title: CYP19 (TTTA)n polymorphism and breast cancer risk in Brazilian women.
abstract: A prolonged or increased exposure to endogenous estrogens associated with genetic factors are considered to be the main risk factors for breast cancer. The CYP19 gene encodes the enzyme aromatase, which catalyzes the conversion of androgens into estrogens. CYP19 alleles containing different numbers of tetranucleotide TTTA repeats in intron 4 have been associated with increased breast cancer risk. In this study we investigated, for the first time, the frequency of CYP19 (TTTA)n alleles in a South American population (n = 475) and analyzed the risk for developing breast cancer in a case-control study comprising 135 cases and 270 age-matched controls. It is shown that Brazilians possess not only the alleles identified in all the other populations studied so far (alleles containing from 7 to 13 TTTA repeats), but also the (TTTA)6 allele, that had never been described before. The (TTTA)10 allele was three times more frequent in cases when compared to controls and presented a significant positive association (p = 0.048) with breast cancer development in Brazilians.
authors.affiliation: Departamento de Bioquímica, Instituto de Biologia Roberto Alcantara Gomes, Universidade do Estado do Rio de Janeiro, Av. 28 de Setembro, 87 fundos, 4 andar, Rio de Janeiro, RJ 20551-013, Brazil.
authors.forename: Fabiana Siqueira
authors.initials: FS
authors.lastname: Ribeiro
authors.forename: Lídia Maria da Fonte
authors.initials: LM
authors.lastname: de Amorim
authors.forename: Tatiana
authors.initials: T
authors.lastname: de Almeida Simão
authors.forename: Gulnar Azevedo
authors.initials: GA
authors.lastname: Mendonça
authors.forename: Cláudia Vitória
authors.initials: CV
authors.lastname: de Moura Gallo
authors.forename: Luis Felipe Ribeiro
authors.initials: LF
authors.lastname: Pinto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001141:Aromatase / Q000235:genetics*; D001938:Brazil / Q000453:epidemiology; D001943:Breast Neoplasms / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D018895:Microsatellite Repeats; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012306:Risk
chemical_list: D001141:Aromatase