Molecular Analysis of Murine KitK641E Melanoma Progression.

Acral and mucosal melanomas are often driven by sequence variants in the KIT receptor tyrosine kinase, with nearly 40% harboring alterations in the KIT locus. Despite advances in the knowledge of KIT-mutated melanomas, little is known about the molecular reprogramming that occurs during KIT-mediated melanoma progression owing to the rarity of acral and mucosal melanomas and the lack of comprehensive biological tools and models. To this end, we used a murine model that allows us to ascertain the molecular underpinnings of the stages of cancer progression-transformation, tumorigenesis, immune engagement, and tumor escalation. We found dramatic increases in biosynthetic demands associated with the transformation stage, including DNA and RNA metabolism, leading to replication stress. Tumorigenesis was closely linked to neuronal and axonal development, likely necessary for invasion into the host. Immune engagement highlighted early immune excitation and rejection pathways, possibly triggered by abrupt neoantigen exposure. Finally, tumor escalation pathways proved consistent with immune evasion, with immune-related pathways becoming significantly downregulated. To our knowledge, it is previously unreported that these critical milestones needed for KIT-driven melanoma tumor formation have been studied at the molecular level using isogenically matched and phenotypically defined cells.

Germline cancer susceptibility in individuals with melanoma.

BACKGROUND: Prior studies have estimated a small number of individuals with melanoma (2%-2.5%) have germline cancer predisposition, yet a recent twin study suggested melanoma has the highest hereditability among cancers. OBJECTIVE: To determine the incidence of hereditary melanoma and characterize the spectrum of cancer predisposition genes that may increase the risk of melanoma. METHODS: Four hundred individuals with melanoma and personal or family history of cancers underwent germline testing of >80 cancer predisposition genes. Comparative analysis of germline data was performed on 3 additional oncologic and dermatologic data sets. RESULTS: Germline pathogenic/likely pathogenic (P/LP) variants were identified in 15.3% (61) individuals with melanoma. Most variants (41, 67%) involved genes considered unrelated to melanoma (BLM, BRIP1, CHEK2, MLH1, MSH2, PMS2, RAD51C). A third (20, 33%) were in genes previously associated with familial melanoma (BAP1, BRCA2, CDKN2A, MITF, TP53). Nearly half (30, 46.9%) of P/LP variants were in homologous repair deficiency genes. Validation cohorts demonstrated P/LP rates of 10.6% from an unselected oncologic cohort, 15.8% from a selected commercial testing cohort, and 14.5% from a highly selected dermatologic study. LIMITATIONS: Cohorts with varying degrees of selection, some retrospective. CONCLUSION: Germline predisposition in individuals with melanoma is common, with clinically actionable findings diagnosed in 10.6% to 15.8%.

Identification of Collagen-Suppressive Agents in Keloidal Fibroblasts Using a High-Content, Phenotype-Based Drug Screen.

Keloids are characterized by excessive extracellular collagen and exaggerated scarring. Large-volume lesions can be functionally debilitating, therapeutically intractable, and psychologically devastating. A key barrier to translational momentum for novel antikeloid agents is the lack of a faithful high-content screen. We devised, to our knowledge, a previously unreported phenotype-based assay that measures secreted collagen by keloidal fibroblasts in tissue hypoxic conditions (1% oxygen). Four keloidal fibroblasts and 1 normal dermal fibroblast line were exposed to 199 kinase inhibitors. Of 199 kinase inhibitors, 41 (21%) and 71 (36%) increased and decreased the CI¯norm (mean collagen inhibition normalized to viability) by more than 10%, respectively. The most collagen suppressive agents were CGP60474 (CI¯norm = 0.36), KIN001-244 (CI¯norm = 0.55), and RAF265 (CI¯norm = 0.58). The top candidate, CGP60474, consistently abolished collagens I and VII production, exhibited minimal global toxicity, and induced a fivefold increase in phosphorylated extracellular signal-regulated kinase. This proof-of-concept high-content screen can identify drugs that appear to target critical keloidal pathophysiology-collagen secretion.

Development and validation of time-to-event models to predict metastatic recurrence of localized cutaneous melanoma.

