Researchers find cause of rare gastric cancer

Vancouver, BC – An international study with BC Cancer Agency researchers has discovered the genetic cause of a rare gastric condition that can lead to stomach cancer.

The team, including Dr. David Huntsman, distinguished scientist at the BC Cancer Agency and professor in the Departments of Pathology and Laboratory Medicine and Obstetrics and Gynaecology at the University of British Columbia, and Dr. Intan Schrader, medical geneticist with the BC Cancer Agency Hereditary Cancer Program, discovered three extremely rare genetic mutations that cause gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). The discovery means that, in future, individuals who have a family member with GAPPS will be able to have a DNA test to determine whether they will develop the condition and stomach cancer.

“This new finding will change the way we test for a very well-known cancer susceptibility gene and has significant implications for how we think about other syndromes known to heighten the risk of cancer and how we clinically screen for the mutations that cause them,” said Dr. Schrader.

The B.C.-based work was supported through the BC Cancer Foundation in the hopes that more answers can be found to pinpoint the causes of both hereditary and sporadic causes of the disease, which is the fourth leading cause of cancer death world-wide.

The study was led by Professor Georgia Chenevix-Trench, the head of the Genetics and Computational Biology Department at QIMR Berghofer in Australia and published recently in The American Journal of Human Genetics.

On the study’s implications to families impacted by GAPPS around the world, Professor Chenevix-Trench said: “Those who do carry the mutation can be closely screened and can decide whether they want to consider surgery, and those who do not carry the mutation will no longer have to have regular screening.”

The findings also drew connections to a long-known hereditary condition— familial adenomatous polyposis or FAP— known to cause colon cancer. Although increased colon cancer risk has not been a recognized feature of GAPPS, now, Dr. Schrader says, further work is required to determine if smaller families in whom we haven’t had a chance to observe, may have a heightened risk for colon cancer, and conversely if individuals with FAP due to similar mutations of the APC gene have a higher risk of gastric cancer.