Elevated serum annexin A1 as potential diagnostic marker for lung cancer: a retrospective case-control study.

Annexin A1 was investigated as prognostic factor because of its apparent association with tumorigenesis. The aim of this study was to investigate the expression of annexin A1 in lung cancer patients, and analysed the relationship with respect to the clinico-pathological features and assessed whether annexin A1 as a potential serum marker for lung cancer.Expression of annexin A1 was examined using immunohistochemistry, in-situ hybridization, western blot and enzyme-linked immunosorbent assay. Sensitivities and specificities for annexin A1 serum test were determined using receiver operator characteristic curve and cutoff was defined based on 95% and 85% sensitivities.Lung cancer tissues exhibited higher expression of annexin A1 than the normal tissues (P < 0.05) and the serum annexin A1 of lung cancer patients also exhibited higher level than control groups (P < 0.05). Moreover, increased serum annexin A1 was significantly associated with the pathological grade and clinical stage of lung cancer patients (P < 0.05). Using receiver operator characteristic curve analysis, the cutoffs for distinguishing lung cancer from normal and benign groups were 4.77 and 4.84 ng/ml respectively. The sensitivities of annexin A1 for distinguishing lung cancer from normal and benign groups were 98.9% and 97.4%, and specificities were 88.3% and 66.4%.Up-regulation of serum annexin A1 was associated with pathological grade and clinical stage of lung cancer patients, which indicated that it could be considered molecular biomarker for diagnosis and prognosis of lung cancer.