Soluble p185/her2 and S100 in yolk sac blood from human melanoma metastases xenotransplanted to chick embryo chorioallantoic membrane

Background: The chorionallantoic membrane (CAM) of the chick embryo has bee n used as an experimental model for studying tumor invasion and metastasis of human malignant melanoma. In search for a model to show graft-host-inter actions in vivo, tumor markers in peripheral blood of the host were investi gated. Materials and Methods: Before collecting melanoma metastasis xenogra fts, blood samples were taken from CAM and a control group. S100 and sp185/ her2 in peripheral blood were evaluated in a blinded manner. Results: 23/28 samples deriving from successfully performed human melanoma metastasis CAM xenografts were positive for S100 versus 2/22 samples for sp185/her2. Conc lusion: Regarding melanoma, in this model sp185/her2 gave no additional inf ormation. S100 levels corresponded to clinical and immunohistological findi ngs concerning adherence of tumors and extravasation of human melanoma cell s. Based on these data S100 levels in the peripheral blood could help to de termine the effect of exogenous stimuli such as radiation and therapeutic a gents on metastatisation of the xenografts.