Cancer is most deadly when it spreads. An international team of researchers – led by Professor Thierry Voet (Wellcome Trust Sanger Institute and KU Leuven) and Professor Peter Van Loo (Francis Crick Institute and KU Leuven) among others – has now shown that breast cancer spreads to other parts of the body relatively late.
The researchers also discovered that these late-to-spread cells are genetically very similar to the cells of the diagnosed tumour in the breast. “This knowledge may help choose the most effective treatment for breast cancer,” explains Jonas Demeulemeester (Francis Crick Institute / KU Leuven). “After all, a treatment that targets a specific mutation in the cells of the breast tumour is most likely to have effect when the cancer has spread.”
The researchers collected samples from the tumour and the bone marrow of six patients with breast cancer. They then compared the genetic changes or mutations in the breast tumour with the ones found in different cells in the bone marrow. The researchers used the latest single-cell sequencing techniques, which allow for the detection of mutations in individual cells.
The detailed genetic information also led to the discovery of cells in the bone marrow that have mutations, yet did not break away from the tumour. The distinction with the real cancer cells may help give breast cancer patients a more accurate prognosis in the future. “Our focus in this case is only on the number of real tumour cells in the bone marrow: the more cells, the poorer the prognosis.”
In the next stage, the researchers will examine the role of the cells in the bone marrow that have mutations without being actual cancer cells. “These cells have different mutations than the original tumour. We want to examine the role of these cells in the development of cancer,” Demeulemeester adds.
This research project was specifically about breast cancer, but the researchers believe that their results may also apply to other types of cancer.