French researchers have developed a blood test that can predict the rate of progression of a tumor and the risk of recurrence.
Predict the risk of cancer recurrence, from a simple blood test. The promise may sound too good. And yet, three French teams are working on this project. Composed of researchers from the Atomic Energy Commission (CEA), Paris-Diderot University and doctors from Saint-Louis Hospital (AP-HP), the group has developed a blood test capable of anticipating the outcome of bladder cancer from two markers.
To define these biomarkers, practitioners profiled the tumors of 100 Parisian patients. They found that an antigen, usually expressed during pregnancy, is also present on the surface of tumor cells: HLA-G.
Normally, HLA-G helps moderate the action of the immune system. During pregnancy, for example, this molecule prevents the fetus from being recognized as a foreign body and from being attacked by the mother’s immune cells. But in cancer, this reaction is counterproductive.
Disrupted lymphocytes
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, it would therefore be possible to anticipate the speed at which the disease will progress.
But HLA-G is not the only function to be disturbed by the presence of a tumor. Some lymphocytes too. 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 lymphocytes. Tumors can benefit from this.
Double prognosis
The French relied on these two disturbances to develop their blood test. In fact, the proportion of CD8 + / ILT2 + cells makes it possible to predict the risk of recurrence. In patients with an ILT2-carrying lymphocyte count greater than 40%, the likelihood of relapse is high. Conversely, if the rate is less than 20%, this risk is considered low.
If brought to the market, and patented, this blood test will have the potential to perform a dual function. This is very useful for medical teams, who can then adapt the treatment of the patient. All using a minimally invasive method. As a reminder, in 2015 bladder cancer affected more than 12,000 French people and killed nearly 5,000.
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