Quantification of liver metastases from LS174T human colorectal cancer cells in nude rats by PCR

Liver metastasis of colorectal cancer is a challenging problem and associat ed with poor prognosis. Appropriate experimental models based for example o n xenografts of human colorectal cancer (HCRC) cells may help to find new t herapeutic options. To establish an orthotopic liver metastasis model, 9 HC RC cell lines (HDC8, HDC63, HDC101, Isreco-1, Isreco-2, Isreco-3, SW480, SW 620, LS174T) were tested for their appropriateness after subcutaneous (s.c. ), intrasplenic, intrahepatic and intraportal injection into rnu-rats. The growth curve of the most appropriate cell line (LS174T) was established in a subsequent experiment. For early tumor detection, a quantitative nested P CR-assay using an internal standard was developed. The detection limit of t he assay ws 10 HCRC cells/mg lie tissue, which was 100-1000 fold more sensi tive than histological examination. LS174T cells showed an exponential, but somewhat irregular growth in the liver of nude rats within the observation period of 6 weeks. The model will be useful for future therapeutic studied .