Photo courtesy of NIH Image Gallery via Flickr.
By Silas Gemma ’26
Science & Environment Editor
Amidst the maelstrom of novel cancer treatments featured in the news, cancer vaccines have become a rapidly advancing method for preventing, treating and personalizing cancer medicine.
According to the Cancer Research Institute, various cancer vaccines either exist or are currently being tested in clinical trials. However, unlike vaccines for influenza and COVID-19, many of them are not meant to be preventative. Instead, cancer vaccines may help the immune system attack pre-existing cancerous cells based on their specific mutations, making them more of a treatment than a prophylaxis — a measure meant to prevent the spread of disease.
While vaccines are typically considered preventative treatments, an article by the Cancer Research Institute reported that cancer vaccines can also be therapeutic or personalized. Preventative cancer vaccines include the hepatitis B virus vaccine and the human papillomavirus vaccine. Since these two viruses are associated with the development of particular types of cancer, reducing the risk of developing these viruses decreases the risk of developing the associated cancers.
Therapeutic vaccines have been produced for cancer treatment using the knowledge of how certain cancer cells behave relative to healthy cells. Cancer Research Institute reported that prostate cancer has been treated by creating a vaccine that targets a protein that is often overexpressed by cancerous prostate cells. In this way, vaccines can be used not only as prophylactic measures but also as therapeutic agents that have cellular specificity. As a result, patients have a reduced risk of damage to their healthy, unaffected cells.
The Cancer Research Institute also explained that personalized cancer vaccines that are even more selective are being developed to target specific gene mutations within cancer cells. Creating a genetic profile of cancer cells allows treatment to be tailored to each patient. According to the American Association for the Advancement of Science, lower costs of DNA sequencing over the past decade have made it more accessible for use in personalized treatments.
The Cancer Research Institute reported that these vaccines aim to attack mutations only present in diseased cells, sparing other healthy cells. According to the National Library of Medicine, immune cells are especially sensitive to these cancerous abnormalities because they more easily recognize them as foreign. Therefore, these treatments can equip the immune system against tumor-specific antigens.
The Center for Personalized Cancer Vaccines at Dana-Farber Cancer Institute described these individualized cancer vaccines as directors and orchestrators of T-cells, which Cleveland Clinic defines as immune cells that rally to attack foreign immune invaders. According to DFCI, these vaccines can redirect T-cells to specific targets on cancer cells, namely the aberrant mutations that cause physiological disruption.
In this way, as Cancer Treatment Reviews explains, these vaccines serve as active immunotherapies, directing immune responses against specific targets rather than simply harnessing pre-existing cancer-fighting mechanisms.
However, as Genetic Engineering and Biotechnology News explained, personalized cancer vaccines can come with high costs and inefficient production. Therefore, a more feasible option may be to synthesize vaccines that target mutations common across various patients with a particular type of cancer.
The same article reported that a vaccine targeting a specific mutation in pancreatic and colorectal cancer cells has yielded promising results in a clinical trial, with 84% of participants demonstrating a decrease in the amount of tumor DNA in their bloodstream and 24% of patients having complete clearance of tumor DNA.
Additionally, results from this trial suggest that these personalized vaccines may increase the response and quantity of T-cells. Patients that demonstrated this increased response of T-cells also tended to have postponed relapse, which is attributable to an event that Cancer Treatment Reviews dubbed “immunological memory.”
According to the American Association for the Advancement of Science, personalized vaccines condition T-cells to respond to foreign antigens specific to cancer cells by exposing them to neoantigens — abnormal proteins found in cancer cells. This prevents immune cells from attacking antigens in healthy cells.
The same article drew parallels to COVID-19 vaccines. Like COVID-19 vaccines, many of the new cancer vaccines are mRNA vaccines, meaning that they harness the ability of mRNA to generate proteins by instructing it to produce neoantigens. According to the National Library of Medicine, the COVID-19 pandemic has inspired renewed research into vaccine delivery methods, therefore allowing strategies employed in the production of the COVID-19 vaccine to be adapted for use in cancer vaccines.
The Science article added that these vaccines are often coupled with other immunotherapies, such as checkpoint inhibitors, drugs that prevent cancer cells from circumventing destruction by T-cells. The coordination of more than one cancer-fighting tool may allow for more effective treatment, as the Dana-Farber Cancer Institute pointed out that using more than one immunotherapy may ensure tumor — or protein — specificity, reducing the risk of deleterious or lethal effects on healthy cells.
Cumulatively, these results suggest that targeted cancer vaccines may be a new frontier of cancer therapy. According to the American Association for the Advancement of Science, by harnessing the immune system’s inherent ability to combat foreign substances, novel cancer therapies can direct it to launch focalized and mutation-specific attacks against cancerous cells while sparing healthy cells, increasing recovery rates and preventing relapse.
Per the Cancer Research Institute, vaccines meant to prevent viruses that have been linked to cancer are already in use. However, more personalized cancer vaccines are still in the animal-testing phase and are not yet available in clinical settings. Nonetheless, according to the American Association for the Advancement of Science, advances in DNA sequencing and vaccinology have allowed for accelerated development of cancer vaccines, which offer the possibility of future use for various types of cancer and cell mutations.
