Cutaneous Melanoma Metastases Research Articles

Regional lymph node metastases in cutaneous melanoma: a single-center analysis from southeast europe

Sentinel lymph node biopsy is the standard of care for nodal staging in clinically node-negative melanoma patients. Our goal was to present 10-year results of sentinel lymph node biopsy at our institution and to evaluate the clinicopathologic factors as potential predictors of sentinel lymph node and non-sentinel lymph node metastatic involvement in patients with cutaneous melanoma. We have analyzed clinicopathologic and lymphoscintigraphic characteristics in 420 patients with cutaneous melanoma who underwent sentinel lymph node biopsy between 2010 and 2019. In addition, we have examined the results of group of patients with positive sentinel lymph node biopsy undergoing complete lymph node dissection. The overall detection rate of sentinel lymph node biopsies was 97.1%, of which 18.8% was metastatic. Drainage to one regional basin was seen in 345 patients (83.1%) and to multiple drainage regions in 71 patients (17%). In-transit lymph nodes were detected in 20 patients. On univariate logistic regression analysis, male gender, primary tumor thickness with nodular histology, acral location, presence of ulceration, and the number of nodes harvested were significantly associated with sentinel lymph node biopsy status (p < 0.05). On multivariate analysis, the Breslow thickness was the only independent predictor of sentinel lymph node biopsy status. The metastases in non-sentinel lymph node found in 26 patients with positive sentinel lymph node (35.6%) correlated on univariate, as well as on multivariate logistic regression, with tumor subtype and number of sentinel lymph node harvested. In addition to the well-established primary tumor thickness as a predictor of sentinel lymph node biopsy positivity, we observed acral location and nodular melanoma subtype to significantly enhance the risk of metastases in sentinel lymph node(s). Primary tumor histology and number of nodes harvested were the only statistically significant variables predicting the non-sentinel lymph node status on multivariate analysis. Lymphoscintigraphy imaging characteristics were not significantly associated with sentinel lymph node status.

Kindlin-3 and RASSF6 are probable biomarkers for predicting metastasis in cutaneous melanoma.

It is well known that metastasis is the most crucial factor in determining the fate of the patient. The prognosis of melanoma is very poor at the stage of metastasis. Recently, several genes and proteins, including kindlin3, dioxin receptor (AhR), RASSF6, and claudin-11, which were shown as possible prognostic biomarkers for human tumours, were described. In this study, we focused on these proteins in melanoma within a clinical setting. Forty-three primary melanomas (PMs), 17 metastatic melanomas (MMs), 15 melanocytic nevi (MN), and two melanoma cell lines were included in this retrospective study. All proteins were investigated using immunohistochemistry, and analysis was performed using a semi-quantitative immunoreactive score (IRS). The nevus group showed lower RASSF6 and AhR IRS levels than PMs. RASSF6 and kindlin-3 levels in the PMs with metastasis (MwM) and also in PMs showing lymphovascular invasion were significantly lower. The logistic regression model also proved that kindlin-3 expression was a significant independent predictor of metastasis. The current study supports the role of kindlin-3 and RASSF6 as prognostic biomarkers in melanoma. Besides the prognostic roles of these proteins, they are probably potential candidates for target-oriented therapies for melanoma metastasis blocking.

BAP1 deletion abrogates growth and metastasis of murine cutaneous melanoma.

Although germline mutations in BRCA-associated protein-1 (BAP1) predispose to cutaneous melanoma (CM), BAP1 is rarely mutated in primary CM outside the familial context. The role of BAP1 in the pathogenesis of CM remains obscure. Here, we discovered an unexpected role of BAP1 in suppressing CM growth and metastasis. BAP1 deletion by CRISPR-Cas9 system severely compromises colony-forming capability of murine CM cell line B16-F10 and human CM cell lines, SK-MEL-28 and A375. Furthermore, BAP1 loss abrogates tumor growth and lung metastasis in murine syngeneic tumor models. Deletion of BAP1 in B16-F10 cells leads to preferential downregulation of genes accompanied with increased H2A ubiquitination at lysine 119. Transcriptomic characterization of BAP1 deletion reveals multiple deregulated cellular functions including extracellular matrix-receptor interaction and MAPK signaling pathway which may contribute to BAP1's effect on metastasis and proliferation. Our findings indicate that BAP1 could be a potential therapeutic target for CM.

