Although the COVID-19 pandemic was a period of grief and stress for most of us, it also created the necessary conditions to bring something out of science fiction to life: a cancer vaccine. 

For years, scientists worldwide have been experimenting with messenger RNA (mRNA) vaccines, unable to secure the funding or interest to reach the answer. This is due to the fact that mRNA degrades very quickly, leaving vaccine companies hesitant to invest. 

However, once it became clear that mRNA-based vaccines were necessary to curb the pandemic, governments around the world devoted all their resources to their development. Not only did this lift us out of our lockdown purgatory, but it also opened the scientific world to a whole new avenue of exploration. 

What is an mRNA vaccine?

A molecule of mRNA takes the information from the nucleus of a cell — where the genetic code is kept — to where the proteins are made. Essentially, it carries the blueprints from the office to the construction site. Where mRNA vaccines differ from regular vaccines is that while regular vaccines use small amounts of the virus itself, mRNA vaccines do not contain any viral material. Instead, they just have proteins around their surface to make them look like they do. When used in a vaccine, the mRNA injected into your arm will have been made synthetically to contain a viral spike protein, like a virus’ clothes. 

Spike proteins bind and fuse with the target antigen’s membrane, appearing all over the cell so that it looks like a virus. Antigens are markers in toxins that evoke an immune system response. White blood cells — the immunity cells that protect you against disease — are trained to look for these spikes and attack the cells they identify. So, inserting this specific spike protein gene into the mRNA will teach your body how to kill the virus it presents.

Introducing your body to a virus as a vaccine teaches your immune system to recognize and kill it without getting overwhelmed, as with a real infection. To kill the virus-like protein the vaccine introduced, the body will produce antibodies that learn what the protein looks like and how to kill it. This is so that the next time the actual virus enters the bloodstream, the antibodies will recognize it, and the immune system will know how to defend itself.

Clinical advances

Lung, breast, prostate, skin, blood, and urinary tract cancers are all showing promising results from several mRNA vaccines currently being tested in clinics. 

One of the notable lung cancer trials is in phase 2 of testing an mRNA vaccine on the antigens found in the lung tumours of patients. The results are encouraging, showing a robust activation of T cells — immune system cells — and meeting the requirements to be deemed completely safe for trial patients. 

Early treatment is key to remission — abatement of symptoms in a patient — from breast cancer. A vaccine already circulating in one’s body would eliminate the cancerous cells the minute they appear rather than trailing the disease’s progression between checkups. One promising trial approaches the disease with the FixVac vaccine, a vaccine with breast cancer-related antigens.

In this case, antigens such as MUC1, human epidermal growth factor receptor 2 (HER2), carcinoembryonic antigen (CEA), and WT1 are targeted. These are all produced by genes that, when too many copies are made, turn cancerous. This method is especially innovative because it specifically targets different tumour types instead of a general treatment for the cancer. Targeting specific tumour types is more effective because each tumour will produce its own specific antigen. 

More advances have been made in the vaccines’ targeting of other types of cancers, all of which are moving forward with their clinical trials. mRNA vaccines are also advantageous for a number of other reasons: they are non-infectious and — most importantly during the pandemic — quick and cheap to produce! 

Of course, some drawbacks are still being addressed. The foremost roadblock is the delivery of the mRNA into our systems — something that must be as efficient as possible so that not a single cancerous cell is allowed to proliferate out of control. 

mRNA is not very stable, as their high production rate often results in mistakes in their coding. They are therefore designed to be very easily degradable to make sure no mutated mRNAs are encoded in our DNA. Researchers are addressing these drawbacks by exploring chemically modified genetic data within the mRNA, which would protect against degradation and generally enhance the expression of the proteins.

Despite these challenges, cancer vaccines are poised to revolutionize the world of medical oncology — saving millions of lives and alleviating a great amount of fear for ourselves and our loved ones. These vaccines could redefine the future of healthcare.