Understanding the biology of cancer
Genome research and new technologies are improving treatments
There is a growing sense in the medical research world that we are finally starting to make real progress on cancer treatments.
Yes, I know this is a big statement considering that survival rates haven’t budged much for the most intractable versions of this terrible disease.
Thanks to early detection and treatment, and declining rates of smoking, cancer-related deaths for breast, prostate, lung and colon have been decreasing steadily for the past 25 years.
But the good news never applies to others, such as pancreatic cancer or glioblastoma (brain cancer).
However, recent advances and breakthroughs are starting to have an effect.
Thanks to huge advances in new technologies, the decoding of the human genome and the cumulative work of thousands of cancer researchers, we understand the tricky, shapeshifting biology of cancer in ways we never did before.
This has led to genuinely promising new categories of treatment. For example: The development of “targeted therapies” for specific types of cancer. This comes from major advances in our understanding of the tiny defects in our cells that multiply, leading to the development and spread of cancer. Knowing what goes wrong that triggers cancer’s out-of-control growth allows us to develop drugs that shut down those malfunctions.
The advent of immunecheckpoint inhibitors. One of the most frustrating aspects of cancer is its invisibility — it has evolved to evade our body’s immune system, which normally would detect and attack a threat like a rapidly growing tumour. Checkpoint inhibitors rip away that cloak of invisibility around the cancer cells, allowing the immune system to do its job and remove the threat. These drugs are showing good success in a variety of cancers, but have been most effective in melanoma and nonsmall cell lung carcinoma.
The burgeoning area of immunotherapy also includes the development of cell therapies, where immune cells are collected from patients, selected and amplified or modified in the laboratory, and re-administered to patients to directly target tumours cells.
The development of cancer vaccines specific for antigens unique to certain cancer cells and the use of viruses to selectively target tumours are among other examples of very promising new approaches.
However, these powerful new medicines are not effective in all patients nor for all tumours — a limitation scientists do not yet fully understand and one that is being heavily investigated. Thousands of clinical trials involving these modalities are currently underway, to better understand how to deploy these new approaches and better identify patients to maximize treatment outcomes.
We are turning the corner in our fight against cancer even though, as it stands today, most newly diagnosed patients are still likely to receive chemoand/or radiotherapies as their first-line treatment. Optimists will say that it has taken only 20 years since the discovery of immune checkpoint mechanisms, which has led to the development of immunotherapies with profound clinical impact and a promising future.
It is an incredibly exciting time for biomedical research as new technologies, such as CRISPR and single cell sequencing, offer unprecedented opportunities to explore the genetic basis of cancer, thereby accelerating the pace and leading to identification of new therapeutic targets.
Of course, when you or a loved one is struck by this terrible disease, the pace of discovery and its translation into safe, effective treatment, sometimes just doesn’t seem fast enough.
The best bet, more than ever, is to double down on our investments in fundamental research and on translation efforts so that the most promising discoveries are not abandoned as academic curiosities but rather rigorously tested and developed as new, life-saving medicine.
Stéphane Angers is the associate dean of research in the Leslie Dan Faculty of Pharmacy, University of Toronto and professor in the department of biochemistry in the Faculty of Medicine, University of Toronto. Doctors’ Notes is a weekly column by members of the U of T Faculty of Medicine.