title: Squamous cell carcinoma antigen as an adjunct tumour marker in primary carcinoma of the lung.
abstract: OBJECTIVE
  To determine (1) the detection rate of primary carcinoma of the lung by serological assay of CEA (carcinoembryonic antigen); and (2) whether addition of seroassay of squamous cell carcinoma related antigen before treatment improves detection sensitivity.
  
  
  METHODS
  A prospective study spanning 27 months was conducted at the University Hospital, Kuala Lumpur. Serum CEA (Abbott IMx) and serum squamous cell carcinoma antigen (Abbott IMx) from patients clinically suspected of having primary carcinoma of the lung, were assayed using the microparticle enzyme immunoassay method.
  
  
  RESULTS
  Thirty seven cases of histologically confirmed primary lung carcinoma were studied. Of these, 17 were squamous cell carcinomas, 10 adenocarcinomas, nine small cell carcinomas, and one large cell carcinoma. The patients' ages ranged from 34-82 years. The male:female ratio was 3.6:1. Squamous cell carcinoma antigen was raised above the cutoff value of 1.5 ng/ml in 94.1% of squamous cell carcinomas, 20.0% of adenocarcinomas, and 11.1% of small cell carcinomas. By comparison, CEA was raised above the cutoff value of 3.0 ng/ml in 70.6% of squamous cell carcinomas, 77.8% of small cell carcinomas, and 100% of adenocarcinomas. CEA and squamous cell carcinoma antigen were not raised in the patient with large cell carcinoma and in 14 healthy volunteers. None of 15 patients with a variety of benign lung diseases showed a rise of CEA, while two patients--a 25 year old Indian woman with pneumonia and a 64 year old Malay man with bronchial asthma--had raised squamous cell carcinoma antigen values above the cutoff. Serum CEA and squamous cell carcinoma antigen values did not seem to correlate with stage or degree of differentiation of the tumours.
  
  
  CONCLUSIONS
  The findings suggest that CEA is a good general marker for carcinoma, particularly adenocarcinoma. In contrast, squamous cell carcinoma antigen is more specific for squamous carcinoma.
authors.affiliation: Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur.
authors.forename: P L
authors.initials: PL
authors.lastname: Cheah
authors.forename: C K
authors.initials: CK
authors.lastname: Liam
authors.forename: S F
authors.initials: SF
authors.lastname: Yap
authors.forename: L M
authors.initials: LM
authors.lastname: Looi
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood; D018288:Carcinoma, Small Cell / Q000175:diagnosis; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D015843:Serpins
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D015843:Serpins; C051072:squamous cell carcinoma-related antigen