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Review
. 2020 Oct;12(14):1083-1100.
doi: 10.2217/imt-2020-0026. Epub 2020 Aug 13.

The tumor microenvironment of colorectal cancer metastases: opportunities in cancer immunotherapy

Yasmin Kamal  1   2 , Stephanie L Schmit  3 , Hildreth Robert Frost  1   2 , Christopher I Amos  1   2   4
Affiliations
Review

The tumor microenvironment of colorectal cancer metastases: opportunities in cancer immunotherapy

Yasmin Kamal et al. Immunotherapy. 2020 Oct.

Abstract

About a fifth of individuals with colorectal cancer (CRC) present with disease metastasis at the time of diagnosis. While the role of the tumor microenvironment (TME) in governing CRC progression is undeniable, the role of the TME in either establishing or suppressing the formation of distant metastases of CRC is less well established. Despite advances in immunotherapy, many individuals with metastatic CRC do not respond to standard-of-care therapy. Therefore, understanding the role of the TME in establishing distant metastases is essential for developing new immunological agents. Here, we summarize our current understanding of the TME of CRC metastases, describe differences between the TME of primary tumors and their distant metastases, and discuss advances in the design and combinations of immunotherapeutic agents.

Keywords: CAR-T-cell therapy; Toll-like receptor agonists; bi-specific T-cell engagers; colorectal cancer; dendritic cell vaccine; immune checkpoint inhibitors; immune microenvironment; liver metastases; metastasis; microsatellite instability.

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Conflict of interest statement

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Figures

Figure 1.
Figure 1.. Common sites of colorectal cancer metastases and their tumor immune environments.
Colorectal cancer metastasizes most commonly to the liver, lungs, peritoneum and bone. Key features of immune microenvironments at distal sites of metastases are highlighted. Immune ‘hot’ micro-metastases are noted in red, while immune ‘cold’ micro-metastases are denoted in blue. CRC: Colorectal cancer; MSI-H: Microsatellite instability high; MSS: Microsatellite stable; NK: Natural killer.
See this image and copyright information in PMC

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