OBJECTIVETo evaluate the specificity, sensitivity and their clinical significance of detecting CK19 mRNA expression by nested RT-PCR for molecular diagnosis of micrometastasis in the peripheral blood and bone marrow of patients with non-small cell lung cancer.

METHODSCK19 mRNA expression was detected by nested RT-PCR in peripheral blood and bone marrow samples from 59 lung cancer patients, with samples of 11 benign pulmonary lesion patients and 20 healthy adults as control.

RESULTSThe sensitivity of nested RT-PCR was 10(-6). The positive rates of micrometastasis were 33.89% (20/59) in peripheral blood and 22.03% (13/59) in bone marrow, with a highly positive correlation existing between the two groups (P < 0.05). The micrometastasis in peripheral blood and bone marrow was closely correlated with the pathological classification and cell differentiation (P < 0.05) and P-TNM stage (P < 0.01). No CK19 mRNA expression was found in the samples from patients with benign pulmonary lesion or healthy adult volunteers.

CONCLUSIONThe peripheral blood and bone marrow from patients with non-small cell lung cancer possesses micrometastasis that can not be detected by common methods. Nested RT-PCR technique shows favorable specificity and sensitivity in detecting the condition with definite clinical prospects.