Vaccines are all the rage. We are in the middle of the flu vaccination season. We wait with hope for favorable news about the vaccine to combat COVID-19. The pseudoscientific discourses of those who deny the value of vaccines, once accepted by many, are today being silenced by common sense. The status does not invite frivolity. And in this favorable environment towards vaccines, it is worth asking ourselves, can we also be vaccinated against cancer?

Vaccines teach our immune system to recognize and eliminate dangerous agents. This reduces the risk of contracting a disease by activating our natural defenses against the invading organism.

Protection against diseases such as measles, chickenpox, influenza and, of course, covid-19 immediately come to mind. All of them infectious diseases. The World Health Organization recognizes more than 25 types of vaccines to prevent as many potentially fatal infectious diseases. It is estimated that immunization prevents between two and three million deaths each year.

What might seem surprising is to learn that some vaccines are used to prevent cancer development . Two such vaccines are in common use today. The human papillomavirus vaccine targets strains of this virus that cause cervical or throat cancers, among others. The hepatitis B vaccine prevents some cases of liver cancer. Both are vaccines that protect against the appearance of cancer, i.e. they have a prophylactic function.

Lung cancer vaccine

Could we one day have a prophylactic vaccine to prevent the deadliest cancer we know of, lung cancer? It seems unlikely, since lung cancer is not caused by a virus or bacteria. This disease, from which more than 2 million people die every year in the world (more than 20,000 in Spain), is caused by damage to the genetic material caused by non-infectious agents, mainly carcinogens from tobacco.

Each lung cancer is an entity with its own genetic alterations. None of these alterations is common to all lung cancers. Therefore, it does not seem a simple task to develop a vaccine against an element common to all lung cancers.

But this does not mean that we have to give up on a lung cancer vaccine.

There are also therapeutic vaccines, designed to enable the immune system to eliminate tumors already present in the body. The existence of these vaccines is almost as old as that of prophylactic vaccines.

Father of cancer immunotherapy

In the late 19th century, William Coley observed that febrile infections in some of his patients were associated with regression of cancer. From these observations he deduced that cancer patients could be treated with therapies that stimulate the immune system against tumors. Dr. Coley is considered the father of cancer immunotherapy.

We may never be able to prevent lung cancer with a vaccine, but, thanks to immunotherapy, the day may come when a vaccine will help fight existing lung cancer. The idea is to teach the immune system how to recognize cancer cells as something foreign, which needs to be eliminated.

Some patients with prostate cancer or bladder cancer are already being treated today with therapeutic vaccines. But this possibility does not yet exist for lung cancer patients, beyond the context of clinical trials.

The latest scientific advances invite optimism

Several attempts have already been made to develop a therapeutic vaccine against lung cancer. So far, the vaccines evaluated have not demonstrated a clear clinical benefit. However, the latest scientific advances invite optimism.

The development of massive sequencing technologies is allowing the design of vaccines adapted to each patient. It is now possible to generate genetically modified immune cells with improved antitumor properties, the so-called CAR-T cells. Finally, vaccines can be combined with drugs such as anti-PD-1/PD-L1 and anti-CTLA-4 antibodies that enhance the antitumor response.

The technology is there. It now needs to be put to work to demonstrate its clinical utility. Numerous clinical trials are underway in lung cancer patients using vaccines based on the latest technological advances and knowledge. These vaccines are developed individually for each patient. A clear example of personalized medicine.

The development, in the 20th century, of vaccines for diseases such as measles, smallpox, polio, mumps or rubella saved, and continues to save, countless lives.

Why not imagine that in the 21st century we will develop vaccines against the main types of cancer? To this end, let us make a firm commitment to biomedical research and trust in its fruits.

This article was originally published in The Conversation. Read the original.