Stage Melanoma Research Articles

The impact of type 2 diabetes on melanoma stage (TNM) at the time of diagnosis and its association with sex: A Danish nationwide study.

Cancer has become the leading cause of death among individuals with type 2 diabetes (T2D) in high-income countries. T2D is suggested to directly influence cancer progression. However, the association between T2D and melanoma stage at diagnosis remains uncertain, as well as any potential sex disparities. To investigate the association between T2D and the melanoma TNM stage (Breslow thickness, ulceration status, lymph node metastases, and distant metastases) at the time of diagnosis and to assess whether the association is affected by sex. A nationwide cross-sectional study was conducted, including all patients diagnosed with melanoma between 2004 and 2022 identified in the Danish Cancer Register. T2D status was ascertained using a validated register based algorithm. The association between T2D and melanoma stage was estimated using univariable and multivariable logistic regression analyses adjusted for sex, age, comorbidity, and year of diagnosis. The study included 30,315 individuals with melanoma. The multivariable analyses showed that T2D was associated with an increased adjust odds ratio (aOR) of tumour thickness > 4 mm (aOR 1.30, 95 %CI: [1.10-1.52]), the presence of ulceration (aOR: 1.25, 95 % CI: [1.09-1.43]), lymph node metastases (aOR 1.27 [1.10-1.47]), and distant metastases (aOR: 1.26 [1.01-1.56]). Furthermore, sex stratified analyses showed that T2D was associated with distant metastases in women, but not in men. Individuals with T2D were more likely to be diagnosed with advanced stages of local, regional, and distant melanoma. This highlights the need for greater melanoma awareness and further research into treatment responses in individuals with T2D.

Cyclin E Expression and p16 Loss Are Strong Prognostic Biomarkers in Primary Invasive Cutaneous Melanoma.

The traditional melanoma staging system is not ideal for predicting patients' individual risk of disease recurrence and death. Subsequently, suboptimal adjuvant treatment may be offered. Hence, identification of biomarkers to optimize risk stratification is warranted. Cyclins and cyclin-dependent kinase inhibitors, key players in the cell cycle regulation, are candidate prognostic biomarkers. Herein, their expression and prognostic value in melanoma are studied. The expression of Cyclin D1, Cyclin E, p16, p21, and p27 were assessed using immunohistochemistry in samples from 59 patients with melanoma and correlated with clinicopathological parameters, as well as relapse-free survival (RFS) and overall survival (OS). Cyclin E expression in the nucleus, observed in 19% of patients, was correlated with Breslow thickness (p=0.017), whereas p16 loss in the cytoplasm and nucleus, detected in 68% and 61% of patients respectively, was correlated with Breslow thickness (p=0.001) and ulceration (p=0.035). The high expression of Cyclin E in the nucleus (p<0.001) and the loss of p16 in the cytoplasm (p=0.012) and nucleus (p=0.002) were associated with shorter OS. Cyclin E in the nucleus was a prognostic factor for RFS and OS at least as strong as Breslow thickness. Expression of Cyclin E and loss of p16 appeared to be significant prognostic biomarkers, with Cyclin E being prognostically at least as strong as Breslow thickness regarding RFS and OS. Both biomarkers may potentially be used to improve stratification of individual patient's risk of recurrent disease and survival, and subsequently optimize adjuvant treatment.

Childhood and Adolescent Melanoma: An Update.

Pediatric melanoma is a rare but clinically significant public health concern, as it can account for 7% of all malignancies in adolescents aged 15-19. Given the overall rarity of pediatric melanoma, especially in pre-adolescents, patients can go undetected, leading to a delay in treatment. We divide pediatric melanoma into three distinct age ranges which include infantile, pre-adolescent and adolescent subtypes and distinguish between each age range their clinical features, prognosis and associated risk factors. We next summarize the three predominant melanoma subtypes that include Spitzoid melanoma, congenital melanocytic nevus associated melanoma and conventional (adult-type) melanoma and provide distinguishing clinical, histologic, and genetic features from their difficult-to-different benign counterparts. We conclude by reviewing consensus guidelines for pediatric melanoma staging and treatment, with a special emphasis on outlining barriers to adapting the advancements in targeted therapeutics into the standard care of pediatric melanoma.

