Fig. 3. Mammosphere-formation assay using 4T1 cells. Quantification (mammosphere-forming unit, MFU, calculated as a percentage of mammospheres formed from the number of cells seeded). Bars, standard error. Representative images of mammospheres derived from the cells employed in this work in two consecutive passages are also shown. Morphological changes are mainly observed in 4T1 Fibulin-5KD and 4T1 Fibulin-5RGE cells. Bar, 50 µm.