Prostatic acid phosphatase is not a prostate specific target

Ileana B. Quintero, Cesar L. Araujo, Anitta E. Pulkka, Riikka S. Wirkkala, Annakaisa M. Herrala, Eeva-Liisa Eskelinen, Eija Jokitalo, Pekka A. Hellstrom, Hannu J. Tuominen, Pasi P. Hirvikoski, Pirkko T. Vihko

Research output: Contribution to journalArticleScientificpeer-review


Prostatic acid phosphatase (PAP) is currently evaluated as a target for vaccine immunotherapy of prostate cancer. This is based on the previous knowledge about secretory PAP and its high prostatic expression. We describe a novel PAP spliced variant mRNA encoding a type I transmembrane (TM) protein with the extracellular NH2-terminal phosphatase activity and the COOH-terminal lysosomal targeting signal (Yxx Phi). TM-PAP is widely expressed in nonprostatic tissues like brain, kidney, liver, lung, muscle, placenta, salivary gland, spleen, thyroid, and thymus. TM-PAP is also expressed in fibroblast, Schwarm, and LNCaP cells, but not in PC-3 cells. In well-differentiated human prostate cancer tissue specimens, the expression of secretory PAP, but not TM-PAP, is significantly decreased. TM-PAP is localized in the plasma membrane-endosomal-lysosomal pathway and is colocalized with the lipid raft marker flotillin-1. No cytosolic PAP is detected. We conclude that the wide expression of TM-PAP in, for instance, neuronal and muscle tissues must be taken into account in the design of PAP-based immunotherapy approaches.
Original languageEnglish
JournalCancer Research
Issue number14
Pages (from-to)6549-6554
Number of pages6
Publication statusPublished - 15 Jul 2007
MoE publication typeA1 Journal article-refereed

Fields of Science


Cite this