Comprehensive analysis of cutaneous and uveal melanoma liver metastases

BackgroundThe profound disparity in response to immune checkpoint blockade (ICB) by cutaneous melanoma (CM) and uveal melanoma (UM) patients is not well understood. Therefore, we characterized metastases of CM and...

16613 PD-1, PD-L1, and BIM as predictors of sentinel lymph node metastasis in primary cutaneous melanoma

Here we tested whether the expression of the immune checkpoint program cell death protein 1 (PD-1), its ligand PD-L1, or its downstream effector Bcl-2 interacting mediator of cell death (BIM) in primary cutaneous melanoma (PCM) diagnostic biopsy tissue is associated with PCM metastasis to sentinel lymph nodes (SLN). We obtained a cohort of 754 patients with thin and intermediate thickness PCM who underwent SLN biopsy within 90 days of diagnosis. We then used real-time quantitative PCR to quantify gene expression in diagnostic biopsy tissue. We found that the expression of BIM but not PD-1 or PD-L1 was significantly associated with SLN metastasis (P = .004). The absence of a significant association between PD-1 and PD-L1 expression in PCM diagnostic biopsy tissue and SLN metastasis was confirmed by immunohistochemistry in a cohort subset. Predictive models that considered the clinicopathologic variables Breslow depth and age were not significantly improved by adding the gene expression variables BIM, PD-1, or PD-L1. In contrast, a highly significant improvement in the predictive ability among the 754 studied patients was observed with the CP-GEP model from SkylineDx. We conclude that while the PD-1/PD-L1 immune checkpoint drives immune tolerance and disease progression its global expression in PCM diagnostic biopsy tissue is not associated with regional metastasis.

Dissecting the Lymphatic System to Predict Melanoma Metastasis

Melanoma is the most lethal form of skin cancer in the United States. Current American Joint Committee on Cancer (AJCC) staging uses Breslow depth and ulceration as the two primary tumor factors that predict metastatic risk in cutaneous melanoma. Early disease stages are generally associated with high survival rates. However, in some cases, patients with thin melanomas develop advanced disease, suggesting other factors may contribute to the metastatic potential of an individual patient’s melanoma. This review focuses on the role of the lymphatic system in the metastasis of cutaneous melanoma, from recent discoveries in mechanisms of lymphangiogenesis to elements of the lymphatic system that ultimately may aid clinicians in determining which patients are at highest risk. Ultimately, this review highlights the need to integrate pathological, morphological, and molecular characteristics of lymphatics into a “biomarker” for metastatic potential.

Comprehensive analysis and identification of key genes and signaling pathways in the occurrence and metastasis of cutaneous melanoma.

