Researchers have found that the rare form of stomach cancer - affecting 200 people in the UK each year - is often caused by the inheritance of a faulty gene.
They were able to detect the damaged gene in a third of families with a history of the disease.
The research was published in the May issue of Human Mutation.
Of the 10,500 cases of stomach cancer in the UK each year, about 10% of these run in families.
Dr Carlos Caldas and his team, at the Cancer Research UK Department of Oncology, Cambridge University, studied hereditary diffuse gastric cancer (HDGC).
Researchers looked at 39 families with a history of stomach cancer from 9 different countries, including the UK.
Eleven of the families were affected by HDGC, while the rest had various other inherited types.
Scientists took blood samples from several cancer patients in each family and used them to analyze the E-cadherin gene, which is involved in helping cells bind together in tissues.
When the gene is mutated, cancers like HDGC can develop, in which tumor cells spread rapidly outwards.
| Damaged E-cadherin gene in a third of hereditary diffuse gastric cancer patients.
|Cancer Research UK|
In 4 of the 11 HDGC families, the patients had faulty versions of the E-cadherin gene.
However, none of the patients with other forms of stomach cancer had the fault, suggesting that it is exclusive to this particular type.
Dr Caldas says, "People with a faulty E-cadherin gene have a 60-80% chance of developing stomach cancer at some stage of their life, with many getting it very young.
"It's not an easily treated disease and survival is very poor."
"However, if we can screen for the damaged gene, those affected could have surgery to prevent the disease.
"This may be a difficult option to take, but it's preferable to having a very high chance of dying young from cancer."
Dr Caldas says, "We know that the gene is damaged in about a third of HDGC families, but apparently in none with other forms of inherited stomach cancer.
"That makes it simpler to screen because you've got a self-selecting target group and a high chance of a positive test."
Dr Caldas now intends to extend his research to look at other genes that may increase the risk of stomach cancer.
He hopes that the success of his current work will encourage people with a family history of the disease to volunteer themselves for large-scale clinical studies.