Localization of the human prostatic secretory protein PSP94 and its mRNA in the epithelial cells of the prostate.

The histologic distribution of a prostatic secretory protein of 94 amino acids (PSP94) and its mRNA were examined simultaneously by conventional immunohistochemistry and in situ hybridization histochemistry. The results show localization of immunoreactive PSP94 and its mRNA in the epithelial cells of the prostate gland, thus providing strong evidence of PSP94 synthesis in these cells. Preliminary analysis of PSP94 by radioimmunoassay and of its mRNA by Northern blot analysis indicates that PSP94 biosynthesis in pathologic prostatic tissues is variable. The value of PSP94 as a marker of prostate gland secretory activity is discussed.