title: Molecular Characteristics of High-Dose Melphalan Associated Oral Mucositis in Patients with Multiple Myeloma: A Gene Expression Study on Human Mucosa.
abstract: BACKGROUND
  Toxicity of the oral and gastrointestinal mucosa induced by high-dose melphalan is a clinical challenge with no documented prophylactic interventions or predictive tests. The aim of this study was to describe molecular changes in human oral mucosa and to identify biomarkers correlated with the grade of clinical mucositis.
  
  
  RESULTS
  Ten patients with multiple myeloma (MM) were included. For each patient, we acquired three buccal biopsies, one before, one at 2 days, and one at 20 days after high-dose melphalan administration. We also acquired buccal biopsies from 10 healthy individuals that served as controls. We analyzed the biopsies for global gene expression and performed an immunohistochemical analysis to determine HLA-DRB5 expression. We evaluated associations between clinical mucositis and gene expression profiles. Compared to gene expression levels before and 20 days after therapy, at two days after melphalan treatment, we found gene regulation in the p53 and TNF pathways (MDM2, INPPD5, TIGAR), which favored anti-apoptotic defense, and upregulation of immunoregulatory genes (TREM2, LAMP3) in mucosal dendritic cells. This upregulation was independent of clinical mucositis. HLA-DRB1 and HLA-DRB5 (surface receptors on dendritic cells) were expressed at low levels in all patients with MM, in the subgroup of patients with ulcerative mucositis (UM), and in controls; in contrast, the subgroup with low-grade mucositis (NM) displayed 5-6 fold increases in HLA-DRB1 and HLA-DRB5 expression in the first two biopsies, independent of melphalan treatment. Moreover, different splice variants of HLA-DRB1 were expressed in the UM and NM subgroups.
  
  
  CONCLUSIONS
  Our results revealed that, among patients with MM, immunoregulatory genes and genes involved in defense against apoptosis were affected immediately after melphalan administration, independent of the presence of clinical mucositis. Furthermore, our results suggested that the expression levels of HLA-DRB1 and HLA-DRB5 may serve as potential predictive biomarkers for mucositis severity.
authors.affiliation: Department of Clinical Medicine, Aalborg University, Sdr. Skovvej 15, Aalborg, Denmark.|Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Mette
authors.identifier: http://orcid.org/0000-0003-0795-2293
authors.initials: M
authors.lastname: Marcussen
authors.affiliation: Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Julie Støve
authors.initials: JS
authors.lastname: Bødker
authors.affiliation: Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Heidi Søgaard
authors.initials: HS
authors.lastname: Christensen
authors.affiliation: Department of Pathology, Aalborg University Hospital, Ladegaardsgade 3, Denmark.
authors.forename: Preben
authors.initials: P
authors.lastname: Johansen
authors.affiliation: Department of Pathology, Aalborg University Hospital, Ladegaardsgade 3, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Nielsen
authors.affiliation: Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Ilse
authors.initials: I
authors.lastname: Christiansen
authors.affiliation: School of Dentistry, Faculty of Health Science, Aarhus University; Vennelyst Boulevard 9, Aarhus, Denmark.
authors.forename: Olav Jonas
authors.initials: OJ
authors.lastname: Bergmann
authors.affiliation: Department of Clinical Medicine, Aalborg University, Sdr. Skovvej 15, Aalborg, Denmark.|Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Bøgsted
authors.affiliation: Department of Clinical Medicine, Aalborg University, Sdr. Skovvej 15, Aalborg, Denmark.|Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Karen
authors.initials: K
authors.lastname: Dybkær
authors.affiliation: Department of Clinical Medicine, Aalborg University, Sdr. Skovvej 15, Aalborg, Denmark.|Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Pathology, Aalborg University Hospital, Ladegaardsgade 3, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Vyberg
authors.affiliation: Department of Clinical Medicine, Aalborg University, Sdr. Skovvej 15, Aalborg, Denmark.|Clinical Cancer Research Center, Aalborg University Hospital, Sdr. Skovvej 15, Aalborg, Denmark.|Department of Haematology, Aalborg University Hospital, Hobrovej 18-22, Aalborg, Denmark.
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Johnsen
mesh_terms: D000368:Aged; D001706:Biopsy; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005786:Gene Expression Regulation; D059847:HLA-DRB5 Chains / Q000276:immunology; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008558:Melphalan / Q000008:administration & dosage / Q000009:adverse effects*; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D009101:Multiple Myeloma / Q000188:drug therapy*; D013280:Stomatitis / Q000097:blood / Q000139:chemically induced* / Q000235:genetics* / Q000276:immunology
chemical_list: D059847:HLA-DRB5 Chains; D008558:Melphalan