DeepMelaNet: Advancing Melanoma Stage Classification in Skin Cancer Diagnosis

Melanoma skin cancer is a global public health threat due to its increasing rates and the possibility of severe outcomes if not adequately addressed. Melanoma is caused by ultraviolet radiation and, among its two stages, malignant is more dangerous than benign. The diagnosis of melanoma is typically based on visual inspection and manual methods carried out by experienced physicians. However, this method is usually slow and has a high probability of error. Deep-learning-based models can offer better and low-cost treatments for people with melanoma. This study aimed to develop a deep-learning model to classify melanoma skin cancer in its early stages. This study presents a modified deep-learning model, named DeepMelaNet, to correctly classify skin cancer images as benign or malignant. The proposed classifier achieved an accuracy of 93.40%, a precision of 98%, a recall of 94%, and an F1 score of 93% on a dataset of 10,000 melanoma skin cancer images, offering a practical solution that can help healthcare professionals in early skin cancer prediction.

Sentinel lymph node biopsy in a case of conjunctival melanoma

Aims/Purpose: To present the first case of a sentinel lymph node biopsy for ocular melanoma in our hospital.Methods: We present the clinical case of a patient treated in our unit for conjunctival melanoma in the right eye. An excision of the conjunctival lesion with safety margins was performed, followed by the application of mitomycin C, cryotherapy, and placement of an amniotic membrane. The histopathological diagnosis confirmed an invasive nodular melanoma pT2aNxMx Breslow 1.5 mm with clear margins. Subsequently, three weekly cycles of 0.04% mitomycin C eye drops were administered. The extension study ruled out disease dissemination.Results: The case was presented to the Melanoma Committee, where it was decided to perform a sentinel lymph node biopsy. The procedure was carried out without evidence of metastasis in the analyzed lymph node (0/1), confirmed by histological examination with Hematoxylin‐eosin and immunohistochemistry with HMB45 and SOX10. This is the first case of a sentinel lymph node biopsy for ocular melanoma in our hospital. Thanks to close collaboration between the Ophthalmology and Radiology departments, the procedure was performed correctly.Currently, the patient continues with successive follow‐ups by Ophthalmology, showing good evolution. This case highlights the importance of interdisciplinary collaboration in the management of conjunctival melanoma and the efficacy of adjuvant treatments, such as mitomycin C, in preventing local recurrencesConclusions: Current literature supports the performance of sentinel lymph node biopsy in cases of conjunctival melanoma due to its ability to detect micrometastases and guide therapeutic management, thus improving patient prognosis. It is a valuable tool in the accurate staging of conjunctival melanoma, allowing for earlier intervention in case of lymphatic dissemination and potentially improving survival rates.

Sentinel lymph node biopsy in a case of conjunctival melanoma

Aims/Purpose: To present the first case of a sentinel lymph node biopsy for ocular melanoma in our hospital.Methods: We present the clinical case of a patient treated in our unit for conjunctival melanoma in the right eye. An excision of the conjunctival lesion with safety margins was performed, followed by the application of mitomycin C, cryotherapy, and placement of an amniotic membrane. The histopathological diagnosis confirmed an invasive nodular melanoma pT2aNxMx Breslow 1.5 mm with clear margins. Subsequently, three weekly cycles of 0.04% mitomycin C eye drops were administered. The extension study ruled out disease dissemination.Results: The case was presented to the Melanoma Committee, where it was decided to perform a sentinel lymph node biopsy. The procedure was carried out without evidence of metastasis in the analyzed lymph node (0/1), confirmed by histological examination with Hematoxylin‐eosin and immunohistochemistry with HMB45 and SOX10. This is the first case of a sentinel lymph node biopsy for ocular melanoma in our hospital. Thanks to close collaboration between the Ophthalmology and Radiology departments, the procedure was performed correctly.Currently, the patient continues with successive follow‐ups by Ophthalmology, showing good evolution. This case highlights the importance of interdisciplinary collaboration in the management of conjunctival melanoma and the efficacy of adjuvant treatments, such as mitomycin C, in preventing local recurrencesConclusions: Current literature supports the performance of sentinel lymph node biopsy in cases of conjunctival melanoma due to its ability to detect micrometastases and guide therapeutic management, thus improving patient prognosis. It is a valuable tool in the accurate staging of conjunctival melanoma, allowing for earlier intervention in case of lymphatic dissemination and potentially improving survival rates.

