Management of Acral and Mucosal Melanoma: Medical Oncology Perspective

Predictive Biomarkers for Immune Checkpoint Inhibitor Therapy in Advanced Melanomas

Biomarkers capable of predicting adverse melanoma patient responses to immune checkpoint inhibitor (ICI) therapies are an unmet need. Clinical biomarkers are largely prognostic and current response guidelines do not reflect the complex tumor-immune cell interaction dynamics attributed to ICI therapies. Validation of enhanced predictive biomarkers is dependent upon adoption of novel spatial imaging platforms capable of quantifying immune checkpoint receptor-ligand interactions within the tumor microenvironment. Assessments of these interactions at multiple points during neoadjuvant ICI regimens would inform biomarker selection based on changes in receptor-ligand interactions that best correlate with patient survival.

Acral Melanoma in Skin of Color: Current Insights and Future Directions: A Narrative Review

Acral melanoma (AM), also known as acral lentiginous melanoma (ALM), is a rare subtype of melanoma that predominantly occurs on the palms, soles, and nail beds (Figure 1) [...].

Primary malignant melanoma of the female urethra: A case report

Primary malignant mucosal melanoma of the female urethra is extremely rare and associated with high recurrence rates and exceptionally poor 5-year survival. Due to its rarity, treatment strategies are heterogenous and often extrapolated from the treatment of other more common types of melanomas. Herein, we describe a case of malignant melanoma of the urethra in a Caucasian female.

High-affinity T cell receptor ImmTAC® bispecific efficiently redirects T cells to kill tumor cells expressing the cancer-testis antigen PRAME

Background

PRAME (Preferentially expressed Antigen in Melanoma) is a cancer-testis antigen expressed in several tumor indications, representing an attractive anticancer target. However, its intracellular location limits targeting by traditional methods. PRAME peptides are presented on the surface of tumor cells by human leukocyte antigen (HLA) molecules, indicating that a T cell receptor (TCR)-based strategy that redirects T cells to kill PRAME+ tumors could be a novel immunotherapeutic option. We confirm that PRAME protein is expressed in cutaneous melanoma, including rare subtypes with limited treatment options, as well as primary and metastatic lung, breast, endometrial, and ovarian tumors. Furthermore, PRAME is expressed homogeneously across tumors with distinct oncogenic mutations, mutation burden, PD-L1 expression, immune infiltration, and features of immune checkpoint resistance. Immunopeptidomic analysis of primary tumors detected HLA class I-restricted PRAME peptides.

Methods

A TCR recognizing PRAME peptide SLLQHLIGL was engineered to high affinity and fused to a CD3 engaging domain to create a TCRxCD3 bispecific molecule (Immune-mobilizing monoclonal TCR Against Cancer, ImmTAC®) with the ability to redirect polyclonal T cells to efficiently kill PRAME+ cells.

Rs

The degree of T cell activation was positively correlated with peptide-HLA abundance, with as few as 10 epitopes per cell sufficient for target cell killing. Impaired ImmTAC®-redirected cytotoxicity of exhausted T cells was rescued using an anti-PD-1 antibody, supporting the use of a combination strategy to treat tumors with active PDL1-PD1 axes.

Conclusions

Our data demonstrate selective and efficient T cell activation and killing by a PRAME-directed TCRxCD3 bispecific, supporting further investigation in multiple cancer indications.

Toripalimab in combination with HBM4003, an anti-CTLA-4 heavy chain-only antibody, in advanced melanoma and other solid tumors: an open-label phase I trial

BACKGROUND

HBM4003 is a novel anti-CTLA-4 heavy chain-only antibody, designed to enhance Treg ablation and antibody-dependent cell-mediated cytotoxicity while ensuring a manageable safety profile. This phase I trial investigated the safety, pharmacokinetics, immunogenicity and preliminary efficacy of HBM4003 plus with anti-PD-1 antibody toripalimab in patients with advanced solid tumors, especially focusing on melanoma.

