Multicenter validation of CEACAM6 and FOXP3 as robust prognostic biomarkers in colon cancer: Combined immunohistochemical and transcriptomic analysis

Colon cancer remains a leading cause of cancer-related mortality worldwide, with metastatic disease exhibiting particularly poor prognosis. To identify robust prognostic biomarkers, the present multicenter study employed immunohistochemistry and reverse transcription-quantitative PCR to evaluate CEACAM6 and FOXP3 expression in 301 colon cancer specimens from three tertiary hospitals in China, analyzing their associations with tumor-infiltrating lymphocytes, clinicopathological features and patient outcomes. Key findings revealed that early-stage (I-II) tumors exhibited significantly higher infiltration of CD3⁺, CD8⁺ and CD45RO⁺ T cells compared with advanced-stage (III-IV) tumors (P<0.001), while FOXP3 and CEACAM6 expression were significantly elevated in late-stage and poorly differentiated tumors (P<0.001). Notably, CEACAM6 overexpression correlated inversely with CD3⁺, CD8⁺ and CD45RO⁺ T-cell infiltration but positively with FOXP3⁺ Tregs. Transcriptomic analysis further confirmed upregulation of CEACAM6 and FOXP3 mRNA in advanced-stage tumors (P<0.001). Kaplan-Meier survival analysis demonstrated that high CEACAM6 and FOXP3 expression were associated with significantly shorter overall survival (P<0.001). Multivariate Cox regression identified TNM stage, tumor differentiation, CEACAM6 and FOXP3 as independent prognostic factors. The present study provides robust multicenter validation of CEACAM6 and FOXP3 as critical biomarkers in colon cancer, highlighting their roles in immune evasion and tumor progression. These findings support their potential integration into clinical risk stratification and the development of targeted immunotherapies. Further mechanistic and prospective studies are warranted to explore their therapeutic applications.