Accumulation of Stabilin-1 Positive Macrophages in the Early Stage of Gastric Cancer is Associated with Short Cumulative Survival

The scavenger receptor stabilin-1 has been reported to be expressed by tumor-associated macrophages (TAMs) and to facilitate tumor growth and metastasis in mouse models of breast carcinoma and melanoma. However, to the best of our knowledge, its expression and association with prognosis in human gastric cancer has not been evaluated. The present study investigated the expression of stabilin-1 and its association with clinicopathological parameters in patients with gastric cancer. The expression of stabilin-1 was evaluated by immunohistochemical staining of gastric cancer tissue samples of 371 Chinese patients with primary gastric adenocarcinoma. Confocal laser scanning microscopy was used to determine the cellular source of stabilin-1 in the gastric cancer tissues using anti-CD68, anti-CD163, anti-stabilin-1 and anti-secreted protein acidic and rich in cysteine antibodies. A higher number of stabilin-1-positive cells were observed in the cancer tissues of primary gastric adenocarcinoma compared with adjacent non-cancerous tissues of primary gastric adenocarcinoma (P<0.001); the majority of stabilin-1-positve cells were CD68/CD163 macrophages. Poorly-differentiated gastric cancer tissue had fewer stabilin-1-positive cells compared with medium- and well-differentiated gastric cancer (P=0.030). A higher number of stabilin-1-positive cells were found in the early Tumor-Node-Metastasis (TNM) stage (TNM I stage) of primary gastric adenocarcinoma (P=0.038) compared with TNM stage IV. For patients with TNM stage I disease, a higher number of stabilin-1-positive TAMs was associated with shorter cumulative survival (P<0.05). Overall, stabilin-1 was found to be expressed by CD68 TAMs in human gastric cancer. The high expression of stabilin-1 in TNM stage I disease was associated with poor patient survival, indicating the clinical significance of stabilin-1 in gastric cancer.