CD44 and glioblastoma: Tso and coworkers [23] have observed that the immortalized glioblastoma cell lines (W-98, D-431, F-502 and S-496) express surface antigen profiles similar to those of MSCs, because these cell lines express variable levels of CD44, CD90, CD105 and CD29, and do not express CD14, CD34 and CD31 cell surface markers.