title: The association between the 844ins68 polymorphism in the CBS gene and breast cancer.
abstract: BACKGROUND
  The cystathionine beta synthase (CBS) gene plays an important role in homocysteine metabolism because it catalyzes the first step of the transsulfuration pathway, during which homocysteine is converted to cystathionine. Polymorphisms of CBS have been associated with cancer.
  
  
  METHODS
  We examined the role of the 844ins68 polymorphism by comparing the genotypes of 371 healthy Mexican women with the genotypes of 323 Mexican women with breast cancer (BC).
  
  
  RESULTS
  The observed genotype frequencies for controls and BC patients were 1% and 2% for Ins/Ins, 13% and 26% for W/Ins, and 86% and 72% for W/W, respectively. We found that the odds ratio (OR) was 2.2, with a 95% confidence interval (95% CI) of 1.5-3.3, p = 0.0001. The association was also evident when comparing the distribution of the W/Ins-Ins/Ins genotypes in patients in the following categories: 1) menopause and high γ-glutamyltransferase (GGT) levels (OR of 2.17, 95% CI: 1.17-4.26, p = 0.02), 2) chemotherapy response and high lactate dehydrogenase (LDH) levels (OR 2.2, 95% CI: 1.08-4.4, p = 0.027), 3) chemotherapy response and high GGT levels (OR 2.46, 95% CI: 1.2-4.8, p = 0.007), and 4) body mass index (BMI) and III-IV tumor stage (OR 3.2, 95% CI: 1.2-8.3, p = 0.013).
  
  
  CONCLUSIONS
  We conclude that the genotypes W/Ins-Ins/Ins of the 844ins68 polymorphism in the CBS gene contribute significantly to BC susceptibility in the analyzed sample from the Mexican population.
authors.affiliation: Laboratorio de Genética Molecular, División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Centro Médico Nacional de Occidente (CMNO), Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco, México.
authors.forename: Martha Patricia
authors.initials: MP
authors.lastname: Gallegos-Arreola
authors.affiliation: División de Genética, CIBO, CMNO, IMSS, Guadalajara, Jalisco, México.
authors.forename: Luis Eduardo
authors.initials: LE
authors.lastname: Figuera-Villanueva
authors.affiliation: Laboratorio de Genética Molecular, División de Medicina Molecular, Centro de Investigación Biomédica de Occidente (CIBO), Centro Médico Nacional de Occidente (CMNO), Instituto Mexicano del Seguro Social (IMSS), Guadalajara, Jalisco, México ; Doctorado en Farmacología, CUCS, UdeG, Guadalajara, Jalisco, México.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ramos-Silva
authors.affiliation: UMAE, Hospital de Gineco-Obstetricia, CMNO, IMSS, Guadalajara, Jalisco, México.
authors.forename: Efraín
authors.initials: E
authors.lastname: Salas-González
authors.affiliation: Laboratorio de Inmunofarmacología, CUCEI, UdeG, Guadalajara, Jalisco, México.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Puebla-Pérez
authors.affiliation: Facultad de Medicina e Ingeniería en Sistemas Computacionales (FMeISC), Universidad Autónoma de Tamaulipas, Matamoros, Tamaulipas, México.
authors.forename: Valeria
authors.initials: V
authors.lastname: Peralta-Leal
authors.affiliation: División de Genética, CIBO, CMNO, IMSS, Guadalajara, Jalisco, México.
authors.forename: José Elías
authors.initials: JE
authors.lastname: García-Ortiz
authors.affiliation: División de Genética, CIBO, CMNO, IMSS, Guadalajara, Jalisco, México.
authors.forename: Ingrid Patricia
authors.initials: IP
authors.lastname: Dávalos-Rodríguez
authors.affiliation: Laboratorio de Mutagénesis, División de Medicina Molecular, CIBO, CMNO, IMSS, Guadalajara, Jalisco, México.
authors.forename: Guillermo Moisés
authors.initials: GM
authors.lastname: Zúñiga-González
keywords: 844ins68; Mexican population; T833C; breast cancer; polymorphism