The vaccine is a biologic preparation that contains the particular agent made from weakened or killed forms of the microbe (virus, bacteria). The agent stimulates the body's immune system to recognize it as a threat and destroy it. In the future, your system will recognize and destroy any of the microbes associated with that agent that it may encounter.

There is two kinds of cancer vaccines:

1. prevent vaccines
2. treatment vaccines

Usual vaccines prevent and help the system against infections. Many people might not realize it, but some cancers are caused or helped by viruses ! These vaccines might also help prevent some of these cancers.

• human papilloma virus (HPV) can lead to cervical, anal and throat cancers.
• hepatitis B virus (HBV) can lead to liver cancers.

Most of cancers are linked to a mutation phenomenon that lead to a set of dysfunctional cells. Therefore none all cancers can be treated with this technique.

Now that is interesting ! Cancer treatment vaccines, also called therapeutic vaccines, are a type of immunotherapy. Cancer treatment vaccines are different from the vaccines that work against viruses. These vaccines try to get the immune system to mount an attack against cancer cells in the body. They can prevent the cancer from coming back, get the immune system to attack cancer cells that already exists and stop a tumor from growing or spreading.

Some cancer treatment vaccines are made up of cancer cells, parts of cells, proteins or pure antigens. Researchers try to find specific cells ' features that can be used by our immune system.

Sipuleucel-T (Provenge ®) is the only one, currently used to treat advanced prostate cancer. For this treatment, we remove some leukocytes from the patient and expose them to a protein called prostatic acid phosphatase (PAP), which should produce an immune response against prostate cancer cells. After that we give back these cells to the patient.
This vaccines do not cure cancer but extend the lifetime of the patient.

But for now, results are not good enough to prescribe for cancer patients.

However, a vaccine test on mice have recently gives good results.

The study on mice consisted to cure different cancers like lymphoma, breast cancer and colon cancer . This treatment has eliminated 97% of the tumors. As the others treatment vaccines, they stimulate the immune system of the body to attack cancer cells. Lymphoma as leukemia can spread the tumors to other parts of the body, and even in this case the vaccines worked.

How it works ?
It is a similar process as before. Researchers have injected a modify version of lymphocytes T (kind of leukocyte) that has already recognized cancer-specific proteins inside the tumor, in the past. Indeed, the dysfunction of cancer-cells they produce specific proteins. Firstly, lymphocytes are used to attack cancer-cells and stop the attack when the tumor grows. Researchers have just reactivated this functionality.
Besides, they noticed that thanks to the immune system memory these lymphocytes prevented the occurrence of future tumors in many cases.

So, researchers from Stanford University will test the therapy in about 35 people with lymphoma by the end of the year.

"We've [gone] one step further down the road" to an immunotherapy for these cancers, Police said. "But it's [still] a long way to go."

PS: This is my first post on steemit, I will be grateful if you can give me a feed back. Also, sorry if the post contain some syntactic mistakes, I am also here to improve my English level. 😁