The vaccine strips away that camouflage.
En los laboratorios y clínicas de más de una docena de países, la medicina oncológica está reescribiendo su relación con el sistema inmunitario humano. Las vacunas terapéuticas contra el cáncer —distintas de las preventivas— llegan después del diagnóstico para enseñarle al cuerpo a reconocer y destruir las células malignas que ya lo habitan. Ensayos recientes han reducido la recurrencia del melanoma casi a la mitad y eliminado tumores completos en pacientes de once países, señalando que este enfoque no es una promesa lejana, sino una realidad en construcción. La pregunta que guía a la ciencia ya no es si estas vacunas funcionan, sino con qué velocidad pueden llegar a quienes más las necesitan.
- Una vacuna contra el melanoma redujo el riesgo de recurrencia y muerte en un 49%, mientras que un ensayo en once países logró eliminar tumores completos con una vacuna de triple acción.
- Millones de pacientes con cánceres avanzados —de pulmón, vejiga, páncreas y colon— enfrentan opciones limitadas y pronósticos inciertos, lo que convierte cada avance en una urgencia clínica real.
- La diversidad de enfoques es global: desde la BCG estadounidense para vejiga hasta la CimaVax-EGF cubana para pulmón, pasando por vacunas de ARN mensajero inspiradas en la tecnología COVID-19.
- Los investigadores combinan vacunas terapéuticas con inhibidores de puntos de control inmunitario para potenciar la respuesta del cuerpo, apuntando a coberturas del 90% en algunos tipos de cáncer.
- El campo avanza hacia vacunas personalizadas y de bajo costo que podrían democratizar el acceso, aunque la mayoría aún transita fases de ensayo clínico antes de llegar al paciente común.
La vacuna contra el cáncer no previene la enfermedad: llega después del diagnóstico para despertar las defensas del propio cuerpo y dirigirlas contra la malignidad ya instalada. Dos resultados recientes han confirmado lo que los investigadores sospechaban desde hace años: una vacuna redujo el riesgo de recurrencia y muerte por melanoma en casi la mitad, y un ensayo en once países eliminó tumores completos en pacientes con cáncer ya desarrollado. No son victorias aisladas, sino señales de que la oncología está girando hacia un nuevo paradigma.
Estas vacunas terapéuticas pertenecen a la familia de las inmunoterapias. A diferencia de las vacunas preventivas —como la del papilomavirus, que bloquea más del 90% de los cánceres relacionados antes de que aparezcan—, estas actúan sobre un enemigo ya presente. Enseñan al sistema inmunitario a identificar marcadores específicos en las células cancerosas, llamados antígenos, que no existen o son escasos en las células sanas. Una vez aprendida la lección, el sistema inmunitario los recuerda durante años, ofreciendo una protección duradera.
El panorama de vacunas disponibles es ya diverso y global. En Estados Unidos, la BCG trata el cáncer de vejiga en estadios tempranos desde los años noventa. La tecnología de ARN mensajero, la misma que produjo las vacunas contra el COVID-19, impulsa ahora la BNT116 de BioNTech para el cáncer de pulmón. Cuba desarrolló durante veinticinco años la CimaVax-EGF, que ha extendido la supervivencia en pacientes con carcinoma pulmonar de células no pequeñas y cuyo bajo costo la hace accesible en entornos con recursos limitados. En Estados Unidos, el Instituto Roswell Park recibió autorización especial para utilizarla.
La frontera sigue expandiéndose. Investigadores de la Universidad de California y el Memorial Sloan Kettering trabajan en ELI-002 2P, orientada a tumores pancreáticos y de colon, con potencial de cubrir el 90% de los cánceres de páncreas con una mutación específica. La combinación de vacunas terapéuticas con inhibidores de puntos de control inmunitario promete amplificar aún más la respuesta del organismo. La medicina ya no concibe el cáncer solo como algo que hay que envenenar desde afuera, sino como un enemigo que el propio cuerpo puede aprender a reconocer y eliminar.
The cancer vaccine is not what most people imagine. It does not prevent the disease. Instead, it arrives after diagnosis, a tool designed to wake up the body's own defenses and turn them against the malignancy already taking root. Two recent developments have crystallized what researchers have long suspected: this approach works. A melanoma vaccine has cut the risk of recurrence and death by nearly half. In a separate trial spanning eleven countries, a three-pronged vaccine eliminated entire tumors in patients who had already developed cancer. These are not isolated victories. They are signals that oncology is shifting, slowly but measurably, toward a new frontier.
Therapeutic cancer vaccines belong to a family of treatments called immunotherapies. Unlike preventive vaccines—like the one against human papillomavirus, which blocks more than ninety percent of HPV-related cancers before they start—these vaccines work on an enemy already inside the body. They teach the immune system to recognize specific markers on cancer cells, called antigens, that either do not exist on healthy cells or exist in much smaller amounts. Once the immune system learns to spot these markers, it mobilizes to destroy the cells carrying them. The elegance of the approach lies in its memory: the immune system remembers these targets long after the vaccine is administered, potentially offering protection that extends years into the future.
