Orexin expression in different prostate histopathologic examinations: Can it be a marker for prostate cancer? A preliminary result.
OBJECTIVE
The aim of this study was to evaluate the expression of the orexin receptor in different prostate pathologies, including prostate adenocarcinoma, benign prostate hyperplasia and chronic prostatitis.


METHODS
A total of 90 patients (mean age 64.01±7.2 years) were enrolled in the study. The patients were divided into three groups of equal numbers based on their histopathologic findings: prostate cancer (Group 1), benign prostate hyperplasia (Group 2) and chronic prostatitis (Group 3). All the tissues were incubated with a primary antibody recognizing the Orexin receptor. The specific cytoplasmic immunoreactivity of the Orexin receptor was semiquantitatively scored for intensity and distribution based on a grading scale. The staining intensity and orexin expression were evaluated using Pearson χ(2) test.


RESULTS
A heterogeneous staining pattern of the Orexin receptor was observed between the groups. The expression rates were 90% (27/30) in Group 1, 53.3% (16/30) in Group 2 and 26.7% (8/30) in Group 3. While 5 patients (9.3%) in Group 1 showed strong staining, all samples from the other 2 groups showed only weak staining. There were significant differences in staining intensity between the three groups. The expression and distribution of the Orexin receptor was more widespread in Group 1 than in the other groups and was higher in patients with poorly differentiated malignancy. However, there was no significant difference based on Gleason score.


CONCLUSIONS
Orexin receptors are found in human prostate tissues and their expression is widespread in prostate cancer and in patients with a higher Gleason score. Therefore, we believe that Orexin immunoreactivity can be considered to be an indicator of poor prognosis and of poorly differentiated prostate cancer cases.
Department of Urology, Faculty of Medicine, Kırıkkale University, Kırıkkale, Turkey.
Murad Mehmet
MM
Başar
Clinic of Pathology, Ankara Dışkapı Yıldırım Beyazıt Education and Training Hospital, Ankara, Turkey.
Ünsal
Ü
Han
Clinic of Urology, Ankara Dışkapı Yıldırım Beyazıt Education and Training Hospital, Ankara, Turkey.
Murat
M
Çakan
Department of Urology, Faculty of Medicine, Kırıkkale University, Kırıkkale, Turkey.
Serhan
S
Alpcan
Department of Urology, Faculty of Medicine, Kırıkkale University, Kırıkkale, Turkey.
Halil
H
Başar
Orexin A; Orexin B; prostate; prostate cancer