CD9 and central nervous system cancer: Taken as a single marker, survivin was present on an average of 9.1% of CD9+ exosomes of glioma patients (range 0.8 – 35%) at baseline (i.e. before vaccination) and on an average of 0.43% of control CD9+ exosomes (range 0.0 – 1.2%; a 21-fold difference; Table 2).