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Personalized Cancer Vaccines: What They Are and Why They Are Still Experimental
Personalized cancer vaccines are designed around features of a person's tumor. Most remain experimental and must be tested in clinical trials.
Original commentary from the Cancer Explained editorial team.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
Two different things share one word
A flu shot teaches the body to fight a germ before it arrives. A cancer treatment vaccine does something else. It is given to someone who already has cancer, and it aims at the cancer cells themselves.
NCI draws that line clearly. Prevention vaccines work against something that causes cancer. Treatment vaccines work against cancer cells. Mixing the two is the most common error in coverage of this field.
What "personalized" adds
Cancer cells carry mutations. Some of those mutations make proteins that do not exist in healthy cells. NCI calls those new proteins neoantigens.
Neoantigens are the flag. In principle, the immune system can be taught to hunt cells that fly it. Because every tumor's mutations differ, that flag differs from person to person.
A personalized vaccine is built from one person's own tumor. Tissue is removed, usually during surgery. The DNA is read. Software picks the mutations most likely to draw an immune response. A product is then made for that one patient.
What the early results actually said
NCI reported on two small trials in 2025. Both gave the vaccine after surgery had removed the tumor.
The pancreatic cancer trial enrolled 16 people. Eight had a strong immune response. Six remained cancer-free, some more than three years after surgery.
The kidney cancer trial enrolled nine people. None had a recurrence. Four were still cancer-free more than three years later.
Side effects in both trials were reported as mild. In many participants, immune cells that recognized the vaccine targets were still in the blood years later.
Why those numbers should slow you down
Sixteen people. Nine people. Neither trial had a comparison group.
Some people who have surgery for these cancers never recur without any vaccine. With groups this small, there is no way to tell how many of these results came from the vaccine and how many would have happened anyway. The research teams said the same thing. Larger trials have started and are needed to confirm the findings.
Read our guide to how clinical trials work for what phase 1 and phase 2 results can and cannot settle.
The approved list is short
NCI lists three ways treatment vaccines are made: from a person's own tumor cells, from antigens shared across many people with one cancer type, and from a person's own dendritic cells. It labels the shared-antigen type as still experimental.
One dendritic cell vaccine has FDA approval. It is sipuleucel-T, used for some men with prostate cancer that has spread, who have few or no symptoms and whose cancer no longer responds to hormone treatment.
A related treatment, talimogene laherparepvec, uses a virus injected into a tumor. It is approved for some people with melanoma that returns after surgery and cannot be removed with more surgery.
That is the approved list. Personalized neoantigen vaccines are not on it.
Side effects are not zero
NCI names flu-like symptoms as common: fever, chills, weakness, aches, and fatigue. Severe allergic reactions can happen. Sipuleucel-T can cause stroke. The virus-based treatment can cause tumor lysis syndrome and herpes infection.
Practical limits
Making a product for one person takes time and tissue. There must be enough tumor to sequence. Someone must pay for it. Trials run at a limited number of centers.
Tumor testing is the entry point for most of this work. Our page on biomarker testing covers what that involves. Personalized vaccines sit inside the wider field of immunotherapy, which includes several approaches with much longer track records.
Before you consider a trial
- Is this a trial, and what phase is it?
- How many people have been treated so far?
- Is there a comparison group?
- What is being measured, and for how long?
- What is the standard treatment I would otherwise receive?
How this article was prepared
An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.
The National Cancer Information Foundation publishes Cancer Explained. This page is for learning. It is not medical advice and does not suggest a test or treatment.
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Put the story in context
Prevention, possible warning signs, screening, and diagnosis
This story relates to Personalized cancer vaccines. The information below is general: it does not reveal anything else about a public person’s health, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
A public story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.