A Telomere-Associated Molecular Landscape Reveals Immunological, Microbial, and Therapeutic Heterogeneity in Colorectal Cancer

Yinmeng ZhangJiawei FanJiahui ZhaoHe ZhuYan XiaHong Xu^*

• Department of Gastroenterology, The First Hospital of Jilin University, Changchun, China

Colorectal cancer (CRC) ranks among the most prevalent malignancies of the gastrointestinal tract and remains a leading cause of cancer-related mortality worldwide. Although telomere biology has been increasingly implicated in immune modulation and tumor progression, its clinical significance in CRC remains poorly understood.We developed the TELscore, by integrating transcriptomic and intratumoral microbiome profiles from publicly available CRC cohorts. To comprehensively characterize TELscore subgroups, we performed biological analysis, TIME profiling, and microbiome analysis. Tissue imaging was utilized to visualize immune features across subgroups. Patients were stratified into high and low TELscore categories, and the predictive robustness was validated across multiple independent training and validation cohorts. Chemotherapeutic drug sensitivity was evaluated using GDSC database. Furthermore, the predictive capacity of TELscore for immunotherapy response was independently assessed in an external cohort. Finally, scRNA-seq analysis was conducted to further dissect the cellular landscape within the TME. The high TELscore group, which exhibited significantly shorter DFS, showed marked enrichment of tumorigenic pathways, along with a distinctly immunosuppressive TIME. This was reflected by elevated ESTIMATE/TIDE scores and corroborated by CIBERSORT, which revealed increased infiltration of M0 macrophages. In contrast, the low TELscore group was enriched for cell cycle related pathways, and demonstrated higher infiltration of M1 macrophages. 16S rRNA sequencing further revealed a divergent intratumoral microbiome between subgroups, the high TELscore group harbored significantly greater relative abundance of Selenomonas and Lachnoclostridium, two pathogenic genera associated with CRC. WSIs assessment demonstrated a marked absence of intraTLSs in high TELscore tumors. From a therapeutic standpoint, high TELscore tumors exhibited reduced sensitivity to standard chemotherapeutic agents-including Fluorouracil, Irinotecan, Oxaliplatin, and Docetaxel-as reflected by elevated IC50 values. Conversely, these tumors demonstrated increased susceptibility to MAPK pathway inhibitors, such as Selumetinib and Trametinib. Notably, TELscore also served as a robust predictor of immunotherapy response, which was validated in the IMvigor210 cohort. Finally, scRNA analysis highlighted profound cellular and functional divergence between TELscore subgroups. TELscore is a robust stratification tool that captures the interplay between tumor biology, immune characteristics, and microbial ecology in colorectal cancer. TELscore offers a powerful framework to advance personalized treatment and precision oncology.