Stat Bite: Improvements in 5-year Relative Survival for Regional and Distant Stage Melanoma of the Skin

Stat Bite: Improvements in 5-year Relative Survival for Regional and Distant Stage Melanoma of the Skin

Nuclear Alpha-Synuclein in Parkinson's Disease and the Malignant Transformation in Melanoma.

Background: Alpha-synuclein (ASyn), a marker of Parkinson's disease (PD) and other neurodegenerative processes, plays pivotal roles in neuronal nuclei and synapses. ASyn and its phosphorylated form at Serine 129 (p-ASyn) are involved in DNA protection and repair, processes altered in aging, neurodegeneration, and cancer. Objective: To analyze the localization of p-ASyn in skin biopsies of PD patients and melanoma. Methods: Biopsies from 26 PD patients, 20 melanoma patients, and 31 control subjects were probed and analyzed with a p-ASyn antibody by immunohistochemistry and immunofluorescence. Nuclear positivity was quantified by image analysis. Results: Peripheral nerve endings from healthy subjects show little p-ASyn immunopositivity but notable axonal presence in PD. Control subjects show immunopositivity to p-ASyn along all epidermic strata and scarce presence in their cytoplasm. In contrast, its nuclear presence in PD is weaker, with a higher cytoplasmic and intercellular presence. Nuclear p-ASyn in melanoma varied from similar to control skin in early stage melanoma to a higher rate of empty nuclei in the intermediate stage and total absence of nuclear p-ASyn in severe cases. Interpretation: These findings support the nuclear localization of p-ASyn in skin cells and show that its presence decreases PD and almost disappears in the malignant transformation of melanocytes, redistributing to the cytoplasm and intercellular spaces. This confirms the association between PD and melanoma, providing crucial insights into the role of p-ASyn in both diseases. Trial Registration: ClinicalTrials.gov identifier: NCT01380899.

The Impact of Medicaid Expansion on Stage at Diagnosis of Melanoma Patients: A Retrospective Study.

This study addresses the lack of research on Medicaid expansion's impact on melanoma staging, treatment utilization, and outcomes by evaluating its effects under the Affordable Care Act (ACA), particularly focusing on staging at diagnosis, treatment use, and 3-year mortality outcomes. The objective is to determine whether Medicaid expansion led to earlier melanoma diagnosis and improved survival rates among non-elderly adults (ages 40-64) by analyzing data from the National Cancer Database (NCDB). A total of 12,667 patients, aged 40-64, diagnosed with melanoma from 2010 to 2020 were identified using the NCDB. Difference-in-difference (DID) analysis was performed to analyze tumor staging at presentation between Medicaid expansion states and non-Medicaid expansion states both prior to the expansion and after the expansion. Of the total patients, 2307 were from the pre-expansion time period residing in Medicaid expansion states (MES) and 1804 in non-Medicaid expansion states. In the post-expansion time period there were 5571 residing in the MES and 2985 in the non-MES. DID analysis revealed a decrease in stage IV melanoma at diagnosis (DID -0.222, p < 0.001) between MES and non-MES before and after Medicaid expansion. After expansion, in stage IV, the occurrence of primary surgery was 0.42 in non-MES and 0.44 (difference 0.02); DID analysis was not statistically significant. The use of immunotherapy in MES was significantly higher than in non-MES after expansion (p < 0.001), although DID analysis did not reveal a statistically significant difference. DID analysis showed a statistically significant decrease in 3-year mortality (DID -0.05, p = 0.001) between MES and non-MES before and after Medicaid expansion. This study revealed the positive impact of the ACA's Medicaid expansion on melanoma stage at presentation, highlighting the importance of public health policies in reducing disparities in mortality rates and early-stage diagnoses. Future research should explore additional barriers to care and evaluate the long-term outcomes of Medicaid expansion to optimize cancer care for vulnerable populations.

Novel FANCI and RAD54B Variants and the Observed Clinical Outcomes in a Hungarian Melanoma Cohort.

