The team used genome screening to look for vulnerabilities in the cancer cells that lack a specific protein, E-cadherin, which inhibits tumours.
In the 1990s, Professor Guilford's work with a large Bay of Plenty Maori family identified E-cadherin as the first known gene for inherited gastric cancer.
It allowed family members to be tested for the gene, and decide whether to take preventative action.
In the new research, the team found another type of protein was abundant in those cells, and then looked for drugs that would interfere with those proteins.
Professor Guilford said the results were promising for developing early treatments for people with the genetic mutation, and as a result are at high risk of the cancers.
"Making such drug treatments a reality would mean delaying or completely avoiding the trauma that high-risk individuals experience by undergoing major preventative surgery at a young age."
Kimihauora Trust Manager Maybelle McLeod, who originally contacted the university to help find the cause of the stomach cancer in her family, said the findings were exciting.
"The only choice at the moment for those of us at genetic risk is to undergo drastic surgery, and having your stomach removed is a hard thing to bite.
"This latest research holds out a new hope for a gentler way to save the lives of our affected whanau members," she said.
The study was in collaboration with researchers from Melbourne's Peter MacCallum Cancer Centre and the University of Melbourne, and supported by the Health Council of New Zealand.
The findings appeared in the US journal Molecular Cancer Theraputics.
