학술논문

Genetic mechanisms of immune evasion in colorectal cancer
Document Type
article
Source
Cancer Discovery. 8(6)
Subject
Biomedical and Clinical Sciences
Oncology and Carcinogenesis
Immunology
Genetic Testing
Digestive Diseases
Cancer
Colo-Rectal Cancer
Genetics
Aetiology
2.1 Biological and endogenous factors
Colorectal Neoplasms
DNA Copy Number Variations
DNA Methylation
Germ-Line Mutation
HLA Antigens
Humans
Loss of Heterozygosity
Microsatellite Instability
Tumor Escape
Wnt Signaling Pathway
beta 2-Microglobulin
Biochemistry and cell biology
Oncology and carcinogenesis
Language
Abstract
To understand the genetic drivers of immune recognition and evasion in colorectal cancer, we analyzed 1,211 colorectal cancer primary tumor samples, including 179 classified as microsatellite instability-high (MSI-high). This set includes The Cancer Genome Atlas colorectal cancer cohort of 592 samples, completed and analyzed here. MSI-high, a hypermutated, immunogenic subtype of colorectal cancer, had a high rate of significantly mutated genes in important immune-modulating pathways and in the antigen presentation machinery, including biallelic losses of B2M and HLA genes due to copy-number alterations and copy-neutral loss of heterozygosity. WNT/β-catenin signaling genes were significantly mutated in all colorectal cancer subtypes, and activated WNT/β-catenin signaling was correlated with the absence of T-cell infiltration. This large-scale genomic analysis of colorectal cancer demonstrates that MSI-high cases frequently undergo an immunoediting process that provides them with genetic events allowing immune escape despite high mutational load and frequent lymphocytic infiltration and, furthermore, that colorectal cancer tumors have genetic and methylation events associated with activated WNT signaling and T-cell exclusion.Significance: This multi-omic analysis of 1,211 colorectal cancer primary tumors reveals that it should be possible to better monitor resistance in the 15% of cases that respond to immune blockade therapy and also to use WNT signaling inhibitors to reverse immune exclusion in the 85% of cases that currently do not. Cancer Discov; 8(6); 730-49. ©2018 AACR.This article is highlighted in the In This Issue feature, p. 663.