Breast Cancer Expression of CD163, a Macrophage Scavenger Receptor, is Related to Early Distant Recurrence and Reduced Patient Survival

Cells of the monocyte/macrophage lineage are important for tumour cell migration, invasion and metastasis. Fusion between macrophages and cancer cells in animal models in vitro and in vivo causes hybrids with increased metastatic potential. Primary breast cancer cells were characterized for macrophage antigens to test if phenotypic resemblance to macrophages is related to early distant recurrence. Immunostaining for CD163, MAC387 and CD68 was performed in a breast cancer tissue micro array from 127 patients consequently followed up for a median of 13 years. Tumour-associated macrophages expressed all 3 antigens. The breast cancers expressed CD163 to 48%, MAC387 to 14% while CD68 was not expressed. TGF-beta staining intensity was positively related to both CD163 and MAC387 expression. Expression of CD163 in the cancer cells was compared to their DNA ploidy, Nottingham Histological Grade, TNM-stage, node state, presence of estrogen receptors and occurrence of distant metastases and survival. Cancers of a more advanced histological grade expressed CD163 to a higher extent. Cells expressing MAC387 were more common in cancers with a high proportion of CD163 positive cells. Multivariate analysis showed that expression of the macrophage antigen CD163 in breast cancer cells has a prognostic impact on the occurrence of distant metastases and reduced patient survival time.