Colorectal cancer (bowel cancer) is a leading cause of cancer death worldwide, and the second most common cause of cancer death in Australia. Tumour growth and whether it spreads to other organs depends on the tumour’s ability to form new blood vessels (to supply oxygen and nutrients) and this process is driven by a tumour growth factor called VEGF.
Recently a new therapy to treat colorectal cancer, using an antibody to fight VEGF has been successful in helping patients with colorectal cancer, however unfortunately this therapy doesn’t work for everyone. Researchers believe that in some patients, their tumours become resistant to the antibody. Unfortunately in these patients, even though the VEGF growth factor has been knocked out by the antibody, other growth factors then switch on to compensate, allowing the tumor to continue growing. Knowing these factors will mean researchers can predict which patients are likely to respond poorly to this treatment and those which will respond better, significantly aiding in tailoring treatment for each patient to improve effectiveness and lessen the cost of treatment. The work at The Basil Hetzel Institute involves investigating genes and their protein products (biomarkers) that may play a role in making some tumours resistant and not others. The levels of each biomarker within tumour samples will be measured using advanced multiplexed bead technology. Researchers expect that patients with high levels of these biomarkers will develop resistance, while those with normal to low levels will be responsive to the therapy. Whilst this is expensive technology, it is the most efficient way of performing this biomarker ‘signature’ analysis.
Identifying patients at high risk of relapse after colorectal cancer surgery…
Some colorectal cancer patients with early stage colorectal cancer still lose their lives to this devastating disease due to a relapse within 5 years of diagnosis, despite undergoing surgery to remove the primary tumour. In these patients, tumour cells with the potential to spread have already escaped from the tumour before or at the time of surgery, into the bloodstream or other areas of the body. The team at The Basil Hetzel Institute is developing a blood test using magnetic antibody-labeled beads which can identify circulating tumour cells (CTC), to identify dangerous cancer cells which have spread.
In a trial of this blood test there were a significant number of patients who tested positive for CTC but did not relapse. The research team now believes that it is only the tumour stem cells within the circulating tumour cell pool that are responsible for cancer spread and relapse. The team is focusing on finding to the best way to identify these colon tumour stem cells, to improve the immunobead blood test. This will ultimately enable researchers & clinicians to better predict cancer relapse and therefore commence appropriate therapy earlier.
Colon Cancer Research Group, Department of Haematology-Oncology
Associate Professor Tim Price, Head of Medical Oncology Unit
Dr Jennifer Hardingham, Group Leader Molecular Oncology Laboratory
Dr Amanda Townsend, Medical Oncology Translational Research Fellow
Professor Peter Hewett, Head Colorectal Surgical Unit, Department of Surgery
Associate Professor Adrian Cummins, Department of Gastroenterology
Dr Kumar Grover, Molecular Aging Laboratory, Department of Surgery