2023-06-19 06:47:37
Pancreatic cancer is one of the deadliest types of cancer in the world. This is largely due to the fact that the symptoms of this cancer generally only appear at an advanced stage of the disease: for very many patients, it is therefore too late to resort to surgery to remove the tumor. – which remains the current best method of treatment.
Even in patients whose tumors have been removed, the risk of the cancer coming back is very high.
But the results of a recent study, published in the journal Nature, suggest that our immune system might be a tool to be used more in the treatment of pancreatic cancer. This research showed that a personalized cancer vaccine was able to stimulate the immune system in half of the patients who received it.
This enhanced immune response was still detectable in these patients a year and a half later.
To understand how this vaccine works, you must first understand the role the immune system plays in preventing cancer.
Immune system and cancer
Our immune system is often effective in fighting cancer, here’s why: a healthy cell has markers on its outer membrane that allow immune cells to identify it correctly. Conversely, on an abnormal cell, the markers are modified. It can therefore be targeted by our defense mechanisms.
Unfortunately, some cancer cells have other types of surface proteins that help them hide from our protective cells… Not recognized as dangerous by our immune system, they are not destroyed.
However, scientists have found a way to block these proteins, so that our immune system is once once more able to recognize cancer cells as a threat and eliminate them.
Immunotherapy, one of the newest cancer treatment techniques, does just that: these therapies harness the power of our immune system.
Antitumor immunotherapy with immune checkpoint inhibitors – Guido4 / Wikimedia CC BY-SA 4.0
There are several types of immunotherapies, but one promising new technique is the use of mRNA vaccines. These use genetic material to stimulate the immune system.
A cancer vaccine?
Cancer cells are characterized by the presence of numerous mutations in their DNA. To create a vaccine that can work once morest them, scientists start by taking their genetic material to identify the most altered parts – called neoantigens. They then place them in a strand of mRNA, or messenger RNA (these RNAs are much smaller molecules than DNA, because they often correspond to the information of a single gene, and more ephemeral).
If we consider DNA as the hard disk storing all the information that makes up our body, mRNA is in a way the software of each of our cells. Its function is essentially to copy and transmit from the nucleus the genetic instructions of DNA to other parts of the cell.
This mRNA “enriched” with material from cancer cells is then administered to patients in the form of a personalized vaccine. It is personalized because each person has different neoantigens: each person therefore receives a slightly different vaccine, specific to their cancer cells, with their own mutations inserted into the mRNA strand.
Once injected into the patient, the mRNA produces a little cancer…very little, but just enough to stimulate the immune system. The idea is that the patient’s immune system reacts to the cancer and protects our body.
This is how the recent mRNA vaccine once morest pancreatic cancer was developed. Pharmaceutical company BioNtech worked with 16 participants using cells from their recently removed tumors.
Half of the patients saw their levels of immune cells (T cells, here in turquoise, attacking a cancer cell) increase – Design_Cells / Shutterstock
Patients were treated with this personalized vaccine, as well as another form of immunotherapy (the drug Atezolizumaba monoclonal antibody) followed by aggressive chemotherapy.
Half of the patients treated with the vaccine and the combination of immunotherapy saw an increase in a specific type of immune cells (T cells, known to protect once morest cancer). This showed the researchers that, for some participants at least, their immune systems were learning to fight off the cancer.
After 18 months of follow-up, patients with increased T cell counts still showed signs of improved immune response. Most of them also showed no signs of cancer recurrence.
The authors concluded that this may have been because the immune system was successfully boosted, which helped prevent the cancer from coming back. The mRNA vaccine was also well tolerated by patients, with no obvious major side effects.
Immune function
Although the results of this trial are intriguing, the number of patients involved is too small to draw any major – and generalizable – conclusions. It will be necessary to carry out larger trials, in particular so-called randomized studies (with integration of a patient in the treated group or the control group of the trial by drawing lots to avoid bias).
Having a control group not receiving the vaccine would allow researchers, following comparison, to really understand its effect – and whether it really does what it is supposed to do, which is to stimulate the immune system and improve time to recurrence (and ultimately survival).
It would also allow them to see if the vaccine has a distinct effect and if this effect is not due to the other treatments or immunotherapies received by the participants.
However, it is promising to see that we may have a new type of therapy to develop to fight once morest pancreatic cancer.
These findings also underscore the potential of mRNA vaccines for the treatment of cancer in general. Already last year, the results of another study showed that an mRNA vaccine was effective once morest melanoma. Positive news in the face of cancers that remain very hard to treat.
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This article is produced by The Conversation and hosted by 20 Minutes.
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