Background and objectives: Elevated levels of
16-hydroxyestrone (16-OHE) have been linked to
increased risk of prostate cancer (PC) and estrogen receptor (ER) had been
expressed in prostate tissue but the combined effect of 16-OHE
and ER () is lacking. We investigated the binding specificity
of antibodies from PC with 16-OHE-ER complex in the sera
from PC patients.
Materials and methods: The antibodies in the serum from 60 PC
patients and 40 control subjects were evaluated from ELISA (direct binding and
competition) and quantitative precipitin titration. Competition ELISA was also
used to estimates 16-OHE concentration and
2-hydroxyestrone (2-OHE)/16-OHE ratio in PC patients.
Results: Antibodies from PC patients demonstrate high binding
to 16-OHE-ER in comparison to ER (p 0.05) or
16-OHE (p 0.001). The relative affinity of PC IgG
was found to be high for 16-OHE-ER (1.19 10 M)
as compared to ER (1.45 10 M) or 16-OHE (1.13
Conclusion: High affinity of PC IgG with 16-OHE-ER
might explain the possible antigenic role and 16-OHE-ER acted as
high affinity antigen for antibodies from PC. The interaction between
16-OHE and ER makes a complex in the prostate tissues
and this may generate antibodies against this complex in the cancer patients.