Is immunotherapy, which is called a new hope for advanced cancer, really that miraculous? Let's hear what doctors say

If we were to select the star in the field of anti-cancer in the past two years, it would undoubtedly be immunotherapy, which is called the new hope for advanced cancer. As a new method of treating cancer, it is called the fourth treatment method for cancer after surgery, radiotherapy, and chemotherapy. The emergence of immunotherapy has changed the fate of many patients with advanced tumors. In recent years, it has been favored by more and more doctors and patients, and the American scientist James P. Allison and the Japanese scientist Tasuku Honjo, who studied it, also won the 2018 Nobel Prize for this. Despite this, I believe that many people are still hearing about immunotherapy for the first time, so what exactly is immunotherapy? Is it really that magical?

What is immunotherapy? Immunotherapy refers to the use of the immune system to treat diseases. We divide it into activation immunotherapy and suppression immunotherapy, which treat diseases by inducing, enhancing or suppressing immune responses respectively.

Take cancer for example. Normal people have cancer cells in their bodies, but most of them will not get cancer. This is because the immune system in normal people can detect cancer cells in time and eliminate them. When various reasons cause the human immune system to be impaired and the immunity to decline, some tumor cells in the body will "escape" the pursuit of the immune system, secretly lurk to replicate and gradually grow stronger. In order to prevent the immune system from discovering themselves, smart tumor cells will produce some substances that inhibit the immune system. Immunotherapy can play a role in inhibiting tumors by repairing our immune system again to fight against tumors.

How does immunotherapy fight cancer? Unlike chemotherapy, which kills one thousand enemies but hurts eight hundred of its own, immunotherapy works entirely by improving the body's immune system to suppress tumors.

If the immune system is compared to a policeman and cancer cells are compared to a thief, then cancer often occurs because the thief is too cunning. Either the thief pretends to be a good person so the police cannot find him; or the thief uses some "unconventional methods" to lure the police, so that even if the police find the thief, they remain indifferent.

Immunotherapy is to repair the above two loopholes, help the immune system accurately identify tumor cells, and deal with them in a timely and correct manner.

What are the current methods of immunotherapy? CAR-T immune cell therapy

In response to the situation where the police (immune cells) always fail to find the thief (cancer cells), scientists invented CAR-T immune cell therapy. By genetically transfecting T cells, it is easier to identify and find cancer cells, thereby mediating T cells to kill cancer cells. CAR-T is a genetic transfection of T cells, which enables them to express antibodies that specifically recognize tumor cells on their surface, thereby mediating T cells to kill cancer cells. CAR-T immune cell therapy became famous when Carl H. June used CAR-T therapy to cure a 6-year-old girl's leukemia.

In response to the situation where the police (immune cells) discover the thief (cancer cells) but remain indifferent, scientists have invented immune checkpoint inhibitors. Immune checkpoint inhibitors can help the police regain their fighting power and thus eliminate cancer cells.

Immune checkpoint inhibitors include CTLA-4 inhibitors, PD-1 inhibitors, and PD-L1 inhibitors. Among them, PD-1/PD-L1 inhibitors are the most popular due to their smaller side effects and greater effects.

When it comes to immune checkpoint inhibitors, we have to praise the cunning of tumor cells. The human body can express PD-L1 on the surface of cells, and PD-1 on the surface of immune cells. When they meet, the two combine and the immune cells will not attack each other. Tumor cells just discovered this, so they also copied their own PD-L1 protein to make the immune cells give up attacking themselves, thus avoiding this disaster. Both PD-1 inhibitors and PD-L1 inhibitors can prevent this mispairing from happening and restore the immune cells' attack on tumor cells, thereby playing a role in fighting tumors. It can be said that this is a new idea for treating tumors.

In short, immunotherapy is to use the body's own immune system to fight tumors. At present, compared with targeted drugs that are prone to drug resistance, the prospects of immunotherapy are brighter. With the deepening of research, we have reason to believe that cancer immune precision medicine will be closer and closer to us.