BackgroundMelanoma is a malignant tumor of melanocytes, and the incidence has increased faster than any other cancer over the past half century. Most primary melanoma can be cured by local excision, but metastatic melanoma has a poor prognosis. Cutaneous melanoma (CM) is prone to metastasis, so the research on the mechanism of melanoma occurrence and metastasis will be beneficial to diagnose early, improve treatment, and prolong life survival. In this study, we compared the gene expression of normal skin (N), primary cutaneous melanoma (PM) and metastatic cutaneous melanoma (MM) in the Gene Expression Omnibus (GEO) database. Then we identified the key genes and molecular pathways that may be involved in the development and metastasis of cutaneous melanoma, thus to discover potential markers or therapeutic targets.MethodsThree gene expression profiles (GSE7553, GSE15605 and GSE46517) were downloaded from the GEO database, which contained 225 tissue samples. R software identified the differentially expressed genes (DEGs) between pairs of N, PM and MM samples in the three sets of data. Subsequently, we analyzed the gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway of the DEGs, and constructed a protein-protein interaction (PPI) network. MCODE was used to seek the most important modules in PPI network, and then the GO function and KEGG pathway of them were analyzed. Finally, the hub genes were calculated by the cytoHubba in Cytoscape software. The Cancer Genome Atlas (TCGA) data were analyzed using UALCAN and GEPIA to validate the hub genes and analyze the prognosis of patients.ResultsA total of 134, 317 and 147 DEGs were identified between N, PM and MM in pair. GO functions and KEGG pathways analysis results showed that the upregulated DEGs mainly concentrated in cell division, spindle microtubule, protein kinase activity and the pathway of transcriptional misregulation in cancer. The downregulated DEGs occurred in epidermis development, extracellular exosome, structural molecule activity, metabolic pathways and p53 signaling pathway. The PPI network obtained the most important module, whose GO function and KEGG pathway were enriched in oxidoreductase activity, cell division, cell exosomes, protein binding, structural molecule activity, and metabolic pathways. 14, 18 and 18 DEGs were identified respectively as the hub genes between N, PM and MM, and TCGA data confirmed the expression differences of hub genes. In addition, the overall survival curve of hub genes showed that the differences in these genes may lead to a significant decrease in overall survival of melanoma patients.ConclusionsIn this study, several hub genes were found from normal skin, primary melanoma and metastatic melanoma samples. These hub genes may play an important role in the production, invasion, recurrence or death of CM, and may provide new ideas and potential targets for its diagnosis or treatment.

A Novel Nomogram and Risk Classification System Predicting the Cancer-Specific Mortality of Patients with Initially Diagnosed Metastatic Cutaneous Melanoma.

Cutaneous melanoma and distant organ metastasis has varying outcomes. Considering all prognostic indicators in a prediction model might assist in selecting cases who could benefit from a personalized therapy strategy. This study aimed to develop and validate a prognostic model for patients with metastatic melanoma. A total of 1535 cases diagnosed with metastatic cutaneous melanoma (stage IV) were identified from the Surveillance, Epidemiology, and End Results database. Patients were randomly divided into the training (n = 1023) and validation (n = 512) cohorts. A prognostic nomogram was established based predominantly on results from the competing-risk regression model for predicting cancer-specific death (CSD). The area under the time-dependent receiver operating characteristic curve (AUC), calibration curves, and decision curve analyses (DCAs) were used to evaluate the nomogram. No significant differences were observed in the clinical characteristics between the training and validation cohorts. In the training cohort, patient-, tumor-, and treatment-related predictors of CSD for metastatic melanoma included age, sex, race, marital status, insurance, American Joint Committee on Cancer T and N stage, number of metastatic organs, surgical treatment, and chemotherapy. All these factors were used for nomogram construction. The time-dependent AUC values of the training and validation cohorts suggested a favorable performance and discrimination of the nomogram. The 6-, 12-, and 18-month AUC values were 0.706, 0.700, and 0.706 in the training cohort, and 0.702, 0.670, and 0.656 in the validation cohort, respectively. The calibration curves for the probability of death at 6, 12, and 18months showed acceptable agreement between the values predicted by the nomogram and the observed outcomes in both cohorts. DCA curves showed good positive net benefits in the prognostic model among most of the threshold probabilities at different time points (death at 6, 12, and 18months). Based on the total nomogram scores of each case, all patients were divided into the low-risk (n = 511), intermediate-risk (n = 512), and high-risk (n = 512) groups, and the risk classification could identify cases with a high risk of death in both cohorts. A predictive nomogram and a corresponding risk classification system for CSD in patients with metastatic melanoma were developed in this study, which may assist in patient counseling and in guiding clinical decision making for cases with metastatic melanoma.

Validation of a clinicopathological and gene expression profile model for sentinel lymph node metastasis in primary cutaneous melanoma.

