At the time of sacrifice a substantial fraction of control Pten+/− mice had hyperplasia of the mammary glands (19/31), with 5/31 having developed adenomyoepithelioma (AME), a benign growth, with only 2/31 showing malignant mammary tumours (Figures 1F and 4A; Table 1). This evidence concerns the gene PTEN and apparent mineralocorticoid excess.