Cutaneous and acral melanoma cross-OMICs reveals prognostic cancer drivers associated with pathobiology and ultraviolet exposure

Adjuvant PD-1 Checkpoint Inhibition in Early Cutaneous Melanoma: Immunological Mode of Action and the Role of Ultraviolet Radiation

Melanoma ranks as the fifth most common solid cancer in adults worldwide and is responsible for a significant proportion of skin-tumor-related deaths. The advent of immune checkpoint inhibition with anti-programmed death protein-1 (PD-1) antibodies has revolutionized the adjuvant treatment of high-risk, completely resected stage III/IV melanoma. However, not all patients benefit equally. Current strategies for improving outcomes involve adjuvant treatment in earlier disease stages (IIB/C) as well as perioperative treatment approaches. Interfering with T-cell exhaustion to counteract cancer immune evasion and the immunogenic nature of melanoma is key for anti-PD-1 effectiveness. Yet, the biological rationale for the efficacy of adjuvant treatment in clinically tumor-free patients remains to be fully elucidated. High-dose intermittent sun exposure (sunburn) is a well-known primary risk factor for melanomagenesis. Also, ultraviolet radiation (UVR)-induced immunosuppression may impair anti-cancer immune surveillance. In this review, we summarize the current knowledge about adjuvant anti-PD-1 blockade, including a characterization of the main cell types most likely responsible for its efficacy. In conclusion, we propose that local and systemic immunosuppression, to some extent UVR-mediated, can be restored by adjuvant anti-PD-1 therapy, consequently boosting anti-melanoma immune surveillance and the elimination of residual melanoma cell clones.

Challenges in diagnosing canine spindle cell tumours using immunohistochemistry, illustrated by three nonpigmented malignant cases from the nictitating membrane

BACKGROUND

Nonpigmented malignant spindle cell tumours of the membrana nictitans are rare in dogs. In twenty-three years only three cases have been diagnosed in Scandinavia. This study describes the three cases of malignant tumours of the membrana nictitans recorded by the Eye Pathology Section, University of Copenhagen, Denmark, with reference to the clinical appearance and work-up, the treatment and prognosis, and the histopathological description including immunohistochemistry. The three cases are compared to previous publications on canine tumours of the nictitating membrane. We emphasize the importance of using protocols that are adapted to the specific species such as dogs. Opposite the human tissue responses, we even need more than one marker when diagnosing melanomas in dogs.

RESULTS

The dogs presented were an 8-year-old Dachshund, a 12-year-old Akita and a 14-year-old Shetland Sheepdog. All three dogs were entire females. All three nictitating membrane tumours developed on the right nictitating membrane as firm or multilobulated hyperaemic masses. Two of the tumours were macroscopically nonpigmented, the third being partly pigmented on the surface and ulcerated. According to the histopathology and for two of the cases immunohistochemistry with dog-adapted protocols the diagnoses included one hemangiosarcoma and two amelanotic melanomas. Tumour regrowth developed in all three cases and repeated resections were completed 1, 2 and 3 times, respectively, with recurrence experienced within 1.5 months - 3 years.

CONCLUSIONS

Nonpigmented malignant spindle cell tumours of the canine membrana nictitans are rare. Treatment of choice should be complete excision with a minimal histologic tumour-free distance and in case of a recurrence a full resection of the nictitating membrane. We strongly recommend a dog-adapted protocol for immunohistochemistry.

Decoding the DNA methylome of central nervous system tumors: An emerging modality for integrated diagnosis

The definitive diagnosis and classification of individual cancers are crucial for patient care and cancer research. To achieve a robust diagnosis of central nervous system (CNS) tumors, a genotype-phenotype integrated diagnostic approach was introduced in recent versions of the World Health Organization classification, followed by the incorporation of a genome-wide DNA methylome-based classification. Microarray-based platforms are widely used to obtain DNA methylome data, and the German Cancer Research Center (Deutsches Krebsforschungszentrum [DKFZ]) has a webtool for a DNA methylation-based classifier (DKFZ classifier). Integration of DNA methylome will further enhance the precision of CNS tumor classification, especially in diagnostically challenging cases. However, in the clinical application of DNA methylome-based classification, challenges related to data interpretation persist, in addition to technical caveats, regulations, and limited accessibility. Dimensionality reduction (DMR) can complement integrated diagnosis by visualizing a profile and comparing it with other known samples. Therefore, DNA methylome-based classification is a highly useful research tool for auxiliary analysis in challenging diagnostic and rare disease cases, and for establishing novel tumor concepts. Decoding the DNA methylome, especially by DMR in addition to DKFZ classifier, emphasizes the capability of grasping the fundamental biological principles that provide new perspectives on CNS tumors.