SummaryBackgroundThe Clinicopathological and Gene Expression Profile (CP‐GEP) model was developed to accurately identify patients with T1–T3 primary cutaneous melanoma at low risk for nodal metastasis.ObjectivesTo validate the CP‐GEP model in an independent Dutch cohort of patients with melanoma.MethodsPatients (aged ≥ 18 years) with primary cutaneous melanoma who underwent sentinel lymph node biopsy (SLNB) between 2007 and 2017 at the Erasmus Medical Centre Cancer Institute were eligible. The CP‐GEP model combines clinicopathological features (age and Breslow thickness) with the expression of eight target genes involved in melanoma metastasis (ITGB3, PLAT, SERPINE2, GDF15, TGFBR1, LOXL4, CXCL8 and MLANA). Using the pathology result of SLNB as the gold standard, performance measures of the CP‐GEP model were calculated, resulting in CP‐GEP high risk or low risk for nodal metastasis.ResultsIn total, 210 patients were included in the study. Most patients presented with T2 (n = 94, 45%) or T3 (n = 70, 33%) melanoma. Of all patients, 27% (n = 56) had a positive SLNB, with nodal metastasis in 0%, 30%, 54% and 16% of patients with T1, T2, T3 and T4 melanoma, respectively. Overall, the CP‐GEP model had a negative predictive value (NPV) of 90·5% [95% confidence interval (CI) 77·9–96.2], with an NPV of 100% (95% CI 72·2–100) in T1, 89·3% (95% CI 72·8–96·3) in T2 and 75·0% (95% CI 30·1–95·4) in T3 melanomas. The CP‐GEP indicated high risk in all T4 melanomas.ConclusionsThe CP‐GEP model is a noninvasive and validated tool that accurately identified patients with primary cutaneous melanoma at low risk for nodal metastasis. In this validation cohort, the CP‐GEP model has shown the potential to reduce SLNB procedures in patients with melanoma.

S2953 Rare Metastatic Gastric Melanoma Causing Iron Deficiency Anemia

INTRODUCTION: Melanoma is the fifth most common cancer in males and sixth most common cancer in females in the United States and accounts for about 1% of all skin cancers. Melanoma is highly metastatic. The most common sites of metastasis are liver, bone and brain and rarely, the gastrointestinal (GI) tract. Within the GI tract, melanomas usually metastasize to the small intestine, followed by colon, rectum and stomach in that order. Here, we present a case of cutaneous melanoma metastatic to the stomach presenting as iron deficiency anemia. CASE DESCRIPTION/METHODS: A 74-year-old Caucasian male presented with progressive fatigue and generalized weakness due to iron deficiency anemia. He had a history of various skin cancers including cutaneous melanoma involving the scalp for which he had undergone Mohs micrographic surgery with adjuvant chemoradiation two years prior. Complete blood count showed a hemoglobin of 6.7 g/dl, MCV 83.8 fL, iron of 58 ug/dL, iron saturations of 4%, and ferritin of 18 ng/mL. An esophagogastroduodenoscopy (EGD) showed at least five, 10 to 15mm, umbilicated lesions, with central dark pigmentation within the antrum, body and fundus of the stomach. Biopsies revealed metastatic melanoma. A computed tomography of the chest, abdomen and pelvis revealed evidence of additional metastases involving bilateral lungs, liver and multiple lymph nodes within the abdomen and pelvis. He was treated with ipilimumab and novilumab as immunotherapy. DISCUSSION: Metastasis of cutaneous melanoma to stomach accounts for less than 5% of all gastrointestinal metastatic melanoma. In a case series of such patients, the median time from initial diagnosis of cutaneous melanoma to gastric metastasis was 2 years. Gastric metastatic melanoma can present with upper GI symptoms, iron deficiency anemia, and frank GI bleeding. Nodules with central umbilication, pigmentation and ulceration, described as “doughnut” or “bull’s eye” appearance is the most common endoscopic finding. Immunohistochemistry of biopsies show homogenous staining for S-100, MART1 and HMB45 proteins. Genetic analysis for BRAF V600 and NRAS mutations guides appropriate treatment with immunotherapy approved for the former. For those with NRAS mutations, gastric resection with adjuvant chemotherapy is required for treatment and palliation.Figure 1.: Multiple, 10 to 15mm, umbilicated lesions, with central dark pigmentation within the antrum, body and fundus of the stomach.Figure 2.: Rare endoscopic finding of metastatic melanoma to the stomach with a lesion with central umbilication, dark pigmentation and ulceration often described as “doughnut” or “bull's eye” appearance.

