Residual brain tumour cells need different treatment from main
15 April 2010
While most of a brain tumour can often be removed surgically,
in virtually every case the tumour reappears.
One reason for this is that sporadic, infiltrative tumour cells
will remain in the brain even after most careful surgery.
Researchers at the University of Bonn have now subjected these
‘forgotten’ cells to closer scrutiny for the first time.
While doing this, they were able to show that many of the
fundamental properties of these tumour cells were substantially
different from the cells in the midst of the tumour mass. The
findings could offer an opportunity to explain why radiation or
chemotherapy cannot entirely prevent this deadly disease to reoccur.
Patients with a glioblastoma generally undergo surgery as quickly
as possible. During the process, starting from the centre of the
tumour, the neurosurgeon gently removes diseased tissue until the
tumour appears to be removed entirely. Unfortunately, the cancer
cells are hard to get hold of. They often migrate far into adjacent,
healthy brain tissue. That is why there are basically always some
malignant cells remaining after every surgery, from which then new
tumours are formed.
The Bonn scientists have now taken a closer look at these
residual cells for the first time.
Apart from being provided with samples from the main mass of the
tumour for their research, the scientists were also provided with
small diagnostic samples from adjacent tissue from 33 patients by
the University of Bonn Department of Neurosurgery. 'From the small
samples we then extracted and enriched the few tumour cells that
would have normally remained in the patient.' Professor Björn
Scheffler from the Institute of Reconstructive Neurobiology
While examining these residual cells, the researchers made an
astonishing discovery. 'The cancer cells in the vicinity of the
tumour have different properties compared to those from the centre
of the tumour,' Björn Scheffler's colleague Dr. Martin Glas from the
Department of Neurology’s Clinical Neurooncology Unit explains. 'For
instance, they are more mobile, they form other receptors, they
react differently to radiation therapy or chemotherapeutic
These findings may offer an intriguing explanation for the yet
meagre therapeutic success against the most frequent malignant brain
cancer. Although there has been intensive research on this case for
more than half a century, a cure is currently not available. On
average, glioblastoma patients survive for only about 15 months from
the time of initial diagnosis. Although radiation and chemotherapy
both are aimed for complete destruction of residual tumour cells
after surgery, these weapons apparently remain blunt. There is no
other way of explaining that basically every glioblastoma patient
will experience a relapse.
The new results could help medicine to upgrade its weapons
arsenal against the remaining cancer cells. Up to now, therapies
were only tested on the extracted tumour tissue. But even if
medication could destroy the actual tumour, this does not have to be
true for the malignant residual cells. 'At least, it is worth
keeping an eye on this aspect,' Martin Glas and Björn Scheffler say.
But at the same time they warn against exaggerated hopes. 'We still
have a lot of work to do. For new approaches to therapy we first
need to understand the biology of these cells even better.’
This research was funded by the Volkswagen Foundation (Volkswagenstiftung)
and the BONFOR Program of the Bonn Faculty of Medicine.
1. Glas M, et al. Residual tumor cells are unique
cellular targets in glioblastoma'. Annals of Neurology. Volume 9999
Issue 999A, Published Online: 6 Apr 2010. DOI: 10.1002/ana.22036