A Single Cell Atlas of MMRd and MMRp Colorectal Cancer
Ontology highlight
ABSTRACT: Immune responses to cancer are highly variable, in particular colorectal cancer tumors with mismatch repair-deficiency (MMRd) show an elevated presence and activity of immune cells as compared to mismatch repair proficient tumors. To understand the immune response patterns, and key differences between these types of colorectal cancer, we transcriptionally profiled 371,223 tumor and adjacent normal cells from 28 MMRp and 34 MMRd patients. Unsupervised analysis identified 88 cell subsets, from 7 distinct cell lineages, and an associated compendium of 204 gene expression programs. Examination of these programs revealed extensive transcriptional and spatial reprogramming, characteristic to MMRd and MMRp tumors.
Project description:Responses to immune checkpoint blockade (ICB) are variable among mismatch repair-deficient (MMRd) cancers. We completed a phase 2 clinical trial of the PD-1 inhibitor pembrolizumab in 24 patients with MMRd endometrial cancer (NCT02899793). Patients with mutational MMRd tumors (6 patients) had higher response rates and longer survival than those with epigenetic MMRd tumors (18 patients). Mutation burden was higher in tumors with mutational MMRd compared to epigenetic MMRd; however, within each category of MMRd, mutation burden was not associated with ICB response. Notably, JAK1 mutations did not confer resistance to pembrolizumab. Longitudinal single-cell RNA-seq of circulating immune cells revealed contrasting modes of anti-tumor immunity against mutational and epigenetic MMRd cancers. Whereas effector CD8+ T cell responses correlated with regression of mutational MMRd tumors, highly active CD16+ NK cells were associated with ICB-responsive epigenetic MMRd tumors. These data highlight the interplay between tumor-intrinsic and extrinsic factors that influence ICB response.
Project description:Neoadjuvant immune checkpoint blockade (ICB) has shown unprecedented activity in mismatch repair deficient (MMRd) colorectal cancers, but its effectiveness in MMRd endometrial cancer (EC) remains unknown. In this investigator-driven, phase I, feasibility study (NCT04262089), 10 women with MMRd EC of any grade, planned for primary surgery, received two cycles of neoadjuvant pembrolizumab (200 mg IV) every three weeks. All patients completed treatment without severe toxicity. A partial radiologic response was observed in 3/10 patients, 5/10 patients had stable disease and 2/10 patients were non-evaluable on Magnetic Resonance Imaging (MRI). Pathologic response was observed in 5/10 patients, with 2 patients showing a major pathologic response. No patient achieved a complete pathologic response. At median duration of follow-up of 22.5 months, two non-responders experienced disease recurrence. Monoclonal T cell expansion significantly correlated with treatment response. Tumour-draining lymph nodes displayed clonal overlap with intra-tumoural T cell expansion. All pre-specified endpoints were reached. Neoadjuvant ICB with pembrolizumab proved safe and induced pathologic, radiologic, and immunologic responses in MMRd EC, warranting further exploration of extended neoadjuvant treatment.
Project description:DNA mismatch repair deficiency (MMRD) drives microsatellite instability (MSI). Cells with MSI accumulate numerous frameshift mutations. Frameshift mutations affecting cancer-related genes may promote tumorigenesis and, therefore, are shared among independently arising MSI tumors. Consequently, such recurrent frameshift mutations can give rise to shared immunogenic frameshift peptides (FSPs) that represent ideal candidates for a vaccine against MSI cancer. Pathogenic germline variants of mismatch repair genes cause Lynch syndrome (LS), a hereditary cancer syndrome affecting approximately 20-25 million individuals worldwide. LS individuals are at high risk of developing MSI cancer. Previously, we demonstrated safety and immunogenicity of an FSP-based vaccine in a Phase I/IIa clinical trial. However, the cancer-preventive effect of FSP vaccination in the scenario of LS has not been demonstrated so far.