METHODS

The multicenter, open-label phase I trial was divided into two parts: dose-escalation phase (part 1) and dose-expansion phase (part 2). In part 1, HBM4003 was administered at doses of 0.03, 0.1, 0.3 mg/kg in combination with toripalimab with fixed dosage of 240 mg every 3 weeks. The recommended phase II dose (RP2D) was used in the expansion phase. Primary endpoints were safety and RP2D in part 1 and objective response rate (ORR) in part 2. Biomarkers based on cytokines and multiplex immunofluorescence staining were explored.

RESULTS

A total of 40 patients received study treatment, including 36 patients treated with RP2D of HBM4003 0.3 mg/kg plus toripalimab 240 mg every 3 week. 36 participants (90.0%) experienced at least one treatment-related adverse event (TRAE), of which 10 (25.0%) patients experienced grade ≥3 TRAEs and 5 (12.5%) experienced immune-mediated adverse events (irAEs) with maximum severity of grade 3. No grade 4 or 5 irAEs occurred. Efficacy analysis set included 32 melanoma patients treated with RP2D and with available post-baseline imaging data. The ORRs of anti-PD-1/PD-L1 treatment-naïve subgroup and anti-PD-1/PD-L1 treatment-failed subgroup were 33.3% and 5.9%, respectively. In mucosal melanoma, the ORR of the two subgroups were 40.0% and 10.0%, respectively. Baseline high Treg/CD4+ratio in the tumor serves as an independent predictive factor for the efficacy of immunotherapy.

CONCLUSIONS

HBM4003 0.3 mg/kg plus toripalimab 240 mg every 3 week demonstrated manageable safety in solid tumors and no new safety signal. Limited data demonstrated promising antitumor activity, especially in PD-1 treatment-naïve mucosal melanoma.

TRIAL REGISTRATION NUMBER

NCT04727164.

Evolving cancer resistance to anti-PD-1/PD-L1 antibodies in melanoma: Comprehensive insights with future prospects

Immunotherapy has transformed the treatment of advanced melanoma. However, up to two-thirds of patients experience disease progression after initially achieving a response to immunotherapy. Furthermore, most research has focused on cutaneous melanoma rather than acral or mucosal melanoma, although the latter predominates in Asian populations. In this review, we examine and summarize current definitions of resistance to immunotherapy and the epidemiology of resistance to PD-1 inhibition. We also review the available literature on molecular mechanisms of resistance, including how the tumor mutational landscape and tumor microenvironments of immunotherapy-resistant acral and mucosal melanomas may influence resistance. Finally, we review strategies for overcoming resistance to PD-1 inhibition and summarize completed studies and ongoing clinical trials. Our review highlights that improving the understanding of resistance mechanisms, optimizing existing therapies and further studying high-risk populations would maximize the potential of immunotherapy and result in optimized treatment outcomes for patients with melanoma.

Beyond the Scalpel: Advancing Strategic Approaches and Targeted Therapies in Nonexcisable Melanomas

Melanoma in challenging anatomical locations such as the face, acral surfaces, and mucosal areas presents unique hurdles for surgical excision. This review examines alternative nonsurgical treatment modalities in the context of these complexities, addressing the gaps in current guidelines and the varied efficacy of existing therapies. A comprehensive literature search was conducted using PubMed, Embase, and Web of Science databases. The review focuses on peer-reviewed articles discussing nonsurgical treatment options for melanoma in complex anatomical locations. Articles were screened by three independent researchers, ensuring a broad analysis of topical agents, immunotherapies, radiotherapies, and targeted therapies. The review highlights significant advancements in localized treatments such as imiquimod and intralesional therapy with talimogene laherparepvec (T-VEC), which show promise in managing nonexcisable melanomas. BRAF and MEK inhibitors, as well as checkpoint inhibitors targeting CTLA-4 and PD-1/PD-L1 pathways, demonstrate improved survival rates but pose challenges with resistance and systemic side effects. Radiotherapy serves as an adjunctive strategy due to melanoma's inherent radioresistant properties. Despite advancements, there is a notable absence of comprehensive, evidence-based protocols to guide the treatment of melanoma in these critical areas. This paper underscores the need for standardized treatment guidelines that account for the efficacy, side effects, and psychosocial impacts of therapies. Future research should focus on refining existing treatments and exploring innovative modalities to enhance patient outcomes in the management of nonexcisable melanomas. Comprehensive guidelines and long-term efficacy studies are essential to optimize care and improve the quality of life for patients afflicted with melanoma in challenging anatomical locations.

