title: Diagnostic utility of interleukin-6 (IL-6) for primary bile duct cancer and changes in serum IL-6 levels following photodynamic therapy.
abstract: OBJECTIVE
  Difficult diagnoses and a lack of effective therapy complicate biliary tract malignancies. Interleukin-6 (IL-6) is a human bile duct epithelium growth factor correlated with tumor burden. We evaluated the usefulness of serum IL-6 in the diagnosis of primary BDC and measured changes in serum IL-6 levels following photodynamic therapy (PDT).
  
  
  METHODS
  We prospectively measured serum IL-6 levels in patients with BDC (N = 26: 14 patients treated with PDT, 12 with biliary drainage alone), hepatocelluar carcinoma (HCC, N = 26), and healthy adults (N = 23). Serum IL-6 levels were measured by an enzyme-linked immunosorbent assay. Patients with clinical conditions known to increase IL-6 levels were excluded.
  
  
  RESULTS
  IL-6 was detected in all patients with BDC and HCC, and in 6 of 23 healthy adults. Median and mean levels of IL-6 were higher in patients with BDC than in both other groups (P < 0.001). Using a 25.8 pg/mL cutoff, IL-6 provided a diagnostic sensitivity of 73% and a specificity of 92%; positive and negative predictive values were 83% and 87%, respectively. Serum levels of IL-6 were correlated with tumor burden in BDC patients. One month after treatment of BDC with PDT, the mean IL-6 level decreased significantly from 282.1 +/- 121.8 to 38.2 +/- 9.9 pg/mL (P= 0.008).
  
  
  CONCLUSIONS
  Serum IL-6 concentration is a useful addition to the available tests for the differential diagnosis of BDC, and serves as a marker for monitoring the response to treatment of BDC with PDT.
authors.affiliation: Institute for Digestive Research and Digestive Disease Center, Soon Chun Hyang University College of Medicine, Seoul, Korea.
authors.forename: Young Koog
authors.initials: YK
authors.lastname: Cheon
authors.forename: Young Deok
authors.initials: YD
authors.lastname: Cho
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Moon
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Kim
authors.forename: Yun Soo
authors.initials: YS
authors.lastname: Kim
authors.forename: Moon Sung
authors.initials: MS
authors.lastname: Lee
authors.forename: Joon Seong
authors.initials: JS
authors.lastname: Lee
authors.forename: Chan Sup
authors.initials: CS
authors.lastname: Shim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D001653:Bile Ducts, Intrahepatic; D015415:Biomarkers / Q000097:blood; D018281:Cholangiocarcinoma / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D011237:Predictive Value of Tests; D047368:Tumor Burden / Q000502:physiology
chemical_list: D015415:Biomarkers; D015850:Interleukin-6