Such strategy of anti-gene, of antisense or triple helix approach [7–9], has permitted to stop the development of the following animal tumours: glioma, hepatoma, melanoma and teratocarcinoma (containing three tissue derivatives) as well as to treat human gliomas, mediated by immune antitumour CD8+ T cells induced in vivo by injection of cellular “vaccines” presenting immunogenic characteristics (expression of MHC-I) (Figure 1) [4, 10–12]. The gene discussed is CD8A; the disease is central nervous system cancer.