Non-acral Cutaneous Melanoma Research Articles

Germline Variants in Patients Affected by Both Uveal and Cutaneous Melanoma.

Uveal melanoma (UM) and nonacral cutaneous melanoma (CM) are distinct entities with varied genetic landscapes despite both arising from melanocytes. There are, however, similarities in that they most frequently affect people of European ancestry, and high penetrance germline variants in BAP1, POT1 and CDKN2A have been shown to predispose to both UM and CM. This study aims to further explore germline variants in patients affected by both UM and CM, shedding light on the underlying genetic mechanism causing these diseases. Using exome sequencing we analysed germline DNA samples from a cohort of 83 Australian patients diagnosed with both UM and CM. Eight (10%) patients were identified that carried pathogenic mutations in known melanoma predisposition genes POT1, MITF, OCA2, SLC45A2 and TYR. Three (4%) patients carried pathogenic variants in genes previously linked with other cancer syndromes (ATR, BRIP1 and MSH6) and another three cases carried monoallelic pathogenic variants in recessive cancer genes (xeroderma pigmentosum and Fanconi anaemia), indicating that reduced penetrance of phenotype in these individuals may contribute to the development of both UM and CM. These findings highlight the need for further studies characterising the role of these genes in melanoma susceptibility.

Three-Year Analysis of Adjuvant Therapy in Postoperative Melanoma including Acral and Mucosal Subtypes.

Adjuvant therapy has improved the clinical prognosis for postoperative melanoma patients. However, the long-term efficacy of this therapy on the melanoma acral and mucosal subtypes has not been fully evaluated in previous trials. This study assessed the 3-year recurrence-free survival and overall survival of patients with melanoma, including the acral and mucosal subtypes, treated with anti-PD-1 antibody (Ab) or with the combination of the BRAF and MEK inhibitors dabrafenib and trametinib. We retrospectively analyzed both the 3-year time to relapse (TTR) and overall survival (OS) of 120 patients treated with anti-PD-1 antibody (Ab), or with the combination of dabrafenib and trametinib. The overall median TTR was 18.4 months, with a range of 0.69 to 36 months. The 3-year TTR of the acral and mucosal types was 28.1% and 38.5%, respectively. Baseline tumor thickness (TT) and acral type were associated with the TTR in subgroup analysis. Moreover, we classified 104 acral and non-acral cutaneous patients into the anti-PD-1 Abs or dabrafenib plus trametinib combined therapies cohort in multiple analyses. The acral subtype and TT were detected as important prognostic factors. In the 3-year OS, only tumor ulceration was associated with the OS in both univariate and multiple analyses. There was no significant difference in baseline or treatment-related factors of the mucosal type (p > 0.05). This study suggests that adjuvant therapy is more effective with non-acral cutaneous melanoma than either the acral or mucosal types at the 3-year TTR endpoint.

Receptor tyrosine kinase inhibition leads to regression of acral melanoma by targeting the tumor microenvironment.

Acral melanoma (AM) is an aggressive melanoma variant that arises from palmar, plantar, and nail unit melanocytes. Compared to non-acral cutaneous melanoma (CM), AM is biologically distinct, has an equal incidence across genetic ancestries, typically presents in advanced stage disease, is less responsive to therapy, and has an overall worse prognosis. Independent analysis of published genomic and transcriptomic sequencing identified that receptor tyrosine kinase (RTK) ligands and adapter proteins are frequently amplified, translocated, and/or overexpressed in AM. To target these unique genetic changes, a zebrafish acral melanoma model was exposed to a panel of narrow and broad spectrum multi-RTK inhibitors, revealing that dual FGFR/VEGFR inhibitors decrease acral-analogous melanocyte proliferation and migration. The potent pan-FGFR/VEGFR inhibitor, Lenvatinib, uniformly induces tumor regression in AM patient-derived xenograft (PDX) tumors but only slows tumor growth in CM models. Unlike other multi-RTK inhibitors, Lenvatinib is not directly cytotoxic to dissociated AM PDX tumor cells and instead disrupts tumor architecture and vascular networks. Considering the great difficulty in establishing AM cell culture lines, these findings suggest that AM may be more sensitive to microenvironment perturbations than CM. In conclusion, dual FGFR/VEGFR inhibition may be a viable therapeutic strategy that targets the unique biology of AM.

A phase I/II study of KD6001, a novel fully human anti-CTLA4 IgG1 monoclonal antibody, in combination with toripalimab in patients with advanced melanoma.

