These Pbsn-positive cells (Supplemental Figure 4H), corresponding to both luminal cells actively secreting prostatic fluid as well as to cells in the tumoral compartment with directed Pten deletion in this PCa mouse model, exhibited the modulation of 138 genes following E2 stimulation, notably the induction of Greb1 expression (Figure 3M and Supplemental Figure 4, I and J). Here, GREB1 is linked to posterior cortical atrophy.