Cancer is basically u're own cells gone wild,
basically they lose the main regulatory principles of cell division, many factors can cause this, one of the factors are certain types of viruses.
Cancer is very hard to kill sine u need to kill u're own cells. Needless to say some innocent cells will die. Its hard even to halt its development, ye u can try to inhibit cell division, but many types of cells in the body divide fast - blood producing cells for instance.
Killing cells by inhibiting major metabolic pathways existent in all the cells in an organism is bad.
The only way I imagine we could cure cancer in the future is by nano particles targeted to the cancer cells. Some therapies are developed even now with monoclonal enzymes that target to certain antigens on cancer cells, most promising is ADEPT method, but there is still a long way to go. And the main obstacle is cost of such treatment (every patient needs to get a treatment suitable for him).
And ye u can cure some cancers in the early stages (sometimes even in the late stages) if u somehow change how u're immune systems sees the cancer cells.
This article has some good info but is just poor journalism.
Pharmaceutical companies are not investing in it because it is a generic drug that is already being produced. If water cured cancer, you wouldn't ask drug company to invest in water. That doesn't make them evil. That won't stop doctors and hospitals from using the drug.
Also... the drug is still in trials... it takes three months to get the drug up to blood levels where it will stop the growth of cancer, and even then it's not a magic bullet cure. It stops the growth of tumors, but it doesn't target and kill them. This drug will need to be used in combination with other treatments. Some side effects, such as nerve malfunction, have been found, and the drug is still being tested for other side effects.