The chorionallantoic membrane (CAM) of the chick embryo has been used as an experimental model for studying tumor invasion and metastasis of human malignant melanoma. In search for a model to show graft-host-interactions in vivo, tumor markers in peripheral blood of the host were investigated.Before collecting melanoma metastasis xenografts, blood samples were taken from CAM and a control group. S100 and sp185/her2 in peripheral blood were evaluated in a blinded manner.23/28 samples deriving from successfully performed human melanoma metastasis CAM xenografts were positive for S100 versus 2/22 samples for sp185/her2.Regarding melanoma, in this model sp185/her2 gave no additional information. S100 levels corresponded to clinical and immunohistological findings concerning adherence of tumors and extravasation of human melanoma cells. Based on these data S100 levels in the peripheral blood could help to determine the effect of exogenous stimuli such as radiation and therapeutic agents on metastatisation of the xenografts.
