi are usually small, well-circumscribed macules but can also present as slightly raised papules. Histologically, nevi can be classified as Junctional, Compound or Intramucosal, with intramucosal being the more common type in the oral cavity.

Case Presentation

In this paper, we report a case of intramucosal nevus in a 25-year-old female patient. The lesion presented as a gingival enlargement in the mandibular anterior region involving the marginal and attached gingiva, which is an extremely rare presentation. The clinical findings, histologic features and surgical management are presented. The patient was followed up for one year and the one year follow up revealed a small area of focal hyperpigmentation at the site of the previous lesion which is being closely monitored.

Conclusion

Nevi located in the mucous membrane have been documented to pose a threat of malignant transformation. Hence, all pigmented lesions of the oral cavity should be cautiously diagnosed.

Discrimination of normal and cancerous human skin tissues based on laser-induced spectral shift fluorescence microscopy

A homemade spectral shift fluorescence microscope (SSFM) is coupled with a spectrometer to record the spectral images of specimens based on the emission wavelength. Here a reliable diagnosis of neoplasia is achieved according to the spectral fluorescence properties of ex-vivo skin tissues after rhodamine6G (Rd6G) staining. It is shown that certain spectral shifts occur for nonmelanoma/melanoma lesions against normal/benign nevus, leading to spectral micrographs. In fact, there is a strong correlation between the emission wavelength and the sort of skin lesions, mainly due to the Rd6G interaction with the mitochondria of cancerous cells. The normal tissues generally enjoy a significant red shift regarding the laser line (37 nm). Conversely, plenty of fluorophores are conjugated to unhealthy cells giving rise to a relative blue shift i.e., typically SCC (6 nm), BCC (14 nm), and melanoma (19 nm) against healthy tissues. In other words, the redshift takes place with respect to the excitation wavelength i.e., melanoma (18 nm), BCC (23 nm), and SCC (31 nm) with respect to the laser line. Consequently, three data sets are available in the form of micrographs, addressing pixel-by-pixel signal intensity, emission wavelength, and fluorophore concentration of specimens for prompt diagnosis.

Expression of active B-Raf proto-oncogene in kidney collecting ducts induces cyst formation in normal mice and accelerates cyst growth in mice with polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by the formation and progressive enlargement of fluid-filled cysts due to abnormal cell proliferation. Cyclic AMP agonists, including arginine vasopressin, stimulate ERK-dependent proliferation of cystic cells, but not normal kidney cells. Previously, B-Raf proto-oncogene (BRAF), a MAPK kinase kinase that activates MEK-ERK signaling, was shown to be a central intermediate in the cAMP mitogenic response. However, the role of BRAF on cyst formation and enlargement in vivo had not been demonstrated. To determine if active BRAF induces kidney cyst formation, we generated transgenic mice that conditionally express BRAFV600E, a common activating mutation, and bred them with Pkhd1-Cre mice to express active BRAF in the collecting ducts, a predominant site for cyst formation. Collecting duct expression of BRAFV600E (BRafCD) caused kidney cyst formation as early as three weeks of age. There were increased levels of phosphorylated ERK (p-ERK) and proliferating cell nuclear antigen, a marker for cell proliferation. BRafCD mice developed extensive kidney fibrosis and elevated blood urea nitrogen, indicating a decline in kidney function, by ten weeks of age. BRAFV600E transgenic mice were also bred to Pkd1RC/RC and pcy/pcy mice, well-characterized slowly progressive PKD models. Collecting duct expression of active BRAF markedly increased kidney weight/body weight, cyst number and size, and total cystic area. There were increased p-ERK levels and proliferating cells, immune cell infiltration, interstitial fibrosis, and a decline in kidney function in both these models. Thus, our findings demonstrate that active BRAF is sufficient to induce kidney cyst formation in normal mice and accelerate cystic disease in PKD mice.

S2C-DeLeNet: A parameter transfer based segmentation-classification integration for detecting skin cancer lesions from dermoscopic images

