Download Change of Thrombospondin-1 Expression and Its Pathological

Change of Thrombospondin-1 Expression and Its Pathological Significance by Hormonal Therapy
in Human Prostate Cancer Tissues
Introduction and Objectives: Thrombospondin (TSP)-1 has been reported to play as inhibitory role in
angiogenesis and cancer cell progression in various malignancies. However, its oncogenic activity and
pathological roles in prostate cancer is controversial. In addition, detailed relationship between TSP-1
expression and androgen deprivation in human prostate cancer tissues is not still fully understood. The
goal of this study is to examine whether TSP-1 expression is increased by hormonal therapy in patients
with non-metastatic prostate cancer.
Materials and Methods: One hundred and six patients who had undergone radical prostatectomy were
examined retrospectively and divided into neo-adjuvant hormonal therapy (NHT) group (n = 52) and nonNHT group (n = 54). All patients showed no metastasis by various imaging examinations before surgery.
We examined the TSP-1 expression and microvessel density (MVD, measured by using CD34 antibody)
by immunohistochemical techniques. Relationships between TSP-1 expression and pathological features
were investigated in non-NHT specimens. In addition, we compared TSP-1 expression and relationship
between its expression and MVD in NHT group with those with non-NHT group.
Results: Among 54 specimens with non-NHT, TSP-1 immunoreactivity was detected in only 9 (16.7%). In
these patients, it was not associated with pT stage (p=0.620) and Gleason’s score (p=0.333). On the
other hand, its positive ratio in NHT group (21/52, 40.4%) was significantly (p<0.001) higher than that in
non-NHT one. In NHT group, mean and SD of MVD in TSP-1-positive-specimen (25.5 and 6.0 /high
power field, HPF) was significantly lower (p=0.036) than it in negative-specimen (29.4 and 6.3 /HPF).
However, such significant correlation was not detected in non-NHT group (p=0.274).
Conclusion: Our data suggest that TSP-1 plays minimal roles for malignant aggressive including
angiogenesis in prostate cancer tissues. However, its expression was up-regulated by hormonal therapy
and its expression was significantly associated with MVD in specimens treated with hormonal therapy.
From these results, TSP-1 is speculated to be useful as therapeutic target and tool of newly treatment
strategy to inhibit cancer cell progression by combined with hormonal therapy in prostate cancer patients.
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