PTEN and brain ischemia: Upregulation of phosphatase and tensin homolog (PTEN) was found in four undifferentiated SH-SY5Y and one undifferentiated SK-N-SH cell models of cerebral ischemia (Gao et al. 2020; Guo 2019; Guo et al. 2018; Jin et al. 2020; Yi et al. 2020).