hNK cells limit invasion, growth, and colony formation in the C3(1)-Tag mouse model of breast cancer. (A) Representative DIC images of tumor organoids alone (top) or in coculture with hNK cells (bottom) at 0 and 24 h. Scale bar, 50 µm. (A′ and A″) Boxplot of inverse circularity of tumor organoids alone or in coculture with hNK cells (A′) and area fold change of tumor organoids alone or in coculture with hNK cells (A″). Error bars represent 5th to 95th percentile. **, P < 0.01; ***, P < 0.001 by Mann–Whitney U test. (B) Quantification of normalized colony counts from tumor clusters cultured alone or in coculture with hNK cells. **, P < 0.01 by Mann–Whitney U test.