KLK3 and posterior cortical atrophy: However, given the heterogeneous expression of PSMA in a subset of PCa and the limited specificity of PSA for aggressive disease, there is an imperative need for biomarkers with dual diagnostic and therapeutic potential, such as the six-transmembrane epithelial antigen of the prostate 1 (STEAP1), which is overexpressed in PCa [5,6,7].