Defects in a gene, called p18, have been found to be the cause of the most common form of breast cancer, say scientists.
Researchers at the University of North Carolina at Chapel Hill School of Medicine and UNC Lineberger Comprehensive Cancer Center, say that their discovery, if combined with new laboratory techniques, could help scientists identify and test new treatments for luminal-type tumours,
Luminal-type tumours account for between 70 and 80 percent of all breast cancers, but are generally slower growing than other types.
Defects in the p18 gene have been observed in different types of human cancer.
"When this gene is not expressed or is deleted, cells have no braking mechanism. They will continue to grow and divide until they turn into cancer," said senior study author Dr. Yue Xiong.
For the research, the team specifically targeted the role that p18 plays in the development of luminal breast cancers.
By using genetically engineered mice with deletion of p18 genes, they created a highly reliable model of human breast cancers.
The researchers tested the model by analysing the gene in samples from approximately 300 human breast cancer patients.
They proved that the decreased expression of the p18 gene was highly correlated with the development of luminal tumours.
"The mechanism behind these tumours is quite different from that of other forms of breast cancer. Understanding this mechanism and having a good mouse model allows us to specifically test how treatments work against these tumours, which may then benefit human patients," said Xiong.
The results of the research appear in the journal Cancer Cell.