OBJECTIVE: Outdoor workers are at increased risk for skin cancer and melanoma. This qualitative study aimed to explore outdoor workers\' perspectives and experiences of primary (i.e. sun protection) and secondary prevention, i.e. skin self-examination (SSE) of skin cancer.
METHODS: Purposive, snowball, and theoretical sampling was used to recruit outdoor workers in Kentucky and Indiana. Semi-structured interviews via telephone or videoconference of approximately 45 min were conducted with interviewer probes and questions about perceptions of cancer risk, prevention, and screening techniques conducted, perceived barriers and facilitators, and preferences for health dissemination venues. The recordings were transcribed verbatim and de-identified. Analysis involved constructivist grounded theory coding strategies. Using peer debriefing and consensus building around themes, the researcher established a codebook for all interviews to utilize within Dedoose software for systematizing and organizing data.
RESULTS: Eighteen interviews were conducted. Interviewees (N = 18) ranged in age from 35 to 78 yr, with 3 females. Outdoor industries included agriculture, maintenance, and grounds maintenance. Themes derived from the data showed the underlying factors and perceptions that influence outdoor workers to conduct primary and secondary cancer prevention activities. The level of alarm attributed to disease and the level of trust in information contribute to intentions to conduct activities. The intentions and trust toward healthcare institutions and providers drive the primary or secondary prevention behaviors. Cultural and contextual factors included masculinity and self-sufficiency, familial and occupational priorities, and community ties.
CONCLUSIONS: These data provide a basis for developing future communications and interventions to decrease skin cancer incidence in outdoor workers. They indicate that secondary prevention and building self-efficacy in conducting SSE should be emphasized in tandem or over primary skin cancer prevention methods in this population. Trusted local healthcare providers should primarily provide prevention information, and materials should utilize testimonials from the local community to best influence this population. Communications and training interventions are needed in this population to induce a proactive level of alarm about cancer and result in the performance of SSE.

Equine melanomas are a common neoplasm in gray horses. However, scientific knowledge about their progression over time is quite scarce. Some owners and veterinarians still believe that early intervention is not necessary, stating that tumors evolve very slowly and intervention could worsen the animal\'s condition. This work aims to identify clinical and histological differences that may exist between equine melanomas with different excision intervals (time between tumor detection and surgical excision). A total of 42 tumors (13 benign and 29 malignant) from 34 horses were included in this study. There was a statistically significant association between excision interval and tumor size (p = 0.038), with tumors excised later being significantly larger than the ones excised sooner. The excision interval was also statistically associated with the number of tumors (p = 0.011), since the horses that carried a tumor for longer seemed to be prone to have multiple tumors. Furthermore, there was an association between excision interval and malignancy (p = 0.035), with tumor excised later being fives times more likely to be malignant. This study provides evidence of delayed excision\'s effect on the progression of equine melanomas. Additionally, it reinforces the importance of the early excision of these tumors.

OBJECTIVE: Melanoma is the leading cause of death from skin cancer in the world. Despite the advances in molecular diagnosis, the differential diagnosis between melanoma and benign melanocytic tumors relies on histopathology. However, not all of the criteria for the microscopy of a biopsy of a melanocytic tumor are applicable to all locations.
METHODS: We highlight these difficulties in the presentation of 2cases of melanocytic tumors in unusual locations which were diagnostically challenging.
RESULTS: After analyzing the relevant literature, the atypical histopathological characteristics of melanocytic tumors could be specified for unusual anatomical sites.

Methionine dependence, the inability to grow in culture when methionine in the medium is replaced by its metabolic precursor homocysteine, occurs in many tumor cell lines. In most affected lines, the cause of methionine dependence is not known. An exception is the melanoma-derived cell line MeWo-LC1, in which hypermethylation of the MMACHC gene is associated with decreased MMACHC expression. Decreased expression results in decreased provision of the methylcobalamin cofactor required for activity of methionine synthase and thus decreased conversion of homocysteine to methionine. Analysis of data in the Cancer Cell Line Encyclopedia Archive demonstrated that MMACHC hypermethylation and decreased MMACHC expression occurred more frequently in melanoma cell lines when compared to other tumor cell lines. We further investigated methionine dependence and aspects of MMACHC function in a panel of six melanoma lines, including both melanoma lines with known methionine dependence status (MeWo, which is methionine independent, and A375, which is methionine dependent). We found that the previously unclassified melanoma lines HMCB, Colo829 and SH-4 were methionine dependent, while SK-Mel-28 was methionine independent. However, despite varying levels of MMACHC methylation and expression, none of the tested lines had decreased methylcobalamin and adenosylcobalamin synthesis as seen in MeWo-LC1, and the functions of both cobalamin-dependent enzymes methionine synthase and methylmalonyl-CoA mutase were intact. Thus, while melanoma lines were characterized by relatively high levels of MMACHC methylation and low expression, the defect in metabolism observed in MeWo-LC1 was unique, and decreased MMACHC expression was not a cause of methionine dependence in the other melanoma lines.

