title: The relationship between Lewis/Secretor genotypes and serum carbohydrate antigen 19-9 levels in a Korean population.
abstract: BACKGROUND
  The Lewis histo-blood group system consists of 2 major antigens-Lea and Leb-and a sialyl Lewis antigen-carbohydrate antigen (CA) 19-9. We investigated the distribution of Lewis genotypes and evaluated the relationship between the Lewis/Secretor genotypes and the serum level of CA 19-9 in a Korean population to identify whether the serum CA 19-9 levels are influenced by the Lewis/Secretor genotypes.
  
  
  METHODS
  The study included 242 individuals who had no malignancies. Lewis genotyping was performed for the 59T>G, 508G>A and 1067T>A polymorphic sites. The Secretor genotype was determined through analysis of the 357C>T and 385A>T polymorphic sites and the fusion gene. Serum CA 19-9 level was analyzed using an electrochemiluminescence immunoassay.
  
  
  RESULTS
  Individuals carrying the 3 common genotypes-Le/Le, Le/le(59,508), and Le/le(59,1067)-accounted for 95% of the study population. In the Korean population, the allelic frequencies of Le, Le(59), le(59,508), and le(59,1067) were 0.731, 0.010, 0.223, and 0.035, respectively. We found a significant difference in serum CA 19-9 concentrations among the 9 Lewis/Secretor genotype groups (P<0.001). The serum CA 19-9 levels in subjects with genotype groups 1 and 2 (Le/- and se/se) were higher than those with genotype groups 3-6 (Le/- and Se/-; 15.63 vs 6.64 kU/L, P<0.001).
  
  
  CONCLUSIONS
  Le/Le, Le/le(59,508), and Le/le(59,1067) are frequent Lewis genotypes in Koreans. Because serum CA 19-9 levels are significantly influenced by the Lewis/Secretor genotypes, caution is suggested when interpreting the serum CA 19-9 levels.
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyung-Doo
authors.initials: HD
authors.lastname: Park
authors.forename: Kyoung Un
authors.initials: KU
authors.lastname: Park
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Ki
authors.forename: Kyou Sup
authors.initials: KS
authors.lastname: Han
authors.forename: Jin Q
authors.initials: JQ
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D044466:Asian People / Q000235:genetics*; D018395:CA-19-9 Antigen / Q000097:blood*; D005260:Female; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007983:Lewis Blood Group Antigens / Q000235:genetics*; D008163:Luminescent Measurements / Q000379:methods; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011110:Polymorphism, Genetic; D056910:Republic of Korea
chemical_list: D018395:CA-19-9 Antigen; D007983:Lewis Blood Group Antigens