Question: why does cancer has no cure ?

Grace Kago answered on 2 Jun 2019:

Hello! Cancer is a very complicated disease that has many moving components. I think in another question I mentioned that one way to think about this disease is to imagine how the traffic policeman directs traffic. Now imagine when there is no policeman, the cars go all over the place. In the same way, cancer occurs when the regulators (the policemen) that tell the cells when to grow vs die are no longer functioning properly.
Our bodies have many many cells and many, many regulators so it is difficult to know which one to fix. In addition, cancer patients often have both sick and healthy cells in their bodies, and it is hard for doctors to specifically kill the sick cells without also killing the healthy cells. There have been a few remedies that have been discovered, and scientists are working hard to firstly understand the disease better, and then develop good, reliable therapeutics for patients.