A new way of fighting prostate cancer by targeting normal cells inside tumours could lead to a revolution in treatment, it has been claimed.
Scientists switched on key genes inside non-cancerous connective tissue cells within tumours.
In mice, the gene therapy procedure caused tumours to shrink dramatically by 75%.
Researchers now want to know whether a similar approach will work in humans.
Like other solid cancers, prostate tumours are a mixture of malignant and normal cells.
But recent work suggests that "healthy" cells in tumours can play an important role in stimulating cancer growth and spread.
The new research used a virus to infect prostate tumours and switch on certain key genes in fibroblast cells.
This appeared to activate signal pathways which led to the suppression of cancer.
Lead scientist Dr Axel Thomson, from The Queen's Medical Research Institute in Edinburgh, said: "Our previous research identified a number of 'puppet-master' genes - so called because they enable fibroblast cells to control the growth of other cells during the formation of the prostate in the embryo.
"In this follow-up study we found that activating these genes in fibroblasts in tumours enabled us to significantly reduce the growth of prostate cancer in mice.
"This is an extremely exciting development that has the potential to form the basis of a revolution in prostate cancer treatments over time if replicated in humans.
"By targeting the fibroblasts that control the growth of the cancer these new treatments could be both more effective and likely to lead to significantly fewer side effects."
Dr Rachel Macdonald, research manager at the charity Prostate Cancer UK, which funded the study, said: "This is an extremely encouraging development which could have positive and far-reaching consequences for prostate cancer treatments in years to come.
"To date, most prostate cancer research has focused on exploring the cancerous cells within the tumour.
"By investigating the behaviour of the non-cancerous cells which control tumour development, the team has been able to make this groundbreaking discovery."
Each year, more than 40,000 men in the UK are diagnosed with prostate cancer, and around 11,000 die from the disease.
Prostate Cancer UK recently launched its MANifesto campaign, which included a major boost in research funding.
Over the next three years, the charity will triple its research spending to £25 million.
The research appears in the journal Disease Models & Mechanisms.