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Background: Macrophages are a component of a tumor's microenvironment and have various roles in tumor progression and metastasis. This study evaluated the relationships between tumor-associated macrophage (TAM) density and clinical outcomes in 14 different types of human cancers. Methods: We investigated TAM density in human tissue microarray sections from 14 different types of human cancers (n = 266) and normal thyroid, lung, and breast tissues (n = 22). The five-year survival rates of each cancer were obtained from the 2011 Korea Central Cancer Registry. Results: Among 13 human cancers, excluding thyroid cancer, pancreas, lung, and gallbladder cancers had the highest density of CD163-positive macrophages (7.0 ± 3.5%, 6.9 ± 7.4%, and 6.9 ± 5.5%, respectively). The five-year relative survival rates of these cancers (pancreas, 8.7%; lung, 20.7%; gallbladder, 27.5%) were lower than those of other cancers. The histological subtypes in thyroid cancer exhibited significantly different CD163-positive macrophages densities (papillary, 1.8 ± 1.6% vs anaplastic, 22.9 ± 17.1%; p < .001), but no significant difference between histological subtypes was detected in lung and breast cancers. Moreover, there was no significant difference in CD163-positive macrophages densities among the TNM stages in lung, breast, and thyroid cancers. Conclusions: Cancers with higher TAM densities (pancreas, lung, anaplastic thyroid, and gallbladder) were associated with poor survival rate.
Key Words: Tumor-associated macrophage; Prognosis; Neoplasms
The tumor microenvironment includes cancer cells and various stromal cells, including immune cells, fibroblasts, and vascular endothelial cells.1 Tumor-associated macrophages (TAMs) are also present in the tumor microenvironment and are important in tumor progression and metastasis.2 TAMs can induce neoplastic cell transformation, elicit tumor destructive reactions, and have either negative or positive effects on tumor growth.3 Several reports have suggested that TAMs are associated with tumor growth, disease progression, and poor prognosis in some human cancers.4-6 Moreover, high densities of TAMs are present in the more advanced stages of cancers that have poor prognoses, such as breast,7 lung,8 thyroid,5 and bladder3 cancers. In contrast, several reports, including those on colorectal,9 stomach,10 lung,11,12 and endometrial13 cancers, have shown that a high density of TAMs is associated with a high survival rate. Collectively, these results suggest that TAMs can have either positive or negative effects depending on the specific tissue type, tumor location, and tumor stage. The aim...