Update on primary mucosal melanoma. J Am Acad Dermatol. 2014;71:366-375. [PMID: 24815565 DOI: 10.1016/j.jaad.2014.03.031]

Effectiveness of immune checkpoint inhibitors and other treatment modalities in patients with advanced mucosal melanomas: a systematic review and individual patient data meta-analysis

Background

Mucosal melanomas (MM) are an aggressive subtype of melanoma. Given the rarity of this disease, the conduct of clinical trials is challenging and has been limited. Current treatment options have been extrapolated from the more common cutaneous melanoma even though MM is distinct in pathogenesis, etiology and prognosis. This is the first meta-analysis to comprehensively assess the efficacy of immune checkpoint inhibitors (anti-PD1 and anti-CTLA4) and other treatment modalities (targeted therapy such as KIT inhibitors and VEGF inhibitors, as well as radiotherapy) on survival outcomes in MM to develop clinical guidelines for evidence-based management.

Methods

The protocol was prospectively registered on PROSPERO (PROSPERO ID: CRD42023411195). PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science and Google Scholar were searched from inception until 25 July 2024, for all cohort and observational studies. Eligible studies included those with five or more participants with locally advanced or metastatic MM treated with anti-PD1, anti-CTLA4, VEGF inhibitors and/or KIT inhibitors. Titles and abstracts of potential articles were screened and full texts of all potentially eligible studies were retrieved and reviewed by two independent reviewers. Individual patient data (IPD) from published Kaplan-Meier curves were reconstructed using a graphical reconstruction method and pooled as a one-stage meta-analysis. A sensitivity analysis using a two-stage meta-analysis approach was conducted. Extracted outcomes included overall survival (OS) and progression-free survival (PFS). For each treatment arm, median survival time and 12-month survival proportion were estimated. Data from double-arm trials was pooled to estimate hazard ratios (HRs), ratios of restricted mean time lost (RMTL) and restricted mean survival time (RMST).

Findings

From a total of 7402 studies, 35 eligible studies comprising a total of 2833 participants were included. Combined anti-PD1 and anti-CTLA4 therapy had the highest 12-month OS and 12-month PFS at 71.8% (95% CI: 67.6%, 76.2%, n = 476) and 35.1% (95% CI: 30.5%, 40.4%, n = 401) respectively, followed by anti-PD1 therapy alone (OS: 64.0% (95% CI: 61.4%, 66.7%, n = 1399); PFS: was 28.3% (95% CI: 25.8%, 31.2%, n = 1142), anti-PD1 and VEGF inhibitor combination therapy (OS: 57.1% (95% CI: 51.0%, 63.9%)), KIT inhibitors (OS: 48.2% (95% CI: 37.6%, 61.8%); PFS: 8.3% (95% CI: 3.7%, 18.7%)) and anti-CTLA4 therapy alone (OS: 33.3% (95% CI: 28.4%, 39.1%); PFS: 9.8% (95% CI: 5.9%, 16.5%)). In the double-arm studies, combination therapy with anti-PD1 and anti-CTLA4 had similar OS and PFS with anti-PD1 alone (OS: HR 0.856 (95% CI: 0.704, 1.04); RMTL ratio 0.932 (95% CI: 0.832, 1.044, P = 0.225); RMST ratio 1.102 (95% CI: 0.948, 1.281, P = 0.204); PFS: HR 0.919 (95% CI: 0.788, 1.07); RMTL ratio 0.936 (95% CI: 0.866, 1.013, P = 0.100); RMST ratio 1.21 (95% CI: 0.979, 1.496, P = 0.078)), however, anti-PD1 therapy alone had significantly better PFS than anti-CTLA4 alone (HR 0.548 (95% CI: 0.376, 0.799); RMTL ratio 0.715 (95% CI: 0.606, 0.844, P < 0.001); RMST ratio 1.659 (95% CI: 1.316, 2.092, P < 0.001)). Anti-PD1 therapy with radiotherapy versus anti-PD1 alone showed no significant difference (OS: HR 0.854 (95% CI: 0.567, 1.29); RMTL ratio 0.855 (95% CI: 0.675, 1.083, P = 0.193); RMST ratio 1.194 (95% CI: 0.928, 1.536, P = 0.168; PFS: HR 0.994 (95% CI: 0.710, 1.39); RMTL ratio 1.006 (95% CI: 0.87, 1.162, P = 0.939); RMST ratio 0.984 (95% CI: 0.658, 1.472, P = 0.939)).

Interpretation

For the systemic treatment of MM, anti-PD1 is the best monotherapy. While combining anti-PD1 with other treatment options such as anti-CTLA4, VEGF inhibitors or radiotherapy might achieve better outcomes, these improvements did not reach statistical significance when evaluated by HR, RMTL and RMST ratios.

Funding

This work was supported by the National Medical Research Council Transition Award (TA20nov-0020), SingHealth Duke-NUS Oncology Academic Clinical Programme (08/FY2020/EX/67-A143 and 08/FY2021/EX/17-A47), the Khoo Pilot Collaborative Award (Duke-NUS-KP(Coll)/2022/0020A), the National Medical Research Council Clinician Scientist-Individual Research Grant-New Investigator Grant (CNIGnov-0025), the Terry Fox Grant (I1056) and the Khoo Bridge Funding Award (Duke-NUS-KBrFA/2024/0083I).

Mucosal Melanoma: Review from a Pathologist Point of View

Mucosal melanomas are rare malignant tumors arising from the epithelia lining the inner mucosal surfaces of the body. Unlike cutaneous melanoma, we have a limited understanding of mucosal melanomas is currently limited. Mucosal melanomas are characterized by genetic alterations quite distinct from cutaneous melanomas; however, their causative and promoting factors are unknown. These melanomas are characteristically diagnosed at a later stage due to their occult locations, leading to a worse prognosis. Dedicated staging systems for mucosal melanomas exist only for sinonasal and conjunctival melanomas. Therefore, risk stratification of patients with mucosal melanomas, particularly those arising from the anogenital area, is challenging. Recent studies have shown that minor modifications of the AJCC 8th Edition cutaneous melanoma staging system can group patients fairly robustly; however, the proposed T-categorization systems have yet to be validated in larger cohorts. We summarize the demographic, clinical, histopathologic, and molecular features of common subtypes of mucosal melanomas and highlight the outstanding needs in this field.

Immunohistochemical and transcriptomic characterization of T and myeloid cell infiltrates in canine malignant melanoma

Immune checkpoint inhibitor therapy can provide significant clinical benefit in patients with certain cancer types including melanoma; however, objective responses are only observed for a subset of patients. Mucosal melanoma is a rare melanoma subtype associated with a poor prognosis and, compared with cutaneous melanoma, is significantly less responsive to immune checkpoint inhibitors. Spontaneous canine tumours have emerged as valuable models to inform human cancer studies. In contrast to human melanoma, most canine melanomas are mucosal-an incidence that may be leveraged to better understand the subtype in humans. However, a more comprehensive understanding of the immune landscape of the canine disease is required. Here, we quantify tumour infiltrative T and myeloid cells in canine mucosal (n = 13) and cutaneous (n = 5) melanomas using immunohistochemical analysis of CD3 and MAC387 expression, respectively. Gene expression analysis using the Canine IO NanoString panel was also performed to identify genes and pathways associated with immune cell infiltration. T and myeloid cell densities were variable with geometric means of 158.7 cells/mm2 and 166.7 cells/mm2, respectively. Elevated T cell infiltration was associated with increased expression of cytolytic genes as well as genes encoding the coinhibitory checkpoint molecules PD-1, CTLA-4, TIM-3 and TIGIT; whereas increased myeloid cell infiltration was associated with elevated expression of protumourigenic cytokines. These data provide a basic characterization of the tumour microenvironment of canine malignant melanoma and suggest that, like human melanoma, inherent variability in anti-tumour T cell responses exists and that a subset of canine melanomas may respond better to immunomodulation.

