TRUS can distinguish between an outer and inner gland encompassing the central, peripheral, and transition zones, though not at the same resolution as MRI [ 82].
Readers should note that the separate identification of the peripheral and transition zones is difficult to do by histopathologic evaluations of core biopsy specimens.
The central zone is located at the base of the prostate between the peripheral and transition zones and accounts for approximately 25% of the glandular tissue.
These assumed pre-existing differences could in part be due to developmental differences of the zones, since the peripheral and transition zones develop from the endoderm of urogenital sinus while the central zone develops from the wolffian duct [ 18, 19].
The Bonferroni method was used to adjust for multiple comparisons (i.e., using a cutoff value of 0.05/7 = 0.007), only bax and p21 remained to show significant differences between the peripheral and transition zone with regards to biomarker expression.
It was first of interest to determine the frequency of individual biomarker expression and to determine the extent to which individual biomarkers correlated with the prostate zone of tumor origin, i.e. peripheral versus transition zone within Gleason grade 3+3 tumors (Table 4).
In 1981, McNeal [23] described the three distinct prostate zonal regions: (1) the peripheral zone, (2) transition zone and (3) central zone (CZ).
The model suggested that there was no significant difference in CD95 or bcl-xL expression between peripheral zone and transition zone tumors (p = 0.61 and 0.12, respectively).
After RT, the entire prostate and the SVs show decreased size and diffusely decreased SI on T2WI, and the peripheral, central, and transition zones appear less distinct from each other [ 78].
On the other hand, in order to be able to cross correlate between TRUS biopsy (where both the peripheral and posterior transition zones are sampled), then the anterior posterior border needs to be adjusted.
