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The Globe and Mail

Take news of cancer ‘breakthrough’ with a big grain of salt

When two of the world's most renowned cancer researchers – Tak Mak, director of the Campbell Family Institute for Cancer Research at the Princess Margaret Hospital, and Dennis Slamon, the chief of hematology-oncology at the University of California, Los Angeles – lay claim to a spectacular breakthrough, the media need to pay attention.

But the newspaper headlines about a "breakthrough cancer drug" and a "sharpshooter drug" that takes "direct aim at tumours" were more than a bit discomforting, even if they did echo the bold language in the press release that convened media to a slick event at Princess Margaret.

Reporters (and headline writers) need to do a little more than genuflect before the gods of science and public relations, especially when writing about something as important as a potential new cancer treatment. We cannot suspend our critical faculties because of wishful thinking.

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So let's examine some of the important details and context that were glossed over a bit too quickly.

This seemingly miraculous "breakthrough" drug has not been tested on a single person. The experimental drug CFI-400945 has "prevented cancer growth" in a bunch of mice. The promising results have yet to be published in a peer-reviewed medical journal (though articles have been submitted), let alone replicated by others.

It has taken two brilliant researchers and their large teams a decade to get to this point. They are understandably excited because the drug will now be tested in humans – and 90 per cent of drugs never get that far. But even in a best-case scenario – meaning the compound works as hoped in humans, doesn't cause any grave side effects, can be produced in a form and at a cost that is marketable, and is not overtaken by newer, more promising approaches – a new cancer drug is at least a decade away.

Hardly blowing-the-trumpets material, nor the stuff of breathless headlines.

So why exactly did Princess Margaret Hospital stage an elaborate press conference? The principal reason seems to have been to thank the donors who paid for the research – $40-million and counting – with a public pep talk from two cancer research superstars. (Dr. Mak is a scientific legend because he cloned the T-cell receptor, the holy grail of cellular immunology; Dr. Slamon developed the cancer drug Herceptin, the first therapy that targets a specific molecule.)

That's a legitimate activity in an environment where the battle for donors is fierce and the longing for new cancer drugs palpable. It's just unfortunate that the media went along for the ride.

This is not to suggest that the scientific advances touted by Dr. Mak and Dr. Slamon are not important. They may well be. But scientific breakthroughs should not be announced at press conferences using the vocabulary of public relations professionals.

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The language of science and medicine should be cautious and humble because diseases like cancer are relentless and humbling.

Here's a quick summary of the "breakthrough," in plain, lay terms: The research team has zeroed in on a specific enzyme, polo-like kinase 4 (PLK4), which plays a role in the process of cell division. Researchers found that removal of PLK4 halted growth and resulted in death of the cancer cells. In mice that are bred specifically to develop cancer, the researchers were able to knock out the enzyme with a compound dubbed CFI-400945 and halt the advance of cancer.

Conventional chemotherapy is designed to kill all fast-dividing cells. The new approach targets only cancerous cells, preventing them from reproducing; hence, the catchy "sharpshooter" designation.

The new drug – if it works in living, breathing humans – has the most potential for treatment of triple-negative breast cancer, a form that does not express the genes for three types of receptors. That's because the DNA sequences of triple-negative breast cancer showed very high levels of PLK4.

CFI-400945 was also tested on mice with other forms of cancer such as ovarian, colorectal, pancreatic, prostate, lung, glioblastoma and melanoma. To suggest it could be used to treat all those forms of cancer, though, is a big stretch.

The Merriam-Webster dictionary defines "breakthrough" as "a sudden advance especially in knowledge or technique, e.g. a medical breakthrough."

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The reality is that biomedical research is a slow process that yields small incremental results. If there is a lesson to retain from the tale of CFI-400945, it's that finding new treatments takes a lot of time and a lot of money. It is a venture worthy of support, but unworthy of exaggerated expectations and casual overstatement.

Hype only serves to create false hope.

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