A Single Cell Atlas of MMRd and MMRp Colorectal Cancer

Immune responses to cancer vary across cancer types and patients. Colorectal cancer tumors with mismatch repair-deficiency (MMRd) show an elevated immune cell activity as compared to mismatch repair proficient (MMRp) tumors. To understand the immune response patterns in these two 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 clusters (that contain epithelial, malignant, stromal and immune cell lineages), and an associated compendium of 204 gene expression programs. Examination of these cell subsets and programs revealed extensive transcriptional and spatial remodeling of malignant, stromal and immune cells in MMRd and MMRp tumors. This dataset was generated as part of a published study (Pelka, Hofree, Chen, et al., Cell 2021 Sep 2;184(18):4734-4752; PMID: 34450029).]]>
Only patients with primary treatment-naive colorectal cancer were included in this study. Patients with known concurrent neoplasms other than colorectal cancer were excluded from this study. Samples were cut by pathology assistants at MGH and BWH hospitals. To preserve the invasive border for clinical pathological evaluation, the pathology assistants did not sample tumor down to the invasive border.]]>