English CD68- and CD163-positive tumor-associated macrophages in renal clear cell carcinoma: Macrophage infiltration in ccRCC

Abstract

Background: This study aimed to analyze the infiltration of tumor-associated macrophages (TAMs) in clear cell renal cell carcinoma (ccRCC) and to assess their prognostic significance.

Methods: This study involved a cohort of 106 patients with ccRCC who underwent partial or radical nephrectomy. Immunohistochemistry (IHC) was employed to assess the expression of two distinct types of macrophages at various tissue locations. The diagnostic utility of CD68-positive (CD68⁺) and CD163-positive (CD163⁺) macrophages was determined via receiver operating characteristic (ROC) curves.

Results: Compared with those in adjacent tissues, the numbers of CD68⁺ and CD163⁺ TAMs were significantly elevated in ccRCC tissues. ROC curve analysis revealed that the area under the curve (AUC) for CD68 was 0.782 and that the AUC for CD163 was 0.879, indicating that these factors are statistically significant for the diagnosis of ccRCC (P = 0.01). Patients with high expression of CD68/CD163 in cancer tissues exhibited shorter overall survival (OS) (P < 0.01). Patients with a low density of both intracellular CD68⁺ and CD163⁺ TAMs experienced a more favorable prognosis (P < 0.01).

Conclusions: TAMs, particularly the M2 subtype (CD163⁺), are identified as adverse prognostic factors for ccRCC patients. Those with a high density of M2 macrophages tend to have a poorer prognosis.