MULTICELLULAR TUMOR SPHEROID FORMATION BY BREAST-CANCER CELLS ISOLATED FROM DIFFERENT SITES

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 38  (8) , 2486-2491
Abstract
Fourteen breast cancer lines (8 human, 5 rat and 1 mouse) were studied in terms of their ability to form multicellular tomor spheroids (MTS) with the agar-base method. Only 8 of the lines formed MTS in contrast to a 100% efficiency in a series of 11 varied tumors reported in the initial studies with this method. The lines that do and do not form MTS were compared in terms of a variety of characteristics (e.g., estrogen receptors, time in serial passage, growth in nude mice, etc.), and only 1 characteristic, the source of the original tumor cells, was predictive of MTS-forming ability. All 8 breast cancer lines (and the original 11 lines) that formed MTS were obtained from solid growths (primaries or metastases), while the 6 breast cancer lines that did not form MTS were derived from pleural effusions. Artificial selection for an ascites variant of the MTS-forming rat 13762 adenocarcinoma line produced the 13762-A line, which could no longer form MTS. These results suggest that breast cancer cells derived from pleural effusions are genetically different from the bulk of the tumor cells in solid breast cancer samples, they are unable to grow in true solid form and these differences persist in spite of prolonged propagation in tissue culture.