NEW YORK (Bloomberg) — Stomach cancer, the second most deadly type of tumour worldwide, has been linked with gene mutations that may point the way to diagnosis and treatments, an international research team said this week.Mutations in a gene called CDH1 appeared in studies of people with an early, inherited stomach cancer whose risk of getting the disease by age 50 is as high as 50 percent, said scientists from six countries led by Pardeep Kaurah of the British Columbia Cancer Agency in Vancouver.

The study of 38 families affected by stomach cancer will help researchers understand why some people at high genetic risk of stomach cancer go on to develop the disease for other, non-genetic reasons, such as diet, the authors said. Screening people in areas such as Newfoundland, where the gene mutations are relatively common, may aid cancer prevention, they said.

“These families are already beginning to recognise that the threshold of preventive molecular medicine has arrived,” said University of Michigan researchers Kirsten Kangelaris and Stephen Gruber, who didn’t contribute to the study, in a commentary in the same journal.

The findings came from studying families afflicted with a form of stomach cancer called hereditary diffuse gastric cancer, or HDGC. In one Michigan family, several members died of the disease before reaching age 50, one of them at age 17. The data was released early to coincide with a presentation at the American Society of Clinical Oncology meeting in Chicago. They will be published in today’s issue of the Journal of the American Medical Association.

The researchers found 13 mutations in the CDH1 gene, which makes a protein called cadherin that binds cells together, that might show more broadly how stomach cancers begin growing. The study shows how important cadherin is to the inherited form of stomach cancer, the researchers said.

As many as 40 percent of families with a family history of stomach cancer have mutations in the gene, they said.

“The identification of CHD1 mutations offers the opportunity of cancer risk-reduction strategies for unaffected at-risk individuals,” they said in the study. The investigation began in 1998 in New Zealand with a family in which 25 people died of stomach cancer, the youngest at age 14. Four other affected families were traced to a coastal area in the Canadian province of Newfoundland.