BACKGROUND: The recent expansion of immunotherapy for stage IIB/IIC melanoma highlights a growing clinical need to identify patients at high risk of metastatic recurrence and, therefore, most likely to benefit from this therapeutic modality. OBJECTIVE: To develop time-to-event risk prediction models for melanoma metastatic recurrence. METHODS: Patients diagnosed with stage I/II primary cutaneous melanoma between 2000 and 2020 at Mass General Brigham and Dana-Farber Cancer Institute were included. Melanoma recurrence date and type were determined by chart review. Thirty clinicopathologic factors were extracted from electronic health records. Three types of time-to-event machine-learning models were evaluated internally and externally in the distant versus locoregional/nonrecurrence prediction. RESULTS: This study included 954 melanomas (155 distant, 163 locoregional, and 636 1:2 matched nonrecurrences). Distant recurrences were associated with worse survival compared to locoregional/nonrecurrences (HR: 6.21, P < .001) and to locoregional recurrences only (HR: 5.79, P < .001). The Gradient Boosting Survival model achieved the best performance (concordance index: 0.816; time-dependent AUC: 0.842; Brier score: 0.103) in the external validation. LIMITATIONS: Retrospective nature and cohort from one geography. CONCLUSIONS: These results suggest that time-to-event machine-learning models can reliably predict the metastatic recurrence from localized melanoma and help identify high-risk patients who are most likely to benefit from immunotherapy.

Mendelian Randomization Analysis reveals Inverse Genetic Risks between Skin Cancers and Vitiligo.

Several observational studies have demonstrated a consistent pattern of decreased melanoma risk among patients with vitiligo. More recently, this finding has been supported by a suggested genetic relationship between the two entities, with certain variants significantly associated with an increased risk of melanoma, basal cell carcinoma, and squamous cell carcinoma but a decreased risk of vitiligo. We compared 48 associated variants from a recently published GWAS and identified three variants-located in the TYR, MC1R-DEF8, and RALY-EIF2S2-ASIP-AHCY-ITCH loci- that correlated with an increased risk for melanoma, basal cell carcinoma, and squamous cell carcinoma and a decreased risk for vitiligo. We then used results of skin cancers and vitiligo GWAS to compare the shared genetic properties between these two traits through an unbiased Mendelian randomization analysis. Our results suggest that the inverse genetic relationship between common skin cancers and vitiligo is broader than previously reported owing to the influence of shared genome-wide significant associations.

Early Detection and Prognostic Assessment of Cutaneous Melanoma: Consensus on Optimal Practice and the Role of Gene Expression Profile Testing.

Importance: Therapy for advanced melanoma has transformed during the past decade, but early detection and prognostic assessment of cutaneous melanoma (CM) remain paramount goals. Best practices for screening and use of pigmented lesion evaluation tools and gene expression profile (GEP) testing in CM remain to be defined. Objective: To provide consensus recommendations on optimal screening practices and prebiopsy diagnostic, postbiopsy diagnostic, and prognostic assessment of CM. Evidence Review: Case scenarios were interrogated using a modified Delphi consensus method. Melanoma panelists (n = 60) were invited to vote on hypothetical scenarios via an emailed survey (n = 42), which was followed by a consensus conference (n = 51) that reviewed the literature and the rationale for survey answers. Panelists participated in a follow-up survey for final recommendations on the scenarios (n = 45). Findings: The panelists reached consensus (≥70% agreement) in supporting a risk-stratified approach to melanoma screening in clinical settings and public screening events, screening personnel recommendations (self/partner, primary care provider, general dermatologist, and pigmented lesion expert), screening intervals, and acceptable appointment wait times. Participants also reached consensus that visual and dermoscopic examination are sufficient for evaluation and follow-up of melanocytic skin lesions deemed innocuous. The panelists reached consensus on interpreting reflectance confocal microscopy and some but not all results from epidermal tape stripping, but they did not reach consensus on use of certain pigmented lesion evaluation tools, such as electrical impedance spectroscopy. Regarding GEP scores, the panelists reached consensus that a low-risk prognostic GEP score should not outweigh concerning histologic features when selecting patients to undergo sentinel lymph node biopsy but did not reach consensus on imaging recommendations in the setting of a high-risk prognostic GEP score and low-risk histology and/or negative nodal status. Conclusions and Relevance: For this consensus statement, panelists reached consensus on aspects of a risk-stratified approach to melanoma screening and follow-up as well as use of visual examination and dermoscopy. These findings support a practical approach to diagnosing and evaluating CM. Panelists did not reach consensus on a clearly defined role for GEP testing in clinical decision-making, citing the need for additional studies to establish the clinical use of existing GEP assays.

