Sistema FMUSP-HC: Faculdade de Medicina da Universidade de São Paulo (FMUSP) e Hospital das Clínicas da FMUSPYAMASHITA, Eliana K.TEIXEIRA, Bianca M.YOSHIHARA, Renata N.KUNIYOSHI, Renata K.ALVES, Beatriz C. A.GEHRKE, Flavia S.VILAS-BOAS, Viviane A.CORREIA, Joao A.AZZALIS, Ligia A.JUNQUEIRA, Virginia B. C.PEREIRA, Edimar CristianoFONSECA, Fernando L. A.2014-09-302014-09-302014JOURNAL OF CLINICAL LABORATORY ANALYSIS, v.28, n.2, p.157-162, 20140887-8013https://observatorio.fm.usp.br/handle/OPI/7732Background 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.engrestrictedAccesshomocysteinefolic acidvitamin B 12breast neoplasmschemotherapy and thromboembolismcirculating tumor-cellsvenous thromboembolismperipheral-bloodadjuvant therapythrombosisriskarticleCopyright JOHN WILEY & SONS INC10.1002/jcla.21660Medical Laboratory Technology1098-2825