Detection of lung cancer micrometastasis in regional lymph nodes by assays of CK19 reverse transcription-polymerase chain reaction.

Abstract

To set up a molecular method(RT-PCR) which can be used to detect micrometastasis of regional lymph nodes (LNs) in patients with lung cancer. Primary lung cancer tissues ( n = 20) and regional LNs ( n = 159) were obtained from 20 patients with lung cancer who underwent lobectomy. Each LN was halved. One half of a LN was subjected to histological examination (HE) and the other half was subjected to RT-PCR amplification of CK19 mRNA. Serial dilution study using LC-5 cells was performed to detect sensitivity of the CK19 RT-PCR method. Serial dilution study for LC-5 cells demonstrated that CK19 mRNA was detectable at a concentration as low as 10 LC-5 cells in 1 *10(7) LN cells. CK19 mRNA was found in 42 LNs that were proved to have metastasis by HE. Of the other 117 LNs which were diagnosed as no metastasis by HE , however , twenty five LNs were found to express CK19 mRNA by RT-PCR. Comparing with HE method , the RT-PCR method can make more accurate assessment of metastatic status in LNs.