Cutaneous immune-related adverse events are associated with longer overall survival in advanced cancer patients on immune checkpoint inhibitors: A multi-institutional cohort study.

BACKGROUND: Cutaneous immune-related adverse events (cirAEs) occur in up to 40% of immune checkpoint inhibitor (ICI) recipients. However, the association of cirAEs with survival remains unclear. OBJECTIVE: To investigate the association of cirAEs with survival among ICI recipients. METHODS: ICI recipients were identified from the Mass General Brigham healthcare system and Dana-Farber Cancer Institute. Patient charts were reviewed for cirAE development within 2 years after ICI initiation. Multivariate time-varying Cox proportional hazards models, adjusted for age, sex, race/ethnicity, Charlson Comorbidity Index, ICI type, cancer type, and year of ICI initiation were utilized to investigate the impact of cirAE development on overall survival. RESULTS: Of the 3731 ICI recipients, 18.1% developed a cirAE. Six-month landmark analysis and time-varying Cox proportional hazards models demonstrated that patients who developed cirAEs were associated with decreased mortality (hazardratio [HR] = 0.87, P = .027), particularly in patients with melanoma (HR = 0.67, P = .003). Among individual morphologies, lichenoid eruption (HR = 0.51, P < .001), psoriasiform eruption (HR = 0.52, P = .005), vitiligo (HR = 0.29, P = .007), isolated pruritus without visible manifestation of rash (HR = 0.71, P = .007), acneiform eruption (HR = 0.34, P = .025), and non-specific rash (HR = 0.68, P < .001) were significantly associated with better survival after multiple comparisons adjustment. LIMITATIONS: Retrospective design; single geography. CONCLUSION: CirAE development is associated with improved survival among ICI recipients, especially patients with melanoma.

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

BACKGROUND: 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. OBJECTIVE: Examine the impact of melanoma subtypes on cirAE onset and survival among ICI recipients. METHODS: Retrospective multi-institutional cohort study. Multivariate time-series regressions were utilized to assess relationships between melanoma subtype, cirAE development, and survival. RESULTS: 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. LIMITATIONS: Retrospective cohort study. CONCLUSION: 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.

Keratinocytic skin cancers-Update on the molecular biology.

Although much attention has been devoted to a detailed genomic exposition of cutaneous melanoma, other nonmelanoma skin cancers have also recently been subjected to similar analytical scrutiny. Chief among these are the most common malignancies worldwide: basal cell carcinomas and cutaneous squamous cell carcinomas. In this review, the authors summarize their latest knowledge about the molecular pathways and therapeutic opportunities attendant to these keratinocytic skin cancers. PLAIN LANGUAGE SUMMARY: The most common cancers in the United States arise from skin cells called keratinocytes. Although these tumors are not formally tracked by the National Cancer Institute, it is estimated that there are millions of skin cancers called basal cell carcinomas and squamous cell carcinomas. This article reviews the current recent genetic insights into these tumors and therapeutic opportunities.

Cutaneous immune-related adverse events are associated with longer overall survival in advanced cancer patients on immune checkpoint inhibitors: a multi-institutional cohort study.

Background: Cutaneous immune-related adverse events (cirAEs) occur in up to 40% of immune checkpoint inhibitor (ICI) recipients. However, the association of cirAEs with survival remains unclear. Objective: To investigate the association of cirAEs with survival among ICI recipients. Methods: ICI recipients were identified from the Mass General Brigham healthcare system (MGB) and Dana-Farber Cancer Institute (DFCI). Patient charts were reviewed for cirAE development within 2 years after ICI initiation. Multivariate time-varying Cox proportional hazards models, adjusted for age, sex, race/ethnicity, Charlson Comorbidity Index, ICI type, cancer type, and year of ICI initiation were utilized to investigate the impact of cirAE development on overall survival. Results: Of the 3,731 ICI recipients, 18.1% developed a cirAE. 6-month landmark analysis and time-varying Cox proportional hazards models demonstrated that patients who developed cirAEs were associated with decreased mortality (HR=0.87,p=0.027), particularly in melanoma patients (HR=0.67,p=0.003). Among individual morphologies, lichenoid eruption (HR=0.51,p<0.001), psoriasiform eruption (HR=0.52,p=0.005), vitiligo (HR=0.29,p=0.007), isolated pruritus without visible manifestation of rash (HR=0.71,p=0.007), acneiform eruption (HR =0.34,p=0.025), and non-specific rash (HR=0.68, p<0.001) were significantly associated with better survival after multiple comparisons adjustment. Limitations: Retrospective design; single geography. Conclusion: CirAE development is associated with improved survival among ICI recipients, especially melanoma patients. Capsule Summary: Patients on immune checkpoint inhibitors (ICIs) who developed cutaneous immune-related adverse events (cirAEs) had favorable outcomes. This was especially notable for melanoma patients who had cirAEs, both those with vitiligo and other morphologies.Development of cirAEs in ICI-treated patients can be used to prognosticate survival and guide treatment decisions.

