RESUMEN
BACKGROUND: Cytogenetic evidence suggests that chromosomal alteration are not randomly occurring events and some malignancies are characterized by specific chromosome abnormalities, which provides cytogenetic basis for the expression of oncogenes.OBJECTIVE: To investigate the characteristics of chromosomal karyotype and marker chromosome of breast cancer cell lines Bcap-37and MCF-7 by means of G-banding chromosomal analysis.DESIGN: A controlled experiment with breast cancer cells as observation subjects.SETTING: Department of Medical Genetics, Peking University Health Science Center.MATERIALS: This study was carried out in the Department of Medical Genetics of Peking University Health Science Center from April 1991 to May 1992 using breast cancer cell lines MCF-7 and Bcap-37.METHODS: The chromosomes of human breast cancer cell lines Bcap-37and MCF-7 were obtained by growth synchronization induced by hypothermia and colchicines treatment. The cells at prometaphase or metaphase underwent G-banding chromosomal analysis. For each cell line, 50 to 60 mitotic figures were counted and 15 or 16 G-binding karyotypes were analyzed, including the mitotic figure at the level of about 320- and 500-band .MAIN OUTCOME MEASURES:Abnormality in chromosome number and structural aberration of the two breast cancer cell lines.RESULTS:The modal chromosomal number of Bcap-37 cell line was 63, of which 17 marker chromosomes had identifiable structure, as compared with 13 out of 56 chromosomes in modal number of MCF-7 cell line.CONCLUSION: Both of the two breast cancer cell lines have complex cytogenetic abnormality in the modal number and structure of the chromosomes, which might result in the rearrangement of DNA sequence of the cancer-related genes or DNA depletion, so as to play important roles in the pathogenesis and development of breast cancer.