title: Indoleamine 2,3-dioxygenase (IDO) is frequently expressed in stromal cells of Hodgkin lymphoma and is associated with adverse clinical features: a retrospective cohort study.
abstract: BACKGROUND
  Regulation of tumor microenvironment is closely involved in the prognosis of Hodgkin lymphoma (HL). Indoleamine 2,3-dioxygenase (IDO) is an enzyme acting as immune modulator through suppression of T-cell immunity. This study aims to investigate role of IDO in the microenvironment of HL.
  
  
  METHODS
  A total of 121 cases of HL were enrolled to do immunohistochemistry for IDO, CD163, CD68, CD4, CD8, and FoxP3. Positivity was evaluated from area fractions or numbers of positive cells using automated image analyzer. Correlations between IDO expression and various cellular infiltrates and clinicopathologic parameters were examined and survival analyses were performed.
  
  
  RESULTS
  IDO was expressed in histiocytes, dendritic cells and some endothelial cells with variable degrees, but not in tumor cells. IDO positive cells were more frequently found in mixed cellularity type than other histologic types, and in cases with EBV+, high Ann Arbor stages, B symptoms, and high IPS (all p < 0.05). High IDO expression was associated with inferior survival (p < 0.001) and reflects an independent prognostic factor in nodular sclerosis HL.
  
  
  CONCLUSIONS
  This is the first study suggesting that IDO is the principle immunomodulator and is involved to adverse clinical outcomes of HL.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Choe
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Yun
authors.forename: Yoon Kyoung
authors.initials: YK
authors.lastname: Jeon
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Gyeongsin
authors.initials: G
authors.lastname: Park
authors.forename: Joo Ryoung
authors.initials: JR
authors.lastname: Huh
authors.forename: Sohee
authors.initials: S
authors.lastname: Oh
authors.affiliation: Department of Pathology, Seoul National University Boramae Hospital, Seoul, Korea. npol181@snu.ac.kr.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D001706:Biopsy; D019070:Cell Lineage; D002648:Child; D018572:Disease-Free Survival; D005260:Female; D006689:Hodgkin Disease / Q000201:enzymology* / Q000401:mortality / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000032:analysis*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D017154:Stromal Cells / Q000201:enzymology* / Q000473:pathology; D013997:Time Factors; D059016:Tumor Microenvironment; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase