Increased frequency of regulatory T cells in peripheral blood and tumour infiltrating lymphocytes in colorectal cancer patients.
Recent results have shown a correlation between survival and frequency of tumour infiltrating T lymphocytes in colorectal cancer patients. However, it remains unclear whether the frequency of regulatory T cells is higher in colorectal cancer as compared to normal colon. To address this question we analysed the frequency and function of regulatory T cells in the peripheral blood and tumour infiltrating lymphocytes of colorectal cancer patients. The proportion of regulatory T cells in the peripheral blood of colorectal cancer patients (mean 8%) was significantly higher than that in normal controls (mean 2.2%). There were significantly more regulatory T cells in tumour infiltrating lymphocytes (mean 19.2%) compared to lymphocytes from an autologous non-malignant portion of the colon (mean 9%). Regulatory T cells from colorectal cancer patients were FOXP3 positive and suppressed the proliferation of autologous CD4+ CD25- cells. A higher density of tumour infiltrating regulatory T cells was found in patients with advanced as compared to early disease. These results support the hypothesis that increased numbers of regulatory T cells in the blood and tumours of colorectal cancer patients may influence the immune response against cancer and suggest that strategies to overcome regulatory T cell activity may be beneficial in the treatment of human colorectal cancer.
Ling
Khoon Lin
KL
Tumor Immunology Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
Pratap
Sarah E
SE
Bates
Gaynor J
GJ
Singh
Baljit
B
Mortensen
Neil J
NJ
George
Bruce D
BD
Warren
Bryan F
BF
Piris
Juan
J
Roncador
Giovanna
G
Fox
Stephen B
SB
Banham
Alison H
AH
Cerundolo
Vincenzo
V
D016022:Case-Control Studies; D003106:Colon / Q000276:immunology; D015179:Colorectal Neoplasms / Q000097:blood / Q000276:immunology*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D006801:Humans; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*
C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors