Undergoing genetic testing for breast cancer creates a "DNA barcode" which can help transform treatment for the deadly cancer and make it more personalised to each patient, scientists say.
According to doctors at the Britain's Cambridge University, mapping the genetic code could help them choose the right treatment as well as predict whether patients are likely to experience side effects, the BBC reported.
It can also reveal whether their cancer, the second most common cancer in women, is becoming resistant to treatment.
"Breast cancer is not one but 10 or 11 diseases that are distinct molecular entities... By sequencing the tumour we have something like a barcode which gives us the pattern of mutations in that cancer," Carlos Caldas, professor at the varsity, was quoted as saying.
The genome sequencing can detect whether patients have inherited mutations in BRCA1, BRCA2 genes which increases their risk of both breast and ovarian cancer. The findings can also have implications for their family.
"We can understand how the body and in particular the immune cells are responding and this enables us to deliver more precision in the medicine," Caldas said.
"This barcode also enables us to do surveillance and identify early whether a tumour is coming back because of developing resistance to treatment. When those cells start releasing their DNA we can detect them in a blood test known as a liquid biopsy," he noted.
Launched in 2016, the varsity's Personalised Breast Cancer Programme has mapped the entire genetic code of nearly 300 women diagnosed with breast cancer, the report said.
These women have a sample of their tumour and of their blood sent for sequencing, with the full results coming back within 12 weeks.
"We want to reduce the number of toxic drugs that we give to patients, and where possible treat them with targeted therapies with fewer side effects," Alejandra Bruna, molecular biologist at the varsity, was quoted as saying.