Background and objectives: The sensitive detection of circulating tumor cells in lung cancer patients is very important for prognosis and selection of appropriate treatment modalities. Based on recent promising data, the authors established reverse transcriptase (RT)-PCR with primers specific for surfactant protein D (SP-D) gene to detect circulating tumor cells in the peripheral blood of lung cancer patients, and to initiatively discuss its clinical significance.
Methods: The expression of SP-D mRNA was analyzed by an improved nested RT-PCR in the peripheral blood of 26 lung cancer patients with metastases, 37 lung cancer patients without metastases, 15 benign pneumonia patients, and 15 healthy volunteers.
Results: 1) The sensitivity of the method was 1 x 10(-6), with high level of specificity. 2) Using this method, the positive detection rate of the expression of SP-D mRNA was 92.3% (24/26) and 24.3% (9/37) in the peripheral blood of lung cancer patients with and without metastases, respectively. While no sample was positive for SP-D mRNA expression in the benign pneumonia patients and in the healthy volunteers.
Conclusions: SP-D mRNA might be a valuable marker to detect circulating tumor cells in the peripheral blood of lung cancer patients. This method may be a valuable tool for early identification of metastases in asymptomatic lung cancer patients. Furthermore, it can also provide important clinical information for the evaluation of prognosis and in the selection of appropriate treatment strategies.