Isolated proximal prostate cells can form complex glandular structures.

Every organ has to have its stem cells. Now, the prostate gets in on the action. On page 1257, Tsujimura et al. identify a population of prostate cells with all the salient properties of stem cells. These cells should provide a useful system for analyzing prostate carcinogenesis.

Stem cells have three important features: they are slow cycling, have high proliferative potential, and can differentiate into progeny cell types. Tsujimura et al. found cells with these properties concentrated in the region of the mouse prostate that lies adjacent to the urethra. Now that their location is known, it will be possible to concentrate on this region of the prostate in the effort to isolate the stem cells.

The isolation of stem cells is necessary for determining what makes them unique compared with differentiated cells in the tissue. Many scientists believe that prostate tumors arise from stem cells, in part because both stem and tumor cells have high proliferative ability. If this is the case, understanding their biology will be important not only from a developmental standpoint, but also to decipher the mechanism behind prostate cancer. ▪