Dermoscopic images ideally depict pigmentation attributes on the skin surface which is highly regarded in the medical community for detection of skin abnormality, disease or even cancer. The identification of such abnormality, however, requires trained eyes and accurate detection necessitates the process being time-intensive. As such, computerized detection schemes have become quite an essential, especially schemes which adopt deep learning tactics. In this paper, a convolutional deep neural network, S2C-DeLeNet, is proposed, which (i) Performs segmentation procedure of lesion based regions with respect to the unaffected skin tissue from dermoscopic images using a segmentation sub-network, (ii) Classifies each image based on its medical condition type utilizing transferred parameters from the inherent segmentation sub-network. The architecture of the segmentation sub-network contains EfficientNet-B4 backbone in place of the encoder and the classification sub-network bears a 'Classification Feature Extraction' system which pulls trained segmentation feature maps towards lesion prediction. Inside the classification architecture, there have been designed, (i) A 'Feature Coalescing Module' in order to trail and mix each dimensional feature from both encoder and decoder, (ii) A '3D-Layer Residuals' block to create a parallel pathway of low-dimensional features with high variance for better classification. After fine-tuning on a publicly accessible dataset, a mean dice-score of 0.9494 during segmentation is procured which beats existing segmentation strategies and a mean accuracy of 0.9103 is obtained for classification which outperforms conventional and noted classifiers. Additionally, the already fine-tuned network demonstrates highly satisfactory results on other skin cancer segmentation datasets while cross-inference. Extensive experimentation is done to prove the efficacy of the network for not only dermoscopic images but also different medical modalities; which can show its potential in being a systematic diagnostic solution in the field of dermatology and possibly more.

Comparison of phenotypic features in patients with single vs multiple primary cutaneous melanomas: a prospective single-center study

BACKGROUND

There is sparse data regarding total body nevus count (TBNC), nevus count in specific locations, phenotypic factors, anthropometric indices, sunburn, and the relation to multiple primary cutaneous melanomas (MPCM) development. We aim to compare these variables in a cohort of patients diagnosed with single primary melanoma (SPM) and MPCM with histologic diagnoses of melanoma in situ, superficial spreading, and nodular melanoma in our clinic.

METHODS

Prospective observational studies for the evaluation of nevus counts in biopsy-proven melanoma patients from 2017 to 2020 at Ankara University were conducted. Age, gender, family history of melanoma, increased sun exposure, nonmelanoma skin cancers (NMSC), height, sunburn history, TBNC, and nevi count in specific anatomical locations were evaluated by multivariate logistic regression analysis.

RESULTS

A total number of 156 patients consisting of 22 MPCM and 134 SPM were included. Mean TBNC for SPM vs MPCM patients were 96.87 (SD ± 124.71) vs 247.00 (SD ± 261.58), respectively (P < 0.0001). TBNC was correlated to the left arm, trunk, lower extremity, and head and neck nevus counts but not with the right arm nevus count. Multiple regression analysis showed that having more than 10 nevi on the head and neck area is associated with MPCM (OR, 3.882 [95% CI, 1.084-13.899]). TBNC and nevus count in specific locations were found to be significantly higher in MPCM.

CONCLUSION

The risk of MPCM was associated with having ≥10 nevi on the head and neck.

Association of Circular RNA and Long Non-Coding RNA Dysregulation with the Clinical Response to Immune Checkpoint Blockade in Cutaneous Metastatic Melanoma

Cutaneous melanoma (CM) is the most lethal form of skin cancer if it becomes metastatic, where treatment options and survival chances decrease dramatically. Immunotherapy treatments based on the immunologic checkpoint inhibitors programmed death cell protein 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) constituted a main breakthrough in the treatment of metastatic CM, particularly for the achievement of long-term benefits. Even though it is a very promising therapy, resistance to primary immune checkpoint blockade (ICB) arises in about 70% of CM patients treated with a CTLA-4 inhibitor, and 40–65% of CM patients administered with a PD-1-targeting treatment. Some long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are implicated in triggering pro- and anti-tumorigenic responses to various cancer treatments. The relationship between lncRNAs, circRNAs and ICB immunotherapy has not been explored in cutaneous metastatic melanoma (CMM). The aim of this pilot study is to evaluate the potential role of circRNA and lncRNA expression as pre-treatment predictors of the clinical response to immunotherapy in CMM patients. RNA-seq from 12 formalin-fixed paraffin-embedded (FFPE) samples from the metastatic biopsies of CMM patients treated with nivolumab was used to identify response-associated transcripts. Our findings indicate that specific lncRNAs and circRNAs, probably acting as competitive endogenous RNAs (ceRNAs), are involved in the regulatory networks of the immune response against metastatic melanoma that these patients have under treatment with nivolumab. Moreover, we established a risk score that yields predictions of the overall survival (OS) and progression-free survival (PFS) of CMM patients with high accuracy. This proof-of-principle work provides a possible insight into the function of ceRNAs, contributing to efforts to decipher the complex molecular mechanisms of ICB cancer treatment response.