9527 Background: Anti-CTLA4 and anti-PD-1 immunotherapies have changed the treatment landscape of patients (pts) with advanced or metastatic melanoma. However, there is still a need to develop an anti-CTLA-4 antibody with further improved safety and efficacy profile. KD6001, a novel fully human anti-CTLA4 IgG1 monoclonal antibody that exhibits immunomodulatory effects, enhances T-cell-mediated anti-tumor immune response, and shows preliminary anti-tumor activity as monotherapy in a FIH phase I trial in pts with advanced solid tumors. Here we report a new study result of KD6001 in combination with toripalimab, an anti-PD-1 monoclonal antibody, in pts with advanced melanoma (KD6001CT02). Methods: KD6001CT02 is a phase I/II study conducted in advanced melanoma. This study consists of dose escalation and dose expansion phases. The primary objective is to evaluate the safety and tolerability of KD6001 in combination with toripalimab and determine the MTD/RP2D. The secondary objectives are to measure antitumor activity, immunogenicity, and pharmacokinetics (PK). Results: As of 15 Dec 2023, 29 pts with melanoma were enrolled (dose escalation n=6 and dose expansion n=23), including 9 (31.0%) acral, 9 (31.0%) nonacral cutaneous, 8 (27.6%) mucosal, and 3 (10.3%) unknown primary subtypes. 18 of them had no brain metastases. The median age was 56 yrs (range 41-78 yrs). The majority of pts previously received anti-PD-1/L1 therapy (16/29, 55.2%) and 27.6% of them received ≥3 lines of therapy. No dose-limiting toxicity or ≥Gr 3 adverse events (AEs) were reported in the dose escalation phase. The study did not reach MTD. 26 (89.7%) pts had treatment-related adverse events (TRAEs), with ≥Gr 3 TRAEs occurring in 3 (10.3%) pts and were well manageable. All other TRAEs were Gr 1 or 2. There were no death events due to TRAEs. No novel safety signals were seen other than the previously reported safety profile of treatment with a combined inhibition of CTLA-4 and PD-1. At data cutoff, among 13 efficacy-evaluable pts without brain metastases, the unconfirmed and confirmed objective response rates (ORR) were 38.5% and 23.1%, respectively. The disease control rate (DCR) was 76.9%. Among 3 pts with confirmed partial response (PR) , 2 pts were mucosal melanoma and 1 patient was nonacral cutaneous melanoma. Among 7 pts who received KD6001 as the ≥2 line treatment and all failed anti-PD-1/L1 therapy, the unconfirmed and confirmed ORR were 57.1% and 42.9%, respectively. DCR was 85.7%. The median PFS and OS were not reached. Conclusions: KD6001 in combination with toripalimab for treatment of advanced melanoma was safe, well-tolerated and showed anti-tumor activity in pts with advanced melanoma. Preliminary analysis indicates that KD6001 combined with toripalimab is efficacious in pts who have progressed after previous anti-PD-1/L1 therapy and in pts with mucosal melanoma. Clinical trial information: NCT05723432 .

Immune phenotype profiling based on anatomic origin of melanoma and impact on clinical outcomes of immune checkpoint inhibitor treatment.

9569 Background: The inflamed immune phenotype is associated with a favorable response to immunotherapy in metastatic malignant melanoma. Although variations in molecular features across melanoma subtypes and differing ethnic distributions have been well reported, studies investigating immune phenotypes across multiple institutions within the context of different melanoma subtypes are scarce. We examined the association of immune phenotypes with outcomes after immunotherapy, based on subtypes of malignant melanoma. Methods: Two institutional advanced melanoma cohortsrepresenting Asian and Western populations (YUHS, n = 123; Stanford University, n = 102) were included. H&E-stained tumor slides were assessed using Lunit SCOPE IO, an AI-powered whole slide image analyzer, to define the inflamed score (IS, % of inflamed area) and the inflamed phenotype (>33.3% IS). Clinical outcomes after immune checkpoint inhibitor (anti-PD-1/PD-L1) treatment, including progression-free survival (PFS) and overall-survival (OS), were assessed. Results: In the overall cohort (n = 225), the inflamed phenotype was associated with prolonged PFS (HR = 0.634, 95% CI: 0.453 – 0.887, p = 0.007) and OS (HR = 0.655, 95% CI: 0.432 – 0.992, p = 0.044). On analysis of melanoma subtypes, we identified non-acral cutaneous melanomas (CM, n = 94), acral melanomas (AM, n = 52), mucosal melanomas (n = 43), uveal melanomas (n = 16), and melanomas of unknown primary site (n = 20), with a disproportionate enrichment of AM (37.4%) and mucosal (29.3%) melanoma cases in the YUHS cohort and CM cases (68.6%) in the Stanford cohort. The IS varied across different melanoma subtypes, with the highest IS observed in CM (median, [IQR]; 34.0, [5.8–52.2]), and significantly lower scores in AM (22.3, [7.7–36.9]), mucosal (13.6, [0–31.4]), and uveal melanoma (5.5, [0–13.6]). Among CM patients, the inflamed phenotype was significantly associated with better post-immunotherapy PFS (HR = 0.476, 95% CI: 0.274 – 0.826, p = 0.007). In contrast, the inflamed phenotype did not correlate with survival in AM patients (p = 0.58), who exhibited universally poorer PFS compared to non-AM patients (HR = 2.124, 95% CI: 1.486 - 3.005). Conclusions: AI-powered immune phenotype assessment highlights a heterogeneity of immune phenotypes across specific melanoma subtypes, as well as differential association with outcomes after immune checkpoint inhibitor treatment. While CM patients were well-stratified by immune phenotype, the predictive value of immune phenotyping was less pronounced in acral melanomas, which demonstrated poorer outcomes following immunotherapy.

