Abstract
Hereditary diffuse gastric cancer (HDGC) is an autosomal dominant hereditary syndrome associated with an increased risk of diffuse gastric cancer and lobular breast cancer. In this chapter, a multidisciplinary and international team of experts on HDGC, including pathologists, a surgeon, a gastroenterologist, molecular biologists, and dedicated researchers gathered to assess the available knowledge on HDGC and areas of emerging research that may be relevant for the translation into clinical practice. Particularly, in this chapter the authors will cover: first, the changes introduced in the updated clinical practice Guidelines on HDGC; second, the HDGC clinical spectrum; third, the models of development and the morphological heterogeneity of HDGC; fourth, the main causal germline defects of HDGC, including CDH1 and CTNNA1 germline variants; fifth, the state-of-art of HDGC-like syndromes; sixth, endoscopic and surgical approaches; seventh, emerging strategies of chemoprevention.