Liver Metastatic Colorectal Tumor Cells Change Their Phenotype During Consecutive Passages on Chick Embryo Chorioallantoic Membrane: Lessons from the Lab to the Clinic.

BACKGROUND/AIM: Colon cancer liver metastases with desmoplastic growth pattern (dGP) have a highly heterogeneous therapy response. The aim of the study was to evaluate the dGP liver metastasis molecular profile from a chemo-naive patient by mimicking metastatic process on an experimental chick embryo chorioallantoic membrane (CAM) model. MATERIALS AND METHODS: Three successive CAM passages of dGP human colorectal liver metastases were immunophenotyped for keratin (K) 8, and 20, CLIC1, VEGF, EGFR, CD34, podoplanin, Ki67, E-cadherin and vimentin. RESULTS: Metastatic cells gradually lost K20 while K8, E-cadherin and vimentin heterogeneously increased during passages. VEGF, CLIC 1, EGFR expression increased in metastatic cells especially at the tumor graft periphery. Scattered proliferating and non-proliferating podoplanin-positive tumor cells, lymphatic and blood vessels were heterogeneously detected in tumor xenografts depending on passage stage. CONCLUSION: By mimicking repetitive metastatic processes we proved that metastatic cells change their phenotype. This may explain why not all metastases have a similar response to therapy.