title: Systemic chemotherapy interferes in homocysteine metabolism in breast cancer patients.
abstract: BACKGROUND
  Hyperhomocysteinemia in breast cancer (BC) patients can be a risk factor for thromboembolic events. This study aimed to evaluate homocysteine and its cofators (folic acid and vitamin B12) concentrations and platelet count at diagnosis of BC, 3 and 6 months after the beginning of chemotherapy treatment and to correlate them with clinical data.
  
  
  METHODS
  Thirty-five BC patients were included; blood samples were obtained by venipuncture. Plasmatic Hcy and cofactors concentrations were measured by competitive chemiluminescent enzyme immunoassay method. Platelet count was done using an automated analyzer. Statistical analysis was performed using the software SPSS.
  
  
  RESULTS
  During chemotherapy, homocysteine (P = 0.032) and vitamin B12 (P < 0.001) concentrations increased, while folate and platelets decreased (P < 0.001). Among the clinical data, the menopausal status showed significant positive correlation (P = 0.022) with homocysteine concentration increase.
  
  
  CONCLUSIONS
  Evaluation of homocysteine concentrations during chemotherapy is extremely important because their levels increase during chemotherapy treatment, thus increasing the risk of thromboembolism development.
authors.affiliation: Oncology and Hematology Department, ABC Medical School, Santo André, SP, Brazil.
authors.forename: Eliana K
authors.initials: EK
authors.lastname: Yamashita
authors.forename: Bianca M
authors.initials: BM
authors.lastname: Teixeira
authors.forename: Renata N
authors.initials: RN
authors.lastname: Yoshihara
authors.forename: Renata K
authors.initials: RK
authors.lastname: Kuniyoshi
authors.forename: Beatriz C A
authors.initials: BC
authors.lastname: Alves
authors.forename: Flávia S
authors.initials: FS
authors.lastname: Gehrke
authors.forename: Viviane A
authors.initials: VA
authors.lastname: Vilas-Bôas
authors.forename: João A
authors.initials: JA
authors.lastname: Correia
authors.forename: Ligia A
authors.initials: LA
authors.lastname: Azzalis
authors.forename: Virginia B C
authors.initials: VB
authors.lastname: Junqueira
authors.forename: Edimar Cristiano
authors.initials: EC
authors.lastname: Pereira
authors.forename: Fernando L A
authors.initials: FL
authors.lastname: Fonseca
mesh_terms: D000970:Antineoplastic Agents / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D000970:Antineoplastic Agents; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12
keywords: breast neoplasms; chemotherapy and thromboembolism; folic acid; homocysteine; vitamin B 12