Two human mesencephalic fetal neural stem lines, LUHMES [23,24] and hVM1 Bcl-XL [25,26], developed for applications concerning the pathogenesis and CRT in PD, have been thoroughly characterized at different stages of differentiation in terms of their gene expression and ability to acquire dopaminergic phenotype [12,13,23, 24, 25, 26, 27, 28, 29]. This evidence concerns the gene BCL2L1 and Parkinson disease.