Despite the high number of previous studies, the role of p53 alterations in prostate cancer is not clearly defined. To address the role of p53 alterations in prostate cancer biology, a total of 2514 cancers treated by radical prostatectomy were successfully analyzed by immunohistochemistry in a tissue microarray format. Overall a low rate of p53-positive tumors was found (2.5%). A significant underestimation of p53-positive cases was excluded by subsequent large section analyses and direct sequencing of the p53 gene in subsets of our patients. Large section analysis of 23 cases considered negative on the tissue microarray yielded only one weakly p53-positive tumor. Only 4 out of 64 (6.4%) high-grade tumors, that were considered negative for p53 by immunohistochemistry, presented exon 5-8 mutations. These data suggest a high sensitivity of our immunohistochemistry approach and confirm the overall low frequency of p53 alterations in clinically localized prostate cancer. A positive p53 immunostaining was strongly associated with presence of exon 5-8 mutations (Po0.0001), advanced pT-stage (Po0.0001), high Gleason grade (Po0.0001), positive surgical margins (P ¼ 0.03) and early biochemical tumor recurrence (Po0.0001). A higher rate of positive p53 immunostaining was detected in late-stage diseases including metastatic prostate cancer (P ¼ 0.0152) and hormone-refractory tumors (P ¼ 0.0003). Moreover, p53 expression was identified as an independent predictor of biochemical tumor recurrence in the subgroup of low-and intermediate-grade cancers. In summary, the results of this study show that p53 mutations characterize a small biologically aggressive subgroup of prostate cancers with a high risk of progression after prostatectomy. The rate of p53 alterations increases with prostate cancer progression.

Purpose: The HER2 oncogene is involved in the biology of many different tumor types and serves as a prognostic marker and a therapeutic target in breast cancer. In contrast to breast cancer, studies on Her2 overexpression and gene amplification in prostate cancer have yielded different results. The purpose of this study was to learn more on the prevalence and clinical significance of HER2 amplification and overexpression in prostate cancer.Experimental Design: A tissue microarray containing >2,000 prostate cancers with follow-up data was used. Tissue microarray sections were analyzed on protein and DNA level using two different antibodies (HercepTest, DAKO; Novocastra NCL-CB11) and fluorescence in situ hybridization.Results: Immunohistochemical analyses showed highly similar results for both antibodies. Detectable Her2 immunostaining was observed in 17.2% for the HercepTest and in 22.5% for the Novocastra antibody with the vast majority of cases showing 1+ or 2+ staining. For both antibodies (HercepTest/ Novocastra), significant associations were found between positive staining and high Gleason grade (P < 0.0001, both), advanced pT stage (P < 0.0001/P = 0.0015), rapid tumor cell proliferation (P = 0.0004/P = 0.0071), and tumor recurrence (P < 0.0001, both). HER2 amplification was only found in 1 of 2,525 analyzable cases (0.04%).Conclusions: Low-level Her2 overexpression occurs at relevant frequency in prostate cancer and in the absence of gene amplification. Increased Her2 expression may potentially lead to an aggressive behavior of tumor cells through the stimulation of tumor cell proliferation because Her2 staining was shown to be significantly associated with Ki67 labeling index. These data argue for reconsidering anti-Her2 therapy, possibly with modified approaches. Clin Cancer Res; 16(5); 1553-60. ©2010 AACR.The Her2 protein, a transmembrane tyrosine kinase growth factor receptor, is found in normal and malignant epithelial cells and is involved in regulation of cell proliferation and differentiation (1). Her2 is well known as a strong prognostic factor and a successfully used therapeutic target in breast cancer (2). In 15% to 20% of breast cancer cases, Her2 is overexpressed as a consequence of gene amplification (2-4). Overexpressed Her2 protein serves as the therapeutic target for trastuzumab, a humanized monoclonal antibody (5, 6), which is now used both in a metastatic setting and as an adjuvant therapy of Her2-positive breast cancer.Many other tumor types, including prostate cancer, express increased levels of Her2, and evidence accumulates that trastuzumab can also be effective in Her2-positive tumors other than breast cancer. In previous studies, widely divergent rates for Her2 expression and amplification in primary prostate cancers have been reported. Rates of positivity range from 0% to 100% in immunohistochemical studies (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and from 0% to 53% in amplification analyses (18,(22)(23)(24). Most likely, these conflicting data are due...

Purpose: Deletions of 8p and gains of 8q belong to the most frequent cytogenetic alterations in prostate cancer. The target genes of these alterations and their biological significance are unknown.Experimental Design: To determine the relationship between chromosome 8 changes, and prostate cancer phenotype and prognosis, a set of 1.954 fully annotated prostate cancers were analyzed in a tissue microarray format by fluorescence in situ hybridization.Results: Both 8p deletions and 8q gains increased in number during different stages of prostate cancer progression. 8p deletions/8q gains were found in 26.1%/4.8% of 1,239 pT 2 cancers, 38.5%/9.8% of 379 pT 3a cancers, 43.5%/8.9% of 237 pT 3b cancers, 40.7%/14.8% of 27 pT 4 cancers, 39.1%/34.8% of 23 nodal metastases, 51.9%/33.3% of 27 bone metastases, and 45.5%/59.9% of 22 hormone refractory cancers (P < 0.0001 each). Both 8p deletions and 8q gains were also significantly associated with high Gleason grade and with each other (P < 0.0001 each). In primary tumors, 8p deletions were seen in only 27.3% of 1,882 cancers without 8q gain but in 57.4% of 122 tumors with 8q gain (P < 0.0001). Among cancers treated with radical prostatectomy, 8p deletions (P = 0.003) and 8q gains (P = 0.02) were associated with biochemical tumor recurrence. However, multivariate analysis (including prostate-specific antigen, pT/pN stage, Gleason score, and surgical margin status) did not reveal any statistically independent effect of 8p or 8q alterations on biochemical tumor recurrence.Conclusions: 8p deletions and 8q gains are relatively rare in early stage prostate cancer but often develop during tumor progression. The prognostic effect does not seem to be strong enough to warrant clinical application. Clin Cancer Res; 16(1); 56-64. ©2010 AACR.Prostate cancer is the most frequently diagnosed malignancy and the second most frequent cause of cancerrelated death among western males (1).Currently, clinical prediction tools rely solely on clinical (clinical stage), serologic (prostate-specific antigen), and histologic variables (Gleason grading; ref. 2).Because the development and progression of cancer is driven by molecular alterations, the analysis of molecular features may eventually allow better prediction of the behavior of individual cancers.Alterations on the DNA level would be especially suitable as prognostic markers. DNA alterations have the advantage of being less vulnerable to perioperative and postoperative ischemia or fixation procedures than RNA or proteins (3, 4). Deletions of 8p and gains of 8q are among the most frequent genomic alterations in prostate cancer. Several studies have proposed a relationship between 8p−/8q+ with adverse histopathologic findings (5-11). Studies suggesting associations with prostatespecific antigen progression, however, were limited to <100 cancers (12)(13)(14). Whereas considerable evidence points toward a role of chromosome 8 changes in prostate cancer biology, it is also evident that much larger patient cohorts are now needed to further cl...

High intratumoral mast cell density is associated with favorable tumor characteristics and good prognosis in prostate cancer. This finding is consistent with a role of mast cells in the immunological host-defense reaction on prostate cancer. Triggering mast cell activity might expand immunotherapeutic strategies in prostate cancer.