Divergent BRAF Inhibitor Resistance Mechanisms Revealed through Epigenetic Mapping.

Although tremendous progress has been made in targeted and immune-based treatments for advanced melanoma, there remains a substantial therapeutic failure rate. For patients with BRAF(V600)-mutant melanomas, resistance to BRAF inhibitors remains a significant survival hurdle. Although multiple compensatory mechanisms to bypass BRAF blockade have been discovered, the epigenetic patterns are still poorly characterized. In this report, we generated eight matched pairs of vemurafenib-sensitive/-resistant melanoma lines and subjected these to concurrent RNA-sequencing and H3K27ac chromatin immunoprecipitation sequencing analysis. Globally, we identified two classes of epigenetic profiles that correlate with resistance. Class 1 resistance involves fewer RNA expression alterations accompanied by fewer enhancer mark changes with H3K27ac. Class 2 resistance shows widespread alterations in transcription and enhancer profiles, which converge on epithelial‒mesenchymal transition and hypoxia-related pathways. We also observed significant and dynamic changes in superenhancers that underpin these transcriptomic patterns. We subsequently verified the two-class structure in pre-BRAF inhibitors and postrelapse human melanoma specimens. Our findings reveal a broad and underappreciated spectrum of epigenetic plasticity during acquired BRAF inhibitor resistance.

Melanoma classification and management in the era of molecular medicine.

Melanoma is the most lethal form of skin cancer although surgery is often curative when combined with early screening and prevention. In recurrent or advanced cancer, the emergence of chemotherapy, targeted therapy, and immune checkpoint inhibitors has demonstrated promising clinical outcomes. Such approaches can remarkably halt the progression of disease for many years, although are limited by the acquisition of resistance. The development and approval of combination therapies has further changed the treatment paradigm for certain melanomas. This review focuses on the current state of melanoma epidemiology and recent advancements in melanoma screening, histopathological classification, staged excision (i.e. wide local excision, sentinel lymph node biopsy, and Mohs micrographic surgery), and systemic treatment.

Factors associated with suspected nonmelanoma skin cancers, dysplastic nevus, and cutaneous melanoma among first-time SpotMe screening program participants during 2009-2010.

BACKGROUND: There have been no studies of the American Academy of Dermatology's SpotMe skin cancer screening program to collectively analyze and determine the factors associated with suspected basal cell carcinoma (BCC), squamous cell carcinoma (SCC), dysplastic nevus (DN), and cutaneous melanoma (CM) diagnoses. OBJECTIVE: Describe the demographics, risk factors, and access to care profiles associated with suspected diagnoses of BCC, SCC, DN, and CM among first-time SpotMe screenees during 2009-2010. METHODS: We conducted a cross-sectional analysis of data from the SpotMe skin cancer screenings conducted in 2009 and 2010. We performed multivariable logistic regression analysis for each diagnosis, incorporating standard demographic, access to care, and risk factor variables in the models. RESULTS: Men, those without a regular dermatologist, persons reporting recently changing moles, and those with a personal history of melanoma were at increased risk for each of the suspected diagnoses analyzed. Uninsured persons were at increased risk for suspected malignancies (BCC, SCC, and CM). LIMITATIONS: Lack of histologic confirmation for diagnoses and cross-sectional design. CONCLUSION: Among first-time SpotMe participants, suspected diagnoses of BCC, SCC, DN, and CM shared several associated factors, which may be considered when planning outreach and screening for populations at risk for skin cancer.

New Insights into Melanoma Tumor Syndromes.

