Purpose Brain metastasis is the major cause of mortality among melanoma patients. A molecular prognostic test that can reliably stratify patients at initial melanoma diagnosis by risk of developing brain metastasis may inform the clinical management of these patients. Experimental Design We performed a retrospective, cohort-based study analyzing genome-wide and targeted microRNA expression profiling of primary melanoma tumors of three patient cohorts (n= 92, n= 119, n= 45) with extensive clinical follow up. We used Cox regression analysis to establish a microRNA-based signature that improves the ability of the current clinicopathologic staging system to predict the development of brain metastasis. Results Our analyses identified a 4-microRNA (miR-150–5p, miR-15b-5p, miR-16–5p, and miR-374b-3p) prognostic signature that, in combination with stage, distinguished primary melanomas that metastasized to the brain from non-recurrent and non-brain-metastatic primary tumors (training cohort: C-index=81.4%, validation cohort: C-index=67.4%, independent cohort: C-index=76.9%). Corresponding Kaplan-Meier curves of high- vs. low-risk patients displayed a clear separation in brain-metastasis-free and overall survival (training: p<0.001, p<0.001, validation: p=0.033, p=0.007, independent: p=0.021, p=0.022, respectively). Finally, of the microRNA in the prognostic model, we found that the expression of a key lymphocyte miRNA, miR-150–5p, which is less abundant in primary melanomas metastatic to brain, correlated with presence of CD45+ tumor infiltrating lymphocytes. Conclusions A prognostic assay based on the described miRNA expression signature combined with the currently used staging criteria may improve accuracy of primary melanoma patient prognoses and aid clinical management of patients, including selection for adjuvant treatment or clinical trials of adjuvant therapies.

Objective In order to better identify melanoma patients who are, at the time of primary melanoma diagnosis, at high risk of developing brain metastases, primary melanoma characteristics were examined as risk factors for brain metastasis development. Methods In a study of two patient cohorts, clinicopathological characteristics prospectively collected at primary cutaneous melanoma diagnosis for patients with/without brain metastasis were assessed in univariate and multivariate analyses using data from two prospectively-collected databases: Melanoma Cooperative Group (MCG) (1972–1982), and Interdisciplinary Melanoma Cooperative Group (IMCG) (2002–2009). Candidate risk factors were evaluated in association with time to brain metastasis via either the log-rank test or Cox proportional hazards regression analysis with/without considering competing risks. Results Out of 2341 total patients included in the study, 222 (9.5%) developed brain metastases (median follow-up: 98 months). The median time to brain metastases was 30.5 months, and the median survival time after brain metastases was 4 months. Increased hazard ratios (HR) for brain metastasis were found among thicker (logarithmic value in mm) (MCG – HR=1.97, P<0.0001; IMCG – HR=1.31, P=0.018), ulcerated (MCG –HR=1.93, P=0.01; IMCG – HR=3.14, P<0.0001), and advanced-stage (MCG – HR=2.08, P=0.008; IMCG – HR=2.56, P=0.0002) primary melanomas based on multivariate Cox regression analysis assuming the presence of competing risks. Conclusions Primary cutaneous melanoma thickness, ulceration, and stage were identified and validated as risk factors associated with time to melanoma brain metastasis.

Melanoma brain metastasis that develops as the isolated first visceral site challenges the current paradigm of tumor progression in which brain metastasis is regarded as the final stage. Here we test the hypothesis that melanoma patients who develop brain metastasis as the isolated first visceral site have distinct clinicopathological features at the time of primary melanoma diagnosis. Cutaneous melanoma patients enrolled in 2 prospectively collected databases were studied (Cohort 1: 1972-1982, Cohort 2: 2002-2009). Patients who developed brain metastasis as isolated first visceral site were compared with (1) all other patients, (2) patients who developed visceral metastasis: extracranial only or extracranial and brain, and (3) patients who progressed to other isolated visceral sites first. Two hundred seven of 2280 (9.1%) patients developed brain metastasis (median follow-up, 5.2 y). Seventy-four of 207 (35.7%) brain metastasis patients progressed to brain metastasis as the isolated first visceral site. These patients presented with primaries that were thinner and had no mitosis compared with all other visceral metastasis patients (Fisher's combined P = .02, .05, respectively), and there was a significant difference in American Joint Committee on Cancer stage distribution at initial melanoma diagnosis (combined P = .02). Post-visceral metastasis survival, however, was shorter in patients with brain metastasis as isolated first visceral site than in patients with visceral metastasis: extracranial and brain (combined P = .03). Brain metastasis as isolated first visceral site is a distinct clinicopathological entity. Studies are needed to better understand the biological factors driving this phenotype at the time of primary melanoma diagnosis and to determine its clinical implications.

