title: Biomarkers of depression in cancer patients.
abstract: BACKGROUND
  Inflammation and perturbation of the hypothalamic-pituitary-adrenal (HPA) axis function appears to play a putative role in the etiology of depression. Patients with metastatic cancer demonstrate elevated prevalence rates for depression. The objective of the current study was to illustrate the efficacy of interleukin-6 (IL-6) and HPA axis function as adjuncts to support the diagnosis of depression in cancer patients.
  
  
  METHODS
  Plasma concentrations of IL-6 and cortisol were measured in 114 cancer patients with and without depression. The relative diurnal variation of cortisol (cortisol VAR), expressed as a percentage, was calculated. Receiver operating characteristics analysis was performed.
  
  
  RESULTS
  Depression was associated with increased plasma concentrations of IL-6 (18.7 pg/mL vs. 2.7 pg/mL; P < .001) and higher cortisol concentrations at 8 AM and 8 PM. The relative cortisol VAR (11.7% vs. 60.6%, respectively; P < .001) was found to be decreased in cancer patients with depression, indicating a disturbed circadian function of the HPA axis. As a biomarker of depression, IL-6 yielded at a cutoff value of 10.6 pg/mL, a sensitivity of 79%, and a specificity of 87% (area under the curve [AUC] = 0.86; 95% confidence interval [95% CI], 0.78-0.94), whereas cortisol VAR demonstrated a sensitivity of 81% and a specificity of 88% (AUC = 0.85; 95% CI, 0.74-0.97) at a cutoff value of 33.5%.
  
  
  CONCLUSIONS
  Depression is associated with increased plasma IL-6 concentrations in patients with cancer. These patients demonstrate a dysfunction of the HPA-axis, characterized by a decreased diurnal variation of cortisol. The high sensitivity and specificity of these parameters biomarkers of depression make IL-6 and cortisol VAR helpful tools in the diagnosis of depression in patients with cancer.
authors.affiliation: Department of Oncology and Hematology, University Hospital Charite, Berlin, Germany. christian.jehn@charite.de
authors.forename: Christian Friedrich
authors.initials: CF
authors.lastname: Jehn
authors.forename: Dagmar
authors.initials: D
authors.lastname: Kuehnhardt
authors.forename: Andrea
authors.initials: A
authors.lastname: Bartholomae
authors.forename: Sebastian
authors.initials: S
authors.lastname: Pfeiffer
authors.forename: Michael
authors.initials: M
authors.lastname: Krebs
authors.forename: Anne Constanze
authors.initials: AC
authors.lastname: Regierer
authors.forename: Peter
authors.initials: P
authors.lastname: Schmid
authors.forename: Kurt
authors.initials: K
authors.lastname: Possinger
authors.forename: Bernd Christian
authors.initials: BC
authors.lastname: Flath
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D003430:Cross-Sectional Studies; D003863:Depression / Q000097:blood* / Q000209:etiology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood* / Q000503:physiopathology / Q000523:psychology*; D010913:Pituitary-Adrenal System / Q000503:physiopathology
chemical_list: D014408:Biomarkers, Tumor; D015850:Interleukin-6; D006854:Hydrocortisone