CDH-1 germ line mutations in diffuse gastric and infiltrating ductal breast cancer

Abstract

e22218 Background: Hereditary Diffuse Gastric Cancer (HDGC) syndrome is characterized by the predisposition to gastric cancer of the diffuse type and to breast cancer of the lobular type. The autosomal dominantly inherited germline mutations of the E- cadherin (CDH1) gene are the defects underlying the HDGC syndrome. The median age of onset for diffuse gastric cancer is 38 years. CDH1 mutations are highly penetrant, conferring a cumulative risk of diffuse gastric cancer of 75%. Methods: Genomic DNA was purified from peripheral blood leukocytes following standard chloroform extraction. The complete coding sequences of the CDH1-gene, including splice junctions, were amplified by Polymerase Chain Reaction (PCR) and electrophorized in an ABI Prism 310 Genetic Analyzer. Results: A pathogenic mutation located on exon 7 of the CDH1 gene was identified in a female patient diagnosed with bilateral breast cancer at the age of 36. She underwent bilateral mastectomy for an infiltrating ductal adenocarcinoma of the left breast and in situ lobular of the right breast. At the age of 45 the patient underwent gastrectomy for diffuse type gastric adenocarcinoma. She had a positive family history for breast and gastric cancer from both sides, but without meeting the absolute clinical criteria for hereditary diffuse gastric cancer syndrome. The nonsense mutation found was probably maternally inherited, since the maternal grandmother was diagnosed with breast cancer at the age of 38. Conclusions: The selection process of patients for genetic testing for the HDGC syndrome is not quite clear at the moment, as it is apparent that more types of breast cancer and not only lobular, can be associated with the syndrome. Criteria should be more flexible in respects to the histopathology of the cancer type. This is the first CDH1 mutation identified in a Greek patient. No significant financial relationships to disclose.