The rarely reported prognostic role of Sox2 in breast cancer patients seems contradictory with its major implications in mammary cancer cell biology (37), as Sox2 has been reported to increase breast cancer cell proliferation (6, 33, 46), favor invasion and metastasis (33, 46, 47), epithelial-to-mesenchymal transition, stemness and the Wnt-β-catenin signaling pathway (8, 44), and is associated with angiogenesis in breast cancer samples (48). Here, SOX2 is linked to breast cancer.