Immunohistochemical study of the receptors for retinoic acid in prostatic adenocarcinoma.
BACKGROUND
Retinoids play an important role in regulating cellular proliferation and differentiation. Although their effects are mediated by retinoic acid receptors (RARs) and retinoid X receptors (RXRs), limited information is available about the expression of RARs and RXRs in prostatic adenocarcinoma. We intended in this study to elucidate further the participation of those receptors in tumor progression of human prostate.


METHODS
The immunohistochemical expression of RARs and RXRs proteins was studied using paraffin-embedded archival tissues obtained from patients with and without neoadjuvant hormonal therapies for prostatic adenocarcinoma.


RESULTS
The immunoreactivity against RAR-alpha, RAR-gamma, RXR-alpha and RXR-gamma were detected in many, if not all, prostatic adenocarcinoma cells of the cases without and with neoadjuvant hormonal therapy, whereas less expression of both RAR-beta and RXR-beta were identified. Positively stained adenocarcinoma cells with RAR-beta and RXR-beta were found to be decreased in the cases with neoadjuvant therapy. In addition, the specimens showing positive immunoreaction of RAR-beta were limited to the cases of moderately- and poorly-differentiated but not well-differentiated, adenocarcinomas.


CONCLUSIONS
We first demonstrated the expression of RARs and RXRs proteins in prostatic adenocarcinoma using subtype-specific antibodies. Immunohistochemistry using those antibodies might give an indication of susceptibility of the patients to retinoid therapy as a possible treatment of prostatic adenocarcinoma.
Kikugawa
T
T
Department of Urology, Ehime University School of Medicine, Shitsukawa, Shigenobu, Onsen-gun, Ehime 791-0295, Japan.
Tanji
N
N
Miyazaki
T
T
Yokoyama
M
M
D000230:Adenocarcinoma / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D000368:Aged; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery; D018168:Receptors, Retinoic Acid / Q000032:analysis*; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D014157:Transcription Factors / Q000032:analysis; D000097768:Retinoic Acid Receptor gamma
D018931:Antineoplastic Agents, Hormonal; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D047488:Retinoid X Receptors; D014157:Transcription Factors; D000097768:Retinoic Acid Receptor gamma; C000607071:RARA protein, human; C082925:retinoic acid receptor beta