Management of acral lentiginous melanoma: current updates and future directions.

Acral lentiginous melanoma is a rare subtype of melanoma generally associated with poor outcomes, even when diagnosed at an early stage. The tumor genetic profile remains poorly understood, but it is known to have a suppressed immune environment compared to that of non-acral cutaneous melanomas, which limits therapy options. There is significant attention on the development of novel therapeutic approaches, although studies are limited due to disease rarity. For local disease, wide local excision remains the standard of care. Due to frequent under-staging on preoperative biopsy, wider margins and routine sentinel lymph node biopsy may be considered if morbidity would not be increased. For advanced disease, anti-PD1 monotherapy or combination therapy with anti-PD1 and anti-CTLA4 agents have been used as first-line treatment modalities. Anti-PD1 and anti-CTLA4 combination therapies have been shown to be particularly beneficial for patients with BRAF-mutant acral lentiginous melanoma. Other systemic combination regimens and targeted therapy options may be considered, although large studies with consistent results are lacking. Regional and intralesional therapies have shown promise for cutaneous melanomas, but studies generally have not reported results for specific histologic subtypes, especially for acral melanoma. Overall, the unique histologic and genetic characteristics of acral lentiginous melanoma make therapy options significantly more challenging. Furthermore, studies are limited, and data reporting has been inconsistent. However, more prospective studies are emerging, and alternative therapy pathways specific to acral lentiginous melanoma are being investigated. As further evidence is discovered, reliable treatment guidelines may be developed.

Baseline Serum neutrophil-to-lymphocyte ratio in acral melanoma compared with nonacral melanoma and its prognostic significance

BackgroundAcral lentiginous melanoma (ALM), a cutaneous melanoma subtype, exhibits a poorer prognosis than non-acral cutaneous melanoma (NACM). The neutrophil-to-lymphocyte ratio (NLR) is emerging as a prognostic indicator across diverse cancers. ObjectiveWe explored the baseline NLR disparities between ALM and NACM, and the NLR’s prognostic significance in patients with ALM. MethodsWe reviewed records of patients with ALM and NACM diagnosed between 1997 and 2022, analyzing medical data. ResultsAmong 327 and 159 patients with ALM and NACM, respectively, baseline NLR varied based on distinct clinicopathological factors between ALM and NACM. In stage 3–4 melanomas, the median NLR for ALM (2.18; interquartile range, 1.70–3.08) significantly surpassed NACM (1.74; interquartile range, 1.33–2.53) (P=0.029). In patients with ALM, high NLR (hazard ratio, 1.64; 95% confidence interval, 1.02–2.66; P=0.043) was independently correlated with poor progression-free survival when adjusting for ulceration, Breslow thickness ≥2 mm, and nodal invasion. LimitationsSingle-center, retrospective design. ConclusionAdvanced-stage ALM exhibited a significantly higher baseline NLR compared to that of NACM. Evaluating baseline NLR could provide valuable prognostic insights for patients with ALM.

