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Immune evasion of microsatellite unstable colorectal cancers
Author(s) -
Kloor Matthias,
Michel Sara,
von Knebel Doeberitz Magnus
Publication year - 2010
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.25283
Subject(s) - microsatellite instability , immune system , dna mismatch repair , context (archaeology) , colorectal cancer , evasion (ethics) , cancer , antigen , biology , immunology , immunogenicity , cancer research , genome instability , genetics , gene , microsatellite , dna damage , dna , allele , paleontology
Colorectal cancers (CRC) develop through 2 major pathways of genetic instability. In contrast to the majority of CRCs, which are characterized by chromosomal instability, high‐level microsatellite unstable (MSI‐H) CRCs arise as a consequence of the loss of DNA mismatch repair (MMR) functions and show accumulation of insertion and deletion mutations particularly in microsatellite sequences. MSI‐H occurs in about 15% of CRCs, and virtually all CRCs occurring in the context of the hereditary cancer‐predisposing Lynch syndrome. These tumors are characterized by a comparably good prognosis and a low frequency of distant metastases. Because of the expression of a defined set of tumor‐specific antigens, MSI‐H CRCs elicit a strong local and systemic antitumoral immune response of the host and therefore use different strategies to evade the control of the immune system. In this review, we will summarize novel molecular mechanisms that at the same time drive pathogenesis, immunogenicity and immune evasion during the development and progression of MSI‐H CRCs. We will focus on the current knowledge about alterations in human leukocyte antigen (HLA) antigen presentation and discuss how immune evasion—while offering protection against local antitumoral immune responses—paradoxically might interfere with the ability of the tumor to form distant organ metastases.