Although surgery is the primary method to treat malignant melanoma, it has drawbacks such as residual tumor that could trigger cancer recurrence and wound infections that are especially difficult to heal in diabetics. In this research, we have constructed anti-cancer peptides/polyvinyl alcohol (PVA) double-network (DN) hydrogels for the treatment of melanoma. The maximum stress of the DN hydrogels is found to be larger than 2 MPa, which endows the DN hydrogels with ideal mechanical performance for therapeutic wound dressing. The peptides naphthalene-FIIIKKK (IK1) and phloretic acid-FIIIKKK (IK3) that were previously developed as effective antibacterial peptides, as well as the peptide/PVA DN hydrogels, are found to have good anti-cancer efficacy and target mouse melanoma cells B16-F10 while being nontoxic to normal cells. Further studies have revealed that IK1 and IK3 damage the tumor cell membrane and mitochondrial membrane and eventually trigger apoptosis. In the mouse melanoma model and the diabetic bacterial infection model, the DN hydrogels exhibit great anti-tumor, anti-bacterial, and wound healing promotion abilities in vivo. Because of their excellent mechanical properties, the DN hydrogels are promising soft materials for directly treating malignant melanomas as well as for preventing recurrence and bacterial infection after melanoma surgery that promote wound healing.

Eumelanin, a macromolecule widespread in all the living world and long appreciated for its protective action against harmful UV radiation, is considered the beneficial component of the melanin family (ευ means good in ancient Greek). This initially limited picture has been rather recently extended and now includes a variety of key functions performed by eumelanin in order to support life also under extreme conditions. A lot of still unexplained aspects characterize this molecule that, in an evolutionary context, survived natural selection. This paper aims to emphasize the unique characteristics and the consequent unusual behaviors of a molecule that still holds the main chemical/physical features detected in fossils dating to the late Carboniferous. In this context, attention is drawn to the duality of roles played by eumelanin, which occasionally reverses its functional processes, switching from an anti-oxidant to a pro-oxidant behavior and implementing therefore harmful effects.

An mRNA with unmodified nucleosides induces type I interferons (IFN-I) through the stimulation of innate immune sensors. Whether IFN-I induced by mRNA vaccine is crucial for anti-tumor immune response remains to be elucidated. In this study, we investigated the immunogenicity and anti-tumor responses of mRNA encoding tumor antigens with different degrees of N1-methylpseudouridine (m1Ψ) modification in B16 melanoma model. Our results demonstrated that ovalbumin (OVA) encoding mRNA formulated in a lipid nanoparticle (OVA-LNP) induced substantial IFN-I production and the maturation of dendritic cells (DCs) with negative correlation with increasing percentages of m1Ψ modification. In B16-OVA murine melanoma model, unmodified OVA-LNP significantly reduced tumor growth and prolonged survival, compared to OVA-LNP with m1Ψ modification. This robust anti-tumor effect correlated with the increase in intratumoral CD40+ DCs and the frequency of granzyme B+/IFN-γ+/TNF-α+ polyfunctional OVA peptide-specific CD8+ T cells. Blocking type I IFN receptor completely reversed the anti-tumor immunity of unmodified mRNA-OVA reflected in a significant decrease in OVA-specific IFN-γ secreting T cells and enrichment of PD-1+ tumor-infiltrating T cells. The robust anti-tumor effect of unmodified OVA-LNP was also observed in the lung metastatic tumor model. Finally, this mRNA vaccine was tested using B16 melanoma neoantigens (Pbk-Actn4) which resulted in delayed tumor growth. Taken together, our findings demonstrated that an unmodified mRNA vaccine induces IFN-I production or the downstream signaling cascades which plays a crucial role in inducing robust anti-tumor T cell response for controlling tumor growth and metastasis.

