High Infiltration of CD203c + Mast Cells Reflects Immunosuppression and Hinders Prognostic Benefit in Stage II-III Colorectal Cancer

Activated mast cells (AMCs) have been fully researched in inflammation and allergic reactions. However, the protumoral role of AMCs and their biomarker CD203c has not yet been investigated in colorectal cancer (CRC). We retrospectively collected 449 postoperative patients with stage II-III CRC at two different hospitals as the training (n=310) and validation (n=139) cohorts. These findings were further validated in the independent cohort (Integration of GSE39582 and GSE17536, n=489). The AMC density was assessed using CD203c staining or the CIBERSORT method. The main analysis was recurrence-free survival (RFS) and overall survival (OS). As an independent factor, high AMC infiltration was associated with worse RFS/OS in the training (hazard ratio [HR]=3.437/3.014, all