Primary Anorectal Mucosal Melanoma: A Unique Presentation of Mucosal Melanomas

Anorectal mucosal melanoma (AMM) is a rare and highly aggressive malignancy. It frequently presents with nonspecific symptoms, often resulting in delayed diagnosis and poor prognosis. This report describes the case of a 60-year-old male who presented with a painful para-anal papule that progressed to a fistula. Histopathological and immunohistochemical analyses confirmed AMM. Imaging revealed a locally advanced tumor without distant metastasis. Due to the locally advanced nature of the disease, a multidisciplinary team recommended neoadjuvant radiotherapy. This case highlights the diagnostic and therapeutic challenges associated with AMM and emphasizes the importance of a tailored, multidisciplinary approach. Surgical resection remains the cornerstone of treatment, with neoadjuvant therapy potentially improving surgical outcomes in advanced cases.

A paradigm shift in understanding vulvovaginal melanoma as a distinct tumor type compared with cutaneous melanoma

OBJECTIVE

Our goal was to compare molecular and immune profiles of vulvovaginal melanoma (VVM) with cutaneous melanoma (CM) and explore the significance of immune checkpoint inhibitor (ICI) agents on survival.

METHODS

Samples from VVM and CM tumors underwent comprehensive molecular and immune profiling. Treatment and survival data were extracted from insurance claims data and OS was calculated from time of ICI treatment to last contact. Statistical significance was determined using chi-square and Wilcoxon rank sum test and adjusted for multiple comparisons.

RESULTS

Molecular analysis was performed on 142 VVM and 3823 CM tumors. VVM demonstrated significantly (q < 0·01) less frequent BRAF and more frequent KIT, ATRX, and SF3B1 mutations. Alterations in pathways involving DNA damage and mRNA splicing were more common in VVM, while alterations in cell cycle and chromatin remodeling were less common. Immunogenicity of VVM was lower than CM, with an absence of high TMB (0% vs 46.9%) and lower PD-L1 positivity (18·0% vs 29·5%). Median immune checkpoint gene expression was lower in VVM, as were cell fractions for type I macrophages and CD8+ T-cells(q < 0·01). Myeloid dendritic cells were increased in VVM(q < 0·01). Median OS was shorter for VVM than for CM patients treated with ICIs (17·6 versus 37·9 months, HR:1·65 (95% CI 1·02-2·67) p = 0·04).

CONCLUSIONS

VVM has a distinct molecular and immune profile compared to CM, which may contribute to the worse survival in VVM compared to CM patients treated with ICI therapy. Though ICIs have been a mainstay of treatment in recent years, our findings suggest that new therapeutic strategies are needed.

Advances in immunotherapy for mucosal melanoma: harnessing immune checkpoint inhibitors for improved treatment outcomes

Mucosal melanoma (MM) poses a significant clinical challenge due to its aggressive nature and limited treatment options. In recent years, immunotherapy has emerged as a promising strategy for MM, with a particular focus on immune checkpoint inhibitors such as PD-1 and CTLA-4 inhibitors. These inhibitors have demonstrated substantial efficacy by harnessing the body's immune response against tumors. Moreover, adoptive cell transfer (ACT), anti-angiogenic therapy, and combination therapies have garnered attention for their potential in MM treatment. ACT involves modifying T cells to target melanoma cells, showing promising antitumor activity. Anti-angiogenic therapy aims to impede tumor growth by inhibiting angiogenesis, while combination therapies, including immune checkpoint inhibitors and targeted therapies, offer a multifaceted approach to overcome treatment resistance. This comprehensive review explores the advancements in immunotherapy for MM, highlighting the role of diverse therapeutic modalities in enhancing treatment outcomes and addressing the challenges posed by this aggressive malignancy.

Exploring the landscape of urinary tract melanomas: A review for pathologists and clinicians

Melanomas originating within the urinary tract represent a rare and clinically challenging subset of malignancies. Despite extensive research on cutaneous melanomas, urinary tract melanomas remain relatively unexplored, presenting diagnostic dilemmas and limited treatment consensus. In this comprehensive review, we synthesize current knowledge on the epidemiology, risk factors, clinical presentation, histopathological characteristics, and treatment strategies specific to this disease. Enhancing clinical awareness, refining diagnostic approaches, and exploring novel therapeutic interventions hold promise for improving outcomes in this challenging malignancy subset.

Electrochemotherapy as adjuvant treatment in a sinonasal mucosal melanoma in elderly patient: a case report

BACKGROUND

Sinonasal Mucosal Melanoma (SNMM) is a rare but aggressive disease. Surgery with free margins, when feasible, is the treatment of choice. In the last three decades, electrochemotherapy (ECT) has emerged as a local ablative procedure, performed with the Cliniporator, for cutaneous and mucosal tumours of different histology. We present a case report of an ECT treatment performed by means of a new endoscopic electrode, on an elderly patient affected by primary SNMM.

METHODS

An 88-year-old man with a diagnosis of SNMM (cT4aN0M0)-Stage IV, of the left nasal fossa presented at our institution. Symptoms were epistaxis and complete left nasal obstruction. He refused sinonasal extended surgery and radiotherapy. He underwent a tumor debulking followed by ECT exclusively for symptom control, with palliative intent.

RESULTS

The patient underwent SNMM debulking under general anaesthesia, followed by ECT on tumour margins. After the procedure, he had been free from symptoms for 5 months, with a good quality of life. Local recurrence was controlled with a new local debulking and ECT procedure on margins. The patient remained symptom free for the next 4 months. Seventeen months after diagnosis, the patient is mild symptomatic for sinonasal disease. Therefore, he developed a systemic disease progression.

CONCLUSIONS

In our experience, ECT can be used as an adjuvant tool for symptom and local control in SNMM when extended surgery is out of curative intent or unfeasible. As expected, ECT does not appear to have any effect on systemic disease progression.

Primary lacrimal sac melanoma: a case report describing the novel use of fine needle aspiration cytology (FNAC) for diagnosis, together with literature review and immunotherapy treatment update

Primary lacrimal sac melanoma (PLSM) is exceedingly rare and associated with high morbidity and mortality. Unfortunately, PLSM often presents insidiously resulting in delayed detection and poor prognosis. A 69-year-old Black man was suspected of having a lacrimal sac tumour following presentation with a left sided watery eye, bloody tears, and a lacrimal mass. Due to the patient's implantable pacemaker, defibrillator, and high anticoagulation, an ultrasound-guided FNAC was performed instead of incisional biopsy, revealing a PLSM. Diagnosis was confirmed following complete tumour resection with free flap reconstruction and neck dissection. Unfortunately, disease progression ensued despite further neck dissection and three cycles of both pembrolizumab and iplimumab. This is the first description of FNAC to accurately diagnose PLSM and highlights its use as an accurate, rapid, and minimally invasive technique that may allow an earlier screening diagnosis of lacrimal sac tumours. We also discuss the outcome of immunotherapy in recent similar cases.

Mucosal Melanoma Clinical Management and Prognostic Implications: A Retrospective Cohort Study

Mucosal melanoma (MM) is an uncommon melanoma subtype affecting mucosal surfaces of the head and neck, anorectal region, and vulvovaginal area. We aimed to present our experience at a tertiary-level hospital regarding MM diagnosis, management, monitoring of progression, mutations, and outcome predictors. We performed a registry-based cohort study including MM cases diagnosed from 2012 to 2022 and retrospectively characterized somatic mutations on BRAF, NRAS and c-KIT. We employed Kaplan-Meier curves, log-rank tests, and Cox regression analysis to explore prognostic factors and survival outcomes in a cohort of 35 patients, mainly women (63%) with a median age of 70 years. Predominantly, MM occurred in the vulvovaginal region (48.6%). At diagnosis, 28.6% had lymph node involvement, and 31.4% also had distant metastasis. Mutations in BRAF and c-KIT were identified in 3/35 (9%) and 2/6 patients (33%), respectively. Surgery was performed in 71.4% of patients, and most received systemic treatment (65.7%). Lower disease stage, thinner Breslow depth, and surgical resection were associated with improved overall survival. Notably, age, sex, radiotherapy, and BRAF mutant status did not affect survival. Standard management typically involves immunotherapy. Cases with BRAF or c-KIT mutations may be considered for targeted therapies. Unfortunately, MM prognosis remains unfavorable, with a less than 50% survival rate at 2 years.

