For this purpose, we developed an orthotopic, syngeneic and immunocompetent mammary cancer model in BALB/cJ mice, and studied the role of P2X7 receptor, expressed or not in 4T1 mammary cancer cells (using genetically engineered cells) or in the host organisms (wild-type P2rx7+/+ versus knock-down P2rx7−/− mice). This evidence concerns the gene P2RX7 and breast cancer.