Objective  To investigate the expression and clinical significance of the leukocyte differentiation antigen CD200 receptor (CD200R) in lung squamous cell carcinoma (LSCC).

  Methods  LSCC specimens were collected from 100 patients who were enrolled in the study and underwent surgical resection from January 2004 to December 2011 at Tianjin Medical University Cancer Institute and Hospital. CD200R expression was detected by immunohistochemistry, and the effect of CD200R expression on cell proliferation and colony formation capacity was determined by in vitro cellular assays.

  Results  CD200R was found to be mainly expressed in the cytoplasm and cell membrane, with 55% (55/100) of the patient specimens exhibiting high expression and 45% (45/100) showing low expression of CD200R. The overall survival (OS) and disease free survival (DFS) of the patients with high CD200R expression were 46 months and 32 months, respectively, and were significantly shorter than those of patients with low CD200R expression (P=0.020 for OS and P=0.001 for DFS). CD200R was an independent prognostic factor for the patients (P < 0.05). The in vitro cellular assays showed that the proliferation and colony forming capacity of the LSCC cells were significantly decreased after knocking down CD200R expression.

  Conclusions  High expression of CD200R in LSCC tissues is associated with poor prognosis. CD200R knockdown inhibits LSCC cell proliferation. Thus, CD200R can be used as a new biomarker to predict the recurrence and survival of LSCC, as well as a therapeutic target for LSCC.