Treatment of acral and mucosal melanoma: Current and emerging targeted therapies

Targeted therapies revolutionized the management of patients with advanced and metastatic cutaneous melanoma. However, despite recent advances in the understanding of the molecular drivers of melanoma and its treatment with targeted therapies, patients with rare and aggressive melanoma subtypes, including acral melanoma (AM) and mucosal melanomas (MM), show limited long-term clinical benefit from current targeted therapies. While patients with AM or MM and BRAF or KIT mutations may benefit from targeted therapies, the frequency of these mutations is relatively low, and there are no genotype-specific treatments for most patients with AM or MM who lack common driver mutations. The poor prognosis of AM and MM can also be attributed to the lack of understanding of their unique molecular landscapes and clinical characteristics, due to being under-represented in preclinical and clinical studies. We review current knowledge of the molecular landscapes of AM and MM, focusing on actionable therapeutic targets and pathways for molecular targeted therapies, to guide the development of more effective targeted therapies for these cancers. Current and emerging strategies for the treatment of these melanoma subtypes using targeted therapies are also summarized.

Melanoma of glans penis and urethra: A case report and systematic review of the literature of a rare and complex neoplasm

OBJECTIVE

To evaluate the features and prognosis of melanoma of glans penis and urethra, with the presentation of a significant case report.

MATERIALS AND METHODS

A systematic literature review was performed using the MEDLINE (PubMed) and Cochrane Libraries databases to identify all cases of male mucosal melanoma reported.

RESULTS

Two hundred fifty-two patients with male mucosal primary melanoma were found. Glans penis and fossa navicularis as primary site includes the 81.6% of all lesions considered. Median Breslow's depth is 2.1 mm, whereas nine in situ melanomas have been reported. At the diagnosis, the disease was at a non-localized stage in 21.4% for glans penis melanomas and 11.7% urethral lesions, respectively. The 2 and 5-year survival for glans melanoma is 62.5% and 38.4%; higher rates were observed in the 2012-2020 period (76% and 58.8%, respectively). Two-year survival for urethral melanomas is 66.7%, while 5-year survival is 12.5%. 22 patients survived over 5 years with a Breslow's depth reported always < 3.3 mm.

CONCLUSION

Melanoma of the glans penis and urethra is a rare neoplasm associated with a poor prognosis, however recent reports show higher survival rates. Surgery remains the mainstay for a localized disease. Taking into account the small number of cases reported, topical imiquimod seems to be a valid non-surgical alterative for melanoma in situ. The use of immunotherapy and targeted therapy should be considered only in an adjuvant setting according to the recommendations of cutaneous melanoma; however, additional clinical data on male mucosal melanoma are needed to draw definitive conclusions.

Mucosal Melanoma: Epidemiology, Clinical Features, and Treatment

PURPOSE OF REVIEW

Summarize the writings published in the last years on the management and novel therapies of mucosal melanoma (MM).

RECENT FINDINGS

New research has demonstrated a difference between MM and cutaneous melanoma (CM) in their genomic and molecular landscapes, explaining the response's heterogeneity. Immunotherapy and targeted therapy have limited benefit, but novel therapies are rapidly expanding. MM is aggressive cancer occurring in gastrointestinal, respiratory, or urogenital mucosa; whose incidence is greater in the Asian population. The etiology and pathogenesis remain unclear since UV exposure is not a proven risk factor as in cutaneous melanoma. In contrast to CM, lesions on the mucosal surface are less likely to be recognized early; therefore, the disease is diagnosed in an advanced stage. Clinical manifestations, such as bleeding or pain, can help to detect this tumor, although the prognosis remains unfavorable with an overall 5-year survival rate of less than 20%. The mutational landscape of MM includes mutations of BRAF and NRAS, as well as mutations in the c-KIT/CD117 gene (in 50% of patients), thus limiting therapeutic interventions to immunotherapy. However, clinical studies show less responsiveness to immunotherapy compared to CM, therefore novel therapeutic strategies targeting new molecules are needed to improve the survival of patients with MM.

Whole-exome sequencing reveals mutational profiles of anorectal and gynecological melanoma

Mucosal melanoma is a rare and highly malignant type of melanoma. Among the sites that mucosal melanoma arises, anorectal and gynecological melanoma has more aggressive behavior and worse prognosis. There was no effective therapy for mucosal melanoma at present. Only a small number of mucosal melanoma patients which harbor mutations in BRAF or KIT benefit from targeted therapy. So it's an urgent need to identify more actionable mutations in mucosal melanoma. To identify more potential therapeutic targets in mucosal melanoma, 48 samples were collected from 44 patients with anorectal or gynecological melanoma and subjected to whole-exome sequencing. The tumor mutation burden was low with a median of 1.75 mutations per Mb. In chromosomal level, 1q, 6p and 8q of mucosal melanoma were significantly amplified while 9p, 10p, 10q, 16p and 16q were significantly deleted. Muc16 was the most frequently mutated oncogene in our samples(25%). The mutation frequency of KIT(20%) was comparable to the "triple-wild" genes-NRAS(20%), NF1(20%), and BRAF(11%). KMT2D mutation was found in 18.18% patients, which is previously unidentified. MAPK signaling pathway and lysine degradation were the most frequently mutated pathways. Moreover, patients with TP53 mutations tend to have worse clinical outcome (median survival time 19 vs. 50 months, log-rank P = 0.006). 2000 ore mutated genes involved in MAPK signaling pathway were identified, which expand the patients potentially benefit from ample MAPK inhibitors. KMT2D could be a potential therapeutic target. Moreover, TP53 could be a potential prognosis marker for mucosal melanoma.

Prognostic models based on lymph node density for primary gastrointestinal melanoma: a SEER population-based analysis

OBJECTIVE

This study aimed to construct prognostic models to predict the overall survival (OS) and cancer-specific survival (CSS) of patients with primary gastrointestinal melanoma (PGIM).

DESIGN

An observational and retrospective study.

SETTING

Data were obtained from the Surveillance, Epidemiology and End Results (SEER) programme database, encompassing a broad geographical and demographic spectrum of patients across the USA.

PARTICIPANTS

A total of 991 patients diagnosed with PGIM were included in this study.

METHODS

A total of 991 patients with PGIM were selected from the SEER database. They were further divided into a training cohort and a validation cohort. Independent prognostic factors were identified by Cox regression analysis. Two prognostic models were constructed based on the results of multivariable Cox regression analysis. The concordance index (C-index) and area under the time-dependent receiver operating characteristic curve (time-dependent AUC) were used to evaluate the discriminative ability. Calibration curves were plotted to evaluate the agreement between the probability as predicted by the models and the actual probability. Risk stratification was developed given the model.

RESULTS

By the multivariable Cox regression analysis, we identified four independent risk factors (age, stage, lymph node density and surgery) for OS, and three independent risk factors (stage, lymph node density and surgery) for CSS, which were used to construct prognostic models. C-index, time-dependent AUC, calibration curves and Kaplan-Meier curves of risk stratification indicated that these two models had good discriminative ability, predictive ability as well as clinical value.

CONCLUSIONS

The prognostic models of OS and CSS had satisfactory accuracy and were of clinical value in evaluating the prognosis of patients with PGIM.

Demographics, Clinical Characteristics and Survival Outcomes of Primary Urinary Tract Malignant Melanoma Patients: A Population-Based Analysis

All primary urinary tract malignant melanoma (ureter vs. bladder vs. urethra) patients were identified from within the Surveillance, Epidemiology, and End Results (SEER) database 2000-2020. Kaplan-Maier plots depicted the overall survival (OS) rates. Univariable and multivariable Cox regression (MCR) models were fitted to test the differences in overall mortality (OM). In the overall cohort (n = 74), the median OS was 22 months. No statistically significant or clinically meaningful differences were recorded according to sex (female vs. male; p = 0.9) and treatment of the primary (endoscopic vs. surgical; p = 0.6). Conversely, clinically meaningful but not statistically significant (p ≥ 0.05) differences were recorded according to the patient's age at diagnosis (≤80 vs. ≥80 years old; p = 0.2), marital status (married 26 vs. unmarried 16 months; p = 0.2), and SEER stage (localized 31 vs. regional 14 months; p = 0.4), and the type of systemic therapy (exposed 31 vs. not exposed 20 months; p = 0.06). Finally, in univariable and MCR analyses, after adjustment for the SEER stage and type of systemic therapy, tumor origin within the bladder was associated with a three-fold higher OM (Hazard ratio: 3.00; p = 0.004), compared to tumor origin within the urethra. In conclusion, primary urinary tract malignant melanoma patients have poor survival. Specifically, tumor origin within the bladder independently predicted a higher OM, even after adjustment for the SEER stage and systemic therapy status.

