Regulatory T cells (Treg cells) are specialised white blood cells that function to down-regulate immune responses, playing an important role in preventing autoimmunity. However, in cancer they can suppress the immune system's attempts to get rid of a growing tumour, allowing cancer to progress and the disease to become more severe. In patients with colon cancer, the transcription factor TCF1 was found to be missing in the Treg cells within the tumour.
'It's extremely important to be able to manage the degree of immune response,' Dr Majid Kazemian, from Purdue University, Indiana, who led the study said. 'That's why understanding these Treg cells is so important. If you have too much of a response, you get autoimmunity. If you have too little, you get cancer. Healthy systems need to strike a balance between autoimmune disease and cancer, and proper Treg cell function plays a key role in doing that.'
Transcription factors are proteins that control the rate that genetic information is copied. Published in Nature Immunology the scientists found that in the absence of TCF1 the Treg cells became inflammatory, multiplying and moving to the intestine and gut, leading to more serious tumours that are much harder to treat.
The research was limited as the interaction between TCF1 and Treg cells was only observed in mice. The activity of Treg cells where TCF1 had been artificially removed in mice was compared to the activity of Treg cells in human patients with colon cancer. Further research confirming a similar pathway in humans is required.
Future drug developers may be able to use the TCF1 gene pathway to manipulate regulatory T cells in the treatment of colon cancers. In addition, presence of cells in the colon which lack TCF1 could help oncologists to better understand a patient's prognosis.
In the UK, colon cancer is the fourth most common type of cancer and accounts for ten percent of all cancer deaths.