DAP12, a macrophage fusion receptor, is expressed in breast cancer cells and associated with skeletal and liver metastases and poor survival
(English)Manuscript (preprint) (Other academic)
DAP12 is a transmembrane receptor present in myeloid cells and is essential for the development of functionally mature osteoclasts and microglia, and for integrin signaling in macrophages and neutrophils. The macrophage specific antigen CD163 is expressed in breast and colorectal cancer and is associated with early cancer recurrence and poor prognosis. We hypothesize that macrophage traits in cancer cells may be explained by fusion between cancer cells and tumor associated macrophages. The role of DAP12 in the fusion between cancer cells and macrophages is not known. This study was performed to investigate the expression of DAP12 in breast cancer cells and its´ relation to macrophage trait manifested by CD163 expression.
Immunostaining of DAP12, CD163 and MAC387 were evaluated in paraffinembedded specimens from totally 133 patients with breast cancer. The outcomes were analyzed in relation to clinicopathological data.
DAP12 expression was positive in the majority of cases (64%) with breast cancer and associated with advanced tumor grade (p= 0.015) and liver metastasis (p= 0.0465) but not lung metastasis (0.997). It tended to correlate with skeletal metastases (p=0.0673). Patients with breast cancer expressing high DAP12 had poor prognosis with higher rates of skeletal (p=0.023) and liver metastases (p=0.028) and overall shorter distant recurrence free survival (p=0.0028). DAP12 expression was neither correlated to CD163 nor MAC387 expression. To our knowledge, this is the first study where DAP12 expression is reported in breast cancer.
In conclusion, DAP12 is expressed in breast cancer and is significantly related to skeletal and liver metastasis as well as poor prognosis. We hypothesize that DAP12 expression may promote fusion between breast cancer cells and macrophages. It may even promote homing of cancer cells in bone and liver tissue and result in increased metastasis at these sites.
Breast cancer, tumour associated macrophages, DAP12, CD163, metastasis, cell fusion
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-54819OAI: oai:DiVA.org:liu-54819DiVA: diva2:310537