CTH and glioblastoma: Most of them related with amino-acid metabolism pathways, such as “histamine biosynthesis”, where histamine is an important regulator of numerous physiological processes including neurotransmission in the central nervous system (CNS) [25]; “L-cysteine degradation process” where cystathionine γ-lyase (CTH) activity has been related with glioblastoma treatment [26] and “serotonin receptor signaling pathway” being serotonin an important neurotransmitter in the CNS during neuronal development [27].