FAS and chordoma: In order to determine the status of activation of Fas/Fasl apoptotic pathway in chordoma, we checked for the expression of the two different isoforms of FAS: the pro-apoptotic (transmembrane) form and the anti-apoptotic (soluble) form [29] by RT-PCR, in the sub-group of 12 tumors and in U-CH1 cells (Fig. 1 B).