Vaginal and endometrial metastasis of primary cutaneous malignant melanoma

Vaginal and endometrial metastasis of primary cutaneous malignant melanoma

β3 integrin immunohistochemistry as a method to predict sentinel lymph node status in patients with primary cutaneous melanoma.

Integrins are heterodimeric proteins composed of noncovalently linked ɑ and β subunits which are essential for a wide range of normal physiology and also play prominent roles in cancer. Here we tested whether integrin expression in diagnostic skin biopsies is associated with sentinel lymph node (SLN) metastasis. We utilized a cohort of 854 consecutive patients with primary cutaneous melanoma to quantify the expression of β integrin subunits by reverse transcriptase quantitative PCR (RT-qPCR). In addition, we quantified the expression of β3 integrin by immunohistochemistry (IHC) in a subset of 271 patients by H score. Outcome of interest was SLN biopsy metastasis within 90days of melanoma diagnosis. Logistic regression analyses were used to develop models for the likelihood of SLN metastasis from molecular, clinical, and histologic variables. β3 integrin expression quantified by IHC or RT-qPCR was associated with SLN metastasis. β1, β5, β6, and β8 integrin expression was not associated with SLN metastasis. The incremental gain in performance of a predictive model which included β3 integrin expression as quantified by IHC in combination with established clinicopathologic variables (Breslow depth and patient age) was limited. β3 integrin is the principal integrin subunit associated with sentinel lymph node biopsy (SLNb) metastasis in primary cutaneous melanoma. However, β3 integrin H score does not significantly improve models for the likelihood of SLN metastasis over Breslow depth and patient age.

Изолированный метастаз кожной меланомы лобковой области в веко

Изолированный метастаз кожной меланомы лобковой области в веко

Distinguishing Tumor and Stromal Sources of MicroRNAs Linked to Metastasis in Cutaneous Melanoma

MicroRNA (miRNA) dysregulation in cancer causes changes in gene expression programs regulating tumor progression and metastasis. Candidate metastasis suppressor miRNA are often identified by differential expression in primary tumors compared to metastases. Here, we performed comprehensive analysis of miRNA expression in The Cancer Genome Atlas (TCGA) skin cutaneous melanoma (SKCM) tumors (97 primary, 350 metastatic), and identified candidate metastasis-suppressor miRNAs. Differential expression analysis revealed miRNA significantly downregulated in metastatic tumors, including miR-205, miR-203, miR-200a-c, and miR-141. Furthermore, sequential feature selection and classification analysis identified miR-205 and miR-203 as the miRNA best able to discriminate between primary and metastatic tumors. However, cell-type enrichment analysis revealed that gene expression signatures for epithelial cells, including keratinocytes and sebocytes, were present in primary tumors and significantly correlated with expression of the candidate metastasis-suppressor miRNA. Examination of miRNA expression in cell lines revealed that candidate metastasis-suppressor miRNA identified in the SKCM tumors, were largely absent in melanoma cells or melanocytes, and highly restricted to keratinocytes and other epithelial cell types. Indeed, the differences in stromal cell composition between primary and metastatic tumor tissues is the main basis for identification of differential miRNA that were previously classified as metastasis-suppressor miRNAs. We conclude that future studies must consider tumor-intrinsic and stromal sources of miRNA in their workflow to identify bone fide metastasis-suppressor miRNA in cutaneous melanoma and other cancers.

