A NEW CELL-LINE FROM HUMAN INFILTRATING DUCTAL CARCINOMA OF THE BREAST - ESTABLISHMENT AND CHARACTERIZATION

We established a novel cancer cell line (MAST) from the ascitic fluid of a metastatic infiltrating ductal carcinoma of the breast. The epith elial and neoplastic nature of the MAST cells was confirmed by ultrast ructural analysis. The cell line was maintained as a monolayer with a doubling time of about 68 h, and it possessed an abnormal karyotype wi th a modal chromosome number of 60, a trisomy of chromosome 18 and oth er unidentified rearranged chromosomes. Among the markers consistently found in MAST metaphases, we noted a t(14; 14) and a very large subte locentric, a large satellited acrocentric and a very large submetacent ric chromosome with striking fluorescent bands. Immunoenzymatic assay demonstrated that the MAST cell line was positive for estrogen and pro gesterone receptors. The in vitro drug-sensitivity assay showed a mark ed resistance of the cell line to 5-fluorouracil and 4-hydroperoxycycl ophosphamide and a moderate resistance to etoposide and 4'-epidoxo-rub icin. The molecular analysis showed a four- to sixfold amplification o f the c-myc gene and no amplification or rearrangement of the int-2, c -erbB-2, c-Ha-ras, c-mos and hst-1 genes.