2021-08-30 | GSE175744 | GEO
Project description:colorectal cancer with mismatch Repair status
Project description:Colorectal cancer (CRC) remains the third most common cancer in the US, with 15% of cases displaying Microsatellite Instability (MSI) secondary to Lynch Syndrome (LS) or somatic hypermethylation of the MLH1 promoter. A cohort of rhesus macaques from our institution developed spontaneous mismatch repair deficient (MMRd) CRC with a notable fraction harboring a pathogenic germline mutation in MLH1. DNA methylation and transcriptome analysis was used to evaluate the rhesus macaque as a model organism to study carcinogenesis, develop immunotherapies and vaccines, and implement chemoprevention approaches pertinent to sporadic MSI-H and LS CRC in humans. NIH grant(s): Grant ID: 5 P30 CA016672-44 Grant title: Cancer Center Support Grant Affiliation: The University of Texas MD Anderson Cancer Center Grantor: NCI
Project description:Colorectal cancer (CRC) remains the third most common cancer in the US, with 15% of cases displaying Microsatellite Instability (MSI) secondary to Lynch Syndrome (LS) or somatic hypermethylation of the MLH1 promoter. A cohort of rhesus macaques from our institution developed spontaneous mismatch repair deficient (MMRd) CRC with a notable fraction harboring a pathogenic germline mutation in MLH1. DNA methylation and transcriptome analysis was performed to evaluate the rhesus macaque as a model organism to study carcinogenesis, develop immunotherapies and vaccines, and implement chemoprevention approaches pertinent to sporadic MSI-H and LS CRC in humans. NIH grant(s): Grant ID: 5 P30 CA016672-44 Grant title: Cancer Center Support Grant Affiliation: The University of Texas MD Anderson Cancer Center Grantor: NCI
Project description:This study examined the expression profile of medullary carcioma of the colon compared to adjacent histologically normal colonic mucosa. Medullary carcinomas of the colon were selected from Rhode Island Hosptial and The Miriam Hospital to identify new molecular markers of this disease. Medullary carcinoma was defined by applying strict morphologic criteria and demonstration of mismatch repair protein deficiency (MMRd) by IHC.
Project description:Lynch syndrome and Familial colorectal cancer type X (FCCTX) are clinically diagnosed using the same criteria, but genomic differences exist between these two groups and the genomic profiles share similarities with their sporadic counterparts, mismatch repair (MMR) deficient and proficient tumors, respectively.
Project description:Lynch syndrome and Familial colorectal cancer type X (FCCTX) are clinically diagnosed using the same criteria, but genomic differences exist between these two groups and the genomic profiles share similarities with their sporadic counterparts, mismatch repair (MMR) deficient and proficient tumors, respectively. Array-based comparative genomic hybridization was performed on 91 tumors, comprising 23 Lynch syndrome (AH), 23 FCCTX (AA), 23 sporadic MMR deficient (AM) and 22 sporadic MMR proficient tumors, in order to identify differences between Lynch syndrome and FCCTX.
Project description:We performed whole exome sequencing and copy number analysis for 15 triplets, each comprising normal colorectal tissue, primary colorectal carcinoma, and its synchronous matched liver metastasis. We analyzed the similarities and differences between primary colorectal carcinoma and matched liver metastases in regards to somatic mutations and somatic copy number alterationss (SCNAs). The genomic profiling demonstrated mutations in APC(73%), KRAS (33%), ARID1A and PIK3CA (6.7%) genes between primary colorectal and metastatic liver tumors. TP53 mutation was observed in 47% of the primary samples and 67% in liver metastatic samples. The grouped pairs, in hierarchical clustering showed similar SCNA patterns, in contrast to the ungrouped pairs. Many mutations (including those of known key cancer driver genes) were shared in the grouped pairs. The ungrouped pairs exhibited distinct mutation patterns with no shared mutations in key driver genes. Four ungrouped liver metastasis samples had mutations in DNA mismatch repair genes along with hypermutations and a substantial number of copy number of alterations. Genomically, colorectal and metastatic liver tumors were very similar. However, in a subgroup of patients, there were genetic variations in liver metastases in the loss of DNA mismatch repair genes. Copy number analysis of Affymetrix CytoScanHD arrays was performed for 15 primary colorectal carcinoma and 15 samples of their matched liver metastases. 15 normal samples prepared from each of the patient was used as the reference for the study. Nexus Copy number 6.1 software was used for somatic copy number alteration analysis.