The intratumoural subsite and relation of CD8+ and FOXP3+ T lymphocytes in colorectal cancer provide important prognostic clues |
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Authors: | A Ling S Edin M L Wikberg ? ?berg R Palmqvist |
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Institution: | 1.Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden;2.Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå, Sweden |
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Abstract: | Background: To find improved tools for prognostic evaluation in patients with colorectal cancer (CRC), we have analysed how infiltration of cytotoxic T lymphocytes (CD8+) and regulatory T lymphocytes (FoxP3+) correlates to prognosis, not only according to quantity and relation, but also to subsite within tumours of different molecular characteristics (microsatellite instability and CpG island methylator phenotype status).Methods: CD8 and FOXP3 expression was evaluated by immunohistochemistry in 426 archival tumour tissue samples from patients surgically resected for CRC. The average infiltration of CD8+ and FOXP3+ cells was assessed along the tumour invasive front, in the tumour centre and within the tumour epithelium (intraepithelial).Results: We found that infiltration of CD8+ T lymphocytes within the tumour epithelium provided the strongest prognostic information (P<0.001). At the tumour invasive front and tumour centre, FOXP3 expression withheld the strongest association to prognosis (P<0.001), suggesting FOXP3+ T-lymphocyte infiltration to be a better prognostic tool than CD8+ T lymphocytes at these intratumoural subsites. We further analysed the possible prognostic impact of the relation between these T-cell subsets, finding that a high intraepithelial CD8 expression was associated with a better patient outcome, independent of FOXP3 infiltration. In groups of low intraepithelial CD8 expression, however, a high infiltration rate of FOXP3+ cells at the tumour invasive front, significantly improved prognosis.Conclusions: Analyses of intraepithelial infiltration of CD8+ T lymphocytes, infiltration of FOXP3+ T lymphocytes at the tumour front or centre, and the relation between these subsets, may be a valuable tool for predicting prognosis in colon cancer. |
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Keywords: | colorectal cancer molecular subgroups lymphocyte subsets FOXP3 CD8 intratumoural subsites prognosis |
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