PGP 9.5

Protein gene product 9.5 (PGP 9.5), also known as ubiquitin carboxyl-terminal hydrolase-1 (UCHL-1), is a 27 kDa protein originally isolated from whole brain extracts.1 Although PGP 9.5 expression in normal tissues was originally felt to be strictly confined to neurons and neuroendocrine cells,2 it has been subsequently documented in distal renal tubular epithelium, spermatogonia, Leydig cells, oocytes, melanocytes, prostatic secretory epithelium, ejaculatory duct cells, epididymis, mammary epithelial cells, Merkel cells, and dermal fibroblasts. 1 A plethora of mesenchymal neoplasms have demonstrated PGP 9.5 expression. 1,3,4