[Genetic determinants of anatomical variants of the prostate]

The determinants of macroscopic and microscopic anatomical variants of the prostate during ageing are poorly defined. The authors evaluated the correlation between specific gene polymorphisms involved in androgen and oestrogen synthesis and gross (prostatic weight) and microscopic anatomy (stroma/epithelium ratio) of the prostate during ageing.

The prostatic weight and stromal surface area of an autopsy series of 85 men over the age of 50 were measured, then compared as a function of gene polymorphisms involved in androgen or oestrogen regulation. The following polymorphisms were studied: number of CAG repeats of the androgen receptor (AR), number of TA repeats and the V89L variant of the 5-alpha-reductase gene (SRD5A2) for androgens, and the A1A2 variant of 17-alpha-hydroxylase (CYP17) and number of TTTA repeats of the aromatase (CYP19) for oestrogens.

No correlation was observed between the number of TA repeats of the SRD5A2 gene or TTTA repeats of the CYP19 gene and anatomical parameters of the prostate. A statistically significant positive correlation was observed between age and prostate weight (r=0.21, p=0.05) and a statistically significant negative correlation was observed between prostate weight and number of CAG repeats (r=-0.32, p=0.003). The group with less than 20 CAG repeats was associated with a higher prostate weight than the other group. The stromal surface area was greater in the [20-23] CAG repeat group (p=0.02), and in the A2A2 group of CYP17 (p=0.016) than in the other groups.

A small number of CAG repeats is associated with a higher prostate weight. The mean number of CAG repeats of the androgen receptor and the A2A2 variant of the CYP17 gene are associated with a larger stromal surface area.