More germane, then, are the studies of exceptional responders: most notably, a response to mTOR inhibition in a Peutz–Jeghers patient,6 and also the trial of an AKT inhibitor in which a patient with metastatic pancreatic cancer with known PTEN loss exhibited a marked response.7 Both these reports nicely illustrate the phenotype-to-genotype approach to targeted therapy. This evidence concerns the gene PTEN and familial pancreatic carcinoma.