In this book the editors and authors provide a comprehensive overview on basic research and clinical aspects of hereditary breast and gastric tumors. In particular, this updated editorial work aims to suggest guidelines for the clinical management of patients with hereditary diffuse gastric and lobular breast cancer. Special attention is given to E-cadherin (CDH1 gene) germline mutations, genetic screening approaches, the underlying molecular mechanisms and pathological and microscopic features. In addition, the book aims to define clinical criteria for genetic screening, and highlights current surgical treatment and clinical approaches for asymptomatic mutation carriers. Other inherited predispositions involving gastric and breast carcinoma are discussed as well.