The sharedneoantigen landscape of MSI cancers reflects immunoediting during tumor evolution
AbstractThe immune system can recognize and attack cancer cells, especially those with a high load of mutation-inducedneoantigens. Suchneoantigens are particularly abundant in DNA mismatch repair (MMR)-deficient, microsatellite-unstable (MSI) cancers. MMR deficiency leads to insertion/deletion (indel) mutations at coding microsatellites (cMS) and toneoantigen-inducing translational frameshifts. The abundance of mutationalneoantigens renders MSI cancers sensitive to immune checkpoint blockade. However, the neoantigen landscape of MMR-deficient cancers has not yet been systematically mapped. In the present study, we used a novel tool to monitorneoantigen-inducing indel mutations in MSI colore…
Distinct Mutational Profile of Lynch Syndrome Colorectal Cancers Diagnosed under Regular Colonoscopy Surveillance
Regular colonoscopy even with short intervals does not prevent all colorectal cancers (CRC) in Lynch syndrome (LS). In the present study, we asked whether cancers detected under regular colonoscopy surveillance (incident cancers) are phenotypically different from cancers detected at first colonoscopy (prevalent cancers). We analyzed clinical, histological, immunological and mutational characteristics, including panel sequencing and high-throughput coding microsatellite (cMS) analysis, in 28 incident and 67 prevalent LS CRCs (n total = 95). Incident cancers presented with lower UICC and T stage compared to prevalent cancers (p <
The shared frameshift mutation landscape of microsatellite-unstable cancers suggests immunoediting during tumor evolution
The immune system can recognize and attack cancer cells, especially those with a high load of mutation-induced neoantigens. Such neoantigens are abundant in DNA mismatch repair (MMR)-deficient, microsatellite-unstable (MSI) cancers. MMR deficiency leads to insertion/deletion (indel) mutations at coding microsatellites (cMS) and to neoantigen-inducing translational frameshifts. Here, we develop a tool to quantify frameshift mutations in MSI colorectal and endometrial cancer. Our results show that frameshift mutation frequency is negatively correlated to the predicted immunogenicity of the resulting peptides, suggesting counterselection of cell clones with highly immunogenic frameshift peptid…
Abstract 571: The shared mutation and neoantigen landscape of MMR-deficient colorectal cancers suggests immunoediting during tumor evolution
Abstract The immune system can recognize and attack cancer cells and their precursors, especially those with a high load of mutation-induced neoantigens. Such neoantigens are particularly abundant in DNA mismatch repair (MMR)-deficient cancers. MMR deficiency results in microsatellite instability (MSI), which leads to multiple insertion/deletion mutations at coding microsatellites and to neoantigen-inducing translational frameshifts. The significance of immune selection and immunoediting potentially shaping the neoantigen landscape during the progression from premalignant MMR-deficient lesions into cancers has not yet been analyzed. We hypothesized that the neoantigen landscape of MSI cance…