title: CYP2D6 gene polymorphisms in Brazilian patients with breast cancer treated with adjuvant tamoxifen and its association with disease recurrence.
abstract: At present, there is controversy regarding the efficacy of tamoxifen in breast cancer patients who are carriers of cytochrome P450 2D6 (CYP2D6) gene polymorphisms, in terms of recurrence and overall survival. Thus, the aim of the present study was to investigate the association of the CYP2D6 *4, *10 and *17 gene polymorphisms with breast cancer recurrence in a Brazilian population. The cohort comprised 40 receptor-positive breast cancer patients without recurrence and 40 with distant recurrence. A 3-ml sample of peripheral blood was collected from each patient to determine the presence of the *4, *10 and *17 single nucleotide polymorphisms of the CYP2D6 gene by quantitative polymerase chain reaction analysis. There was no statistically significant difference between the two groups regarding the polymorphism frequency (P=0.246). The results revealed that intermediate metabolizers occurred in 5% of patients without recurrence and in 15% of those with distant recurrence. Poor metabolizers occurred in only 1 patient (2.5%) per group, and there was no significant difference between the groups (P=0.789). The present study concluded that the CYP2D6 gene polymorphism in women with hormone-sensitive breast cancer treated with tamoxifen was not associated with disease recurrence.
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil; Department of Oncology, São Marcos Hospital, Teresina, PI 64001-280, Brazil.
authors.forename: Mariella
authors.initials: M
authors.lastname: De Ameida Melo
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil; Department of Oncology, São Marcos Hospital, Teresina, PI 64001-280, Brazil.
authors.forename: Rodrigo José
authors.initials: RJ
authors.lastname: De Vasconcelos-Valença
authors.affiliation: Department of Oncology, São Marcos Hospital, Teresina, PI 64001-280, Brazil.
authors.forename: Fidelis Manes
authors.initials: FM
authors.lastname: Neto
authors.affiliation: Department of Mastology, Getulio Vargas Hospital, Federal University of Piauí, Teresina, PI 64001-020, Brazil.
authors.forename: Rafael Soares
authors.initials: RS
authors.lastname: Borges
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil.
authors.forename: Danylo Rafhael
authors.initials: DR
authors.lastname: Costa-Silva
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: Da Conceição Barros-Oliveira
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil.
authors.forename: Umbelina Soares
authors.initials: US
authors.lastname: Borges
authors.affiliation: Department of Statistics, State University of São Paulo, São Paulo, SP 05508-900, Brazil.
authors.forename: Airlane Pereira
authors.initials: AP
authors.lastname: Alencar
authors.affiliation: Department of Molecular Biology, Natan Portella Hospital, Federal University of Piaui, Teresina, PI 64001-450, Brazil.
authors.forename: Vladimir Costa
authors.initials: VC
authors.lastname: Silva
authors.affiliation: Department of Gynecology, Federal University of Piauí, Health Sciences Center, Teresina, PI 64001-020, Brazil.
authors.forename: Benedito Borges
authors.initials: BB
authors.lastname: Da Silva
keywords: breast cancer; cytochrome P450 2D6 gene; polymorphism; recurrence; tamoxifen