[Primary pigmented malignant melanoma of the bladder treated with radical urethrocystectomy and adjuvant therapy]

Primary malignant melanoma of the urinary tract is a rare entity with less than 50 cases reported worldwide. The following case concerns a 64-year-old woman whom we first saw in our emergency room due to gross haematuria. As part of the subsequent diagnostic investigation, we detected a primary malignant melanoma of the bladder and the urethra. The patient was treated with radical urethrocystectomy including pelvic lymphadenectomy and an ileum conduit. This was followed by a year of adjuvant therapy using checkpoint inhibitors.

Diagnosis and Management of Dermatologic Adverse Events from Systemic Melanoma Therapies

The advent of protein kinase inhibitors and immunotherapy has profoundly improved the management of advanced melanoma. However, with these therapeutic advancements also come drug-related toxicities that have the potential to affect various organ systems. We review dermatologic adverse events from targeted (including BRAF and MEK inhibitor-related) and less commonly used melanoma treatments, with a focus on diagnosis and management. As immunotherapy-related toxicities have been extensively reviewed, herein, we discuss injectable talimogene laherparepvec and touch on recent breakthroughs in the immunotherapy space. Dermatologic adverse events may severely impact quality of life and are associated with response and survival. It is therefore essential that clinicians are aware of their diverse presentations and management strategies.

Treatment and outcome trends and predictors of overall survival of rectal melanoma: Analysis of the National Cancer Database

BACKGROUND

We aimed to assess characteristics, treatment, and outcomes of rectal melanoma (RM).

METHODS

This retrospective cohort study looked at patients with RM from National Cancer Database (2004-2019) analyzed characteristics and outcomes of the entire cohort and across three time periods (2004-2009; 2010-2014; 2015-2019). Main outcome measures were change in treatment and survival trends across time periods and overall survival (OS).

RESULTS

641 patients (58.5% female; mean age: 68.2 ± 13.6 years) were included. OS rate was 26%; median survival duration was 17.9 (IQR: 15.93-20.67) months. There was a significant decrease in the use of chemotherapy (17.3%-6.6%; p = 0.001) and surgery (62.9%-41.8%; p = 0.00004) but increased use of immunotherapy (11.9%-52%; p < 0.001) across time periods. OS was longer in the last time period than in the first two (21.8 vs 16.8 vs 16.5 months; p = 0.09). Surgical excision was an independent predictor of improved OS (HR = 0.266, 95%CI: 0.089-0.789, p = 0.017) whereas older age (HR = 1.039, 95%CI: 1.007-1.072, p = 0.016), positive resection margins (HR = 5.06, 95%CI: 1.902-13.48, p = 0.001) and metastasis (HR = 34.62, 95%CI: 3.973-301.6, p = 0.001) were predictors of poor survival.

CONCLUSIONS

Over time, chemotherapy and surgery have been used less often in the treatment of RM while the use of immunotherapy increased by more than four-fold. Older age, surgical treatment, positive resection margins, and metastasis were predictive of survival of RM.

Experimental Models for Rare Melanoma Research-The Niche That Needs to Be Addressed

Melanoma, the tumor arising from the malignant transformation of pigment-producing cells-the melanocytes-represents one of the most severe cancer types. Despite their rarity compared to cutaneous melanoma, the extracutaneous subtypes such as uveal melanoma (UM), acral lentiginous melanoma (ALM), and mucosal melanoma (MM) stand out due to their increased aggressiveness and mortality rate, demanding continuous research to elucidate their specific pathological features and develop efficient therapies. Driven by the emerging progresses made in the preclinical modeling of melanoma, the current paper covers the most relevant in vitro, in vivo, and in ovo systems, providing a deeper understanding of these rare melanoma subtypes. However, the preclinical models for UM, ALM, and MM that were developed so far remain scarce, and none of them is able to completely simulate the complexity that is characteristic to these melanomas; thus, a continuous expansion of the existing library of experimental models is pivotal for driving advancements in this research field. An overview of the applicability of precision medicine in the management of rare melanoma subtypes is also provided.

Differentiating sinonasal malignant melanoma from squamous cell carcinoma using DWI combined with conventional MRI

PURPOSE

This study aimed to investigate the feasibility of diffusion-weighted imaging (DWI) in combination with conventional MRI features to differentiate sinonasal malignant melanoma (SNMM) from sinonasal squamous cell carcinoma (SNSCC).

METHODS

A total of 37 patients with SNMM and 44 patients with SNSCC were retrospectively reviewed. Conventional MRI features and apparent diffusion coefficients (ADCs) were evaluated independently by two experienced head and neck radiologists. ADCs were obtained from two different regions of interest (ROIs) including maximum slice (MS) and small solid sample (SSS). Multivariate logistic regression analysis was performed to identify significant MR imaging features in discriminating between SNMM and SNSCC. Receiver operating characteristic (ROC) curves were used to assess the diagnostic performance.

RESULTS

SNMMs were more frequently located in the nasal cavity, with well-defined border, T1 Septate Pattern (T1-SP) and heterogeneous T1 hyperintensity, whereas SNSCCs were more frequently located in the paranasal sinus, with homogenous T1 isointensity, ill-defined border, reticular or linear T2 hyperintensity, and pterygopalatine fossa or orbital involvement (all p < 0.05). The mean ADCs of SNMM (MS ADC, 0.85 × 10^-3mm²/s; SSS ADC, 0.69 × 10^-3mm²/s) were significantly lower than those of SNSCC (MS ADC, 1.05 × 10^-3mm²/s; SSS ADC, 0.82 × 10^-3mm²/s) (p < 0.05). With a combination of location, T1 signal intensity, reticular or linear T2 hyperintensity, and a cut-off MS ADC of 0.87 × 10^-3mm²/s, the sensitivity, specificity, and AUC were 97.3%, 68.2%, and 0.89, respectively.

CONCLUSION

DWI combined with conventional MRI can effectively improve the diagnostic performance in differentiating SNMM from SNSCC.

PRAME Expression in Mucosal Melanoma of the Head and Neck Region

PRAME (PReferentially expressed Antigen in MElanoma), a cancer-testis antigen expressed in normal and neoplastic tissues with several functions, proved to be a useful diagnostic tool in the differential diagnosis between benign and malignant melanocytic lesions. The current study aims to perform PRAME stain on a retrospective case series of mucosal melanocytic tumors of the head and neck region to compare 3 different scores and evaluate the most reliable one in this diagnostic set. Immunohistochemical analysis for PRAME was performed in 54 benign and malignant mucosal melanocytic tumors of the head and neck region collected from 41 patients. The best-performing cutoff of PRAME-positive cells (nuclear stain) to differentiate benign and malignant mucosal melanocytic tumors of the head and neck region is that proposed by Raghavan and colleagues (<60%/≥60% of PRAME-positive cells), with 100% and 77.8% of benign lesions and malignant tumors respectively correctly identified. Applying this score, PRAME stain showed the best results (sensitivity, specificity, accuracy, and positive and negative predictive values) for the diagnosis of head and neck melanocytic tumors. However, a subset of PRAME-negative malignant tumors was identified, especially located in the palatal area (hard and soft palate). Finally, high PRAME expression (≥60%) was associated with specific sites (nasal cavity/nasal septum/turbinates nasopharynx, and the maxillary sinus), nodular histotype, and female sex.

The human and animals' malignant melanoma: comparative tumor models and the role of microbiome in dogs and humans

Currently, the most progressively occurring incident cancer is melanoma. The mouse is the most popular model in human melanoma research given its various benefits as a laboratory animal. Nevertheless, unlike humans, mice do not develop melanoma spontaneously, so they need to be genetically manipulated. In opposition, there are several reports of other animals, ranging from wild to domesticated animals, that spontaneously develop melanoma and that have cancer pathways that are similar to those of humans. The influence of the gut microbiome on health and disease is being the aim of many recent studies. It has been proven that the microbiome is a determinant of the host's immune status and disease prevention. In human medicine, there is increasing evidence that changes in the microbiome influences malignant melanoma progression and response to therapy. There are several similarities between some animals and human melanoma, especially between canine and human oral malignant melanoma as well as between the gut microbiome of both species. However, microbiome studies are scarce in veterinary medicine, especially in the oncology field. Future studies need to address the relevance of gut and tissue microbiome for canine malignant melanoma development, which results will certainly benefit both species in the context of translational medicine.

