Avaliação citogenética da resposta ao tratamento quimioterápico em mulheres portadoras de câncer de mama.

Abstract

Breast cancer has been considered the second most frequent malignant neoplasia among women. During the carcinogenesis stages there are mutation accumulations in cell DNA. The test of chromosomal aberrations (CA) in lymphocytes of peripheral blood is sensitive for detection of cytogenetic damages caused by exposition to mutagenic and carcinogenic agents which are related to the increase of the risk of cancer development. The actual drugs used in cancer treatment are anti-proliferatives, which means, they work in cell blocking the processes of grow and division. The clinical use of drugs during the chemical therapy may increase the CA frequency contributing for a second neoplasia. This work aimed to evaluate the presence of chromosomal aberrations induced in lymphocytes of peripheral blood from patients with breast cancer in relation to a control group; as well as to compare among these patients the frequency of residual chromosomal aberrations after each chemical therapy cycle. Ten patients diagnosed with breast cancer in Mastology Clinic of Obstetrics and Gynecology Discipline of University Hospital of UFTM was treated with neoadjuvante chemotherapy and ten women without breast cancer diagnostic were evaluated. Patients were treated with six cycles of chemical therapy and the blood was sampled before starting the treatment and immediately before starting each cycle. Lymphocytes were cultured in medium of RPMI or Dubeccos supplemented with Fetal Bovine Serum and stimulated with phytohemagglutinin (PHA) per 72 h at 37° C. The metaphases were found after blocking with colchicine. By the light-microscopy analysis of 100 metaphases we found an increase in cell CA frequency and mitotic index (MI) between the control and the patients before chemical therapy. In relation to the pretreatment period, there was an increase in number of CA and in CA cells among patients at forth treatment cycle. In relation to MI, there were statistic differences between third cycle and pretreatment period; and when the first and fifth cycles were compared to third and fourth cycles. Thus, the increase of CA until the fourth cycle and the decrease in the last cycle should be happened as consequence of a putative cell repair mechanism. The evaluation of cytogenetic damage in lymphocytes of breast cancer patients is being indicated for estimating the sensitivity of the chemical therapy since the stable chromosomal aberrations may lead to the increase of a secondary neoplasia occurrence.