UK researchers have developed a three-dimensional model of human breast cancer in the laboratory.
The researchers grew breast cancer cells alongside normal cells
The model, which includes normal cells and tumour cells, should help experts understand how breast cancer develops in the early stages.
And it may replace the need for experiments in animals, the team at Queen Mary, University of London said.
More women are being diagnosed with cancer in the early stages and the model could lead to new treatments.
The model replicates a specific type of early breast cancer - known as ductal carcinoma in situ (DCIS).
Around one in five breast cancers start out as DCIS and the researchers wanted to find out more about how the early cancerous changes in cells grow into larger tumours.
Professor Louise Jones, professor of breast pathology at the Institute of Cancer at Queen Mary, University of London, explained that they needed to develop a test tube model that was more complex than a layer of cells in a Petri dish.
Instead the team grew three types of cells from normal and cancerous breast tissue.
And using a collagen gel to form three-dimensional structures they have been able to create structures which closely resemble the ways the cells would be organised in the breast.
They discovered that one type of cell - myoepithelial cells - from healthy breast tissue can suppress the growth of breast cancer cells, but this ability is absent in cancerous breast myoepithelial cells.
Also, fibroblasts obtained from tumours disrupt the structure of the glandular-like cell cultures, but healthy fibroblasts do not.
Professor Jones said working out why the cells behave like this could help doctors decide which patients with early cancer to treat and pave the way for developing new treatments.
The model could also replace the need for some experiments which are done in animals such as mice, which can be implanted with human tumours.
Mouse models of cancer differ from the human condition, and there has been a growing interest in developing alternatives.
Professor Jones said: "We grew the cells in three dimensions which allows them to form structures similar to the structures found in breast tissue.
"We feel this is a huge advance, we've started to get the complexity which we normally get with animal experiments.
"Once this is validated it could certainly reduce if not replace animal experiments.
Professor Jones added: "Because of screening, we're detecting DCIS much more frequently and so it's become much more of a clinical problem."
Nicky Gordon, science officer at the Dr Hadwen Trust, who funded the research said: "With breast cancer, there is an urgent need to move away from animal research models because their similarity to human cancer can be so poor.
"Unreliable research costs valuable time, money and lives - animal as well as human - so we are delighted that our three-dimensional breast cancer model is looking so promising.
"Further work is needed but the signs are good and this really could revolutionise breast cancer research."
Dr Julie Sharp, Science information officer at Cancer Research UK, said: "This technique offers a new way of studying early breast cancer in the lab.
"If it lives up to its potential this method could reduce the need for animal models for this type of research."