A nomogram for predicting overall survival of patients with sinonasal melanoma: A population-based study

Objective

Sinonasal melanoma (SMM) is a rare but aggressive malignancy with 5-year overall survival (OS) rates below 40% in published studies. However, the clinicopathological predictors of the prognosis of SMM remain undefined. We aimed to establish a model to predict the survival outcomes of SMM.

Methods

We searched the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with SMM between 1975 and 2016. Data on patient demographics, treatment modalities, and survival outcomes were retrieved. Risk factors for OS were evaluated by survival and Cox regression analyses. We also developed and validated a nomogram for OS, and compared its performance with that of conventional staging systems.

Results

Overall, 305 SMM patients were included in this population-based study. Multivariate Cox regression showed that primary site, American Joint Committee on Cancer stage, radiotherapy, and surgery were significant risk factors for survival. A nomogram was established using the regression model. The C-indices, areas under the receiver operating characteristic curves, calibration plots, and decision curve analysis demonstrated reliable performance of the nomogram.

Conclusion

The nomogram predicting survival outcomes of SMM patients based on clinical information showed good discriminative ability and prognostic accuracy compared with conventional stage classifications. Our nomogram could be used to predict the survival probabilities for SMM patients at different timepoints.

Level of Evidence

2b.

Genitourinary melanoma: An overview for the clinician

Genitourinary (GU) melanoma is a rare presentation of melanoma accounting for approximately 0.5% of all melanomas. GU melanomas include primary melanomas of the vulva, vagina, uterine cervix, ovary, penis, scrotum, urethra, bladder, ureter, and kidney. These melanomas are often diagnosed in advanced stages and stigma is thought to contribute to delays in presentation. As the likely diagnosing provider, it is imperative that dermatologists, urologists, and gynecologists are aware of these uncommon sites of presentation. While there have been major advances in the treatment of melanomas as a whole in the last 10 years, their applications to GU melanomas have often been overlooked. GU melanomas have not been included in many of the major phase III clinical trials which brought contemporary advanced treatments to market and the prognoses for GU melanomas remain poor. Due to the rarity of GU melanomas, much of the literature provides generalized recommendations across multiple different organs affected by GU melanomas or omits certain topics, making it difficult to appreciate the fundamentals of the individual presentations. This review aimed to provide background information on the pathogenesis and epidemiology of the different sites of GU melanomas and categorize data specific to the presentation, staging, treatment, and prognosis of each type of GU melanoma to guide the clinician. It was also meant to encourage a multidisciplinary approach to the management of these patients as it spans the expertise of surgical oncologists, medical oncologists, radiation oncologist, dermatologists, urologists, and gynecologists.

Single-agent anti-PD-1 or combined with ipilimumab in patients with mucosal melanoma: an international, retrospective, cohort study

BACKGROUND

Mucosal melanoma (MM) is a rare melanoma subtype with distinct biology and poor prognosis. Data on the efficacy of immune checkpoint inhibitors (ICIs) is limited. We determined the efficacy of ICIs in MM, analysed by primary site and ethnicity/race.

PATIENTS AND METHODS

Retrospective cohort study from 25 cancer centres in Australia, Europe, USA and Asia. Patients with histologically confirmed MM were treated with anti-PD1+/-ipilimumab. Primary endpoints were response rate (RR), progression-free survival (PFS), overall survival (OS) by primary site (naso-oral, urogenital, anorectal, other), ethnicity/race (Caucasian, Asian, Other) and treatment. Univariate and multivariate Cox proportional hazard model analyses were conducted.

RESULTS

In total, 545 patients were included: 331 (63%) Caucasian, 176 (33%) Asian and 20 (4%) Other. Primary sites included 113 (21%) anorectal, 178 (32%) urogenital, 206 (38%) naso-oral and 45 (8%) other. 348 (64%) received anti-PD1 and 197 (36%) anti-PD1/ipilimumab. RR, PFS and OS did not differ by primary site, ethnicity/race or treatment. RR for naso-oral was numerically higher for anti-PD1/ipilimumab (40%, 95% CI 29-54%) compared with anti-PD1 (29%, 95% CI 21-37%). 35% of patients that initially responded progressed. Median duration of response (mDOR) was 26 months (95% CI 18-NR [Not Reached]). Factors associated with short PFS were ECOG PS ≥3 (p<0.01), LDH >ULN (p=0.01), lung metastases (p<0.01) and ≥1 previous treatments (p<0.01). Factors associated with short OS were ECOG PS ≥1 (p<0.01), LDH >ULN (p=0.03), lung metastases (p<0.01) and ≥1 previous treatments (p<0.01).

CONCLUSIONS

MM has poor prognosis. Treatment efficacy of anti-PD1+/-ipilimumab was similar and did not differ by ethnicity/race. Naso-oral primaries had numerically higher response to anti-PD1/ipilimumab, without difference in survival. The addition of ipilimumab did not show greater benefit over anti-PD1 for other primary sites. In responders, mDOR was short and acquired resistance was common. Other factors, including site and number of metastases were associated with survival.

Anorectal and Genital Mucosal Melanoma: Diagnostic Challenges, Current Knowledge and Therapeutic Opportunities of Rare Melanomas

Mucosal melanomas (MM) are rare tumors, being less than 2% of all diagnosed melanomas, comprising a variegated group of malignancies arising from melanocytes in virtually all mucosal epithelia, even if more frequently found in oral and sino-nasal cavities, ano-rectum and female genitalia (vulva and vagina). To date, there is no consensus about the optimal management strategy of MM. Furthermore, the clinical rationale of molecular tumor characterization regarding BRAF, KIT or NRAS, as well as the therapeutic value of immunotherapy, chemotherapy and targeted therapy, has not yet been deeply explored and clearly established in MM. In this overview, focused on anorectal and genital MM as models of rare melanomas deserving of a multidisciplinary approach, we highlight the need of referring these patients to centers with experts in melanoma, anorectal and uro-genital cancers treatments. Taking into account the rarity, the poor outcomes and the lack of effective treatment options for MM, tailored research needs to be promptly promoted.

Canine Oral Melanoma Genomic and Transcriptomic Study Defines Two Molecular Subgroups with Different Therapeutical Targets

Simple Summary

In humans, mucosal melanoma (MM) is a rare and aggressive cancer. The canine model is frequently and spontaneously affected by MM, thus facilitating the collection of samples and the study of its genetic bases. Thanks to an integrative genomic and transcriptomic analysis of 32 canine MM samples, we identified two molecular subgroups of MM with a different microenvironment and structural variant (SV) content. We demonstrated that SVs are associated with recurrently amplified regions, and identified new candidate oncogenes (TRPM7, GABPB1, and SPPL2A) for MM. Our findings suggest the existence of two MM molecular subgroups that could benefit from dedicated therapies, such as immune checkpoint inhibitors or targeted therapies, for both human and veterinary medicine.

Abstract

Mucosal melanoma (MM) is a rare, aggressive clinical cancer. Despite recent advances in genetics and treatment, the prognosis of MM remains poor. Canine MM offers a relevant spontaneous and immunocompetent model to decipher the genetic bases and explore treatments for MM. We performed an integrative genomic and transcriptomic analysis of 32 canine MM samples, which identified two molecular subgroups with a different microenvironment and structural variant (SV) content. The overexpression of genes related to the microenvironment and T-cell response was associated with tumors harboring a lower content of SVs, whereas the overexpression of pigmentation-related pathways and oncogenes, such as TERT, was associated with a high SV burden. Using whole-genome sequencing, we showed that focal amplifications characterized complex chromosomal rearrangements targeting oncogenes, such as MDM2 or CDK4, and a recurrently amplified region on canine chromosome 30. We also demonstrated that the genes TRPM7, GABPB1, and SPPL2A, located in this CFA30 region, play a role in cell proliferation, and thus, may be considered as new candidate oncogenes for human MM. Our findings suggest the existence of two MM molecular subgroups that may benefit from dedicated therapies, such as immune checkpoint inhibitors or targeted therapies, for both human and veterinary medicine.