PD-1, PD-L1, and BIM as Predictors of Sentinel Lymph Node Metastasis in Primary Cutaneous Melanoma

PD-1, PD-L1, and BIM as Predictors of Sentinel Lymph Node Metastasis in Primary Cutaneous Melanoma

Transcriptomic identification of miR-205 target genes potentially involved in metastasis and survival of cutaneous malignant melanoma

Cutaneous melanoma is an aggressive neoplasm and is responsible for the majority of skin cancer deaths. Several miRNAs are involved in melanoma tumor progression. One of them is miR-205, the loss of which contributes to the development of melanoma metastasis. We evaluated whole-genome mRNA expression profiling associated with different miR-205 expression levels in melanoma cells. Differential expression analysis identified 243 differentially expressed transcripts including inositol polyphosphate 5′-phosphatase-like protein-1 (INPPL1) and BTB/POZ Domain-Containing Protein 3 (BTBD3). INPPL1 and BTBD3 were downregulated when melanoma cells expressed miR-205, indicating that these genes are potential miR-205 targets. Additionally, the target prediction algorithm TargetScan revealed that INPPL1 and BTBD3 genes had predicted target sites of miR-205 in their 3′UTRs and functional analysis demonstrated that these genes were directly linked to miR-205. Interestingly, our clinical data showed that INPPL1 was significantly associated with lymph node metastasis-free survival (LNMFS), distant metastasis-free survival (DMFS) and melanoma specific survival (MSS). This study supports INPPL1 as a miR-205 target gene and, therefore, that the involvement of miR-205 in the metastatic dissemination of malignant melanoma is, at least in part, via INPPL1.

Abject health concern in elderly: Cutaneous metastasis of malignant melanoma of anal canal.

Abject health concern in elderly: Cutaneous metastasis of malignant melanoma of anal canal.

Prediction and Analysis of Skin Cancer Progression using Genomics Profiles of Patients

The metastatic Skin Cutaneous Melanoma (SKCM) has been associated with diminished survival rates and high mortality rates worldwide. Thus, segregating metastatic melanoma from the primary tumors is crucial to employ an optimal therapeutic strategy for the prolonged survival of patients. The SKCM mRNA, miRNA and methylation data of TCGA is comprehensively analysed to recognize key genomic features that can segregate metastatic and primary tumors. Further, machine learning models have been developed using selected features to distinguish the same. The Support Vector Classification with Weight (SVC-W) model developed using the expression of 17 mRNAs achieved Area under the Receiver Operating Characteristic (AUROC) curve of 0.95 and an accuracy of 89.47% on an independent validation dataset. This study reveals the genes C7, MMP3, KRT14, LOC642587, CASP7, S100A7 and miRNAs hsa-mir-205 and hsa-mir-203b as the key genomic features that may substantially contribute to the oncogenesis of melanoma. Our study also proposes genes ESM1, NFATC3, C7orf4, CDK14, ZNF827, and ZSWIM7 as novel putative markers for cutaneous melanoma metastasis. The major prediction models and analysis modules to predict metastatic and primary tumor samples of SKCM are available from a webserver, CancerSPP (http://webs.iiitd.edu.in/raghava/cancerspp/).

Kinesin family member 18B: A contributor and facilitator in the proliferation and metastasis of cutaneous melanoma.

