To evaluate whether intestinal tissue shows signs of biological stress, expression of the molecular chaperone BiP or Grp78 (Glucose Regulate Protein 78), a heat shock protein 70 kDa family member known as the master negative regulator of the unfolded protein response (UPR) in mammals [21], was assessed in duodenal biopsies from controls and CD patients. This evidence concerns the gene HSPA5 and Cowden disease.