Repeated confocal microscopy was used to evaluate changes in cell morphology, i. e., cell elongation, as well as quantitative changes in total cellularity and cell populations, i. e., ratio of cancer epithelial cells (green) to CAF (red) (E:F), over time, with the same ER+ surrogate imaged on days 0, 3, and 7 of culture (Fig. 5a). Here, ESR1 is linked to cancer.