In order to assess the role of P2X7R in mammary tumour growth and metastatic progression, we genetically modified 4T1 cells for its expression, using the CRISPR/Cas9 gene-editing technique, generating three cell lines, two of which were named Crispr#1 and Crispr#2 with the P2rx7 knocked-down with an efficacy of >95%, and one cell line named CTL expressing the P2rx7 gene at a level similar to that in the parental 4T1 cells (Figure 4a). This evidence concerns the gene P2RX7 and breast cancer.