title: CYFRA 21-1 is a useful marker for esophageal squamous cell carcinoma.
abstract: BACKGROUND
  CYFRA 21-1 measures soluble cytokeratin-19 fragments in serum and is a useful marker for lung carcinoma, especially squamous cell carcinoma (SCC). The authors conducted this study to determine the significance of CYFRA 21-1 in patients with esophageal SCC.
  
  
  METHODS
  Expression and production of cytokeratin-19 in the authors' six established esophageal SCC cell lines were determined by immunocytochemical staining and enzyme-linked immunoadsorbent assay, respectively. The correlation between serum CYFRA 21-1 levels and expression of cytokeratin-19 in human tumors was investigated by immunohistochemical staining. The correlation between serum CYFRA 21-1 levels and clinicopathologic factors was examined in 48 patients with esophageal SCC, as were SCC antigen and carcinoembryonic antigen (CEA).
  
  
  RESULTS
  Of the 6 cell lines, 5 lines expressed cytokeratin-19 in their cytoplasm and produced soluble cytokeratin-19 fragments. Twenty-three of 48 patients had elevated CYFRA 21-1 levels (>3.5 ng/mL), whereas none of the reference group (consisting of healthy volunteers or patients with benign disease) showed positive levels. The specificity, sensitivity, and accuracy of CYFRA 21-1 were 100%, 47.9%, and 66.7%, respectively. CYFRA 21-1 showed significantly higher sensitivity and accuracy than SCC antigen or CEA (P < 0.05). Univariate analysis revealed that CYFRA 21-1 levels correlated with disease progression (including tumor size, tumor depth, and pTNM stage), resectability, and curability. There was a significant association between the level of CYFRA 21-1 and its intensity of immunohistochemical staining in vitro as well as in vivo.
  
  
  CONCLUSIONS
  CYFRA 21-1 appears to be a useful marker for human squamous cell carcinoma of the esophagus.
authors.affiliation: Department of Surgery II, Yamaguchi University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Oka
authors.forename: H
authors.initials: H
authors.lastname: Hayashi
authors.forename: A
authors.initials: A
authors.lastname: Tangoku
authors.forename: T
authors.initials: T
authors.lastname: Gondo
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000097:blood / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D004938:Esophageal Neoplasms / Q000097:blood / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D015843:Serpins; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D015843:Serpins; C051072:squamous cell carcinoma-related antigen; D007633:Keratins