“…NSCs display high variability in the chromosome complement when cultured. For example, neither numerical nor structural chromosome abnormalities were detected in both rat and human NSC samples, cultivated up to 70 passages and analyzed with G-banding [Bai et al, 2004;Jiang et al, 2008;Sareen et al, 2009]; on the contrary, using the same technique, other samples (human NSCs derived from the striatum fetal) displayed different numerical (from 60-70 chromosomes per metaphase) and structural chromosome aberrations [Wu et al, 2011]. Also, the analysis of more than 70 other human NSC samples identified trisomy of chromosomes 7, 10, 18, or 19 [Sareen et al, 2009;Ben-David et al, 2011] and monosomy of chromosome 18 [Ben-David et al, 2011] in longterm cultures ( table 2 ).…”