NAD/NAMPT and mTOR Pathways in Melanoma: Drivers of Drug Resistance and Prospective Therapeutic Targets

Malignant melanoma represents the most fatal skin cancer due to its aggressive behavior and high metastatic potential. The introduction of BRAF/MEK inhibitors and immune-checkpoint inhibitors (ICIs) in the clinic has dramatically improved patient survival over the last decade. However, many patients either display primary (i.e., innate) or develop secondary (i.e., acquired) resistance to systemic treatments. Therapeutic resistance relies on the rewiring of multiple processes, including cancer metabolism, epigenetics, gene expression, and interactions with the tumor microenvironment that are only partially understood. Therefore, reliable biomarkers of resistance or response, capable of facilitating the choice of the best treatment option for each patient, are currently missing. Recently, activation of nicotinamide adenine dinucleotide (NAD) metabolism and, in particular, of its rate-limiting enzyme nicotinamide phosphoribosyltransferase (NAMPT) have been identified as key drivers of targeted therapy resistance and melanoma progression. Another major player in this context is the mammalian target of rapamycin (mTOR) pathway, which plays key roles in the regulation of melanoma cell anabolic functions and energy metabolism at the switch between sensitivity and resistance to targeted therapy. In this review, we summarize known resistance mechanisms to ICIs and targeted therapy, focusing on metabolic adaptation as one main mechanism of drug resistance. In particular, we highlight the roles of NAD/NAMPT and mTOR signaling axes in this context and overview data in support of their inhibition as a promising strategy to overcome treatment resistance.

3D Bioprinting: An Enabling Technology to Understand Melanoma

Melanoma is a potentially fatal cancer with rising incidence over the last 50 years, associated with enhanced sun exposure and ultraviolet radiation. Its incidence is highest in people of European descent and the ageing population. There are multiple clinical and epidemiological variables affecting melanoma incidence and mortality, such as sex, ethnicity, UV exposure, anatomic site, and age. Although survival has improved in recent years due to advances in targeted and immunotherapies, new understanding of melanoma biology and disease progression is vital to improving clinical outcomes. Efforts to develop three-dimensional human skin equivalent models using biofabrication techniques, such as bioprinting, promise to deliver a better understanding of the complexity of melanoma and associated risk factors. These 3D skin models can be used as a platform for patient specific models and testing therapeutics.

Melanoma RBPome identification reveals PDIA6 as an unconventional RNA-binding protein involved in metastasis

RNA-binding proteins (RBPs) have been relatively overlooked in cancer research despite their contribution to virtually every cancer hallmark. Here, we use RNA interactome capture (RIC) to characterize the melanoma RBPome and uncover novel RBPs involved in melanoma progression. Comparison of RIC profiles of a non-tumoral versus a metastatic cell line revealed prevalent changes in RNA-binding capacities that were not associated with changes in RBP levels. Extensive functional validation of a selected group of 24 RBPs using five different in vitro assays unveiled unanticipated roles of RBPs in melanoma malignancy. As proof-of-principle we focused on PDIA6, an ER-lumen chaperone that displayed a novel RNA-binding activity. We show that PDIA6 is involved in metastatic progression, map its RNA-binding domain, and find that RNA binding is required for PDIA6 tumorigenic properties. These results exemplify how RIC technologies can be harnessed to uncover novel vulnerabilities of cancer cells.

Fractal Dimension Analysis of Melanocytic Nevi and Melanomas in Normal and Polarized Light-A Preliminary Report

Clinical diagnosis of pigmented lesions can be a challenge in everyday practice. Benign and dysplastic nevi and melanomas may have similar clinical presentations, but completely different prognoses. Fractal dimensions of shape and texture can describe the complexity of the pigmented lesion structure. This study aims to apply fractal dimension analysis to differentiate melanomas, dysplastic nevi, and benign nevi in polarized and non-polarized light. A total of 87 Eighty-four patients with 97 lesions were included in this study. All examined lesions were photographed under polarized and non-polarized light, surgically removed, and examined by a histopathologist to establish the correct diagnosis. The obtained images were then processed and analyzed. Area, perimeter, and fractal dimensions of shape and texture were calculated for all the lesions under polarized and non-polarized light. The fractal dimension of shape in polarized light enables differentiating melanomas, dysplastic nevi, and benign nevi. It also makes it possible to distinguish melanomas from benign and dysplastic nevi under non-polarized light. The fractal dimension of texture allows distinguishing melanomas from benign and dysplastic nevi under polarized light. All examined parameters of shape and texture can be used for developing an automatic computer-aided diagnosis system. Polarized light is superior to non-polarized light for imaging texture details.