Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the genetic changes related to hereditary diffuse gastric cancer ?
    ### Response:
    It is likely that 30 to 40 percent of individuals with HDGC have a mutation in the CDH1 gene. The CDH1 gene provides instructions for making a protein called epithelial cadherin or E-cadherin. This protein is found within the membrane that surrounds epithelial cells, which are the cells that line the surfaces and cavities of the body.
    