Elevated plasma thymosin-alpha1 levels in lung cancer patients.

OBJECTIVE: Prothymosin-alpha, the precursor of thymosin-alpha1, may play a role in cell proliferation, and the plasma level of thymosin-alpha1 may reflect the degree of proliferation of the tumor cells. METHODS: Recently, a new sandwich immunoradiometric assay for thymosin-alpha1 was developed using monoclonal and polyclonal antibodies. In this investigation, we used this assay to measure plasma and tissue level of thymosin-alpha1 in 131 lung cancer patients. RESULTS: We found that the mean plasma thymosin-alpha1 levels in lung cancer patients were higher than in normal individuals (P < 0.001). However, half of the patients showed normal levels. Thymosin-alpha1 levels correlated neither with the stage nor pathological subtype of the lung cancer, and did not decrease significantly in the 4 weeks after the resection of the tumor. Thymosin-alpha1 levels of lung cancer patients with another cancer were higher than those without evidence of other cancers (P = 0.03). Survival of patients with normal levels of plasma thymosin-alpha1 was significantly better than that with higher levels (P = 0.04). CONCLUSIONS: The plasma level of thymosin-alpha1 may be used as a marker for the prognosis of lung cancer patients. Further investigations are warranted to determine its role in the lung cancer.