Accumulating evidence suggests that inherited melanoma is not rare and approx. one in seven individuals with melanoma has clinically relevant hereditable cancer-predisposing and/or -susceptibility variant(s). Concerning its germline genetic background, genetic screening aims to identify either variants of predisposing genes with high penetrance or variants of susceptibility genes with medium or low penetrance. However, less attention is paid to genetic testing of germline variants of genes influencing patients' survival outcomes or enhancing the design of new therapies. We aimed to investigate whether the germline genetic background of a Hungarian melanoma cohort (n = 17) contains any pathogenic or likely pathogenic variants of the BRCA2, POLE, WRN, FANCI, PALB2, and RAD54B genes and if the presence of these variants correlate with the clinical findings of the patients, including the advanced stage of melanoma, poor prognosis, and poor survival. We identified three novel variants in the FANCI gene and one novel variant in the RAD54B gene. We detected rapid disease progression, unfavorable outcome, and therapeutic resistance in the patient carrying the likely pathogenic FANCI variant. Our study highlights the importance of screening germline variants of genes influencing melanoma progression, therapy resistance, and survival of patients.

Downregulation of MHC-I on melanoma cells and decreased CD8+ T-cell infiltration are associated with metastatic spread and resistance to immunotherapy.

The success of immune checkpoint inhibitors (ICI) for melanoma therapy has catalyzed the introduction of ICI in increasingly early stages of disease. This exposes many patients with lower risk of relapse to the risk of protracted adverse events, highlighting the need for biomarkers guiding the use of ICI. Already many years ago, brisk infiltration of primary melanomas by lymphocytes has been linked to improved patient outcome, but controversial findings due to a high variability in classification systems have been described. CD8+ T-cells have been identified as a primary mediator of antitumor immunity in patients treated with ICI. As CD8+ T-cells require the presentation of antigen via MHC-I on target cells, downregulation and loss of MHC-I has been observed as resistance mechanisms to ICI. Here, we revisit the role of MHC-I expression and CD8+ T-cell infiltration in melanoma evolution using a cohort of advanced primary and matched metastatic melanomas by using an automated immunohistochemistry and digital pathology workflow. Our results show that downregulation of MHC-I expression is a frequent event in advanced primary melanomas that is associated with decreased CD8+ T cell infiltration and early metastatic spread to sentinel lymph nodes. Furthermore, MHC-I downregulation and decreased infiltration with CD8+ T-cells is also associated with resistance to ICI. Our results suggest that analyses of MHC-I expression and CD8+ T-cell infiltration patterns could serve as future biomarkers to guide the decision to treat patients in early stages of melanoma with ICI.

The Development and Evaluation of a Convolutional Neural Network for Cutaneous Melanoma Detection in Whole Slide Images.

The current melanoma staging system does not account for 26% of the variance seen in melanoma-specific survival, therefore our ability to predict patient outcome is not fully elucidated. Morphology may be of greater significance than in other solid tumors, with Breslow thickness remaining the strongest prognostic indicator despite being subject to high levels of interobserver variation. The application of convolutional neural networks to whole slide images affords objective morphologic metrics, which may reveal new insights into patient prognosis. To develop and evaluate a convolutional neural network for invasive cutaneous melanoma detection in whole slide images for the generation of objective prognostic biomarkers based on tumor morphology. One thousand sixty-eight whole slide images containing cutaneous melanoma from 5 data sets have been used in the initial development and evaluation of the convolutional neural network. A 2-class tumor segmentation network with a fully convolutional architecture was trained using sparse annotations. The network was evaluated at per-pixel and per-tumor levels as compared to manual annotation, as well as variation across 3 scanning platforms. The convolutional neural network located conventional cutaneous invasive melanoma tissue with an average per-pixel sensitivity and specificity of 97.59% and 99.86%, respectively, across the 5 test sets. There were high levels of concordance between the tumor dimensions generated by the model as compared to manual annotation, and between the tumor dimensions generated by the model across 3 scanning platforms. We have developed a convolutional neural network that accurately detects invasive cutaneous conventional melanoma in whole slide images from multiple data sources. Future work should assess the use of this network to generate metrics for survival prediction.

