Relationship Between Mast Cell Population of Microenvironment and Prognosis in Colorectal Cancer

Background: Mast cells are integral components of the tumor microenvironment and have been implicated in the regulation of tumor progression in various malignancies. The association between inflammation and colorectal cancer (CRC) development has become increasingly recognized. Depending on the tumor microenvironment, mast cells may exert either pro-tumorigenic or antitumorigenic functions. Objective: This study aimed to evaluate the relationship between stromal mast cell density and prognostic factors in patients with CRC. Methods: In this retrospective cohort study, 81 patients who underwent curative surgical resection for CRC were analyzed. Immunohistochemical staining for mast cell tryptase (MCT) was performed on paraffin-embedded tumor specimens. Mast cells were quantified in regions of hot spots within the tumor stroma. Patients were categorized as high mast cell density (MCC-H, ≥22 cells/HPF) or low mast cell density (MCC-L, <22 cells/HPF). Associations with clinicopathological parameters were assessed using chi-square or Fisher's exact tests. Progression-free survival (PFS) and overall survival (OS) were analyzed using Kaplan-Meier estimates and log-rank tests. Independent prognostic factors were identified using multivariate Cox proportional hazards regression, with hazard ratios (HRs) and 95% confidence intervals (CIs) reported. Results: ROC analysis identified an MCC cut-off of 22 cells/HPF (AUC = 0.61; sensitivity = 0.67, specificity = 0.52) for mortality prediction. Multivariate analysis revealed lymph node involvement (HR: 1.41, 95% CI: 1.03-1.94, p = 0.033) and macroscopic tumor perforation (HR: 0.15, 95% CI: 0.04-0.55, p = 0.004) as independent predictors of PFS. High MCC (≥22) independently predicted improved OS (HR: 0.07, 95% CI: 0.006-0.87, p = 0.039). A significant association was observed between OS, MCC, and lymph node stage. Conclusions: Stromal mast cell count is an independent prognostic factor for overall survival in patients with CRC. Our findings suggest that MCC may serve as a reliable prognostic biomarker following surgical resection and could aid in postoperative risk stratification.