Abstract: Objective To set up means of reverse transcription-polymerase chain reaction(RT-PCR)which could be used to detect micrometastases in regional lymph nodes (LNs) of ESC patients and to compare the method with histological examination(HE). Methods Serial dilution study using ESC tissue was performed to detect the sensitivity of CK19RT-PCR assay.The regional LNs(n=104) were obtained from 23 ESC patientswho underwent operation.Each LN was cut into halvers.One half of each LN was subjected to HE.The other half was subjected to RT-PCK. Results The sensitivity of this assay was 10-6～10-4μg ESC RNA/1μg normal LN RNA.Twnnty-two of 104 LNs were histologically involved by carcinoma cells and 21 of these yielded the expected product by RT-PCK.Of the 82 Lns which were diagosed to be devoid of metastases by HE,ten Lns were found to express CK19mRNA. Conclusion The assay of RT-PCK may lead to an earlier diagnosis and treatment of ESC patients with subclinical LNs metastasis.