Early termination and nonpublication of phase III/IV melanoma clinical trials: a cross-sectional study

Introduction Melanoma is a common cancer worldwide. Introduction of new treatments through clinical trials is essential to reduce the global burden from melanoma; however, it is estimated that 22% of oncological clinical trials are terminated early. We conducted the first cross-sectional study to assess melanoma clinical trial termination and nonpublication with an aim to guide scientists conducting such trials. Methods We identified all phase III/IV clinical trials evaluating melanoma therapies in the ClinicalTrials.gov database between 2010 and 2024. For each trial, we extracted data on the trial’s status, melanoma stage, melanoma subtype, included age, funding sources, trial locations, publication status, and reasons for termination. A descriptive and frequency analysis was performed in JASP 0.19 software. Results A total of 108 trials were analyzed; the majority of trials included stage III/IV melanoma (n = 95), and cutaneous melanoma was the most common subtype. Only 15 trials included pediatric patients. Industrial funding accounted for 74% (n = 80) of trials’ financing. Most of the trials were conducted internationally in North America, Europe, Australia, and New Zealand, with a few trials conducted in South Africa (n = 1), South America (n = 1), or China (n = 5). Early termination was observed in 21% (n = 23) of trials, with no association between early termination and melanoma stage, subtype, age, funding source, or trial locations. Notably, the most common reason for early termination was publication of interim efficacy and safety results (n = 14/23). Conclusion Our study confirms that early termination of phase III and IV melanoma trials doesn’t raise a significant concern; however, diversified funding and broader geographic representation are needed to create more equitable and inclusive trials. We also suggest conducting further cross-sectional studies on phase I/II melanoma trials.

Defining high-risk patients: beyond the 8the AJCC melanoma staging system.

Since melanoma incidence is steadily increasing, guidelines regarding the diagnosis, staging, and treatment of melanoma are constantly being updated. In particular, the use of adjuvant therapy in stage IIb/c melanoma has been recently approved by the international regulatory agenicies. We performed a retrospective study with 92 melanoma patients namely 42 patients with IIb/c melanoma and 42 patients with IIIa stage melanoma, describing demographics, clinical, histology and disease course during the 5-year follow-up.Several significant evidences emerged between the two groups. Stage IIb/c patients possess a higher age of disease onset (69.6 vs. 55.5 years) with respect to stage III patients and the acral localization appeared as the most frequent (24% vs. 4%). Histologically, stage IIb/c melanomas more frequently exhibit ulceration (70% vs. 2%), angiotropism (54% vs. 8%) and are characterized by a greater presence of TILS (52% vs. 15%). Although it is not statistically significant, we observed a difference in terms of presence of metastasis during the 5-year follow-up: 15% of stage IIb/c patients showed metastasis vs. 4% of stage IIIa patients. Our data support the use of adiuvant immunotherapy in stage IIb/c patients.

Melanoma in the head and neck region: the value of preoperative imaging in melanoma stage I-II.

The management of head and neck melanoma (HNM) is constantly being fine-tuned in the era of immunotherapy. HNM have different metastatic patterns and a worse prognosis than melanoma of the trunk, asking for a more fine-tuned managing strategy. In clinically node-negative HNM patients, the ultrasound (US) with fine needle aspiration cytology (FNAC) and chest X-ray (CXR) are optional modalities in the preoperative staging workup. The contribution of imaging seems limited in this stage of disease. This study aims to research the value of the US-FNAC and CXR in clinically node-negative HNM patients. Clinical stage I-II HNM patients from 2016 to 2021 were retrospectively reviewed. A total of 373 patients were analyzed. Patient characteristics, surgery and follow-up details, recurrences, tumor characteristics, staging, imaging, sentinel node procedure (SNP) details, and lab results were collected from the patient files. All patients received preoperative US. A total of 65 FNACs were performed, which found metastatic lymph nodes in two patients (0.54%). The CXR was performed in 336/373 patients and did not find any pulmonary metastases. The SNP was performed in 242 patients and demonstrated 40 positive patients, with 86% having micrometastases, isolated tumor cells, or submicrometastases. This study demonstrated a low number of relevant findings by both the US and CXR. We can conclude that both imaging modalities do not have a significant contribution to the routine staging procedure of clinical stage I-II HNM in our study group, with our results being in line with current general melanoma guidelines.

