GSTP1 and posterior cortical atrophy: All of the proteomics studies so far that have detected GSTP1 [23,26,28,29,30,69] and GSTM2 [22,28] as significantly dysregulated in PCa were analyzing tissue and all have come to a uniform conclusion, i.e., that these two Glutathione S-transferases were down-regulated in PCa tissue.