Primary Duodenal Melanoma: Challenges in Diagnosis and Management of a Rare Entity

Primary melanoma of the duodenum is an extremely rare, aggressive and life-threatening malignant neoplasm. Published data regarding the effectiveness of current treatment strategies is limited, and our knowledge relies mostly on sporadic case reports. The diagnosis of primary duodenal melanoma is challenging and is based on the patient's medical history and findings from physical examination and radiological and endoscopic imaging as well as proper and careful pathological examinations of the tumor. Despite the many advances in cancer treatment, the prognosis for patients with this type of melanoma remains extremely poor. Delayed diagnosis at advanced disease stage, the general aggressive behavior of this neoplasm, the technical difficulty in achieving complete surgical resection, along with the rich vascular and lymphatic drainage of the intestinal mucosa, all have a negative impact on patients' outcome. In the present review, we aimed to collect and summarize the currently available data in the literature regarding the pathogenesis, clinical features, diagnosis, management and long-term outcomes of this rare, malignant tumor, in order to expand knowledge of its biological behavior and investigate optimal therapeutic options for these patients. Additionally, we present our experience of a case involving a 73-year-old female with primary duodenal melanoma, who was successfully treated with complete surgical resection.

OUP accepted manuscript

Primary mucosal melanoma of the tonsil is rare, with 27 reported cases. Careful diagnosis is necessary, as the tonsil is more often a site of metastatic melanoma from a cutaneous primary tumour. In this report, we present a case of primary right tonsillar mucosal melanoma with widespread metastasis in a 31-year-old man who presented with a 3-month history of enlarging neck lumps. On examination, he had cervical lymphadenopathy and a pigmented, vascular lesion of his right tonsil, which was diagnosed as melanoma following investigation. He had widespread metastases upon presentation, and is currently undergoing palliative immunotherapy. Owing to the aggressive behaviour, late presentations and lack of effective treatment to cure mucosal melanomas, they have a poor prognosis. Treatment involves wide local excision in local disease, and immunotherapy as the first-line for metastatic disease.

Companion Animal Model in Translational Oncology; Feline Oral Squamous Cell Carcinoma and Canine Oral Melanoma

Simple Summary

Laboratory rodents are the most common animal models used in preclinical cancer research. Companion animals with naturally occurring cancers are an under-utilized natural model for the development of new anti-cancer drugs. Dogs and cats develop several types of cancers that resemble those arising in humans with similar clinical and histopathological features and often with similar molecular and genetic backgrounds. Exposure to environmental carcinogens, including air, food and water are also common between people and their pets. Dogs and cats are a unique model that could be integrated between the preclinical laboratory animal model and human clinical trials.

Abstract

Companion animals with naturally occurring cancers can provide an advantageous model for cancer research and in particular anticancer drug development. Compared to commonly utilized mouse models, companion animals, specifically dogs and cats, share a closer phylogenetical distance, body size, and genome organization. Most importantly, pets develop spontaneous, rather than artificially induced, cancers. The incidence of cancer in people and companion animals is quite similar and cancer is the leading cause of death in dogs over 10 years of age. Many cancer types in dogs and cats have similar pathological, molecular, and clinical features to their human counterparts. Drug toxicity and response to anti-cancer treatment in dogs and cats are also similar to those in people. Companion animals share their lives with their owners, including the environmental and socioeconomic cancer-risk factors. In contrast to humans, pets have a shorter life span and cancer progression is often more rapid. Clinical trials in companion animals are cheaper and less time consuming compared to human trials. Dogs and cats with naturally occurring cancers are an ideal and unique model for human cancer research. Model selection for the specific type of cancer is of pivotal importance. Although companion animal models for translational research have been reviewed previously, this review will try to summarize the most important advantages and disadvantages of this model. Feline oral squamous cell carcinoma as a model for head and neck squamous cell carcinoma and canine oral melanoma as a model for mucosal melanoma and immunotherapy in people will be discussed as examples.

Targeting cyclin-dependent kinase 4/6 as a therapeutic approach for mucosal melanoma

Mucosal melanoma is a rare but devastating subtype of melanoma which typically has a worse prognosis than other melanoma subtypes. Large-scale next-generation sequencing studies, including our recent research, have also proved that the molecular landscape and potential oncogenic drivers of mucosal melanoma remain distinct from that of cutaneous melanoma. Recently, a number of selective cyclin-dependent kinase 4 (CDK4)/6 inhibitors have been approved for clinical application in breast cancer or entered phase III clinical trial in other solid tumors. Additionally, we have revealed that the dysregulation of cell cycle progression, caused by CDK4 amplification, is a key genetic feature in half of mucosal melanoma and targeting of CDK4 in selected mucosal melanoma patients is a potentially promising direction for precision cancer treatment by using molecular-characterized mucosal melanoma patient-derived-xenograft models. This review summarizes the current literature regarding CDK4/6 dysregulation in mucosal melanoma, preclinical and clinical studies of CDK4/6 inhibitors and potential combinational strategies in treating mucosal melanoma.

Comparative investigation of cell cycle and immunomodulatory genes in mucosal and cutaneous melanomas: Preliminary data suggest a potential promising clinical role for p16 and the PD-1/PD-L1 axis

Mucosal melanomas arise from the mucosal lining of various organs. Their etiology is currently unknown and there are no tissue-based methods to differentiate it from cutaneous melanomas. Furthermore, prognostic and predictive markers (e.g. for immune checkpoint inhibition) are lacking. In this study, we aimed to assess the protein expression levels of cell cycle-associated proteins and immune checkpoint markers in a cohort of mucosal melanomas in comparison to cutaneous melanomas and evaluated the effect of potential regulatory mechanisms. We performed immunohistochemistry, DNA methylation analysis and copy number profiling of 47 mucosal and 28 cutaneous melanoma samples. Protein expression of CD117, Ki67 and p16 was higher in mucosal melanomas, while BCL2, Cyclin D1, PD-1 and PD-L1 were overexpressed in cutaneous melanomas. CDKN2A deletions were the most prevalent numeric chromosomal alterations in both mucosal and cutaneous melanoma and were associated with decreased p16 expression. KIT was frequently amplified in mucosal melanomas, but not associated with CD117 expression. On the other hand, amplification of CCND1 lead to Cyclin D1 overexpression. In mucosal melanoma patients high PD-1 expression and high PD-L1 promoter methylation levels were associated with improved survival. PD-L1 expression correlated with response to immune checkpoint inhibitor therapy in the combined group of melanoma patients. Mucosal and cutaneous melanomas show different expression levels of cell cycle-associated and immunomodulatory proteins that are partially regulated by DNA methylation and copy number alterations. PD-1 expression and PD-L1 promoter methylation levels might be a prognostic marker for mucosal melanomas.

Adjuvant systemic treatment for high-risk resected non-cutaneous melanomas: What is the evidence?

Non-cutaneous melanomas (mucosal, uveal, leptomeningeal, unknown primaries) represent around 5-10 % of all melanoma diagnoses. Non-cutaneous melanomas demonstrate differences in tumour biology, generally present with more advanced stages and have an overall poorer prognosis compared to skin melanomas. The cornerstone of their treatment is surgery followed by radiotherapy in some cases. Unfortunately, in many of these patients their melanoma will recur. Adjuvant therapy for non-cutaneous melanomas remains controversial. To date, almost all of the tested adjuvant agents have failed to demonstrate any benefit; the two randomised positive trials were criticized for methodological reasons, small sample size and conflicting results. The aim of this review is to assess the current evidence on systemic adjuvant treatments for high-risk resected non-cutaneous melanomas. We also provide a summary table with the currently recruiting clinical trials in these settings and we discuss some strategies to improve trial design in this particularly niche area of oncology.

Mucosal Melanoma

Mucosal melanoma is a rare but aggressive cancer arising in mucosal surfaces most commonly in the head and neck. The clinical presentation is often nonspecific and differs in relation to the site of origin so often diagnosis is delayed resulting in poor prognosis. Mucosal melanoma has a 5-year survival of only 25%. Surgery with negative margins is the mainstay of treatment but dependent on several variables including anatomic location, involved structures, and size of tumor. Although not well defined given the rarity of mucosal melanoma, there is a role for radiation and systemic therapy in the treatment of this disease.