Outcomes of patients with resected stage III/IV acral or mucosal melanoma, treated with adjuvant anti-PD-1 based therapy

ImportanceAcral (AM) and mucosal melanomas (MM) are rare subtypes with a poor prognosis. In those with advanced disease, anti-PD-1 (PD1) therapy has reduced activity compared to that seen in non-acral cutaneous melanoma. ObjectiveTo determine the efficacy of adjuvant PD1 in resected AM or MM. DesignAn international, retrospective cohort study SettingData up to November 2021 collected from 20 centres across 10 countries. ParticipantsOne hundred and ninety four patients with resected stage III or IV1 AM or MM who received adjuvant PD1 were included and compared to matched patients from the Melanoma Institute Australia (MIA) database using a propensity score matching analysis. Main outcomes and measuresRecurrence-free survival (RFS), distant metastasis-free survival (DMFS) and overall survival (OS) were investigated. ResultsForty five of 139 (32%) AM and 9 of 55 (16%) MM patients completed adjuvant therapy. The main reason for early treatment cessation in both groups was disease recurrence: 51 (37%) and 30 (55%) in the AM and MM groups, respectively. In the AM group adjuvant PD1 was associated with a longer RFS [HR-0.69 (0.52–0.92, p = 0.0127)], DMFS [HR0.58 (0.38–0.89, p = 0.0134)] and OS [HR of 0.59 (0.38–0.92, p-value 0.0196)] when compared to the historical cohort. In the MM group there was no statistical difference in RFS [HR1.36 (0.69–2.68,p-value 0.3799], DMFS or OS. Conclusion and relevanceAfter adjuvant PD1, both AM and MM have a high risk of recurrence. Our data suggests a benefit to using adjuvant PD1 therapy in resected AM but not in resected MM. Additional studies to investigate the efficacy of adjuvant PD1 for MM are needed.

Adverse events associated with postoperative outcomes of adjuvant anti-PD-1 antibody therapy in both acral and non-acral cutaneous melanomas: A multicenter, observational, post hoc analysis study.

Since anti-PD-1 Abs can cause irreversible immune-related adverse events (irAEs), the associations between their efficacies and the incidence of irAEs are important to evaluate the use of anti-PD-1Abs for the treatment of melanoma, especially in the adjuvant setting. The purpose of this post hoc analysis study was to retrospectively analyze the associations between recurrence-free survival (RFS) at 12 months and the onset of any irAEs in 31 non-acral cutaneous and 30 acral melanoma cases treated with anti-PD-1 Abs therapy at the adjuvant setting in Asians. There were 20 cases with greater than grade 1 AEs in both the acral and non-acral cutaneous groups. Of the acral melanoma, 10 cases were nails or toes, and 20 cases were soles and heels. The log-rank test showed that RFS was better in cases with AEs than in cases without AEs. The present study suggested that the different profiles of irAEs between non-acral cutaneous and acral melanoma might correlate with the different response to anti-PD1 Abs of melanoma in the adjuvant setting.

Telomerase reverse transcriptase immunohistochemical expression is sensitive but not specific for TERT gene amplification in acral melanoma.

TERT gene amplification (TGA) is a mechanism of telomerase reverse transcriptase (TERT) upregulation frequently utilized by acral melanomas (AMs). Currently, the utility of TERT immunohistochemistry (IHC) to predict TGA status in AMs is poorly documented. AMs (26 primary and 3 metastatic) and non-acral cutaneous melanomas (6 primary) were subjected to immunohistochemical analysis using anti-TERT antibody to demonstrate protein expression and fluorescence in situ hybridization (FISH) to assess genomic copy number alteration. The relationship between TERT immunoreactivity and TGA confirmed by FISH was assessed using logistic regression. TERT expression was seen in 50% (13/26) of primary and 100% (3/3) of metastatic AMs and 50% (3/6) of primary non-acral cutaneous melanomas. TGA was found in 15% (4/26) and 67% (2/3) of primary and metastatic AMs and 17% (1/6) of non-acral cutaneous melanomas. The intensity of TERT immunoreactivity correlated with TGA (p = 0.04) and a higher TERT copy number-to-control ratio in AMs, with a correlation coefficient of 0.41 (p = 0.03). The sensitivity and specificity of TERT immunoreactivity for predicting TGA in AMs were 100% and 57%, with corresponding positive and negative predictive values of 38% and 100%, respectively. The clinical utility of TERT IHC to predict TGA status in AMs appears to be limited given its low specificity and positive predictive value.

