Thursday September 20 2007
Granulocytes from one individual reportedly killed 97% of cancer cells
A study claims to have found hope for a new method of fighting and possibly even curing cancer, news sources reported today.
The method, which would involve transplanting immune cells from other people into cancer sufferers, has shown success when tested in laboratory mice, and The Daily Telegraph said that it could be curing cancer sufferers within two years. Researchers have apparently been given permission to begin trials in humans, after the latest studies on human cancer cells in the laboratory showed some promising results.
New Scientist, the science magazine that originally reported the preliminary results of the study, and on which the news stories were based, said it amounted to “cancer-resistant people lending out their killer cells”.
As the results of this study have been presented only at a conference and are not yet available in published peer-reviewed format we are unable to fully assess the validity of the claim; however, certain general observations can be made.
The safety of the new technique and risk of rejections will need further assessment. Both articles quoted Dr John Gribben of the Cancer Research UK’s experimental medicine centre in London as saying “If they are using live cells there is a theoretical risk of graft-versus-host disease, which can prove fatal”.
Where did the story come from?
Dr Zheng Cui, a professor of pathology at the Department of the Wake Forest University of Medicine in Winston-Salem, North Carolina, carried out this research with colleagues. The source of any funding for this study is not clear from the information available.
This study is unpublished. Preliminary results were presented by Dr Cui, at a 20-minute presentation at the third conference on “Strategies for Engineered Negligible Senescence (SENS)” held at Queen’s College Cambridge, UK.
What kind of scientific study was this?
Limited information about the methods of the study were available from the conference abstract and the New Scientist article reporting it. We can describe the following however:
The researchers took blood samples from more than 100 people, extracted a particular type of white blood cell, the granulocyte, from each sample and mixed these with human cervical cancer cells in the laboratory. For each blood donor, they appear to have measured what proportion of the cancer cells died over a period of time after being mixed with the white blood cells.
What were the results of the study?
The results suggest a wide variation in “cancer-killing ability” between different individuals. Although no figures were reported in the conference abstract, the New Scientist article reports that granulocytes from one individual killed around 97% of cancer cells within 24 hours, whereas the cells from another individual only killed about 2%. This variation in cancer killing ability was associated in the conference abstract with other factors such as age and season. The researcher has applied for permission to carry out further studies in humans, and according to the Telegraph has received it.
What interpretations did the researchers draw from these results?
The researcher claims that "Using a newly developed in vitro assay to measure the ability of white cells to kill various cancer cell line targets, we surveyed human volunteers and found that a significant number of healthy humans have cancer-killing activity (CKA) similar to that of cancer-resistant mice".
This quote from the conference abstract suggests that the researcher claims to have developed a new test of how well human white cells can kill cancer cells in the laboratory. He notes that this ability/activity of white cells is similar to an ability he has recorded in previous studies on mice.
Based on these findings the researchers propose that people whose granulocytes have high cancer-killing activity could be identified, and their granulocytes used to treat people with cancer. They say that this “ new cancer treatment strategy, termed "GIFT" (Granulocyte InFusion Therapy)… will soon enter phase II clinical trials”. Phase II trials are done to see if a new treatment works well enough to test in a larger phase III trial, they aim to find out more about a drug’s side effects and how to manage them, and more about the best dose of a drug to use in humans. Usually, a phase 1 trial assessing the safety of a drug in humans will have been completed first.
What does the NHS Knowledge Service make of this study?
This NHS Knowledge Service is unable to appraise the validity and usefulness of this study until all the data are published.
We should be cautious about offering hope to people who are unfortunate enough to have developed cancer. Studies come in many shapes and sizes demonstrating different levels of evidence. This means that we can have confidence in the results of some and not others. Some techniques which show initial promise in laboratory experiments or in animals never reach trials in humans because of unforeseen difficulties with the techniques and procedures required.
The Daily Telegraph’s suggestion that cancer sufferers could be cured within two years should be interpreted as an optimistic forecast for the reportedly approved human trials, and not a claim that cancer sufferers will have access to any treatment resulting from these studies within that timeframe.
Prior to further published research of this technique, we should base our hope on treatments that have been well tested and confirmed in humans.
Sir Muir Gray adds...
The SENS workshop sounded like a really good event with lots of radical thinking and ideas, but without a published report of the study which we can evaluate, it is impossible to say anything more than that this is an interesting idea.