Protective Mechanisms of Polyphenol-Enriched Blueberry Preparation in Preventing Inflammation in the Skin against UVB-Induced Damage in an Animal Model

UVB significantly impacts the occurrence of cutaneous disorders, ranging from inflammatory to neoplastic diseases. Polyphenols derived from plants have been found to exhibit photoprotective effects against various factors that contribute to skin cancer. During the fermentation of the polyphenol-enriched blueberry preparation (PEBP), small oligomers of polyphenols were released, thus enhancing their photoprotective effects. This study aimed to investigate the protective effects of PEBP on UVB-induced skin inflammation. Topical preparations of polyphenols were applied to the skin of dorsally shaved mice. Mice were subsequently exposed to UVB and were sacrificed 90 min after UVB exposure. This study revealed that pretreatment with PEBP significantly inhibited UVB-induced recruitment of mast and neutrophil cells and prevented the loss of skin thickness. Furthermore, the findings show that PEBP treatment resulted in the downregulation of miR-210, 146a, and 155 and the upregulation of miR-200c and miR-205 compared to the UVB-irradiated mice. Additionally, PEBP was found to reduce the expression of IL-6, IL-1β, and TNFα, inhibiting COX-2 and increasing IL-10 after UVB exposure. Moreover, DNA methylation analysis indicated that PEBP might potentially reduce the activation of inflammation-related pathways such as MAPK, Wnt, Notch, and PI3K-AKT signaling. Our finding suggests that topical application of PEBP treatment may effectively prevent UVB-induced skin damage by inhibiting inflammation.

Engineering tanshinone-loaded, levan-biofunctionalized polycaprolactone nanofibers for treatment of skin cancer

Skin cancer is a challenging condition of the highest prevalence rate among other types of cancer. Thus, advancement of local therapeutic approaches for skin cancer is highly needed. Recently, the use of phytotherapeutics, like tanshinone IIA (Tan), as anticancer agents has become promising. In this work, we engineered Tan-loaded polycaprolactone nanofibers, biofunctionalized with levan and egg-lecithin (Tan@Lev/EL/PCL-NF) for local skin cancer therapy. Novel Tan@Lev/EL/PCL-NF were prepared using w/o-emulsion electrospinning, employing a 23-factorial design. Composite NF exhibited nanofiber diameter (365.56 ± 46.25 nm), favorable surface-hydrophilicity and tensile strength. Tan@Lev/EL/PCL-NF could achieve favorably controlled-release (100% in 5 days) and Tan skin-deposition (50%). In vitro anticancer studies verified prominent cytotoxicity of Tan@Lev/EL/PCL-NF on squamous-cell-carcinoma cell-line (SCC), with optimum cytocompatibility on fibroblasts. Tan@Lev/EL/PCL-NF exerted high apoptotic activity with evident nuclear fragmentation, G2/M-mitosis cell-cycle-arrest and antimigratory efficacy. In vivo antitumor activity was established in mice, confirming pronounced inhibition of tumor-growth (224.25 ± 46.89%) and relative tumor weight (1.25 ± 0.18%) for Tan@Lev/EL/PCL-NF compared to other groups. Tan@Lev/EL/PCL-NF afforded tumor-biomarker inhibition, upregulation of caspase-3 and knockdown of BAX and MKi67. Efficient anticancer potential was further confirmed by histomorphometric analysis. Our findings highlight the promising anticancer functionality of composite Tan@Lev/EL/PCL-NF, as efficient local skin cancer phytotherapy.

Photosensitizers-Loaded Nanocarriers for Enhancement of Photodynamic Therapy in Melanoma Treatment

Malignant melanoma poses a significant global health burden. It is the most aggressive and lethal form of skin cancer, attributed to various risk factors such as UV radiation exposure, genetic modifications, chemical carcinogens, immunosuppression, and fair complexion. Photodynamic therapy is a promising minimally invasive treatment that uses light to activate a photosensitizer, resulting in the formation of reactive oxygen species, which ultimately promote cell death. When selecting photosensitizers for melanoma photodynamic therapy, the presence of melanin should be considered. Melanin absorbs visible radiation similar to most photosensitizers and has antioxidant properties, which undermines the reactive species generated in photodynamic therapy processes. These characteristics have led to further research for new photosensitizing platforms to ensure better treatment results. The development of photosensitizers has advanced with the use of nanotechnology, which plays a crucial role in enhancing solubility, optical absorption, and tumour targeting. This paper reviews the current approaches (that use the synergistic effect of different photosensitizers, nanocarriers, chemotherapeutic agents) in the photodynamic therapy of melanoma.

Two subtypes of cutaneous melanoma with distinct mutational signatures and clinico-genomic characteristics

Background: To decipher mutational signatures and their associations with biological implications in cutaneous melanomas (CMs), including those with a low ultraviolet (UV) signature.

Materials and Methods: We applied non-negative matrix factorization (NMF) and unsupervised clustering to the 96-class mutational context of The Cancer Genome Atlas (TCGA) cohort (N = 466) as well as other publicly available datasets (N = 527). To explore the feasibility of mutational signature-based classification using panel sequencing data, independent panel sequencing data were analyzed.

Results: NMF decomposition of the TCGA cohort and other publicly available datasets consistently found two mutational signatures: UV (SBS7a/7b dominant) and non-UV (SBS1/5 dominant) signatures. Based on mutational signatures, TCGA CMs were classified into two clusters: UV-high and UV-low. CMs belonging to the UV-low cluster showed significantly worse overall survival and landmark survival at 1-year than those in the UV-high cluster; low or high UV signature remained the most significant prognostic factor in multivariate analysis. The UV-low cluster showed distinct genomic and functional characteristic patterns: low mutation counts, increased proportion of triple wild-type and KIT mutations, high burden of copy number alteration, expression of genes related to keratinocyte differentiation, and low activation of tumor immunity. We verified that UV-high and UV-low clusters can be distinguished by panel sequencing.

Conclusion: Our study revealed two mutational signatures of CMs that divide CMs into two clusters with distinct clinico-genomic characteristics. Our results will be helpful for the clinical application of mutational signature-based classification of CMs.