High-level expression of EphA2 receptor tyrosine kinase in prostatic intraepithelial neoplasia.
EphA2 is a transmembrane receptor tyrosine kinase that is overexpressed in many carcinomas. Specific targeting of EphA2 with monoclonal antibodies is sufficient to inhibit the growth, migration and invasiveness of aggressive cancers in animal models. Using immunohistochemical analyses, we measured the expression of EphA2 in prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia, and adjacent benign prostate tissue from ninety-three radical prostatectomy specimens. These results were related to multiple clinical and pathologicalcharacteristics. The fraction of cells staining positively with EphA2 in benign prostatic epithelium (mean, 12%) was significantly lower than that in high-grade prostatic intraepithelial neoplasia (mean, 67%, P < 0.001) and prostatic adenocarcinoma (mean, 85%, P < 0.001). Moreover, the intensity of EphA2 immunoreactivity in prostatic adenocarcinoma was significantly higher than in benign prostatic tissue (P < 0.001) or high-grade prostatic intraepithelial neoplasia (P < 0.001). Benign prostatic epithelium showed weak or no immunoreactivity for EphA2 in all cases examined. Whereas EphA2 immunoreactivity related to neoplastic transformation, it did not correlate with other clinical and pathological parameters examined. Our data suggest that EphA2 levels increase as prostatic epithelial cells progress toward a more aggressive phenotype. Progressively higher levels of EphA2 in high-grade prostatic intraepithelial neoplasia and prostatic carcinoma are consistent with recent evidence that EphA2 functions as a powerful oncogene. Moreover, the presence of high levels of EphA2 in these cells suggests opportunities for prostate cancer prevention and treatment.
Zeng
Guangyuan
G
Departments of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
Hu
Zhiqiang
Z
Kinch
Michael S
MS
Pan
Chong-Xian
CX
Flockhart
David A
DA
Kao
Chinghai
C
Gardner
Thomas A
TA
Zhang
Shaobo
S
Li
Lang
L
Baldridge
Lee Ann
LA
Koch
Michael O
MO
Ulbright
Thomas M
TM
Eble
John N
JN
Cheng
Liang
L
D000230:Adenocarcinoma / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D019048:Prostatic Intraepithelial Neoplasia / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism*; D036104:Receptor, EphA2 / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D036104:Receptor, EphA2