title: The clinical and pathological significance of RCAS1 expression as a prognostic biomarker in non-small cell lung cancer.
abstract: BACKGROUND
  Lung cancer remains a major health problem due to its incidence and mortality. Receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is a protein that can be expressed in cancer cells and is involved in tumor cell escape from immune system surveillance.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the clinical significance of immunohistochemical staining for RCAS1 in non-small cell lung cancer (NSCLC).
  
  
  METHODS
  Tissue microarrays of tumor specimens from 112 consecutive patients with newly diagnosed primary NSCLC were constructed. RCAS1 and Ki-67 immunohistochemistry were studied through computerized image analysis. Associations between RCAS1 and Ki-67 expression and clinico-pathological variables and survival were analyzed.
  
  
  RESULTS
  RCAS1 expression was higher in grade III tumors (p=0.009), regardless of the histological type, and in adenocarcinomas with lymphovascular invasion (p=0.014). A positive correlation between RCAS1 and Ki-67 levels was observed (p=0.002). Moreover, there was an inverse correlation of overall survival with RCAS1 (hazard ratio=0.99, p<0.001) and Ki-67 (hazard ratio=1.05, p=0.003) levels. Particularly, patients with higher expression of RCAS1 or Ki-67 had a significantly shorter survival than those with lower expression.
  
  
  CONCLUSIONS
  RCAS1 could be a useful immunohistochemical biomarker, indicating not only tumor aggressiveness but also a poorer prognosis for patients with NSCLC.
authors.affiliation: M.Sc., Medical Oncologist, Department of Medical Oncology, 401 General Military Hospital, Gennimata N. 10-12, Ampelokipi 11524, Athens, Greece. Mob.: +30 6977366056, tsoukn@yahoo.gr.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Tsoukalas
authors.forename: Ioannis D
authors.initials: ID
authors.lastname: Kostakis
authors.forename: Spyros
authors.initials: S
authors.lastname: Siakavellas
authors.forename: Constantinos
authors.initials: C
authors.lastname: Giaginis
authors.forename: Evangelos
authors.initials: E
authors.lastname: Bournakis
authors.forename: Ioannis
authors.initials: I
authors.lastname: Sfiniadakis
authors.forename: Andreas
authors.initials: A
authors.lastname: Karameris
authors.forename: Efstratios
authors.initials: E
authors.lastname: Patsouris
authors.forename: Stamatios
authors.initials: S
authors.lastname: Theocharis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D014408:Biomarkers, Tumor; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000401:mortality / Q000473:pathology*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D011379:Prognosis; D012307:Risk Factors
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C120762:EBAG9 protein, human
keywords: Non-small cell lung cancer; RCAS1; biomarker; immunoescape; immunosurveillance; prognosis; survival