Fig. 1. Loss of SOX4 in murine PyMT organoids inhibits primary tumor formation and metastasis formation.

A Schematic representation of setup of primary tumor experiment. B Growth curves for control and SOX4^KO organoids after mammary transplantation. Data represented as mean volume (mm³). Error bars represent standard error of the mean (SEM). P-values were determined by the “compare growth curves” method [41]. C Immunohistochemical images showing H&E staining for isolated tumors/glands. Scale bar is 100 µm. D Number of macrometastases in lungs of mice as determined by eye by 2 scientists. E Schematic representation of experimental setup for tail vein experiment. Organoids were injected into the tail veins of recipient mice. Mice were sacrificed and lungs were isolated and assessed for metastases outgrowth. F Images showing lungs that were isolated after tail vein experiment. Examples of macrometastases are highlighted by black circles and arrowheads. G Representative images of CFP-staining on paraffin sections to identify metastases in lungs. Examples of metastatic lesions are highlighted by black encirclement and arrowheads. Scale bar = 1 mm. H Quantification of the number of lung macrometastases per field of view. I Quantification of surface area of lungs covered by tumors expressed in percentage. J Relative size per macrometastasis. Data in D–J is represented as average ± SD. P-values were calculated by ANOVA using Dunnett test for multiple comparisons (*p < 0.05, **p < 0.01, ****p-value < 0.0001).