Analyzing the relationship between the efficacy of first-line immune checkpoint inhibitors and cumulative sun damage in Japanese patients with advanced BRAF wild-type nonacral cutaneous melanoma: A retrospective real-world, multicenter study

BackgroundEfficacy of anti-PD-1 antibody monotherapy (PD1) or anti-PD-1 plus anti-CTLA-4 combination therapy (PD1 +CTLA4) for melanoma is affected by its clinical subtype. The amount of tumor mutation burden (TMB) caused by cumulative sun damage (CSD) is occasionally used to explain this; however, their relationship in Japanese nonacral cutaneous melanoma (NACM) is still unclear. ObjectiveTo analyze the ICI efficacy and its relationship with CSD of the primary lesion in Japanese patients with NACM. MethodsJapanese patients with advanced BRAF wild-type NACM who received first-line ICIs were recruited. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS), and the degree of solar elastosis (SE) were evaluated. ResultsA total of 146 patients (PD1 group 113 and PD1 +CTLA4 group 33) were included. No significant differences in ORR were observed between the PD1 and PD1 +CTLA4 groups (35 % vs. 36 %; P = 0.67) or PFS and OS (median PFS 6.1 months vs. 8.5 months; P = 0.46, median OS 28.1 months vs. not reached; P = 0.59). Multivariate survival analysis revealed that PD1 +CTLA4 did not prolong the PFS and OS. The SE score had no effect on either PFS or OS. ConclusionsICI efficacy was not as high as those reported in Western countries, and PD1 +CTLA4 did not present better clinical efficacy compared to PD1. Indicators of CSD did not serve as a predictor for clinical advantage. These findings may partially support the theory that ICI efficacy is affected by CSD; however, other unrecognized factors may also exist.

Surgical resection margin for T3–T4 primary acral melanoma: a multicenter retrospective cohort study

Although the National Comprehensive Cancer Network (NCCN) guidelines include clear recommendations for the appropriate resection margins in non-acral cutaneous melanoma, the required margin for acral melanoma is controversial. In this retrospective study, we aimed to investigate whether narrow-margin excision is warranted for thick acral melanoma. Records from 277 melanoma patients with stage T3–T4 disease who underwent radical surgery in three centers in China from September 2010 to October 2018 were reviewed. Clinicopathologic data, including age, gender, excision margin (1–2 cm versus ≥ 2 cm), Clark level, Breslow thickness, ulceration, N stage and adjuvant therapy, were included for survival analysis. The patients were followed up until death or March 31, 2021. Log-rank and Cox regression analyses were used to identify prognostic factors for overall survival (OS), disease-free survival (DFS) and local and in-transit recurrence-free survival (LITRFS). Among all enrolled patients, 207 (74.7%) had acral melanoma, and 70 (25.3%) had non-acral cutaneous melanoma. No significant difference in baseline characteristics was identified between non-acral and acral melanoma, except for age (p = 0.004), gender (p = 0.009) and ulceration (p = 0.048). In non-acral melanoma, a resection margin of 1–2 cm was a poor independent prognostic factor for OS [p = 0.015; hazard ratio (HR) (95% CI), 0.26 (0.009–0.77)] and LITRFS [p = 0.013; HR (95% CI), 0.19 (0.05–0.71)] but not for DFS [p = 0.143; HR (95% CI), 0.51 (0.21–1.25)]. Forty-three (20.8%) patients in the acral melanoma group had a 1–2-cm resection margin. The resection margin was not correlated with patients’ OS (p = 0.196 by log-rank analysis, p = 0.865 by multivariate survival analysis), DFS (p = 0.080 by log-rank analysis, p = 0.758 by multivariate survival analysis) or LITRFS (p = 0.354 by log-rank analysis) in acral melanoma. As recommended in the NCCN guidelines, a resection margin ≥ 2 cm is required for non-acral cutaneous melanoma. Meanwhile, a narrow resection margin (1–2 cm) may be safe for patients with acral melanoma.

Nail Apparatus Melanoma: Current Management and Future Perspectives.

Nail apparatus melanoma (NAM) is a rare type of cutaneous melanoma that belongs to the acral melanoma subtype. NAM is managed principally in accordance with the general treatment for cutaneous melanoma, but there is scarce evidence in support of this in the literature. Acral melanoma is genetically different from non-acral cutaneous melanoma, while recently accumulated data suggest that NAM also has a different genetic background from acral melanoma. In this review, we focus on recent advances in the management of NAM. Localized NAM should be surgically removed; amputation of the digit and digit-preserving surgery have been reported. Sentinel lymph node biopsy can be considered for invasive NAM for the purpose of accurate staging. However, it is yet to be clarified whether patients with metastatic sentinel lymph nodes can be safely spared completion lymph node dissection. Similar to cutaneous melanoma, immune checkpoint inhibitors and BRAF/MEK inhibitors are used as the first-line treatment for metastatic NAM, but data on the efficacy of these therapies remain scarce. The therapeutic effects of immune checkpoint inhibitors could be lower for NAM than for cutaneous melanoma. This review highlights the urgent need to accumulate data to better define the optimal management of this rare melanoma.

