Metformin treatment significantly reduced tumor growth (0.12 cm3 versus 0.24 cm3 tumor volume, in treated and control groups, respectively) only in the ID8 Trp53/Brca2‐deleted cells (Fig 5A and B), as compared to ID8 Trp53‐deleted cells that were unaffected by metformin treatment (0.13 cm3 versus 0.11 cm3 tumor volume, in control and metformin‐treated groups, respectively). This evidence concerns the gene BRCA2 and neoplasm.