Plasma ceramides as a sexually dimorphic biomarker of pancreatic cancer-induced cachexia

Background Cancer patients who lose weight have low treatment tolerance and poor outcomes compared to cancer patients without weight loss, termed cachexia. Despite the clear increased risk for patients, diagnosing cachexia still primarily relies on self-reported weight loss. A reliable biomarker to identify patients with cancer cachexia would be a valuable tool to improve clinical decision making and identification of patients at risk of adverse outcomes. Methods Targeted metabolomics, including panels of amino acids, tricarboxylic acids, fatty acids, acylcarnitines, and sphingolipids, were conducted on plasma samples from patients with confirmed pancreatic ductal adenocarcinoma (PDAC) with and without cachexia and control patients without cancer. Receiver Operating Characteristic (ROC) analysis was undertaken to establish if any metabolite could effectively serve as a biomarker of cachexia. Results Targeted profiling revealed that cachectic patients had decreased circulating levels of three sphingolipids compared to either non-cachectic PDAC patients or patients without cancer. The ratio of C18-ceramide to C24-ceramide (C18:C24) outperformed a number of other previously proposed biomarkers of cachexia (area under ROC = 0.810). It was notable that some biomarkers, including C18:C24, were only elevated in cachectic males. Conclusion Our findings identify C18:C24 as a potentially new biomarker of PDAC-induced cachexia that also highlight a previously unappreciated sexual dimorphism in cancer cachexia. Trial registration None. Funding Support was provided through a pilot grant from U24DK100469 from the National Institute of Diabetes and Digestive and Kidney Diseases (The Mayo Clinic), National Cancer Institute P30CA016058 (The Ohio State University), National Cancer Institute R01CA180057 (DCG), American Cancer Society PF-15-156-01-CSM (EET), and a Weiss Postdoctoral Fellowship (EET). ### Competing Interest Statement Conflict of interest: JMC, MED, CRS, PVR, TMW, and EET declare that they have no conflicts of interest. DCE declares that he has received research support and has a speaking and consulting agreement with Abbott Laboratories. DCG declares that he receives research support from Pfizer and consults for Immuneering and Catabasis. ### Clinical Trial This study is a retrospective use of a tissue bank without an intervention and thus does not have a clinical trial registration. ### Funding Statement Support was provided through a pilot grant from U24DK100469 from the National Institute of Diabetes and Digestive and Kidney Diseases (The Mayo Clinic), National Cancer Institute P30CA016058 (The Ohio State University), National Cancer Institute R01CA180057 (DCG), Funding. Support was provided through a pilot grant from U24DK100469 from the National Institute of Diabetes and Digestive and Kidney Diseases (The Mayo Clinic), National Cancer Institute P30CA016058 (The Ohio State University), National Cancer Institute R01CA180057 (DCG), American Cancer Society PF-15-156-01-CSM (EET), and a Weiss Postdoctoral Fellowship (EET). ### 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: All aspects of the study were approved by The Ohio State University Institutional Review Board. Written informed consent was obtained from each patient prior to enrollment in the tissue bank. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. 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 Requests for primary data will be considered after consultation with the involved IRBs.