Send to

Choose Destination
Lab Invest. 1997 Sep;77(3):213-20.

Detection of cytokeratin-19 transcripts by reverse transcriptase-polymerase chain reaction in lung cancer cell lines and blood of lung cancer patients.

Author information

Department of Medical Oncology, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.


Conflicting results have been reported on the use of cytokeratin-19 (CK-19) in the detection of tumor cells in the peripheral blood of patients with solid tumors. We investigated the expression of CK-19 in lung cancer cell lines and in human lung tumor samples using a nested reverse transcriptase (RT)-PCR to determine the sensitivity and specificity of this method. In addition, blood samples of lung cancer patients and healthy controls were analyzed for the presence of CK-19 transcripts. Amplification products were visualized by ethidium bromide staining and radioactive hybridization with a CK-19-specific probe. Application of a previously described nested RT-PCR for the detection of CK-19 resulted in amplification of the processed pseudogene. Therefore, a more stringent RT-PCR was developed by increasing the annealing temperature. RT-PCR amplification products for CK-19 were detected in 38 of 41 lung cancer cell lines. The three negative cell lines were all variant small-cell lung cancer cell lines. Concordant results were observed between CK-19 detection by immunohistochemistry and by RT-PCR. In serial RNA dilution experiments, CK-19 transcripts could be detected in 18 to 80 pg of total cellular RNA in three cell lines and in 60 ng total RNA in one cell line. The nested RT-PCR had the sensitivity of detecting 50 tumor cells in 10(6) peripheral blood mononuclear cells (PBMNC), and CK-19 transcripts were randomly detected in normal PBMNC. This study shows the necessity in processing parallel samples without reverse transcriptase enzyme to avoid amplification of pseudogenes. A serious problem in the detection of tissue-specific transcripts in PBMNC is the detection of illegitimate transcription levels. In conclusion, although CK-19 may be a useful marker for the detection of lung cancer cells, its application for the detection of circulating tumor cells is not recommended.

Comment in

[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center