PTEN and central nervous system cancer: Next, in ∼75% of >40 human glioma samples, the protein expression level of TRPC6 or p21 was ∼3.3- or 3.5-fold higher whereas that of POX or PTEN was ∼6.4- or 1.4-fold lower than in normal tissues (Figure 1D;, Supplementary Figure S1B).