Influence of melanoma type on incidence and downstream implications of cutaneous immune-related adverse events in the setting of immune checkpoint inhibitor therapy

Emerging evidence suggests that cutaneous immune-related adverse events (cirAEs) are associated with a survival benefit in the setting of advanced melanoma treated with immune checkpoint inhibitor (ICI) therapy. Previous studies have not examined the role of melanoma subtypes on cirAE development and downstream therapeutic outcomes. Examine the impact of melanoma subtypes on cirAE onset and survival among ICI recipients. Retrospective multi-institutional cohort study. Multivariate time-series regressions were utilized to assess relationships between melanoma subtype, cirAE development, and survival. Among 747 ICI recipients, 236 (31.6%) patients developed a cirAE. Patients with acral melanoma were less likely to develop a cirAE (hazard ratio [HR]=0.41, P=.016) compared to patients with nonacral cutaneous melanoma. Across all melanoma subtypes, cirAEs were associated with reduced mortality (HR=0.76, P=.042). Patients with acral (HR=2.04, P=.005), mucosal (HR=2.30, P<.001), and uveal (HR=4.09, P<.001) primaries exhibited the worst survival. Retrospective cohort study. This is the first study to demonstrate differences in cirAE development among melanoma subtypes. The presence of cirAEs was associated with better survival. Further, the lower incidence of cirAEs may be a marker of immunotherapy response, which is reflected in the association between acral melanoma and mortality.

Impact of response patterns for patients with advanced acral melanoma treated with anti-programmed death-1 monotherapy.

Acral melanoma (AM) is less responsive to immunotherapy than nonacral cutaneous melanoma. Variable responses are seen during immunotherapy, including pseudoprogression, hyperprogressive disease (HPD) and heterogeneous responses. There are currently no studies on the response patterns of patients with AM treated with immunotherapy and the impact on the outcome. To evaluate the response patterns and prognosis of patients with AM treated with anti-programmed death (PD)-1 antibodies. Patients with advanced AM treated prospectively in five clinical trials of anti-PD-1 monotherapy at Peking University Cancer Hospital were included. Responses of individual metastases and heterogeneous responses were evaluated during immunotherapy. Cox proportional hazards regression analysis was conducted to identify the possible predictive factors and generate a nomogram to predict the risk of 1-year and 2-year mortality. The overall response rate was 18·0%, the disease control rate was 36·1%, median progression-free survival was 3·5 months [95% confidence interval (CI) 1·7-5·3] and median overall survival was 17·5 months (95% CI 15·1-19·9) for anti-PD-1 monotherapy. Overall, 9·8% of patients met the criteria of HPD, and displayed a dramatically worse outcome than patients without HPD. In total, 369 metastatic lesions were assessed, with the highest response rate in lymph nodes (20·4%) and the lowest in the liver (5·6%). Homogeneous response, heterogeneous response and heterogeneous or homogeneous progression had different prognoses from the best to the worst. A predictive model was constructed and achieved good accuracy with a C-index of 0·73 (95% CI 0·63-0·84) in the training set and 0·74 (95% CI 0·61-0·86) in the validation set. HPD during immunotherapy serves as an essential biomarker of poor prognosis in advanced AM. Metastases in different sites respond distinctively to immunotherapy. Clinically heterogeneous responses to immunotherapy affect the outcome of patients. A predictive model was built to distinguish the prognosis of acral melanoma under immunotherapy.

809P Outcomes of patients with resected stage III/IV acral or mucosal melanoma treated with adjuvant anti-PD-1 therapy

Acral (AM) and mucosal melanomas (MM) are rare subtypes with a poor prognosis. In those with advanced disease anti-PD-1 (PD1) therapy has reduced activity compared to that seen in non-acral cutaneous melanoma. While adjuvant (adj) PD1 is used for resected stage III/IV AM and MM, there are no data regarding efficacy in these subgroups.

