a. Detection of spiked KPL-4 cells and cells after i.v. injection. 10 cells were spiked into 100 μl or 1 ml of native murine blood samples. Cells of the KPL-4 line stably expressed EpCAM, Her2 and the housekeeping-genes for up to 4 h. The cells could be detected by AdnaTest and without antibody enrichment (a.). 100,000 cells of the KPL-4 cell line were injected into the tail vein of native mice. Tumour cells could not be detected by the AdnaTest, whereas human mRNA was visible without antibody enrichment for up to 4 h after injection. The detected cells showed serial changes and reduced EpCAM expression already 30 min after i.v. injection (b.). b. Tissue analyses for human mRNA after injection of 100,000 KPL-4 cells into the tail vein. Tissues were homogenised and RNA was purified followed by cDNA synthesis and PCR reaction. Human breast cancer cells detectable in the lungs and one liver were positive for EpCAM and Her2 expression up to 2 h after KPL-4 cell injection. c. MDA-MB-231 breast cancer cells were injected into the heart and blood was analysed for human mRNA signals. CTCs were detectable in all animals for up to 5 h after injection. The detected cells showed changes of mRNA expression including downregulation of EpCAM and MUC-1, whereas mRNA of the housekeeping-genes and mesenchymal Vimentin was visible permanently.
Gorges et al. BMC Cancer 2012 12:178 doi:10.1186/1471-2407-12-178