BACKGROUND: In the current study, we examined the real-world prevalence of highly pigmented advanced melanomas (HPMel) and the clinicopathologic, genomic, and ICPI biomarker signatures of this class of tumors.
METHODS: Our case archive of clinical melanoma samples for which the ordering physician requested testing for both PD-L1 immunohistochemistry (IHC) and comprehensive genomic profiling (CGP) was screened for HPMel cases, as well as for non-pigmented or lightly pigmented advanced melanoma cases (LPMel).
RESULTS: Of the 1268 consecutive melanoma biopsies in our archive that had been submitted for PD-L1 IHC, 13.0% (165/1268) were HPMel and 87.0% (1103/1268) were LPMel. In the HPMel cohort, we saw a significantly lower tumor mutational burden (TMB, median 8.8 mutations/Mb) than in the LPMel group (11.4 mut/Mb), although there was substantial overlap. In examining characteristic secondary genomic alterations (GA), we found that the frequencies of GA in TERTp, CDKN2A, TP53, and PTEN were significantly lower in the HPMel cases than in LPMel. A higher rate of GA in CTNNB1, APC, PRKAR1A, and KIT was identified in the HPMel cohort compared with LPMel.
CONCLUSIONS: In this study, we quantified the failure rates of melanoma samples for PD-L1 testing due to high melanin pigmentation and showed that CGP can be used in these patients to identify biomarkers that can guide treatment decisions for HPMel patients. Using this practical clinical definition for tumor pigmentation, our results indicate that HPMel are frequent at 13% of melanoma samples, and in general appear molecularly less developed, with a lower TMB and less frequent secondary GA of melanoma progression.

T cell immunoglobulin and mucin domain-containing-3 (TIM-3) is an immune checkpoint expressed mainly on CD4+ and CD8+ T cells. In addition to negatively regulating inflammatory T cell function, TIM-3 is a promising immunotherapy target. Herein, the aim is to develop an immuno-positron emission tomography (immunoPET) probe for noninvasively characterizing TIM-3 expression. Flow cytometry is used to detect the expression levels of TIM-3 in B16F10 cells. RMT3-23, a rat antimouse TIM-3-specific monoclonal antibody, is radiolabeled with 64Cu and the performance of 64Cu-NOTA-RMT3-23 is interrogated by immunoPET in murine melanoma models before and after radiation therapies. Biodistribution and immunofluorescent staining studies are carried out after the immunoPET imaging studies. TIM-3 is negatively expressed in B16F10 cells, and its expression is not induced by radiation therapies. ImmunoPET imaging with 64Cu-NOTA-RMT3-23 precisely tracks the unique distribution of TIM-3-positive lymphocytes in immunocompetent melanoma models, and tumor uptake of the radiotracer is not affected by either single-dose or fractionated radiation therapies. The 64Cu-NOTA-RMT3-23 immunoPET imaging results are further mirrored by the immunofluorescent staining studies. These results demonstrate the feasibility of 64Cu-NOTA-RMT3-23 immunoPET in tracking TIM-3 and highlight a new opportunity to optimize TIM-3-targeted immunotherapies with this novel imaging strategy.

Uveal melanoma (UM) is an aggressive and deadly neoplasm. In recent decades, great efforts have been made to obtain a more comprehensive understanding of genetics, genomics and molecular changes in UM, enabling the identification of key cellular processes and signalling pathways. Still, there is no effective treatment for the metastatic disease. Intratumoural heterogeneity (ITH) is thought to be one of the leading determinants of metastasis, therapeutic resistance and recurrence. Crucially, tumours are complex ecosystems, where cancer cells, and diverse cell types from their microenvironment engage in dynamic spatiotemporal crosstalk that allows cancer progression, adaptation and evolution. This highlights the urgent need to gain insight into ITH in UM and its intersection with the microenvironment to overcome treatment failure. Here we provide an overview of the studies and technologies to study ITH in human UMs and tumour micro-environmental composition. We discuss how to incorporate ITH into clinical consideration for the purpose of advocating for new clinical management. We focus on the application of single-cell transcriptomic analysis and propose that understanding the driving forces and functional consequences of the observed tumour heterogeneity holds promise for changing the treatment paradigm of metastatic UMs, surmounting resistance and improving patient prognosis.