| 1. |
- Ling, Agnes, 1976-, et al.
(författare)
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TAP1 down-regulation elicits immune escape and poor prognosis in colorectal cancer
- 2017
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Ingår i: Oncoimmunology. - 2162-4011 .- 2162-402X. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- The anti-tumor immune response has been shown to be of great prognostic importance in colorectal cancer (CRC) and so has the tumors ability for immune evasion. Our aim of this study was to investigate tumor factors that influence immunity. We used a gene expression array to search for potential mechanisms of tumor immune escape. One candidate gene identified was TAP1, involved in antigen presentation by MHC class I. TAP1 protein expression was evaluated by immunohistochemistry in 436 CRC patients of the Colorectal Cancer in Umeå Study cohort. We found a significant association between a downregulated expression of TAP1 and low infiltration of various subtypes of lymphocytes as well as macrophages. A downregulated expression of TAP1 was further found to be independent of molecular characteristics, suggesting TAP1 down-regulation to reach beyond the well described highly immunogenic MSI CRCs. A low expression of TAP1 was also significantly associated with poor prognosis in patients with CRC, a result that stayed significant in tumor front of early stage tumors (stage I-II) through multivariable analyses. Furthermore, we found that TAP1 expression was inversely correlated with methylation at sites in close proximity to the promoter region. In summary, our results show down-regulation of TAP1 to be a general mechanism of tumor immune escape in CRC and a poor prognostic factor in stage I-II CRC patients. We also suggest that methylation of the TAP1 gene may be a putative mechanism for TAP1 downregulation.
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| 2. |
- Wikberg, Maria L., et al.
(författare)
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Neutrophil infiltration is a favorable prognostic factor in early stages of colon cancer
- 2017
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Ingår i: Human Pathology. - : Elsevier BV. - 0046-8177 .- 1532-8392. ; 68, s. 193-202
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Tidskriftsartikel (refereegranskat)abstract
- The tumor immune response has been proven critical to prognosis in colorectal cancer (CRC), but studies on the prognostic role of neutrophil infiltration have shown contradictory results. The aim of this study was to elucidate the prognostic role of infiltrating neutrophils at different intratumoral subsites and in different molecular subgroups of CRC. The relations between neutrophil infiltration and infiltration of other immune cells (T-cell and macrophage subsets) were also addressed. Expression of the neutrophil marker CD66b was assessed by immunohistochemistry in 448 archival human tumor tissue samples from patients surgically resected for CRC. The infiltration of CD66b-positive cells was semi-quantitatively evaluated along the tumor invasive front, in the tumor center, and within the tumor epithelium (intraepithelial expression). We found that poor infiltration of CD66b-positive cells in the tumor front indicated a worse patient prognosis. The prognostic significance of CD66b infiltration was found to be mainly independent of tumor molecular characteristics and maintained significance in multivariable analysis of stage I-II colon cancers. We further analyzed the prognostic impact of CD66b-positive cells in relation to other immune markers (NOS2, CD163, Tbet, FOXP3, and CD8) and found that neutrophil infiltration, even though strongly correlated to infiltration of other immune cell subsets, had additional prognostic value. In conclusion, we find that low infiltration of neutrophils in the tumor front is an independent prognostic factor for a poorer patient prognosis in early stages of colon cancers. Further studies are needed to elucidate the biological role of neutrophils in colorectal carcinogenesis.
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