CBS and glioblastoma: Unfortunately, inhibition of the expression of cystathionine β-synthase (CBS), a key protein in the transsulfuration pathway, has been shown to promote GBM progression (103), while in other tumor models, CBS inhibition effectively causes cell death (104), which suggests that GBM cells could be resistant to ferroptosis induction, including that mediated through inhibition of system xc− and the transsulfuration pathway.