<div>Abstract<p><b>Purpose:</b> Brain metastasis is the major cause of mortality among patients with melanoma. A molecular prognostic test that can reliably stratify patients at initial melanoma diagnosis by risk of developing brain metastasis may inform the clinical management of these patients.</p><p><b>Experimental Design:</b> We performed a retrospective, cohort-based study analyzing genome-wide and targeted microRNA expression profiling of primary melanoma tumors of three patient cohorts (<i>n</i> = 92, 119, and 45) with extensive clinical follow-up. We used Cox regression analysis to establish a microRNA-based signature that improves the ability of the current clinicopathologic staging system to predict the development of brain metastasis.</p><p><b>Results:</b> Our analyses identified a 4-microRNA (<i>miR-150-5p</i>, <i>miR-15b-5p</i>, <i>miR-16-5p</i>, and <i>miR-374b-3p)</i> prognostic signature that, in combination with stage, distinguished primary melanomas that metastasized to the brain from nonrecurrent and non–brain metastatic primary tumors (training cohort: C-index = 81.4%, validation cohort: C-index = 67.4%, independent cohort: C-index = 76.9%). Corresponding Kaplan–Meier curves of high- versus low-risk patients displayed a clear separation in brain metastasis-free and overall survival (training: <i>P</i> < 0.001; <i>P</i> < 0.001, validation: <i>P</i> = 0.033; <i>P</i> = 0.007, independent: <i>P</i> = 0.021; <i>P</i> = 0.022, respectively). Finally, of the microRNA in the prognostic model, we found that the expression of a key lymphocyte miRNA, <i>miR-150-5p</i>, which is less abundant in primary melanomas metastatic to brain, correlated with presence of CD45⁺ tumor-infiltrating lymphocytes.</p><p><b>Conclusions:</b> A prognostic assay based on the described miRNA expression signature combined with the currently used staging criteria may improve accuracy of primary melanoma patient prognoses and aid clinical management of patients, including selection for adjuvant treatment or clinical trials of adjuvant therapies. <i>Clin Cancer Res; 21(21); 4903–12. ©2015 AACR</i>.</p></div>

<div>Abstract<p><b>Purpose:</b> Brain metastasis is the major cause of mortality among patients with melanoma. A molecular prognostic test that can reliably stratify patients at initial melanoma diagnosis by risk of developing brain metastasis may inform the clinical management of these patients.</p><p><b>Experimental Design:</b> We performed a retrospective, cohort-based study analyzing genome-wide and targeted microRNA expression profiling of primary melanoma tumors of three patient cohorts (<i>n</i> = 92, 119, and 45) with extensive clinical follow-up. We used Cox regression analysis to establish a microRNA-based signature that improves the ability of the current clinicopathologic staging system to predict the development of brain metastasis.</p><p><b>Results:</b> Our analyses identified a 4-microRNA (<i>miR-150-5p</i>, <i>miR-15b-5p</i>, <i>miR-16-5p</i>, and <i>miR-374b-3p)</i> prognostic signature that, in combination with stage, distinguished primary melanomas that metastasized to the brain from nonrecurrent and non–brain metastatic primary tumors (training cohort: C-index = 81.4%, validation cohort: C-index = 67.4%, independent cohort: C-index = 76.9%). Corresponding Kaplan–Meier curves of high- versus low-risk patients displayed a clear separation in brain metastasis-free and overall survival (training: <i>P</i> < 0.001; <i>P</i> < 0.001, validation: <i>P</i> = 0.033; <i>P</i> = 0.007, independent: <i>P</i> = 0.021; <i>P</i> = 0.022, respectively). Finally, of the microRNA in the prognostic model, we found that the expression of a key lymphocyte miRNA, <i>miR-150-5p</i>, which is less abundant in primary melanomas metastatic to brain, correlated with presence of CD45⁺ tumor-infiltrating lymphocytes.</p><p><b>Conclusions:</b> A prognostic assay based on the described miRNA expression signature combined with the currently used staging criteria may improve accuracy of primary melanoma patient prognoses and aid clinical management of patients, including selection for adjuvant treatment or clinical trials of adjuvant therapies. <i>Clin Cancer Res; 21(21); 4903–12. ©2015 AACR</i>.</p></div>

<p>Supplementary Figure S1. This figure depicts in waterfall plots the individual patient risk scores derived from the miRNA signature + stage prognostic model.</p>

<p>Supplementary Figure S2. This figure depicts brain metastatsis-free and overall survival, as plotted kaplan-meier survival curves, of high- vs low-risk patients (determined by the miRNA signature + stage model) for patients stratified by stage at diagnosis.</p>

<p>Supplemental methods, legends, and tables. This file contains supplemental methods for the sensitivity analyses performed to test the robustness of the miRNA model and RT-qPCR quality control. It also contains four supplemental tables (described below) and supplemental figure legends TableS1 - Hazard ratios of miRNA signature TableS2 - Odds ratios of logistic regression-derived miRNA signature TableS3 - Performance metrics of miRNA signature in each cohort TableS4 - Performance of miRNA signature within individual stages.</p>