Survival of patients with mucosal melanoma in Cali, Colombia: a retrospective cohort study

BACKGROUND

Mucosa melanoma is a rare condition with aggressive behavior and a less favorable prognosis compared to cutaneous melanoma. The objective of this study was to estimate the overall survival and clinical outcomes of patients diagnosed with mucosal melanoma in a Colombian hospital.

METHODS

A retrospective cohort study was conducted at Fundación Valle del Lili, a single center located in Cali, Colombia. Patients aged ≥ 18 years, both sexes, diagnosed with mucosal melanoma by histopathology study were included between 2010-2019. Patients who received extra-institutional treatment or whose vital status was unknown during follow-up were excluded. Demographic, clinical and laboratory data were obtained from medical records and laboratory and pathology databases. A descriptive analysis was performed. Survival analysis was conducted using the Kaplan-Meier method.

RESULTS

A total of 23 patients were included. Median age was 63 years old (IQR: 57-68) and 52.2% were woman. Clinical stage was 34.8% early, 26.1% locally advanced and 39.1% metastatic. The main primary locations were nasopharynx (30.4%), genitals (26.1%), rectum (21.7%), oral cavity (13%) and paranasal sinuses (8.7%). The majority received surgery (30.4%) and immunotherapy (26.1%) as first line treatment. Overall survival at one year was 80.8%, at three years 44.3%, and at five years 36.9%.

CONCLUSION

Mucosal melanoma is a rare, aggressive disease with adverse oncological outcomes due to late diagnosis and limited treatment options. This study provides real-world data in a single-center of Colombia.

The genetic evolution of acral melanoma

Acral melanoma is an aggressive type of melanoma with unknown origins. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. We examine exome sequencing data of 139 tissue samples, spanning different progression stages, from 37 patients. We find that 78.4% of the melanomas display clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These complex genomic aberrations are typically shared across all progression stages of individual patients. TERT activating alterations also arise early, whereas MAP-kinase pathway mutations appear later, an inverted order compared to the canonical evolution. The punctuated formation of complex aberrations and early TERT activation suggest a unique mutational mechanism that initiates acral melanoma. The marked intratumoral heterogeneity, especially concerning MAP-kinase pathway mutations, may partly explain the limited success of therapies for this melanoma subtype.

Primary oral and sinonasal mucosal melanomas in Latin America: a systematic review

Primary oral and sinonasal mucosal melanomas (POSNMMs) are aggressive neoplasms with limited therapeutic alternatives. The aim of this review was to characterize the demographic, clinical, immunohistochemical, and molecular information regarding these tumors in the Latin American population. Articles published in English, Spanish, or Portuguese (1990-2022) retrieved from the PubMed/MEDLINE, Scopus, CAS, Web of Science, EBSCO, and Google Academic databases were included. Thirty-three studies, with a total of 1212 cases, were identified. Clinicopathological data were available for 870 cases and immunohistochemical and/or molecular information for 342. Nineteen studies (57.6%) reported cases of oral melanoma, three (9.1%) sinonasal melanoma, and 11 (33.3%) oral and sinonasal melanoma. Fifteen studies (45.5%) provided only clinicopathological data, 12 (36.4%) reported only immunohistochemical data, two (6.1%) shared clinicopathological and immunohistochemical data, one (3.0%) offered clinicopathological, immunohistochemical, and molecular data, one (3.0%) provided immunohistochemical and molecular data, one (3.0%) clinicopathological and molecular data, and one (3.0%) only molecular data. The mean age of individuals with POSNMMs was 58 years, and slightly more were male (male 51.3%, female 48.7%). In Latin America, POSNMMs are a rare but aggressive malignancy with a poor prognosis and limited treatment options. Although molecular data and targeted therapy are still being researched, data from Latin America indicate the need for multicenter collaborative clinical trials to unite individual and isolated efforts.

