Clin Chem Lab Med 2019; aop Letter to the Editor Sok-Ja Janket, Leland K. Ackerson and Eleftherios P. Diamandis* Potential risks in fecal microbiota transplantation https://doi.org/10.1515/cclm-2019-1076 Received October 17, 2019; accepted November 13, 2019 Keywords: fecal microbiota; live bacteria; microbiota transplatation; tumor growth. To the Editor, Several researchers presented preliminary data at the 2019 American Association for Cancer Research (AACR) Annual Conference, showing tumor growth arrest or shrinkage in some patients after fecal microbiota transplantation (FMT). Recently, however, two patients who received FMT developed severe infections due to multi-drug resistant organisms and one has died. Now, the USA Food and Drug Administration (FDA) requires more careful screening of donor stool. We welcome the FDA’s action on this matter. In our previous commentary, we stated that diverse gut microbiome in its totality could enhance immunity, but supplementing a few live bacteria or FMT could pose a risk [1]. This is especially true in immunocompromised individuals such as persons undergoing cancer treatment. The adverse events associated with FMT include bacte- remia, sepsis and multi-organ failure [1]. Furthermore, infection-derived pathologies such as autoimmune dis- eases including Sjogren’s syndrome, idiopathic throm- bocytopenic purpura [2], pneumonia, heart failure and complete heart block were reported [3]. Additionally, FMT effects on gut microbiota reverted to the original composition after 3 months [4]. Until FMT safety is well established, exposing cancer patients to potentially infectious material should be postponed. The British Society for Microbiology has recently published relevant guidelines [5]. A safer strategy is reconstituting the gut microbiome through dietary intervention [6], or wait until ongoing controlled clinical trials comparing dif- ferent therapeutic approaches are reported. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission. Research funding: None declared. Employment or leadership: None declared. Honorarium: None declared. Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication. References 1. Janket SJ, Ackerson LK, Diamandis EP. Gut microbiotas and immune checkpoint inhibitor therapy response: a causal or coin- cidental relationship? Clin Chem Lab Med 2019:31527292. 2. Kao D, Roach B, Silva M, Beck P, Rioux K, Kaplan GG, et al. Efect of oral capsule- vs colonoscopy-delivered fecal microbiota trans- plantation on recurrent clostridium difcile infection: a rand- omized clinical trial. J Am Med Assoc 2017;318:1985–93. 3. Brandt LJ, Aroniadis OC, Mellow M, Kanatzar A, Kelly C, Park T, et al. Long-term follow-up of colonoscopic fecal microbiota trans- plant for recurrent Clostridium difcile infection. Am J Gastroen- terol 2012;107:1079–87. 4. Nieuwdorp M, Vrieze A, de Vos WM. Reply to Konstantinov and Peppelenbosch. Gastroenterology 2013;144:e20–1.23499287. 5. Mullish BH, Quraishi MN, Segal JP, McCune VL, Baxter M, Mars- den GL, et al. The use of faecal microbiota transplant as treatment for recurrent or refractory Clostridium difcile infection and other potential indications: joint British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS) guidelines. J Hosp Infect 2018;100 Suppl 1:S1–31. 6. David LA, Maurice CF, Carmody RN, Gootenberg DB, Button JE, Wolfe BE, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature 2014;505:559–63. *Corresponding author: Eleftherios P. Diamandis, MD, PhD, FRCP(C), FRSC, Head of Clinical Biochemistry, Mount Sinai Hospital and University Health Network, 60 Murray St. Box 32, Floor 6, Rm L6-201, Toronto, ON M5T 3L9, Canada; Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; and Department of Clinical Biochemistry, University Health Network, Toronto, Ontario, Canada, Phone: +(416) 586-8443, E-mail: Eleftherios.diamandis@sinaihealthsystem.ca Sok-Ja Janket: Section of Translational Oral Medicine, Forsyth Institute, Cambridge, MA, USA Leland K. Ackerson: Department of Public Health, University of Massachusetts at Lowell, Lowell, MA, USA Brought to you by | Uppsala University Library Authenticated Download Date | 12/8/19 3:15 PM