Mucosal Melanoma: Pathological Evolution, Pathway Dependency and Targeted Therapy

Mucosal melanoma (MM) is a rare melanoma subtype that originates from melanocytes within sun-protected mucous membranes. Compared with cutaneous melanoma (CM), MM has worse prognosis and lacks effective treatment options. Moreover, the endogenous or exogenous risk factors that influence mucosal melanocyte transformation, as well as the identity of MM precursor lesions, are ambiguous. Consequently, there remains a lack of molecular markers that can be used for early diagnosis, and therefore better management, of MM. In this review, we first summarize the main functions of mucosal melanocytes. Then, using oral mucosal melanoma (OMM) as a model, we discuss the distinct pathologic stages from benign mucosal melanocytes to metastatic MM, mapping the possible evolutionary trajectories that correspond to MM initiation and progression. We highlight key areas of ambiguity during the genetic evolution of MM from its benign lesions, and the resolution of which could aid in the discovery of new biomarkers for MM detection and diagnosis. We outline the key pathways that are altered in MM, including the MAPK pathway, the PI3K/AKT pathway, cell cycle regulation, telomere maintenance, and the RNA maturation process, and discuss targeted therapy strategies for MM currently in use or under investigation.

Tumor Immune Microenvironment Characterization Identifies Prognosis and Immunotherapy-Related Gene Signatures in Melanoma

Background

The tumor microenvironment (TME) involves infiltration of multiple immune cell subsets, which could influence the prognosis and clinical characteristics. The increasing evidence on the role of tumor-infiltrating lymphocytes (TILs) in primary and metastatic melanomas supports that the immune system is involved in the progression and outcomes of melanoma. However, the immune infiltration landscape in melanoma has not been systematically elucidated.

Methods

In this study, we used CIBERSORT and ESTIMATE algorithms to analyze immune infiltration pattern of 993 melanoma samples. Then we screened differential expression genes (DEGs) related to immune subtypes and survival. The immune cell infiltration (ICI) score was constructed by using principal-component analysis (PCA) based on immune signature genes from DGEs. Gene set enrichment analysis (GSEA) was applied to explore high and low ICI score related pathways. Finally, the predictive ability of ICI score was evaluated in survival prognosis and immunotherapy benefit.

Result

We identified three ICI clusters and three gene clusters associated with different immune subtypes and survival outcomes. Then the ICI score was constructed, and we found that high ICI score exhibited activated immune characteristics and better prognosis. High ICI score was significantly enriched in immune pathways and highly expressed immune signature genes. More importantly, we confirmed that melanoma patients with high ICI score had longer overall survival and rate of response to immunotherapy.

Conclusion

We presented a comprehensive immune infiltration landscape in melanoma. Our results will facilitate understanding of the melanoma tumor microenvironment and provide a new immune therapy strategy.

Mucosal Melanomas of the Anogenital Tract: Clinical and Pathologic Predictors of Patient Survival

Primary anogenital mucosal melanomas (AGMs) are rare aggressive malignancies that are typically diagnosed at an advanced stage. Ulceration is a common feature in AGMs and may not correlate with outcome. Therefore, staging of AGMs similar to primary cutaneous melanomas, based on tumor thickness and ulceration, may not robustly predict outcome. Derivation of site-specific staging systems is essential for prognostication and optimal management of these patients. To this end, recent retrospective studies have revealed tumor thickness (TT) and mitotic rate (MR) as features of most prognostic significance as follows: in anorectal (TT only) and vulvar (TT and MR) melanomas.

Melanoma of the lacrimal drainage system: A systematic review

Melanoma of the lacrimal drainage system (LDSM) is a rare and subtle condition that is frequently misdiagnosed. In the present work, we conducted a systematic review investigating the clinical features, management, and prognosis of LDSM. A structured search, according to PRISMA criteria, was performed in April 2020 and updated in February 2021 on Pubmed, EMBASE, Cochrane, and SCOPUS. The articles found underwent a double-reviewer selection and the main data were extracted. After complete screening, 30 articles reporting 38 cases were included. The time from the first symptom to medical contact ranged from 1 month to 4 years. Surgery was the treatment proposed to all patients, with a variable extension of resection. LDSM is a rare disease that is burdened by poor prognosis. Early diagnosis is crucial, even if difficult to achieve. Surgery and radiotherapy are standardized treatments, while targeted therapy and immunotherapy are attractive prospects.

Clinical Implications of Acquired BRAF Inhibitors Resistance in Melanoma

Understanding the role of mitogen-activated protein kinase (MAPK) pathway-activating mutations in the development and progression of melanoma and their possible use as therapeutic targets has substantially changed the management of this neoplasm, which, until a few years ago, was burdened by severe mortality. However, the presence of numerous intrinsic and extrinsic mechanisms of resistance to BRAF inhibitors compromises the treatment responses’ effectiveness and durability. The strategy of overcoming these resistances by combination therapy has proved successful, with the additional benefit of reducing side effects derived from paradoxical activation of the MAPK pathway. Furthermore, the use of other highly specific inhibitors, intermittent dosing schedules and the association of combination therapy with immune checkpoint inhibitors are promising new therapeutic strategies. However, numerous issues related to dose, tolerability and administration sequence still need to be clarified, as is to be expected from currently ongoing trials. In this review, we describe the clinical results of using BRAF inhibitors in advanced melanoma, with a keen interest in strategies aimed at overcoming resistance.

Efficacy, Tolerability, and Pharmacokinetics of Combined Targeted MEK and Dual mTORC1/2 Inhibition in a Preclinical Model of Mucosal Melanoma

Melanomas arising in the mucous membranes are a rare and aggressive subtype. New treatment approaches are needed, yet accumulating sufficient evidence to improve patient outcomes is difficult. Clinical and pathological correlates between human and canine mucosal melanomas are substantial, and the relatively greater incidence of spontaneous naturally occurring mucosal melanoma in dogs represents a promising opportunity for predictive modeling. The genomic landscapes of human and canine mucosal melanoma appear highly diverse and generally lack recurring hotspot mutations associated with cutaneous melanomas. Although much remains to be determined, evidence indicates that Ras/MAPK and/or PI3K/AKT/mTOR signaling pathway activations are common in both species and may represent targets for therapeutic intervention. Sapanisertib, an mTORC1/2 inhibitor, was selected from a PI3K/mTOR inhibitor library to collaborate with MEK inhibition; the latter preclinical efficacy was demonstrated previously for canine mucosal melanoma. Combined inhibition of MEK and mTORC1/2, using trametinib and sapanisertib, produced apoptosis and cell-cycle alteration, synergistically reducing cell survival in canine mucosal melanoma cell lines with varying basal signaling activation levels. Compared with individual inhibitors, a staggered sapanisertib dose, coupled with daily trametinib, was optimal for limiting primary mucosal melanoma xenograft growth in mice, and tumor dissemination in a metastasis model, while minimizing hematologic and renal side effects. Inhibitors downmodulated respective signaling targets and the combination additionally suppressed pathway reciprocal crosstalk. The combination did not significantly change plasma sapanisertib pharmacokinetics; however, trametinib area under the curve was increased in the presence of sapanisertib. Targeting Ras/MAPK and PI3K/AKT/mTOR signal transduction pathways appear rational therapies for canine and human mucosal melanoma.

Uncommon Subtypes of Malignant Melanomas: A Review Based on Clinical and Molecular Perspectives

Malignant melanoma represents the most aggressive type of skin cancer. Modern therapies, including targeted agents and immune checkpoint inhibitors, have changed the dismal prognosis that characterized this disease. However, most evidence was obtained by studying patients with frequent subtypes of cutaneous melanoma (CM). Consequently, there is an emerging need to understand the molecular basis and treatment approaches for unusual melanoma subtypes. Even a standardized definition of infrequent or rare melanoma is not clearly established. For that reason, we reviewed this challenging topic considering clinical and molecular perspectives, including uncommon CMs-not associated with classical V600E/K BRAF mutations-malignant mucosal and uveal melanomas, and some unusual independent entities, such as amelanotic, desmoplastic, or spitzoid melanomas. Finally, we collected information regarding melanomas from non-traditional primary sites, which emerge from locations as unique as meninges, dermis, lymph nodes, the esophagus, and breasts. The aim of this review is to summarize and highlight the main scientific evidence regarding rare melanomas, with a particular focus on treatment perspectives.