Current State of Melanoma Therapy and Next Steps: Battling Therapeutic Resistance

Melanoma is the most aggressive and deadly form of skin cancer due to its high propensity to metastasize to distant organs. Significant progress has been made in the last few decades in melanoma therapeutics, most notably in targeted therapy and immunotherapy. These approaches have greatly improved treatment response outcomes; however, they remain limited in their abilities to hinder disease progression due, in part, to the onset of acquired resistance. In parallel, intrinsic resistance to therapy remains an issue to be resolved. In this review, we summarize currently available therapeutic options for melanoma treatment and focus on possible mechanisms that drive therapeutic resistance. A better understanding of therapy resistance will provide improved rational strategies to overcome these obstacles.

Unlocking the potential: phenylboronic acid as a nuclear-targeting boron agent for neutron capture therapy

It has been proposed that boron neutron capture therapy (BNCT) holds promise as a treatment modality for melanoma. However, the effectiveness of boron agents in delivery remains a critical issue to be addressed for BNCT. To this end, phenylboronic acid, which exhibits good water solubility and low cytotoxicity similar to BPA, has been investigated as a potential nuclear-targeting boron agent. The boron concentration of phenylboronic acid was found to be 74.47 ± 12.17 ng/106 B16F10 cells and 45.77 ± 5.64 ng/106 cells in the nuclei. Molecular docking experiments were conducted to investigate the binding of phenylboronic acid to importin proteins involved in nuclear transport. The potential of phenylboronic acid to serve as a desirable nucleus-delivery boron agent for neutron capture therapy in melanoma warrants further exploration.

Multi-omics and tumor immune microenvironment characterization of a prognostic model based on aging-related genes in melanoma

Melanoma is a common and fatal cutaneous malignancy with strong invasiveness and high mortality rate. Clinically, elderly melanoma patients tend to exhibit stronger invasion ability and poorer prognosis. Given the heterogeneity of tumors, we analyzed the prognosis and risk assessment of melanoma through aging-related genes rather than age stratification. FOXM1 and CCL4 were identified to be closely associated with melanoma prognosis. Single-cell transcriptome analysis showed that FOXM1 was significantly up-regulated in tumor cells, while CCL4 was markedly elevated in immune cells. A melanoma prognostic model was constructed based on the two independent prognostic factors. This model showed a high accuracy in predicting the mortality of melanoma patients over several years. The patients in low-risk group appeared to have more immune cell infiltration and better immune therapy efficacy. Cellular experiments showed that CCL4 could promote apoptosis of melanoma cells through immune cells, and apoptosis could regulate the expression of FOXM1. In addition, the results of the spatial transcriptome and immunohistochemistry suggested that CCL4 was highly expressed in macrophages and the expression of FOXM1 in melanoma cell was negatively correlated with immune cell infiltration, especially macrophages. Here, we established a novel prognostic model for melanoma, which showed promising predictive performance and may serve as a biomarker for the efficacy of immune checkpoint inhibition therapy in melanoma patients. In addition, we explored the function of two genes in the model in melanoma.

Pressure and Skin: A Review of Disease Entities Driven or Influenced by Mechanical Pressure

Skin perceives and reacts to external mechanical forces to create resistance against the external environment. Excessive or inappropriate stimuli of pressure may lead to cellular alterations of the skin and the development of both benign and malignant skin disorders. We conducted a comprehensive literature review to delve into the pressure-induced and aggravated skin disorders and their underlying pressure-related mechanisms. Dysregulated mechanical responses of the skin give rise to local inflammation, ischemia, necrosis, proliferation, hyperkeratosis, impaired regeneration, atrophy, or other injurious reactions, resulting in various disease entities. The use of personal devices, activities, occupations, weight bearing, and even unintentional object contact and postures are potential scenarios that account for the development of pressure-related skin disorders. The spectrum of these skin disorders may involve the epidermis (keratinocytes and melanocytes), hair follicles, eccrine glands, nail apparatuses, dermis (fibroblasts, mast cells, and vasculature), subcutis, and fascia. Clarifying the clinical context of each patient and recognizing how pressure at the cellular and tissue levels leads to skin lesions can enhance our comprehension of pressure-related skin disorders to attain better management.

