Increased Id-1 expression is significantly associated with poor survival of patients with prostate cancer.
The levels of Id-1 (inhibitor of DNA binding or inhibitor of cell differentiation) expression in a series of prostate cell lines and in an archival set of prostate tissues were examined. Western blot analysis showed that the level of Id-1 expressed in the androgen sensitive cell line LNCaP was 1.2 +/- 0.2 times that detected in the benign cell line PNT-2. The level of Id-1 increased further to 1.8 +/- 0.2 and 2.9 +/- 0.3 in the androgen-insensitive cell lines Du-145 and PC-3, respectively. Immunohistochemical staining with Id-1 antibody performed on 113 cases of prostate tissues showed that among the 7 normal cases, 6 (86%) stained either negative or weakly positive whereas only 1 (14%) stained moderately positive. Among the 36 benign prostatic hyperplasia (BPH) samples, 34 (94%) stained either negative or weakly positive; only 1 (3%) stained moderately and 1 (3%) stained strongly. Of the 70 carcinomas, 8 (11.5%) stained weakly, 34 (48.5%) stained moderately, and 28 (40%) stained strongly positive. The intensity of Id-1 staining in carcinomas was significantly stronger than that detected in the normal prostate and BPH (chi(2) test, P < .001) and it was significantly increased as the increasing malignancy of carcinomas measured by Gleason score (chi(2) test, P < .001). The intensity of Id-1 staining was partially associated with the levels of prostate-specific antigen, but not related to the level of androgen receptor. Kaplan-Meier survival curve analysis showed that, similar to Gleason scores, overexpression of Id-1 was significantly associated with the reduced length of patient survival (log-rank test, P = .01). These results suggest that Id-1 is a useful prognostic marker to predict the outcomes of patients with prostate cancer.
Forootan
Shiva S
SS
Molecular Pathology Laboratory, School of Cancer Studies, Faculty of Medicine, University of Liverpool, L69 3GA Liverpool, United Kingdom. shifor@liv.ac.uk
Wong
Yong-Chuan
YC
Dodson
Andrew
A
Wang
Xianghong
X
Lin
Ke
K
Smith
Paul H
PH
Foster
Christopher S
CS
Ke
Youqiang
Y
D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D051798:Inhibitor of Differentiation Protein 1 / Q000032:analysis*; D053208:Kaplan-Meier Estimate; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000737:chemistry* / Q000401:mortality* / Q000473:pathology
D014408:Biomarkers, Tumor; D051798:Inhibitor of Differentiation Protein 1; D017430:Prostate-Specific Antigen