Background. Chordomas are rare malignant tumors occurring along the axial skeleton that originate from notochordal remnants. It is hypothesized that embryonic factors are involved in their aetiology. In the present study, four such factors are of interest: EVX1, which mediates posterior patterning of the embryo and is found in prostate. Wnt3a, localized to the placenta, is involved in different proliferation signaling pathways. Twist is a mediator of the epithelial-mesenchymal transition (EMT) and is expressed in the neuroblastoma cell line SHSY 5Y. Finally, brachyury is a crucial EMT mediator and involved in cell cycle regulation. Research question. The research question is tripartite. (I) It is the aim to obtain positive control tissue for validation of embryonic primers for the EVX1, Wnt3a and Twist genes. (II) Second, expression of brachyury mRNA in cultured chordoma cells will be assessed in order to validate the cell line. (III) Last, it will be investigated whether fibroblast conditioned cell culturing medium exerts a positive effect on chordoma proliferation in vitro. Materials and methods. (I) Placenta and prostate samples were obtained from patients in the Maastricht University Hospital. mRNA was isolated from prostate, placenta and SHSY 5Y cells and cDNA of the genes of interest was generated after which PCR and gel electrophoresis was employed to yield amplicon bands. (II) Chordoma cells were cultured and brachyury mRNA expression was assessed by PCR assay. (III) Cultured chordoma cells were grown in enriched DMEM or in enriched DMEM containing 33% fibroblast conditioned medium and proliferation was assessed. Results. (I) Both EVX1 and Twist are positive in prostate and SHSY 5Y respectively. Wnt3a is not positive in placenta. (II) Brachyury expression is either strongly downregulated or not expressed in two slowly growing chordoma cell cultures. (III) First data indicate enriched DMEM containing 33% fibroblast conditioned medium does not stimulate chordoma proliferation in vitro as compared to enriched DMEM without fibroblast conditioned medium