Why cancer hasn’t been cured, and the success stories that give us hope

Every year, researchers from around the world spend billions of dollars chasing the same goal: a cure for cancer.

Success in this endeavor would have a colossal impact on life as we know it. Cancer is the leading cause of death worldwide, with nearly 10 million lives lost every year. Furthermore, as the population grows older, it is estimated that soon one in two people will develop cancer at some stage in their lifetime; that’s a lot of people who could benefit from a cure.

So, what’s taking so long?

The answer, much like cancer itself, is highly complex. We now know that, rather than being just one single disease, cancer actually constitutes at least two hundred very different diseases. Currently, we do not have a full and comprehensive understanding of the complex mechanisms within cells that promote different types of cancer.

Without this understanding it is very difficult to develop drugs that successfully wipe out cancer cells whilst leaving healthy cells unharmed. As a result, we often still rely on the old-school and rather brutal chemotherapy approaches to treat many cancers. Although chemotherapy can be an effective treatment option for some patients, side effects and high rates of relapse mean this approach will never serve as as an all-out cure for cancer.

But it isn’t all doom and gloom. Thanks to international research investment we have dramatically improved our understanding of cancer biology in recent decades. This knowledge has enabled the development of therapies that specifically target cancer cells whilst leaving healthy cells relatively unharmed. Scientists refer to this approach as ‘targeted therapy’.

One success story for targeted therapy involves a cancer-fighting drug called imatinib. This drug blocks the activity of a protein called BCR-Abl, which promotes cell growth in certain types of leukemia. Importantly, BCR-Abl isn’t present in healthy cells. Thus, by directly targeting BCR-Abl, imatinib potently kills off leukemia cells with relatively little impact on normal cells, and so patients experience less debilitating side effects.

Treating BCR-Abl-associated leukemia with imatinib represents one of the biggest successes in the switch from conventional chemotherapy to targeted therapies, rapidly turning a near-fatal cancer into an effectively treated disease with close to normal life expectancy.

Unfortunately, even this success story has its downfalls. Some patients experience more severe side effects and have to stop treatment, whilst others don’t respond to imatinib at all. The reasons for these cases are not fully understood, but include the development of mutated forms of BCR-Abl in some patients, such that the mutated BCR-Abl is able to ‘shrug-off’ imatinib and the effect of the drug is lost.

These patients need new forms of therapy, and this is the main focus of my research.

Our group works to discover new drugs that specifically target cancer cells possessing the BCR-Abl protein without affecting normal healthy cells. We have identified several new drugs, many of which have never been used before in the clinic. We are now working to develop these drugs into useable therapies that can provide further treatment options for leukemia patients. To achieve this, we first need to determine the mechanism of the new drugs – for example, what proteins they target and how they kill leukemia cells. From there, we will look to test the safety and efficacy of the drugs, first using mouse models and eventually using human clinical trials.

We hope these new drugs will add to the ever-growing arsenal of weaponry available to combat cancer. Our goal, and the goal of many other cancer research scientists, is to continue improving our understanding of the biology underlying leukemia and other cancers. This understanding will help in the development of more specific, more effective cancer drugs – and hopefully many more success stories.

By Joseph Mark Robertson
Published June 29, 2018 10:37 AM - Last modified June 29, 2018 10:37 AM

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