Australian scientists say that a gene called MCC could be playing a key role in determining the efficacy of treatment in colorectal cancer.
Drs Laurent Pangon and Maija Kohonen-Corish of the Garvan Institute, Sydney have been investigating the tumour cells of over 200 colorectal cancer patients. Their findings are published in Genes and Cancer, now online.
The gene MCC has an important role to play in a well-known phenomenon known as the 'DNA damage response.' Every cell in the body is regularly exposed to DNA damage from things like toxins, viruses or radiation.
Any genes that help regulate this DNA damage - find it, correct it, or make sure cells deal with it - are really important. If such genes lose their effect, DNA damage would accumulate, and cancer would probably develop, the researchers explain.
"Our findings show that MCC appears to be involved at a kind of DNA damage checkpoint, when the cell recognises that there is DNA damage, and that it needs to do something to correct it, "says Dr Laurent Pangon.
"If you lose MCC, therefore, you lose the ability of the cell to repair DNA damage."
"We know that 50 per cent of our patient cohort had tumours with a defective MCC gene, which causes lack of expression. We believe that these patients are more responsive to radiotherapy or some types of chemotherapy."
"That is because those therapies kill cancer cells through inducing DNA damage - and if the DNA damage response of the tumour is already defective, the therapies work better."
The group has developed a biomarker test that can identify MCC defects in tissue. Pangon says that the next step is to do a retrospective study of the patient cohort, checking therapy response against the presence of the biomarker in each patient.
"I think this study is important for colon cancer, but even more important for rectal cancer, because rectal cancer has a real disparity when it comes to radiotherapy, which is not well explained. Some patients do really well, and others don't respond at all," he said.
"Our study has the potential to provide a scientific explanation as to why some patients respond to treatment better than others and a practical test to identify those patients who are likely to respond."
This research was supported by a Cancer Council NSW Grant.