The co-localisation of Δ40p53 and Sox2 was further confirmed in 3D ZR75-1 cell spheroids (Fig. 2C) and in five (S#4–7: ER+/PR+/Her2- and S#8: ER-/PR-/Her2+) IDCs (correlation value: 0.52; p < 0.05) (Fig. 2D), indicating that Δ40p53 is expressed in more pluripotent breast cancer cells. The gene discussed is PGR; the disease is breast cancer.