Melanoma biology and treatment: a review of novel regulated cell death-based approaches

The incidence of melanoma, the most lethal form of skin cancer, has increased due to ultraviolet exposure. The treatment of advanced melanoma, particularly metastatic cases, remains challenging with poor outcomes. Targeted therapies involving BRAF/MEK inhibitors and immunotherapy based on anti-PD1/anti-CTLA4 antibodies have achieved long-term survival rates of approximately 50% for patients with advanced melanoma. However, therapy resistance and inadequate treatment response continue to hinder further breakthroughs in treatments that increase survival rates. This review provides an introduction to the molecular-level pathogenesis of melanoma and offers an overview of current treatment options and their limitations. Cells can die by either accidental or regulated cell death (RCD). RCD is an orderly cell death controlled by a variety of macromolecules to maintain the stability of the internal environment. Since the uncontrolled proliferation of tumor cells requires evasion of RCD programs, inducing the RCD of melanoma cells may be a treatment strategy. This review summarizes studies on various types of nonapoptotic RCDs, such as autophagy-dependent cell death, necroptosis, ferroptosis, pyroptosis, and the recently discovered cuproptosis, in the context of melanoma. The relationships between these RCDs and melanoma are examined, and the interplay between these RCDs and immunotherapy or targeted therapy in patients with melanoma is discussed. Given the findings demonstrating melanoma cell death in response to different stimuli associated with these RCDs, the induction of RCD shows promise as an integral component of treatment strategies for melanoma.

Single-cell RNA sequencing in melanoma: what have we learned so far?

Over the past decade, there have been remarkable improvements in the treatment and survival rates of melanoma patients. Treatment resistance remains a persistent challenge, however, and is partly attributable to intratumoural heterogeneity. Melanoma cells can transition through a series of phenotypic and transcriptional cell states that vary in invasiveness and treatment responsiveness. The diverse stromal and immune contexture of the tumour microenvironment also contributes to intratumoural heterogeneity and disparities in treatment response in melanoma patients. Recent advances in single-cell sequencing technologies have enabled a more detailed understanding of melanoma heterogeneity and the underlying transcriptional programs that regulate melanoma cell diversity and behaviour. In this review, we examine the concept of intratumoural heterogeneity and the challenges it poses to achieving long-lasting treatment responses. We focus on the significance of next generation single-cell sequencing in advancing our understanding of melanoma diversity and the unique insights gained from single-cell studies.

The genetic evolution of acral melanoma

Acral melanoma is an aggressive type of melanoma with unknown origins, arising on the sole, palm, or nail apparatus. It is the most common type of melanoma in individuals with dark skin and is notoriously challenging to treat. Our study examined exome sequencing data from 139 tissue samples, spanning different progression stages, collected from 37 patients. We found that 78.4% of the melanomas displayed one or more clustered copy number transitions with focal amplifications, recurring predominantly on chromosomes 5, 11, 12, and 22. These genomic "hailstorms" were typically shared across all progression stages within individual patients. Genetic alterations known to activate TERT also arose early. By contrast, mutations in the MAP-kinase pathway appeared later during progression, often leading to different tumor areas harboring non-overlapping driver mutations. We conclude that the evolutionary trajectories of acral melanomas substantially diverge from those of melanomas on sun-exposed skin, where MAP-kinase pathway activation initiates the neoplastic cascade followed by immortalization later. The punctuated formation of hailstorms, paired with early TERT activation, suggests a unique mutational mechanism underlying the origins of acral melanoma. Our findings highlight an essential role for telomerase, likely in re-stabilizing tumor genomes after hailstorms have initiated the tumors. The marked genetic heterogeneity, in particular of MAP-kinase pathway drivers, may partly explain the limited success of targeted and other therapies in treating this melanoma subtype.

