BACKGROUNDTo detect the micrometastases status in peripheral blood and regional lymph nodes of lung cancer patients by reverse transcription-polymerase chain reaction (RT-PCR).

METHODSCK19 mRNA expression in peripheral blood and regional lymph nodes was detected in 78 patients with lung cancer, and 30 patients with pulmonary benign lesions and 10 healthy volunteers as controls by RT-PCR. Meanwhile, all lymph nodes were also examined by traditional pathological method.

RESULTSThe positive rate of CK19 mRNA expression was 38.5% in peripheral blood of lung cancer patients, and 6.7% in patients with pulmonary benign lesions (6.7%) (Chi-square=10.505,P=0.001). No positive CK19 mRNA expression was found in peripheral blood of 10 healthy volunteers. The positive rates of CK19 mRNA of lymph nodes were 36.9% and 0 in lung cancer patients and pulmonary benign disease patients respectively (Fisher's exact=0.014). In lung cancer group, the metastatic rate of lymph nodes was 17.9% by traditional pathological examination, which was much lower than that by RT-PCR (Chi-square=7.664, P=0.006).

CONCLUSIONSRT-PCR amplification of CK19 mRNA is an sensitive method to detect early haematogenous and regional lymph nodes dissemination of cancer cells for patients with lung cancer. This method may lead to an earlier diagnosis and treatment of patients with subclinical metastasis in circulation and regional lymph nodes.