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Bowel cancer

Australia has some of the highest rates of bowel cancer in the world. Australia has one of the highest rates of Bowel cancer in the world. It is the third most diagnosed form of cancer in Australia and the second largest killer. Regular screening and early detection are key with a 98% successful rate, when detected early. Bowel cancer outcomes in Western Victorian are poor with a 4% higher mortality rate than the Victorian average.

The incidence of early-onset colorectal cancer in Australia has more than doubled in the past 15 years, with a 60% increase in mortality rates among individuals aged 20 to 39. In stark contrast, mortality rates for other cancers, such as melanoma, have seen declines of up to 80% in the same age group. New-generation cancer treatments that are used in melanoma empower a patient’s immune system to kill the cancer, reducing the need for conventional chemotherapy. But sadly, these new treatments do not work in a bowel cancer, and bowel cancer treatment has not changed in the past 20 years. This divergence underscores the critical need for innovative approaches to combat bowel cancer.

CRC is a cancer of the barrier that lines the large intestine. Most Bowel cancers start as benign, non-threatening growths – called polyps – on the wall or lining of the bowel.This cancer compromises this protective barrier, allowing the faecal microbes within the bowel to interact with the underlying tissue. The immune system would typically fight these microbes, causing pain and fever within patients. However this cancer appears to suppress this immune response, and patients are largely asymptomatic. This CRC immune suppression may also allow the tumour to evade the immune system. Recent advances in the treatment of other cancers harness the immune system to fight tumours; however, these treatments are ineffective in treating CRC due to the immune suppression within these tumours. Targeting the immune suppression produced by CRC cells may enable the successful treatment of CRC with immunotherapeutic agents.

Our researchers have discovered that immune cells in the walls of the bowel can misbehave and release chemical messengers that promote Bowel cancer. The cells (called ‘MAIT’ cells) are typically helpful for fighting normal bacterial infections in the gut but the Ballarat team found that long term stimulation caused the immune cells to release a chemical message. This message triggering the growth and spread of the cancer, while suppressing nearby anti-cancer immune responses.

The Fiona Elsey Cancer Research Institute is investigating how types of immune cells respond to the large bowel microbes in colorectal cancer tissue and the role that these microbes play in weakening the body’s defences against cancer. We have identified a novel subset of immune cells within colorectal cancer tissue that responds to microbes and appears to suppress the immune system within the tumour. Our research endeavours to uncover how bowel cancer evades immune destruction, leading to a pathway to new clinical treatments.

 

 

Group Leaders
  • Professor George Kannourakis
Scientists
  • Dr Jason Kelly
PhD Candidates
  • Revati Sharma