Tumor-associated macrophage expression in colorectal adenomas and carcinomas: relationship to infection.

[OBJECTIVE] This study investigated the association between infection and the expression of CD163 and CD86 tumor-associated macrophages (TAMs) in colorectal adenoma (CRA) and colorectal cancer (CRC) tissues.

[METHODS] Immunohistochemistry (IHC) was used to evaluate the expression of CD163 and CD86 TAMs isolated from colorectal tissues, Multiplex immunofluorescence (mIF) co-staining was employed to identify CD68CD163 and CD68CD86 TAMs, and the C-urea breath test (UBT) was used to detect infection.

[RESULTS] The progression of colorectal lesions was significantly associated with increased expression of CD163 and CD86 TAMs, as well as infection (all 0.05). The expression of CD163 and CD86 TAMs were positively correlated with each other and with the severity of colorectal lesions (all 0.001). Patients with infection exhibited significantly higher expression of both TAM subsets compared with non-infected individuals (all 0.05). Multiple linear regression analysis showed that in colorectal adenomas measuring ≥ 1 cm, expression of CD163 and CD86 TAM was significantly greater than in adenomas <1 cm ( 0.05), Expression of CD163 TAM was notably higher in obese patients with CRC. Multiplex immunofluorescence (mIF) quantification revealed significantly increased densities of both CD68CD86 and CD68CD163 TAMs, and a higher CD68CD163/CD68CD86 ratio in colorectal cancer (CRC) (all 0.001).

[CONCLUSIONS] The expression of CD68CD163 and CD68CD86 TAMs change dynamically with the progression of colorectal lesions. These changes are influenced by infection, adenoma size, tumor differentiation, and patient metabolic status.