CXCL12 and cancer: Although CXCL12 concentrations in CXCL12 overexpressing cancer cells and senescent tumor cells in the cancer tissue were not directly compared, the distance between the zone of polarity loss and CXCL12‐expressing cells in the μ‐slide experiment (approximately 200 μm) was similar to that between p16INK4A and CD8+ T cells (Figure S12E, Supporting Information).