Microenvironment of Adjacent Non-Neoplastic Regions Determines Prognostic Outcomes in Locally Advanced Colorectal Cancer after Surgical Resection: A Multi-Center & Multi-Omics study

Abstract We aimed to predict postoperative prognosis of stage II/III colorectal cancer (CRC). Tumor-like normal microenvironment (tNME) and healthy normal microenvironment (hNME) groups were created using RNA sequencing (RNA-seq) data derived from 273 tumors and 273 paired normal tissues from margins of resected specimens. With a median follow-up of 58.2 months, the tNME group showed poor 5-year recurrence-free survival (54.7 vs. 73.0%, HR = 1.94, P = 0.002) and 5-year overall survival (78.2 vs. 83.0%, HR = 1.76, P = 0.033). Only the tNME group showed similar microbiome diversity between tumor and normal tissues. scRNA-seq revealed a positive co-occurrence of Th17, GZMK high CD8+T cells, and IL1B high neutrophils in the tumor and normal tissues of tNME. A high proportion of EMP1 high epithelial cells was observed in the tNME group, with upregulated epithelial-mesenchymal transition and leukocyte signaling pathways. In conclusion, the microenvironmental status of normal tissues offers a promising biomarker for stage II/III CRC.