Bladder Cancer : a blood test that predicts the severity
Published the 17.07.2017 at 16: 57
Predict the risk of recurrence of a cancer from a simple blood test. The promise may seem too good. And yet, three French teams are working on this project. Composed of researchers from the Commissariat à l’énergie atomique (CEA), the université Paris-Diderot and doctors of the hospital Saint-Louis (AP-HP), the group has developed a blood test able to anticipate the outcome of a cancer of the bladder from the two markers.
To define these biomarkers, practitioners have profiled the tumors of 100 patients in paris. They found that an antigen normally expressed during pregnancy, is also present at the surface of tumor cells : HLA-G.
In normal times, HLA-G allows to moderate the action of the immune system. During a pregnancy, for example, this molecule prevents the fetus to be recognized as a foreign body and attacked by the immune cells of the mother. But in cancer, this reaction turns out to be counter-productive.
By inhibiting the immune system, HLA-G prevents the destruction of the tumor. The molecule serves as a shield. And cancer can develop. According to the blood results, so it would be possible to anticipate the speed at which the disease will progress.
But HLA-G is not the only function to be disrupted by the presence of a tumor. Some lymphocytes also. CD8 cells are normally responsible for destroying cancer cells. But some of them express a receptor (ILT2) which, when activated, blocks the arrival of new CD8 cells. Tumors can take advantage of them.
The French relied on these two perturbations in order to develop their blood test. In fact, the proportion of CD8+cells/ILT2+ allows to predict the risk of recurrence. In patients in whom the rate of cell holders of ILT2 is greater than 40 %, the probability of relapse is important. Conversely, if the rate is lower than 20 %, this risk is considered low.
If it is put on the market, and patented, this blood test has the potential to fill a dual function. A very useful tool for the medical teams, who can then adapt the management of the patient. All, using a minimally invasive method. As a reminder, the cancer of the bladder is touched, by 2015 more than 12 000 French and has killed nearly 5 000.