KLK3 and neoplasm: Another distinct feature of prostatic NE cells is the absence of the nuclear androgen receptor (AR), thus NE cells are androgen insensitive.[19] Immunohistochemical data have shown that NE tumor cells in conventional prostate cancer express both endocrine (cgA) and exocrine (PSA) markers indicating that NE tumor cells derive from the exocrine (PSA positive) cell types and appear during tumor progression.[16]