Specific Detection of Metastasized Human Tumor Cells in Embryonic Chicks by the Polymerase Chain Reaction

We have established a highly sensitive method for specific detection of metastasized human tumor cells in embryonic chicks using the polymerase chain reaction (PCR). The cells (HT‐1080 or KMST‐6) were inoculated into the chorioallantoic membrane vein of the chick embryo and DNA of each embryonic organ was extracted. Then, a human β‐globin‐related sequence (576 bp) in the DNA from the embryonic liver and lung was specifically amplified and detected by gel electrophoresis and by a specific oligonucleotide probe. The amplified fragments from the liver DNA samples increased gradually from 2 h to 7 days after HT‐1080 inoculation. On the other hand, with inoculation of non‐tumorigenic human embryonal fibroblast KMST‐6 cells, the DNA from the embryonic liver 7 days after inoculation did not show the PCR‐amplified product. This detection technique can contribute significantly to the precise detection of microscopic metastasis.