4T1 cells, another common breast cancer cell line, showed a similar phenotype to Met-1 cells; coinjecting apoptotic 3T3 cells resulted in a robust increase in 4T1 metastasis, whereas apoptotic 4T1 cells resulted in a smaller increase in tumor cell metastasis (Fig. 1H, Supplementary Fig. 2C–F). This evidence concerns the gene GZMM and breast carcinoma.