Sentinel lymph node mapping with Indocyanine green fluorescence (ICG) for pediatric and adolescent tumors: a prospective observational study

Sentinel lymph node biopsy (SLNB) is an important technique in the staging of pediatric melanomas, sarcomas, and potentially useful for other solid tumors. Precise visual localization of the sentinel lymph node (SLN) during the operation is a key challenge of this procedure. Presently, the gold standard method employing Technetium 99 (99mTc) for localization carries a notable false-negative rate. In this context, we propose evaluating the use of Indocyanine Green near-infrared (ICG-NIR) as a supplementary tool to enhance the identification of SLN. A prospective observational study focused on pediatric and adolescent patients undergoing SLNB using ICG-NIR at a single institution from 2019 to 2022. Lymphoscintigraphy with 99mTc was performed before surgery and 99mTc was detected intraoperatively using a handheld gamma probe. ICG was administered intraoperatively and assessed using transcutaneous NIR. The study collected demographic data, intra-operative findings (Technetium 99 m, ICG fluorescence), and histopathological data. Eight patients with a median age of 16 years (range: 8–19 years) underwent fluorescence-guided sentinel lymph node harvesting with 100% sensitivity. Sentinel lymph node fluorescence was verified with a positive radiosignal in all patients. No adverse events were recorded. Fluorescence-guided assessment of the lymphatic system is both feasible and effective for sentinel lymph node identification. Nevertheless, larger-scale studies are essential to establish indocyanine green as a viable alternative rather than a complementary technique alongside the gold-standard radioisotope-guided method for sentinel lymph node assessment in children.

Braf-Mutant Melanomas: Biology and Therapy.

The incidence of melanoma, the most lethal form of skin cancer, has increased mainly due to ultraviolet exposure. The molecular characterization of melanomas has shown a high mutational burden led to the identification of some recurrent genetic alterations. BRAF gene is mutated in 40-50% of melanomas and its role in melanoma development is paramount. BRAF mutations confer constitutive activation of MAPK signalling. The large majority (about 90%) of BRAF mutations occur at amino acid 600; the majority are BRAFV600E mutations and less frequently BRAFv600K, V600D and V600M. The introduction of drugs that directly target BRAF-mutant protein (BRAF inhibitors) and of agents that stimulate immune response through targeting of immune check inhibitor consistently improved the survival of melanoma BRAFV600-mutant patients with unresectable/metastatic disease. In parallel, studies in melanoma stage II-III patients with resectable disease have shown that adjuvant therapy with ICIs and/or targeted therapy improves PFS and RFS, but not OS compared to placebo; however, neoadjuvant therapy plus adjuvant therapy improved therapeutic response compared to adjuvant therapy alone.

Trends in incidence, mortality, and survival of cutaneous malignant melanoma over three decades: a population-based study in Southern Spain.

Cutaneous malignant melanoma (CMM) represents a global public health problem. Epidemiological studies about CMM trends tend to focus on single indicators or lack information about tumor characteristics that can help gain a more thorough understanding of CMM epidemiology. To fill this gap, we studied CMM trends in incidence, mortality, and survival over three decades and considering sex, age, and tumor characteristics. Data were obtained for all new cases of CMM diagnosed 1985-2017 from the population-based cancer registry in Granada (Southern Spain) and for deaths due to CMM by the Ministry of Health of the Spanish government. Incidence, mortality, and survival estimates were obtained according to sex, age group, anatomical site, histological type, Breslow index, and Clark level. Observed and net survival were calculated for 1, 3, and 5 years using the Kaplan-Meier and Pohar-Perme methods, respectively. Log-linear jointpoint regression was used to assess temporal trends in age-standardized rates of incidence and mortality. Between 1985-2017, 2,446 patients aged 15 years and older were newly diagnosed with CMM. There was a significant increase in incidence, both in men and women (APC 4.4% and 3.7% respectively), mainly in superficial spreading and nodular melanomas, and more pronounced among those with <1mm Breslow index. Mortality rates increased, mainly driven by increases among men and individuals ≥65 years old. Nodular melanoma had the worst prognosis, with a 5-year observed survival of 67.1% compared to survival greater than 90% for the other subtypes. 5-year net survival improved from 78.3% in 1985-1997 to 88.6% in 2008-2017, with a clear trend by Breslow index. The incidence of melanoma in early stages in Southern Spain has increased over the past decades. This has been accompanied by noticeable improvements in mortality and survival, especially among younger age groups, suggesting the potential effectiveness of prevention strategies, and new treatment regimens.