Cancer cells are not invisible to the body's defenses—they are simply good at hiding. The vaccine strips away that camouflage. It can work in three ways: preventing cancer from returning after treatment ends, eliminating any remaining cancer cells left behind, or halting the growth and spread of existing tumors. The mechanism is straightforward in concept but complex in execution. Some vaccines are made from cancer cells themselves, or fragments of them, or pure antigens extracted from tumor tissue. Others use the patient's own immune cells, extracted and trained in the laboratory before being reintroduced into the body. Many are combined with adjuvants—helper substances that amplify the immune response. A few are built from bacteria or viruses engineered to trigger a specific immune reaction.
The landscape of available vaccines is already diverse and global. In the United States, the BCG vaccine—derived from a bacterium related to the one that causes tuberculosis—has treated early-stage bladder cancer since the 1990s, delivered directly into the bladder where it provokes the immune system to attack cancer cells. For patients whose bladder cancer resists BCG, nadofarageno firadenovec offers an alternative: a virus that carries a gene instructing bladder cells to produce interferon, a protein that summons immune cells to the fight. Sipuleucel-T, approved in the United States since 2010 but not yet in Spain, uses dendritic cells—immune cells trained in the laboratory—to treat advanced prostate cancer in some men. Germany's BioNTech has developed BNT116, an experimental vaccine for lung cancer built on messenger RNA technology, the same platform that produced COVID-19 vaccines during the pandemic. This vaccine uses encoded RNA to express antigens that trigger an immune response directed only at cancer cells, sparing healthy tissue the collateral damage of chemotherapy.
Cuba's contribution to this field is CimaVax-EGF, a vaccine for non-small-cell lung carcinoma developed over twenty-five years at the Center for Molecular Immunology in Havana. It has extended survival, particularly in patients under sixty, and carries low toxicity. Its cost is modest, making it accessible in resource-limited settings. The vaccine has even reached the United States through a special authorization granted to Roswell Park Cancer Institute. Russia has developed Enteromix, a personalized vaccine still in testing phases, which authorities claim showed one hundred percent efficacy in preclinical studies. The University of California and Memorial Sloan Kettering are collaborating on ELI-002 2P, designed for pancreatic and colon tumors, which entered its second development phase in 2025 and could eventually cover ninety percent of pancreatic cancers and fifty percent of colon cancers carrying a specific mutation.
The frontier is expanding. Researchers are refining how they identify the precise targets for these vaccines, working to destroy cancer cells more effectively. Messenger RNA technology is opening new possibilities. Scientists are exploring combinations of therapeutic vaccines with checkpoint inhibitors—another class of immunotherapy that removes the brakes cancer places on the immune system, allowing it to fight harder and longer. Each trial, each approval, each new vaccine in development represents a shift in how medicine approaches cancer: not as a disease to poison out of the body, but as an enemy to be recognized and eliminated by the body's own intelligence. The question is no longer whether these vaccines work. It is how quickly they can be refined, combined, and deployed to the patients who need them.
Notable Quotes
These vaccines teach the immune system to recognize specific markers on cancer cells that either do not exist on healthy cells or exist in much smaller amounts.— Medical understanding of therapeutic cancer vaccines
Unlike chemotherapy, which targets both cancer and healthy cells, the immune response from mRNA-based vaccines is directed only at cancer cells.— Mechanism of BNT116 and similar mRNA vaccines
The Hearth Conversation Another angle on the story
Why call these cancer vaccines if they don't prevent cancer the way a flu shot does?
Because they train the immune system the same way preventive vaccines do—by teaching it to recognize a specific threat. The difference is timing. A preventive vaccine prepares defenses before the enemy arrives. A therapeutic vaccine mobilizes them after the invasion has already begun.
So the immune system was already fighting the cancer, and the vaccine just makes it better at it?
Exactly. Cancer cells hide by looking like normal tissue. The vaccine removes that disguise. It shows the immune system what to look for—specific markers on the cancer cell surface—and then the body's own defenses do the destroying.
If the immune system has memory, does that mean someone vaccinated against their melanoma won't get melanoma again?
Not necessarily. The vaccine reduces the risk of recurrence by about half, based on recent trials. But cancer is unpredictable. The vaccine is a powerful tool, not a guarantee.
Why are there so many different vaccines? Are some better than others?
They're designed for different cancers and use different approaches. Some use the patient's own immune cells. Others use messenger RNA. Some use bacteria or viruses as delivery systems. The best one depends on the cancer type, the patient's condition, and what's been proven to work. There's no single answer yet.
Cuba developed one of these vaccines? How is that possible?
Twenty-five years of focused research at one institution. CimaVax-EGF extends survival in lung cancer patients and costs very little to produce. It's now being tested in the United States. Sometimes the breakthrough comes from unexpected places.
What happens next? Are these vaccines going to replace chemotherapy?
Probably not entirely. But they're being combined with other immunotherapies and traditional treatments to make them more effective. The future is likely a mix of approaches tailored to each patient's specific cancer.