Comprehensive characterization of tumor microenvironment in colorectal cancer via histopathology-molecular analysis

Purpose To explain how the tumor microenvironment (TME) contributes to biological and clinical heterogeneity of colorectal cancer (CRC). Methods Using multi-omics analysis, single cell transcriptomic sequencing analysis and artificial intelligence-enabled spatial analysis of whole-slide images, we performed a comprehensive characterization of TME in colorectal cancer (CCCRC). Results CRC samples were classified into four CCCRC subtypes with distinct TME features, namely, C1 as the proliferative subtype with low immunogenicity; C2 as the immunosuppressed subtype with the terminally exhausted immune characteristics; C3 as the immune-excluded subtype with the distinct upregulation of stromal components and a lack of T cell infiltration in tumor core; and C4 as the immunomodulatory subtype with the remarkable upregulation of anti-tumor immune components. The four CCCRC subtypes had distinct histopathological and molecular characteristics, therapeutic efficacy, and prognosis. The C1 subtype was more sensitive to chemotherapy, the C2 and C3 subtypes were more sensitive to WNT pathway inhibitor SB216763 and Hedgehog pathway inhibitor vismodegib, and the C4 subtype was suitable for ICB treatment. Finally, we established a single-sample gene classifier for identifying the CCCRC subtypes. Conclusions Our integrative analyses ultimately established a holistic framework to thoroughly dissect the TME of CRC, and the CCCRC classification system with high biological interpretability might facilitate biomarker discoveries and clinical treatment decisions in the future.