In 1973, R. Cailleau, R. Young, M. Olivé, and W. J. Reeves, Jr. isolated four new epithelial tumor cell lines from pleural effusions of breast cancer patients. They describe three of these lines: MDA-MB-134 (mean chromosome number 43), MDA-MB-175 (mean chromosome number 49), and MDA-MB-231 (mean chromosome number 65-69). The isolation of these cell lines from pleural effusions offers several advantages, including a large amount of material, high viability of tumor cells, scarcity or absence of fibroblasts, and the ability to separate tumor cells from other cell types. The authors found that sequential samples from the same patient yielded similar cell lines, while different patients had distinct lines. No viruses or mycoplasmas were detected in any of the lines. The study highlights the potential of pleural effusions as a source for culturing and studying breast tumor cells.In 1973, R. Cailleau, R. Young, M. Olivé, and W. J. Reeves, Jr. isolated four new epithelial tumor cell lines from pleural effusions of breast cancer patients. They describe three of these lines: MDA-MB-134 (mean chromosome number 43), MDA-MB-175 (mean chromosome number 49), and MDA-MB-231 (mean chromosome number 65-69). The isolation of these cell lines from pleural effusions offers several advantages, including a large amount of material, high viability of tumor cells, scarcity or absence of fibroblasts, and the ability to separate tumor cells from other cell types. The authors found that sequential samples from the same patient yielded similar cell lines, while different patients had distinct lines. No viruses or mycoplasmas were detected in any of the lines. The study highlights the potential of pleural effusions as a source for culturing and studying breast tumor cells.