Detecting lingering cancer before it grows back
We are conducting research into whether cerebrospinal fluid (CSF), which is in the ventricles in the brain, contains lables (which we call biological markers or biomarkers for short) of brain cancer. Focussing on ependymoma, we have been looking for metabolite biomarkers, which are used in cell metabolism and may be released into the CSF from tumour cells.
Cell metabolism creates energy for the cell and builds components of the cell structure. Indeed we found some biomarkers of ependymoma in CSF samples taken from children by lumbar puncture, as the biomarker metabolites were found at a different level in ependymoma CSF compared to healthy CSF. These biomarkers were seen after sugery when most tumour was removed, and should therefore be markers of lingering cancer cells. Lingering cancer cells are normally treated by radiotherapy but the cancer grows back in half of the ependymoma patients. We wish to see if these nine biomarkers are found in CSF from relapsed ependymoma patients and then, across a time frame, how early on in treatment we can see these labels of relapse. If the biomarkers are found only in the patients who relapse, after the end of treatment and in their relapsed tumours, we could predict who will relapse and treat them further. In future we could find these biomarkers by monitoring patients during and following radiotherapy for 2 years. This could lead to diagnosing relapse earlier than by using MRI scans, which could facilitate earlier treatment and perhaps a better outcome for the child. This addresses one of the Top 10 Children’s Cancer Priority Setting Partnership Research Priorities (number 5), which is "Why do children relapse, how can it be prevented, and what are the best ways to identify relapse earlier?" The metabolite biomarkers that we found point towards metabolic pathways that are potential new therapeutic targets for patients who need further therapy to prevent relapse. Those most abundant in ependymoma included metabolites in the export of acetyl- CoA from the mitochondrion (2 metabolites), in aerobic glycolysis (2 metabolites), and some amino acids (5 metabolites), whilst a sugar acid and an amino acid derivative were decreased in abundance (2 metabolites).
Therefore we might also address Research Priority number 1, "Can we find effective ... treatments for cancer including relapsed cancer?". Our proven method, liquid chromatography coupled to mass spectrometry targeted at our biomarkers, can effectively separate out, detect and quantify our biomarkers. We expect to deliver a test based on quantities of some of these biomarkers which can accurately determine if a patient is relapsing early on after the treatment for their primary tumour has ended.