Abstract 1822P
Background
PCa is an androgen-dependent disease, however, estrogens and ER also play an important role in disease development and progression. Two major subtypes of ER are ER alpha and ER beta that may have opposing effects. The expression of both types of ER in PCa and their coexpression was investigated.
Methods
ER subtypes expression was evaluated in a cohort of 36 PCa radical prostatectomy samples using double immunofluorescence. 5-15 random high power fields (HPF) per case were microphotographed and characteristics of staining (proportion of stained nuclei (0 – absence, 1 – up to 1/3 of nuclei, 2 – 1/3 to 2/3, 3 – more than 2/3) and staining intensity (1 – weak, 2 – moderate, 3 – strong)) were assessed semiquantitatively, separately for both ER subtypes and in tumor epithelium and stroma.
Results
The results of staining assessment (% of analyzed HPFs) are shown in the table. Table: 1822P
| Proportion of cells | Staining Intensity | ||||||||
| 0 | 1 | 2 | 3 | 0 | 1 | 2 | 3 | ||
| ER beta | Epithelium | 7.9 | 34.8 | 20.1 | 37.1 | 7.9 | 77.4 | 13.4 | 9.1 |
| ER beta | Stroma | 0.6 | 26.8 | 36.6 | 42.1 | 0.6 | 61.0 | 23.8 | 11.6 |
| ER alpha | Epithelium | 67.1 | 26.8 | 1.8 | 4.3 | 67.1 | 32.9 | 0 | 0 |
| ER alpha | Stroma | 26.8 | 43.9 | 20.7 | 7.3 | 26.8 | 54.9 | 17.1 | 0 |
ER alpha was expressed mainly in PCa stroma while ER beta in both cancer and stromal cells. ER alpha expression in epithelium was seen in less than 1/3 of HPFs and was weak, while in stroma it was seen in ¾ of cases. ER beta staining was more prevalent in both compartments including strong staining. In cases of ER alpha staining in cancer cells and ER beta in stroma both receptor subtypes were coexpressed in the same nuclei (though not all of the nuclei within a single HPF). In the studied cohort no significant associations of both ER subtypes staining characteristics (proportions of cells or intensities) were found (pKruskall-Wallis>0,05), possibly due to a relatively small sample size. Also no special features of relative distribution and location of ER alpha and ER beta positive cells were seen.
Conclusions
In the present work direct coexpression of ER alpha and beta subtypes in PCa clinical tissue samples was demonstrated. Further work is ongoing to explain possible biological mechanisms and consequences of this coexpression and its influence on disease course.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
M. Puchinskaya.
Funding
Belarusian Republican Foundation for Fundamental Research, Grant number M19M-123.
Disclosure
M. Puchinskaya: Financial Interests, Personal, Invited Speaker: Roche.