Selected Articles from This Issue

Interleukin-15 (IL-15) regulates the generation, persistence, and differentiation of natural killer (NK) and CD8 T cells. To expand its role in cancer immunotherapy, Chen and colleagues designed a multitumor model treated with the combination of intratumoral anti-CD40, parenteral IL-15 and anti-PD-1. Anti-CD40 given intratumorally not only reduced dosing requirements and toxicity, but it also stimulated the antitumor activity of the distal tumors, suggestive of an abscopal effect. IL-15 with intratumoral anti-CD40 was additive/synergistic, and the inclusion of the anti-PD-1 was additive to the combination. Thus, this treatment shows promise for patients with solid tumors or resistance to anti-PD-1 therapy.Cancer-associated fibroblasts (CAF) are a heterogenous cell population with a complex immunoregulatory role, which has not been well defined in head and neck squamous cell carcinoma (HNSCC). Leveraging protein activity inference tools to analyze scRNA-sequencing of HNSCC patients, pre- and post-nivolumab, Obradovic and colleagues identified distinct subpopulations of head and neck CAF (HNCAF). Enrichment of a T-cell stimulating population (tsCAF) was found to associate with treatment response and ex vivo assays confirmed this CAF subset reduces CD8 T-cell exhaustion. Analysis of an independent HNSCC cohort treated with pembrolizumab validated this tsCAF subset as a potential biomarker of response.Approximately 30% of MSI-H/dMMR tumors do not respond to immune checkpoint inhibitors (ICI), highlighting the importance of identifying predictive biomarkers or molecular profiling correlated with resistance to these agents. Here, Chida and colleagues performed transcriptomic profiling of MSI-H/dMMR gastrointestinal tumors treated with PD-1 blockade. The study revealed that nonresponders had the enrichment of epithelial mesenchymal transition, angiogenesis, hypoxia, mTORC1, KRAS, Wnt/β-catenin, TGF-β, and various metabolism-related signaling pathways, which have been associated with an immunosuppressive tumor microenvironment. Meanwhile, the IFN-γ pathway was upregulated in responders. High expression of VEGF-A might predict a negative response to ICI in this population.Acral melanoma is a rare subtype of melanoma that arises on non-sun exposed skin of the hands, feet, and nailbeds. Patients with acral melanoma have lower response rates to immunotherapy than those with nonacral cutaneous melanoma, suggesting unique microenvironmental features. In their study, Li and colleagues performed comprehensive single cell analysis of a cohort of acral melanoma specimens and found them to harbor fewer effector CD8 T cells and NK cells and a complete absence of γδ T cells compared to non-acral cutaneous melanoma. VISTA, TIGIT, and adenosine signaling were identified as targetable immune checkpoints in acral melanoma.

Second Primary Malignancies in Patients With Melanoma Subtypes: Analysis of 120,299 Patients From the SEER Database (2000-2016).

PurposeEvaluate incidence of second primary malignancies (SPM) after non-acral cutaneous melanoma (NACM), acral lentiginous melanoma (ALM), mucosal melanoma (MM), and uveal melanoma (UM).Patients and MethodsFirst primary NACM, ALM, MM, and UM cases diagnosed 2000-2016 were extracted from SEER. Seer*Stat was used to calculate excess absolute risks (EAR) and standardized incidence ratios (SIR) of SPMs relative to a matched cohort from the general population. P-value of 0.05 determined significance.ResultsInclusion criteria was met by 109,385 patients with NACM, 2166 with ALM, 2498 with MM, and 6250 with UM. Increased incidence of malignancies occurred after NACM (SIR 1.51; 95%CI, 1.49-1.54), ALM (SIR 1.59; 95%CI, 1.40-1.81), MM (SIR 2.14; 95%CI, 1.85-2.45), and UM (SIR 1.24; 95%CI, 1.14-1.34) relative to the general population. Cutaneous melanoma occurred more frequently after NACM (SIR 9.54; 95%CI, 9.27-9.83), ALM (SIR 12.19; 95%CI, 9.70-15.14), MM (SIR 10.05; 95%CI, 7.18-13.68), and UM (SIR 2.91; 95%CI, 2.27-3.66). Patients with initial NACM (SIR 2.44; 95%CI, 1.64-3.51) and UM (SIR 44.34; 95%CI, 29.91-63.29) demonstrated increased incidence of eye and orbit melanoma. Renal malignancies occurred more frequently after NACM (SIR 1.24; 95%CI, 1.11-1.38), MM (SIR 3.54; 95%CI, 1.62-6.72) and UM (SIR 1.68; 95%CI, 1.09-2.48). Increased incidence of thyroid malignancies was observed after NACM (SIR 1.83; 95%CI, 1.61-2.06), ALM (SIR 3.74; 95%CI, 1.71-7.11), MM (SIR 4.40; 95%CI, 1.77-9.06), and UM (SIR 3.79; 95%CI, 2.52-5.47). Increased incidence of lymphoma was observed after NACM (SIR 1.20; 95%CI, 1.09-1.31) and ALM (SIR 2.06; 95%CI, 1.13-3.46).ConclusionPatients with NACM, ALM, MM, and UM have increased incidence of SPMs compared to that expected from the general population. Each of these melanoma subtypes had increased occurrence of cutaneous melanoma and thyroid cancer; some, but not all, had increased occurrence of renal malignancies, eye and orbit melanoma, and lymphoma.