ICG-guided sentinel lymph node biopsy in melanoma is as effective as blue dye: A retrospective analysis

IntroductionSentinel lymph node biopsy (SLNB) is a key procedure in the staging and management of melanoma. Traditionally, it is performed using a dual-mapping technique combining a radioactive isotope (RI) and blue dye (BD). Fluorescence-guided surgery with indocyanine green (ICG) has emerged as an alternative tracer, offering potential advantages in real-time visualization and operative efficiency. This study compares the efficacy of RI + ICG with RI + BD in SLNB for melanoma. MethodsWe conducted a retrospective cohort study at a single center, including 311 patients who underwent SLNB for melanoma. Patients were divided into two groups: RI + BD (n = 227, January 2010–August 2022) and RI + ICG (n = 84, August 2022–February 2024). SLN detection rates, positive SLN rates, operative times, and postoperative complications were compared between the two groups. ResultsBoth groups were clinically and pathologically comparable. SLN detection rates were 100 % in the RI + BD group and 98.8 % in the RI + ICG group (p = 0.1). The median number of lymph nodes resected was lower in the RI + ICG group as compared to the RI + BD group (p = 0.047). While positive SLN rates were higher in the RI + ICG group (9.5 % vs. 6.2 %), this difference was not statistically significant (p = 0.3). ICG alone could not identify all the positive SLN. Postoperative complications, including seroma, did not differ significantly between groups. ConclusionsICG-guided SLNB is comparable to BD-guided SLNB in terms of detection rate and SLN positivity, although it can not be used alone to identify all positive SLNBs. ICG-based fluorescence imaging is a promising technique that may enhance surgical efficiency in melanoma management.

Abstract A012: g3bp1-mediated stress granule formation drives melanoma initiation in zebrafish

Abstract Stress granules confer cancer cells the ability to withstand harsh biological conditions and impart tumorigenic translational states through mRNA sequestration. Despite advances in in vitro knowledge, mechanistic understanding of the endogenous influence of stress granules during tumorigenesis in vivo remains understudied. To address this, we use a zebrafish melanoma model where oncogenic human BRAF V600E is driven by the melanocyte master regulator mitfa in a p53 -/- background. Through vector-based genetic engineering, endogenous melanoma induction in these zebrafish can be developmentally staged from single cell to tumor. BRAF V600E ::p53 -/- melanocytes form a cancerized field (CF), from which a subset upregulate the melanocyte master regulator mitfa, creating a cancer precursor zone (CPZ). Transformation of CPZ cells to an embryonic, neural crest-like state facilitates their formation of an early tumor patch that inevitable develops into an overt tumor. Single cell RNAseq analysis of cells representing each melanoma stage showed that CPZ cells upregulate core stress granule markers, including g3bp1, tia1, tia1l, and nufip2. Immunostaining of g3bp1 in CF, CPZ, patch, and tumor cells revealed a significant induction of stress granules from the CF to CPZ transition (2 vs 10 stress granules/cell; N=3; p=0.034) that persists during the patch and tumor stage, indicating cell stress accompanies melanoma initiation and progression. Genetic disruption of g3bp1 through cell autonomous, melanocyte-specific CRISPR editing in zebrafish (N=10-13) causes delayed CPZ onset (P=0.012) and fewer CPZs to form (P=0.021). In turn, g3bp1-edited zebrafish have delayed tumor formation (P=0.026) and develop fewer tumors (P=0.006). To decipher the RNAs sequestered by stress granules during melanomagenesis, we performed RIPseq for G3BP1 in human A375 melanoma cells stressed with sodium arsenite. RNAs significantly bound to G3BP1 upon stress induction include major tumor suppressors, such as CDKN2A, RBM5, BIK, and RHOB. Together, these results suggest that endogenous g3bp1-mediated stress granule formation in melanoma initiating cells is tumorigenic in vivo and operates through the sequestration of tumor suppressive RNAs. Citation Format: Kyle D Drake, Emily Formato, Leonard Zon. g3bp1-mediated stress granule formation drives melanoma initiation in zebrafish [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr A012.