Efficacy of salvage therapies for advanced acral melanoma after anti-PD-1 monotherapy failure: a multicenter retrospective study of 108 Japanese patients

Background

Anti-programmed cell death protein 1 (PD-1) monotherapy is one of the standard systemic therapies for advanced melanoma; however, the efficacy of salvage systemic therapies after PD-1 monotherapy failure (PD-1 MF), particularly in acral melanoma (AM), the main clinical melanoma type in Japanese patients, is unclear. This study aimed to investigate the efficacy of salvage systemic therapies in Japanese patients with AM after PD-1 MF.

Patients and methods

The study included 108 patients with advanced AM (palm and sole, 72; nail apparatus, 36) who underwent salvage systemic therapy at 24 Japanese institutions. We mainly assessed the objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

Results

Thirty-six (33%) patients received ipilimumab, 23 (21%) received nivolumab and ipilimumab (nivo/ipi), 10 (9%) received cytotoxic chemotherapy, 4 (4%) received BRAF and MEK inhibitors (BRAFi/MEKi), and the remaining 35 (32%) continued with PD-1 monotherapy after disease progression. The ORRs in the ipilimumab, nivo/ipi, cytotoxic chemotherapy, and BRAFi/MEKi groups were 8, 17, 0, and 100%, respectively. The nivo/ipi group showed the longest OS (median, 18.9 months); however, differences in ORR, PFS, and OS between the groups were insignificant. The OS in the nivo/ipi group was higher in the palm and sole groups than in the nail apparatus group (median: not reached vs. 8.7 months, p < 0.001). Cox multivariate analysis demonstrated that nail apparatus melanoma independently predicted unfavorable PFS and OS (p = 0.006 and 0.001). The total OS (from PD-1 monotherapy initiation to death/last follow-up) was insignificant between the groups.

Conclusion

Nivo/ipi was not more effective than cytotoxic chemotherapy and ipilimumab after PD-1 MF in patients with advanced AM. The prognosis after PD-1 MF would be poorer for nail apparatus melanoma than for palm and sole melanoma.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Baseline neutrophil-to- ratio combined with the change during treatment provides risk stratification for metastatic malignant melanoma patients treated with PD-1 inhibitors in a Chinese population

Background

Previous studies have suggested that an elevated baseline neutrophil-to-lymphocyte ratio (BLNLR) and elevated relative change of NLR (ΔNLR%) is associated with worse outcomes in patients with a variety of cancers. This study aims to investigate the value of BLNLR and ΔNLR% before the third cycle of treatment on the prognosis of patients with metastatic malignant melanoma treated with PD-1 inhibitors.

Methods

A total of 63 patients with metastatic malignant melanoma treated with PD-1 inhibitors in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2021 were retrospectively analyzed. BLNLR and ΔNLR% before the third cycle of treatment were collected. The Kaplan-Meier method was used to draw survival curves and Log-Rank test was used for survival analysis. Univariate and multivariate Cox regression analysis were used to analyze the relationship between BLNLR, ΔNLR% and clinical characteristics with progression-free survival (PFS) and overall survival (OS).

Results

Univariate analysis showed that PFS and OS were associated with BLNLR, ΔNLR%, BMI and number of metastatic organs (P < 0.05). Multivariate analysis showed that BLNLR, ΔNLR%, BMI and number of metastatic organs were independent predictors of OS and BLNLR and ΔNLR% were independent predictors of PFS. Patients were divided into four groups according to BLNLR (<3, ≥3) and ΔNLR% (< 30%, ≥30%): low-BLNLR + low-ΔNLR% group, low-BLNLR + high-ΔNLR% group, high-BLNLR + low-ΔNLR% group, high-BLNLR + high-ΔNLR% group. The median OS was 20 months, 8 months, 9 months, 5 months and the median PFS was 8 months, 3 months, 2 months, 2 months, respectively.

Conclusion

BLNLR combined with ΔNLR% can be used to predict the prognosis of PD-1 inhibitors in patients with metastatic malignant melanoma.