Cross-sectional study of acral melanoma awareness in a group of South African final phase medical students.

Acral melanoma refers to melanoma arising on the palms, soles and nail unit, which are sun-protected areas and ultraviolet exposure is not a risk factor. Acral melanoma is associated with a poorer prognosis than other melanoma subtypes most likely due to the high rates of delayed diagnosis. Acral melanoma affects all skin types equally. There is a misconception that people with more pigmented skin types (Fitzpatrick 4-6) do not develop melanoma, due to the protective effect of melanin. The aim of the study was to determine acral melanoma knowledge and awareness of a group of South African, final phase medical students. This was a quantitative and cross-sectional study. A questionnaire consisting of 20 clinical images of skin lesions requiring a diagnosis and management plan was distributed. Responses to six images of melanomas were analysed. Further questions to measure acral melanoma knowledge and related issues were included in the study. A biostatistician appropriately managed statistical analysis. Hundred and one final phase medical students' answers were gathered and analysed. Only 7.9% of the participants diagnosed all six melanomas correctly; 61.4% correctly diagnosed ≥50% of the melanomas. While 77.2% of the participants identified all non-acral cutaneous melanoma correctly, only 8.9% identified all acral melanomas. However, of all participants making the correct diagnosis, >90% selected the appropriate management plan (urgent referral). This study examined a small sample of trainee healthcare workers. The results cannot be assumed to apply to all South African healthcare workers. Responses given in a questionnaire may not reflect actual behaviour. The dermatology division in question has made acral melanoma a research priority, thus acral melanoma knowledge in this group may in fact be better than in other institutions. The present study demonstrates that groups of imminent doctors have low rates of recognition of melanoma, particularly acral melanoma. This is consistent with high levels of primary misdiagnosis of acral melanoma reported in the literature. Fortunately, these participants managed the melanomas they diagnosed appropriately in >90% of cases. This confirms that the deficit in the participant group is awareness and knowledge. Those aware of the disease immediately acknowledged the need for urgent referral.

Single-cell Characterization of the Cellular Landscape of Acral Melanoma Identifies Novel Targets for Immunotherapy.

Acral melanoma is a rare subtype of melanoma that arises on the non-hair-bearing skin of the palms, soles, and nail beds. In this study, we used single-cell RNA sequencing (scRNA-seq) to map the transcriptional landscape of acral melanoma and identify novel immunotherapeutic targets. We performed scRNA-seq on nine clinical specimens (five primary, four metastases) of acral melanoma. Detailed cell type curation was performed, the immune landscapes were mapped, and key results were validated by analysis of The Cancer Genome Atlas (TCGA) and single-cell datasets. Cell-cell interactions were inferred and compared with those in nonacral cutaneous melanoma. Multiple phenotypic subsets of T cells, natural killer (NK) cells, B cells, macrophages, and dendritic cells with varying levels of activation/exhaustion were identified. A comparison between primary and metastatic acral melanoma identified gene signatures associated with changes in immune responses and metabolism. Acral melanoma was characterized by a lower overall immune infiltrate, fewer effector CD8 T cells and NK cells, and a near-complete absence of γδ T cells compared with nonacral cutaneous melanomas. Immune cells associated with acral melanoma exhibited expression of multiple checkpoints including PD-1, LAG-3, CTLA-4, V-domain immunoglobin suppressor of T cell activation (VISTA), TIGIT, and the Adenosine A2A receptor (ADORA2). VISTA was expressed in 58.3% of myeloid cells and TIGIT was expressed in 22.3% of T/NK cells. Acral melanoma has a suppressed immune environment compared with that of cutaneous melanoma from nonacral skin. Expression of multiple, therapeutically tractable immune checkpoints were observed, offering new options for clinical translation.