Melanoma tumor syndromes (MTS) represent an important minority of familial melanoma cases. In these patients, the accumulation of sequence alterations in essential genes may prelude the risk of internal malignancies, in addition to melanoma. Although several host and environmental factors have been implicated in familial melanoma, the exact mechanisms of cancer predisposition-particularly in the context of mixed cancer syndromes-still remain unclear. In this paper, we review new insights into MTS and elucidate recent efforts that guide individualized prognostication and treatment for these diseases in the past quarter century.

DNA promoter hypermethylation of melanocyte lineage genes determines melanoma phenotype.

Cellular stress contributes to the capacity of melanoma cells to undergo phenotype switching into highly migratory and drug-tolerant dedifferentiated states. Such dedifferentiated melanoma cell states are marked by loss of melanocyte-specific gene expression and increase of mesenchymal markers. Two crucial transcription factors, microphthalmia-associated transcription factor (MITF) and SRY-box transcription factor 10 (SOX10), important in melanoma development and progression, have been implicated in this process. In this study we describe that loss of MITF is associated with a distinct transcriptional program, MITF promoter hypermethylation, and poor patient survival in metastatic melanoma. From a comprehensive collection of melanoma cell lines, we observed that MITF-methylated cultures were subdivided in 2 distinct subtypes. Examining mRNA levels of neural crest-associated genes, we found that 1 subtype had lost the expression of several lineage genes, including SOX10. Intriguingly, SOX10 loss was associated with SOX10 gene promoter hypermethylation and distinct phenotypic and metastatic properties. Depletion of SOX10 in MITF-methylated melanoma cells using CRISPR/Cas9 supported these findings. In conclusion, this study describes the significance of melanoma state and the underlying functional properties explaining the aggressiveness of such states.

Oncogenic KIT Induces Replication Stress and Confers Cell Cycle Checkpoint Vulnerability in Melanoma.

Acral and mucosal melanomas arise from sun-protected sites, disproportionately impact darker-skinned individuals, and exact higher mortality than common types of cutaneous melanoma. Genetically, acral and mucosal melanomas harbor more alterations of KIT than typical cutaneous melanomas. Because KIT-mutated melanomas remain largely treatment resistant, we set out to create a faithful murine KIT-driven allograft model to define newer therapeutic strategies. Using the prevalent human KITK642E activating mutation, the murine mKITK641E cellular avatars show features of transformation in vitro and tumorigenicity in immunocompetent C57BL/6J mice. mKITK641E cells proliferate more rapidly, exhibit greater chromosomal aberrations, and sustain three-dimensional spheroid expansion and aggressive tumor growth in C57BL/6J mice compared with their vector-controlled cells. We further verified the functional dependence of these cells on KITK641E with both genetic and pharmacologic suppression. Using these cells, we performed a screen of 199 kinase inhibitors and identified a selective vulnerability to Chk1/ATR inhibition in the KITK641E-activated cells. Mechanistically, we subsequently showed that KITK641E induces a significantly increased level of replication stress compared with murine vector‒controlled cells. These results showcase an allograft model of human KIT-driven melanomas, which uncovered an unappreciated role for replication stress in KIT melanomagenesis and implicated a possible therapeutic strategy with Chk1/ATR inhibitors.

Unsupervised Phenotype-Based Clustering of Clinicopathologic Features in Cutaneous Melanoma.

Pathogenic phenotypes in cutaneous melanoma have been vastly cataloged, although these classifications lack concordance and are confined to either morphological or molecular contexts. In this study, we perform unsupervised k-medoids clustering as a machine learning technique of 2,978 primary cutaneous melanomas at Mass General Brigham and apply this information to elucidate computer-defined subsets within the clinicopathologic domain. We identified five optimally separated clusters of melanoma that occupied two distinct clinicopathologic subspaces: a lower-grade partition associated with common or dysplastic nevi (i.e., nevus-associated melanomas) and a higher-grade partition lacking precursor lesions (i.e., de novo melanomas). Our model found de novo melanomas to be more mitogenic, more ulcerative, and thicker than nevus-associated melanomas, in addition to harboring previously unreported differences in radial and vertical growth phase status. The utilization of mixed clinicopathologic variables, reflective of actual clinical data contained in surgical pathology reports, has the potential to increase the biological relevance of existing melanoma classification schemes and facilitate the discovery of new genomic subtypes.