PTEN and gastric cancer: Figure 1 presents the main genes associated with GC hereditary syndromes. The majority of these syndromes are most commonly associated with intestinal GC, except for hereditary diffuse GC (Figure 2). However, diffuse GC may be found in small proportions across most hereditary syndromes. Lynch syndrome, familial adenomatous polyposis, Peutz–Jeghers syndrome, juvenile polyposis syndrome, MUTYH-associated polyposis, and PTEN hamartoma tumor syndrome will be discussed in the colorectal section (Section 12 and Section 21).