“Huge leap” forward is just a small step for cancer vaccine research

Headlines can be misleading

This weekend, newspaper headlines announced that “Cancer Scientists hail ‘huge’ leap towards jab that targets tumours” and “’Holy Grail’ cancer vaccine that blasts tumours in weeks hailed as huge leap in fighting disease”.

Not only are these headlines overhyped and misleading, but the stories themselves are slightly confusing, combining the launch of a clinical trial with newly published results from a completely different area of research.

Let’s look in more detail at the story behind the headlines.

The cancer vaccine trial

The first part of both articles covers the announcement of the launch of an early-stage clinical trial of a new vaccine for treating advanced melanoma. Usually, this kind of trial involves testing the treatment for the first time in a small number of patients. The idea is to work out some basic issues like whether the treatment is safe, rather than how effective it is. It’s also important to stress that this is not a vaccine to prevent people from getting cancer – instead, it triggers a patient’s immune system to recognise and destroy cancer cells.

Developed by Professor Lindy Durrant at Nottingham University – whose research in this area has been funded by Cancer Research UK in the past – the vaccine is one of many immunotherapy approaches being tested around the world for treating cancer. As we’ve written about before, some early trials have had promising results,  and the new stories also feature a young mum who benefited from a similar vaccine treatment in the past.

While cancer vaccines and immunotherapy are very exciting areas of research that we’re actively involved in funding, this story itself does not represent a ‘huge leap’ forwards. Using such language is at best misleading and at worst cruelly raises false hopes in cancer patients and their families.

In this case, the trial has not even started yet, and there aren’t any results to suggest that the vaccine can safely and effectively treat people with melanoma. As we’ve mentioned before, the journey from potential treatment in the lab to licensed cancer therapy is long and tortuous.  That’s precisely why this trial and further, larger trials are needed – firstly to prove that this vaccine is safe to give to patients, and secondly to prove that it actually works to treat cancer.

As the articles point out, it could take many years before the vaccine is widely available, when (or, indeed, if) it passes the significant and essential hurdles of small-scale and large-scale clinical trials.  We must wait for solid results before assessing whether the vaccine treatment genuinely represents a significant step forward in the treatment of melanoma or other types of cancer.

Breast stem cells

Halfway through both reports, there is an abrupt and somewhat puzzling switch to a completely different story, describing new research from scientists in Canada and Australia, along with Dr John Stingl from the Cancer Research UK Cambridge Research Institute.

Writing in the journal Nature earlier this month, the researchers have discovered that breast stem cells in mice go through a ‘growth spurt’ at a particular time in the menstrual cycle, increasing in number by up to fourteen times.

In a series of detailed experiments, the researchers showed that the mouse version of the female hormone progesterone is probably fuelling the dramatic growth of these breast stem cells.

This is an intriguing piece of research, as many scientists now believe that rogue stem cells lie at the heart of a wide range of cancers, as we’ve explained before.  So the discovery opens up some interesting avenues for ways to prevent or treat breast cancer by targeting the progesterone pathways.

But although mice are similar to humans in many respects, they’re not identical. This research has only been done using mice, so the claim in the news reports that “progesterone during a woman’s menstrual cycle causes an upsurge in the number of breast stem cells” is over-stated.  More work needs to be done before we know how well these findings bear up in women, and how relevant they are to human breast cancer.

Don’t believe the hype

To sum up, these news reports jumble together two unrelated stories – one about a clinical trial that hasn’t yet started (billed as a ‘huge leap forwards’) and the other about research into breast stem cells in mice, directly projected onto women.

It’s important to read news stories about cancer carefully, and there are a number of resources to help you uncover the science behind the headlines. For example, we’ve got loads of handy advice for reading cancer news stories on our website, there’s the excellent NHS Choices Behind the Headlines blog and Dr Len Lichtenfeld’s blog for the American Cancer Society, and – of course – our very own Science Update blog too.

Kat

Reference:
Joshi, P., et al. (2010). Progesterone induces adult mammary stem cell expansion Nature DOI: 10.1038/nature09091