KLK2 and posterior cortical atrophy: Several novel bsAbs constructs are currently under development targeting alternative PCa antigens, including glypican-1 [62], a disintegrin and metalloproteinase 17 (ADAM17), also known as TNF-α converting enzyme (TACE) [63], prostate stem cell antigen (PSCA) [64], human kallikrein 2 (KLK2) [65], and six-transmembrane epithelial antigen of prostate 1 (STEAP1) [66].