Vasoactive intestinal peptide (VIP) is a potent inductor of
cyclooxygenase-2 (COX-2) expression in human
prostate cancer cell lines. There are conflicting data regarding the role of COX-2 in the progression of this disease. Here we examined the expression of
VIP receptors (VPAC1 and VPAC2) and COX-2 in
prostate cancer specimens. Correlations among
protein levels and various clinicopathological factors and prognosis of patients were statistically analyzed. For these purposes,
formaldehyde-fixed,
paraffin-embedded prostate tissue specimens from 63 patients with
prostate cancer and 9 control samples were used. The expression of VPAC1 and VPAC2 receptors and COX-2 was analyzed at
mRNA levels by quantitative
reverse transcriptase-PCR. The corresponding expression at
protein level was studied by immunohistochemistry, scored as negative, weak, moderate, or strong, and correlated with different clinicopathological factors by means of multivariate analysis. 88% of
prostate cancer tissues overexpressed VPAC1-receptor at
mRNA level, 72% VPAC2-receptor and 77% COX-2. Simultaneous overexpression of the three genes was seen in 52% of patients. Similar overexpression patterns were observed at
protein level. The correlation between VPAC1 and
VPAC2 receptor protein levels was statistically significant. However, no significant correlations existed among
protein levels of VPAC receptors and COX-2 with patient age,
prostate-specific antigen (PSA) levels,
tumor stage, Gleason score and survival time. The overexpression of VPAC1 and VPAC2 receptors and COX-2 in
cancer tissue gives them a potential role as targets for diagnosis of
prostate cancer but results do not support a clear value as
biomarkers for the clinical prognosis of this disease.