Copy Neutral LOH Affecting the Entire Chromosome 6 Is a Frequent Mechanism of Class I Alterations in Cancer.

Total or partial loss of class I antigens reduce the recognition of specific tumor peptides by cytotoxic T lymphocytes favoring cancer immune escape during natural tumor evolution. These alterations can be caused by genomic defects, such as loss of heterozygosity at chromosomes 6 and 15 (LOH-6 and LOH-15), where class I genes are located. There is growing evidence indicating that LOH in contributes to the immune selection of loss variants and influences the resistance to immunotherapy.