**1. Introduction**

Oncoproteins like alpha-fetoprotein (AFP), serum albumin (AS), and growth factors such as GH, IGF, TGF-beta, and EGF are present in embryo-fetal tissues and reappear in neoplastic developing tissues, including the central nervous system; this concerns especially AFP [1–8] and IGF-I [9–17]. AFP is present in both neural and glial developing and cancerous cells, whereas IGF-I is only present in glial developing and tumoral cells [10, 18]. This striking difference has helped us orientate a strategy to manage the most malignant brain tumor expressing IGF-I gene—glioblastoma.

IGF-I plays an important role in growth as a mediator of growth hormone [19–21]. Blocking IGF-I synthesis induces apoptotic and immunogenic phenomena [12, 22]. Both phenomena, apoptosis and immunogenicity, related to arrest of IGF-I expression in neoplastic glial cells, were used to prepare antitumor cell vaccines for therapy of brain malignant tumor—glioblastoma [12, 23].

An efficient strategy targeting IGF-I was established by construction of vectors stopping the synthesis of this oncoprotein on translation and transcription levels: vectors expressing either IGF-I antisense RNA or IGF-I RNA forming RNA-DNA triple helix, respectively. The glioma cells transfected with these vectors, when injected *in vivo* in animals bearing tumors like glioma or teratocarcinoma or applied in clinical treatment of glioblastoma patients, induced an immune antitumor effect (CD8+) accompanied by increase of the median survival of patients (successful clinical results obtained in the USA, E.U., China) [22, 23].