Primary melanoma of the urinary tract; Clinicopathologic and molecular review of a case series

Primary melanoma of the urinary tract is a very rare and aggressive cancer. It accounts for less than 1% of all the melanoma cases, making it difficult to histopathologically diagnose and manage. We present a retrospective case series of eight primary urinary tract melanoma with clinical, pathological, and molecular findings to add more insight to this challenging disease. These cases were evaluated for histopathological, immunohistochemical, and molecular features of melanoma that were most commonly found in the urethra, followed by those in the bladder and ureter. Identification of nested growth patterns and in situ melanocytic components at cell edges are helpful in the histopathological diagnosis of amelanotic or hypomelanotic tumors. Our results indicate that urinary tract melanoma has several molecular traits, such as gene expression patterns. Genetic mutations may be related to metastasis, as well as provide targets for the management programs.

Talimogene Laherparepvec in Advanced Mucosal Melanoma of the Urethra Upon Primary Resistance on Immune Checkpoint Inhibition: A Case Report

Background: Mucosal melanomas including melanomas of the urogenital tract represent a rare type of melanoma characterized by low mutational burden and poor prognosis. Immune checkpoint inhibition has so far only been assessed in a limited number of mucosal melanoma patients and, in contrast to response in cutaneous melanoma, was associated with disappointing response rates. The oncolytic viral immunotherapy Talimogene laherparepvec (T-VEC) has recently been approved for treatment of locally advanced or unresectable melanoma. T-VEC combines direct oncolytic effects with local and systemic immune-mediated anti-tumor response. Our rationale to use T-VEC in this case was an expected augmentation of immunogenicity by tumor lysis to overcome primary resistance of a mucosal melanoma to immune checkpoint blockade.

Objective: To report the first case of an advanced mucosal melanoma of the urethra treated with intralesional application of Talimogene laherparepvec.

Case Report: A 78-years old female patient was diagnosed with an advanced mucosal melanoma of the urethra with inguinal lymph node metastases and intravaginal mucosal metastases. Shortly after surgical resection of the tumor mass, intravaginal mucosal metastases, and new nodal metastases in proximity of the left iliac vessels were diagnosed. The patient was treated with the anti-PD1 antibody pembrolizumab and obtained a stable disease lasting for 30 weeks. However, upon checkpoint inhibition the patient developed a loco-regional progressive disease featuring bleeding intravaginal metastases, while nodal metastases remained stable. We stopped treatment with pembrolizumab and administered T-VEC directly into the intravaginal mucosal metastases. After five injections T-VEC yielded a partial response with clinical regression of the injected mucosal metastases. Disease remained stable for 16 weeks under biweekly T-VEC treatment. Thereafter the patient showed disease progression in nodal metastases. T-VEC was discontinued. Immunotherapy with pembrolizumab was restarted but failed to achieve a response. Finally, targeted therapy with imatinib was induced in presence of a druggable c-KIT mutation, leading to a considerable response of all tumor sites that is still ongoing.

Conclusion: T-VEC represents an effective and well-tolerated treatment option for patients with loco-regionally advanced mucosal melanoma. In combination with immunotherapy, T-VEC bears the potential of synergistic effects to overcome the specific primary resistance of mucosal melanoma to immune checkpoint blockade.

Prognostic factors in 161 patients with mucosal melanoma: a study of German Central Malignant Melanoma Registry

BACKGROUND

Mucosal melanoma is a rare malignancy which represents approximately 1% of all melanomas. It is shown that mucosal melanomas have a different biology and less favourable prognosis than its cutaneous counterpart.

OBJECTIVES

Predictive and prognostic factors of survival for mucosal melanoma have not yet been elucidated. The aim of this study was to investigate risk factors affecting the course of mucosal melanoma patients followed in our clinic.

METHODS

One hundred and sixty-one patients with mucosal melanoma prospectively documented in the German Central Malignant Melanoma Registry (CMMR) were included in this study. Gender, age, localization, stage at first medical examination, tumour thickness and mutational status were documented. The American Joint Committee on Cancer (AJCC), 7th edition was used to define tumour stage. Kaplan-Meier survival curves were evaluated compared with the log-rank test. Multivariate Cox proportional hazard models were used to identify significant independent prognostic factors.

RESULTS

According to the localization, patients were categorized in 44.7% oral-nasal, 28.6% genital, 20.5% anorectal and 6.2% visceral. Genital mucosal melanomas had the most favourable 5-year OS rate (58.6%) followed by visceral (58.3%) and oral-nasal (39.3%). Anorectal melanomas had the worst OS time (median: 21 ± 4.8 months) and 5-year survival rate (22.7%). Patients <60 years had a better survival than the older group (P = 0.013). Tumour stage at the time of the first medical examination was also a significant factor for survival (P = 0.001). Gender and mutational status were found to have no effect on survival. Age (<60 years vs. ≥60 years; HR = 2.1) and stage at first medical examination (Stage I vs. Stage IV; HR = 8.2) are shown to be significant independent prognostic factors on multivariate Cox regression analysis, but not localization.

CONCLUSION

In this study, we observed that older age and advanced stage have significant negative effects on the survival of mucosal melanoma. Thus, the AJCC staging system is applicable for mucosal melanoma.

Long-term survival after surgical treatment followed by adjuvant systemic therapy for primary duodenal melanoma

Primary mucosal malignant melanomas of the gastrointestinal tract are rare tumors associated to poor prognosis. Primary duodenal involvement by pigmented lesions is even more uncommon, and only a few reports exist in the literature. We report the case of a patient with large primary duodenal melanoma that presented with upper intestinal obstruction and bleeding that was submitted to urgent pancreaticoduodenectomy followed by adjuvant systemic therapy with an oral alkylating agent (temozolomide) plus intravenous cisplatin. The patient presents no signs of recurrence 3 years after the surgery. We consider that radical surgical resection followed by systemic therapy is a safe and effective treatment strategy option for primary mucosal gastrointestinal melanomas.

Systemic adjuvant therapy for adult patients at high risk for recurrent cutaneous or mucosal melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline

Background

Previous versions of the guideline from the Program in Evidence-Based Care (pebc) at Ontario Health (Cancer Care Ontario) recommended that the use of high-dose interferon alfa 2b therapy be discussed and offered to patients with resected cutaneous melanoma with a high risk of recurrence. Subsequently, several clinical trials in patients with resected or metastatic melanoma found that immune checkpoint inhibitors and targeted therapies have a benefit greater than that with interferon. It was therefore considered timely for an update to the guideline about adjuvant systemic therapy in melanoma.

Methods

The present guideline was developed by the pebc and the Melanoma Disease Site Group (dsg). Based on a systematic review from a literature search conducted using medline, embase, and the Evidence Based Medicine Reviews databases for the period 1996 to 28 May 2019, the Working Group drafted recommendations. The systematic review and recommendations were then circulated to the Melanoma dsg and the pebc Report Approval Panel for internal review; the revised document underwent external review.

Recommendations

For patients with completely resected cutaneous or mucosal melanoma with a high risk of recurrence, the recommended adjuvant therapies are nivolumab, pembrolizumab, or dabrafenib-trametinib for patients with BRAF V600E or V600K mutations; nivolumab or pembrolizumab are recommend for patients with BRAF wild-type disease. Use of ipilimumab is not recommended. Molecular testing should be conducted to help guide treatment decisions. Interferon alfa, chemotherapy regimens, vaccines, levamisole, bevacizumab, bacillus Calmette-Guérin, and isolated limb perfusion are not recommended for adjuvant treatment of cutaneous melanoma except as part of a clinical trial.

Epidemiological profile of mucosal melanoma in Brazil

Mucosal melanomas are primary malignant neoplasias originated from melanocytes within mucous membranes in any part of mucosal surface lining, more commonly, in the nasal cavity and accessory sinuses, oral cavity, lips, pharynx, vulvar, vaginal, cervix and anorectal mucosa. Epidemiology data regarding mucosal melanomas in Brazil is scarce, hence the motivation to conduct this research paper. The χ2 test was used to compare categorical variables. Forward stepwise logistic regression method was used in the multivariate analysis to identify independent predictors of early death. A total of 801 patients were included in the analysis. Surgical resection is frequently the first approach to primary tumours (65.3%), even though the utility of lymph node surgery and radiation therapy is not well established. Advanced stage was observed in more than two thirds of patients. Early death was observed in 28.3%. MM cases with regional or distant metastases as well as those located in unusual locations had almost 4 times more risk for early death. Besides that, MM located in lips, oral cavity and pharynx and those receiving chemotherapy had 2 times more risk of early death.