Background: This study aimed to explore the prognostic significance of tumor-associated macrophage (TAM) infiltration in colorectal cancer (CRC) patients.
Methods: Tissue microarray and immunohistochemistry were used to detect the infiltration of CD163+ TAMs in 209 CRC samples, and the Kaplan-Meier method was used for survival analysis. Cox proportional hazards analysis was used for univariate analysis and multivariate analysis of clinically relevant confounders.
Results: The samples were divided into low-level (n = 105) and high-level infiltration groups (n = 104) by the median number of CD163+ TAMs detected. The overall survival (OS) and disease-free survival (DFS) of CRC patients in the low-level CD163+ TAM infiltration group were longer than those in the high-level CD163+ TAM infiltration group (P < 0.001). Infiltration of CD163+ TAMs in CRC tissues was a negative prognostic factor for CRC patients. Risks of death and disease recurrence for CRC patients in the low-level CD163+ TAM infiltration group were lower than those in the high-level CD163+ TAM infiltration group (HROS = 0.183, 95% CI 0.052-0.647, P = 0.008; HRDFS = 0.191, 95% CI 0.078-0.470, P = 0.000).
Conclusions: The infiltration of CD163+ TAMs in CRC tissue is an independent adverse factor for the prognosis of CRC patients. High-level infiltration of CD163+ TAMs is associated with shorter OS and DFS.
Keywords: CD163; Colorectal cancer; Immunohistochemistry; Prognosis; Tumor-associated macrophages.