Blood Plasma Metabolomics to Support Uveal Melanoma Diagnosis

Importance Uveal Melanomas (UM) micro-metastasis can be present prior to diagnosis and relapse after treatment. Earlier detection resulted in an increased incidence of small (T1 and T2) tumors allowing for novel eye-preserving treatment strategies but reducing available tumor tissue needed for prognostic genomic profiling, creating the need for minimal-invasive detection and novel prognostication methods. Objective To determine whether tumor presence can be confirmed using metabolite patterns in blood plasma and to evaluate if these patterns differ between high risk (BRCA1-associated protein-1, BAP1 ), intermediate risk (Splicing Factor 3b Subunit 1, SF3B1 ) and low risk (Eukaryotic Translation Initiation Factor 1A X-Linked, EIF1AX ) mutated tumors. Design Retrospective observational study including discovery (n=53) and replication (n=42) convenience sample sets compared to unaffected control-participants (n=46) as well as across mutation-based subgroups. Setting Patients from two tertiary referral centers specialized in ocular oncology: The Rotterdam Eye Hospital and the Erasmus MC Cancer Institute were included. Participants Sex-matched controls and patients were included based on their prognostic relevant secondary driver mutations. Peripheral blood plasma was collected at diagnosis, prior to treatment. Exclusion criteria were the presence of other malignancies or co-occurrence of systemic diseases at time of diagnosis. Main outcome and measure Metabolite profiles of patients and control-participants were generated as mass/charge (m/z) features using ultra-high performance liquid chromatography mass-spectrometry. After normalization, discriminatory feature patterns were determined using a random forest classifier and leave-one-out cross-validation. Results We detected differential metabolic patterns with a sensitivity of 0.95 and 0.90 and a specificity of 0.98 and 0.98 in the positive and negative ion modes, respectively. The accuracy of the model for classifying the subgroups was insufficient for the discovery (0.600 and 0.614 in the positive and negative ion modes, respectively) and replication cohort (0.544 and 0.672 in the positive and negative ion modes, respectively). Conclusion and relevance Minimally invasive metabolomics does not discriminate between the prognostic relevant BAP1, SF3B1 and EIF1AX mutated UM-subgroups. However, this technique has the potential to allow for minimal invasive screening as it distinguishes metabolite patterns in peripheral blood derived plasma of UM-patients from control-participants. Question Can we discriminate uveal melanoma patients and mutation subgroups from unaffected control-participants using the metabolome of peripheral blood plasma taken at time of diagnosis? Findings In this retrospective observational study, we find a low sensitivity and specificity to detect subgroups but a high sensitivity and specificity to discriminate patients from control-participants by measuring metabolite abundancy in plasma using ultra-high performance liquid chromatography mass-spectrometry and reach a receiver operating characteristic area under the curve of 0.993. Meaning These results suggest that surveying the metabolome of uveal melanoma patients could aid in the minimal invasive detection of uveal melanoma. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by CORR (Combined Ophthalmic Research Rotterdam) and the BAYER Ophthalmology research award. The Combined Ophthalmic Research Rotterdam Biobank of the Department of Ophthalmology and the Rotterdam Eye Hospital is supported by the Combined Ophthalmic Research Rotterdam Foundation. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Medical Ethics Committee of Erasmus MC gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors