Why "Cancer" can not be cured like a cold or infectious disease?

bySimon Fraser University

The disease naturally occurring from our body "cancer"One of the Japanese people takes something cancerAlthough it is said that it is actually a familiar place as it is said to be said, there are many people who do not know exactly why "cancer cells survive with immunity from whatever mechanism and why it is difficult to cure"? An animation depicting the difficulty of treating "cancer" has been made public from "TED" which is open to the experts' lecture on a wide range of fields free of charge.

Why is it so hard to cure cancer? - Kyuson Yun | TED-Ed
https://ed.ted.com/lessons/why-is-it-so-hard-to-cure-cancer-kyuson-yun

The content of the lecture published by TED can be seen in the following movie.

Why is it so hard to cure cancer? - Kyuson Yun - YouTube


Mankind has solved various problems with advanced technology. For example, I scared terror around the worldsmallpoxOvercome ... ...


Human genomeTo analyze the secrets engraved on human genes.


However, there is a problem that it will not be solved even if it searches for billions of yen or more.


It is a solution to the disease "cancer" that plagues many people and families all over the world.


Disease that cancer transforms healthy cells into "cancer cells" due to genetic damage and mutations overlap.


In many cases the cell itself repairs damage or chooses the way to self-destruct, so it will not turn into cancer cells.


However, it rarely produces cancer cells. And as this cancer cell grows nearby cells ... ...


It may also spread to distant organs. Once cancer has metastasized, it is almost impossible to treat.


When cancer occurs, in most cases surgery and radiotherapy are applied to the tumor where the cancer cells are present to remove the majority ... ...


We will combine the remaining cancer cells with chemotherapy, hormone therapy, immunotherapy, and molecular target treatment.


Then the patient is released from cancer, but ...


In this treatment method the success rate is not 100% at present.


Why is not it 100%, in fact, the disease called "cancer" is not a single disease, but over 100 different symptoms are collectively called "cancer". Also, cancer is a surprisingly "complex" trait. And yet there is no magic bullet for every kind.


When we mention three complexities of cancer cells, firstly, as mutation of cancer cells in tumor increases, "cancer cells grow and propagate subclones with different characteristics" There are things.


This property is called "heterogeneity of clones" or "clone heterogeneity", making treatment difficult.


For example, even a therapeutic drug effective for subclone A ...


Subclone B has the characteristic that the therapeutic agent does not work.


The second complication is to "flow information convenient to you for surrounding healthy cells".


As cancer cells live, "nutrition" is necessary just like ordinary cells. Cancer cells are classified as "Connect tumor to blood vesselI will shed convenient information as you can. Then, we use the connected blood vessels to intercept nutrients from healthy cells, further waste the waste and treat it.


In addition, we will also send information to the body's immune system.


By shedding information that diminishes the function of the body's immune system, we prevent foreign objects themselves from being attacked by the immune system.


The last third of the complexity is "cancer stem cells" that resuscitate with the tumor even if they are removed.


In theory, when cancer cells are treated, the rest of the tumor shrinks to such an extent that it can not be detected. However, if one cancer stem cell remains, it will create another cancer cell from there again.


In rare cases, "cancer cells with special characteristics" that neither chemotherapy nor radiation therapy are effective, many researchers say that "means to eradicate cancer stem cells is necessary" It is crowded.


It is also one of the reasons for making cancer "difficult to eradicate" difficult. Regular cancer research will be conducted by culturing human cancer cells in the laboratory.


There were many discoveries in cancer characteristics in this way.


However, cancer cells that have been increased in the laboratory do not have "complexity". For example, even if a drug is effective in a laboratory ... ...


Frequently there is no effect on cancer cells in the actual patient's body.


In order to break down the characteristics of cancer cells, scientists have to create an observation method that can be adjusted to the complex structure of cancer and a means of treatment.


If you solve these causes with science, cancer cells may use new adaptation methods and face new problems.


But there is good news. It means that science and technology are progressing day by day. Statistically, the average mortality rate for most types of cancer has declined markedly since the 1970s and continues to fall. New scientific knowledge will become a weapon against cancer.