Melanoma is the most aggressive type of cutaneous tumor and the occurrence of metastasis makes it resistant to almost all available treatment and becomes incorrigible. Hence, identifying metastasis-related biomarkers and effective therapeutic targets will assist in preventing metastasis and ameliorating cutaneous melanoma. In our present study, we reported kinesin family member 18B (KIF18B) as a novel contributor in cutaneous melanoma proliferation and metastasis, and it was found to be of great significance in predicting the prognosis of cutaneous melanoma patients. Bioinformatics analysis based on ONCOMINE, The Cancer Genome Atlas, and Genotype-Tissue Expression database revealed that KIF18B was highly expressed in cutaneous melanoma and remarkably correlated with unfavorable clinical outcomes. Consistently, the results of the quantitative real-time polymerase chain reaction exhibited that the expression of KIF18B was significantly higher in cutaneous melanoma cell lines than that in normal cells. In vitro, biological assays found that knockdown of KIF18B in cutaneous melanoma cells noticeably repressed cell proliferation, migration, and invasion, while inducing cell apoptosis. Moreover, the protein expression of E-cadherin was enhanced while the expression of N-cadherin, vimentin, and Snail was decreased in M14 cells after knocking down KIF18B. In addition, the phosphorylation of phosphoinositide 3-kinase (PI3K) and extracellular-signal-regulated kinase (ERK) was significantly suppressed in M14 cells with silenced KIF18B. Above all, our results indicated that the repression of cutaneous melanoma cell migration and proliferation caused by KIF18B depletion suggested an oncogenic role of KIF18B in cutaneous melanoma, which acts through modulating epithelial-mesenchymal transition and ERK/PI3K pathway.

1325P - Validation of a clinicopathological and gene expression profile (CP-GEP) model for sentinel lymph node metastasis in primary cutaneous melanoma

BackgroundAs primary cutaneous melanoma patients with a positive sentinel lymph node (SLN, stage III) are now considered candidates for adjuvant systemic therapy, a SLN biopsy (SLNB) is indicated in more patients. However, SLNB is an invasive procedure and is negative in approximately 80% of patients. Therefore, there is a need for a non-invasive test to accurately identify patients with primary cutaneous melanoma without nodal metastases. Here we describe the first independent validation of a recently developed CP-GEP model to predict nodal metastasis. This risk model combines Breslow thickness, age, and gene expression variables from the primary melanoma. MethodsThis study focused on all patients >18 years who underwent a SLNB at the Erasmus Medical Center (between January 2007 and December 2017), within 90 days after diagnosis of primary cutaneous melanoma. Total RNA was extracted from formalin-fixed paraffin-embedded (FFPE) primary cutaneous melanomas, reversed transcribed into cDNA and subsequently analyzed for the expression of 8 target genes involved in melanoma metastasis (ITGB3, PLAT, SERPINE2, GDF15, TGFBR1, LOXL4, IL8, MLANA) using an optimized qPCR protocol. ResultsFFPE tissue samples from 211 patients were analyzed using the CP-GEP model. At diagnosis, the median age was 55 years (interquartile range [IQR] 45-65), and the median Breslow thickness was 2.1mm (IQR 1.4-3.4). Most patients presented with a T2 or T3 melanoma, accounting for 94 and 70 patients, respectively. Overall, 27.5% of patients had a positive SLN. The CP-GEP model had a negative predictive value (NPV) of 89.4%. In patients with stage T1-T2 melanoma, the model was able to achieve an SLNB reduction rate of 40.1% with an NPV of 90.7%. ConclusionsThe CP-GEP model is a non-invasive and validated tool that is able to predict nodal metastasis in an independent Dutch population. Consequently, this risk model is able to accurately identify patients with primary cutaneous melanoma that can safely forego SLNB. Therefore, the CP-GEP model is a promising tool for patient care, preventing unnecessary surgery in the majority of patients. Legal entity responsible for the studyErasmus University Medical Center, Department of Dermatology. FundingSkylineDx. DisclosureJ.T. Dwarkasing: Shareholder / Stockholder / Stock options, Full / Part-time employment: SkylineDx BV. D. Tempel: Shareholder / Stockholder / Stock options, Full / Part-time employment: SkylineDx BV. L. Bosman: Shareholder / Stockholder / Stock options, Full / Part-time employment: SkylineDx. A.A.M. Van der Veldt: Advisory / Consultancy: BMS; Advisory / Consultancy: MSD; Advisory / Consultancy: Roche; Advisory / Consultancy: Novartis; Advisory / Consultancy: Pierre Fabre; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Ipsen. All other authors have declared no conflicts of interest.