Contribution of HER-2/neu oncogene expression to tumor grade and DNA content analysis in the prediction of prostatic carcinoma metastasis

The prevalence and clinical significance of HER2 expression in prostate adenocarcinoma

AIMS

Abnormalities in HER2 are well-established oncogenic drivers and are approved therapeutic targets in various malignancies. Prior studies evaluating HER2 expression in prostate cancer (PCa) have yielded variable results. Most of these studies used immunohistochemistry scoring systems based on breast cancer data. The goal of this study was to determine the prevalence and clinical significance of HER2 expression using a scoring system that better reflects the HER2 staining pattern observed in PCa.

METHODS

We randomly selected similar numbers of localized low risk (AJCC stage I), locally advanced (AJCC stages II & III), and metastatic (AJCC stage IV) PCa patients treated at the DC VA Medical Center between 2000 and 2022. Among them, we included patients who had sufficient PCa tissue samples and clinical information required for this analysis. Two experienced pathologists independently scored HER2 expression (Ventana Pathway anti-HER2) according to a modified gastric cancer HER2 scoring system.

RESULTS

Out of the 231 patients included, 85 % self-identified as Black. 58.9 % of patients expressed HER2 (1+: 35.5 %; 2+: 18.2 %; 3+: 5.2 %). Validity of the results was confirmed using the HercepTest antibody. Higher HER2 expression was associated with a higher Gleason Score/Grade Group and advanced disease.

CONCLUSIONS

Our findings support the adverse prognostic impact on HER2 in PCa. We propose the use of a modified scoring system to evaluate HER2 expression in PCa. The observed high prevalence of HER2 expression supports the consideration of novel HER2-targeted therapies addressing even low levels of HER2 expression in future PCa trials.

Her-2/Neu Receptor in Prostate Cancer Development and Progression to Androgen Independence

Development of prostate cancer and progression to androgen-independent disease is correlated with increased expression of growth factors and receptors capable of establishing autocrine and/or paracrine growth-stimulatory loops. A thorough review was made of the current literature and recent abstract presentations at scientific meetings focusing on the role of the HER-2/neu (c-erbB2) receptor in prostate cancer and the potential clinical usefulness of its specific inhibitors. In the past 10 years, conflicting results on HER-2/neu expression in prostate cancer have been reported. More recently, four studies have shown experimental evidence of HER-2/neu in the development of prostate cancer and, more specifically, in the progression to a hormone-refractory clinical behavior. Furthermore, it has been proposed that HER-2 family and androgen receptors function synergistically in the absence of androgen, which suggests a crosstalk between the HER-2/neu and androgen receptor pathways. Finally, clinical trials are in progress in prostate cancer patients to test novel agents that selectively interfere with HER-2/neu activity.

HER2 overcomes PTEN (loss)-induced senescence to cause aggressive prostate cancer

Prostate cancer (CaP) is the most common cancer among adult men in the Western world. Better insight into its tumor-activating pathways may facilitate the development of targeted therapies. In this study, we show that patients who develop prostate tumors with low levels of PTEN and high levels of HER2/3 have a poor prognosis. This is functionally relevant, as targeting Her2 activation to the murine prostate cooperates with Pten loss and drives CaP progression. Mechanistically, this is associated with activation of the MAPK pathway and abrogation of the Pten loss-induced cellular senescence program. Importantly, inhibition of MEK function strongly suppressed proliferation within these tumors by restoring the Pten loss-induced cellular senescence program. Taken together, these data suggest that stratification of CaP patients for HER2/3 and PTEN status could identify patients with aggressive CaP who may respond favorably to MEK inhibition.

From man to mouse and back again: advances in defining tumor AKTivities in vivo

AKT hyperactivation is a common event in human cancers, and inhibition of oncogenic AKT activation is a major goal of drug discovery programs. Mouse tumor models that replicate AKT activation typical of human cancers provide a powerful means by which to investigate mechanisms of oncogenic signaling, identify potential therapeutic targets and determine treatment regimes with maximal therapeutic efficacy. This Perspective highlights recent advances using in vivo studies that reveal how AKT signaling supports tumor formation, cooperates with other mutations to promote tumor progression and facilitates tumor-cell dissemination, focusing on well-characterized prostate carcinoma mouse models that are highly sensitive to AKT activation. The implications of these findings on the therapeutic targeting of AKT and potential new drug targets are also explored.

Modeling prostate cancer: a perspective on transgenic mouse models

Despite considerable success in treatment of early stage localized prostate cancer (PC), acute inadequacy of late stage PC treatment and its inherent heterogeneity poses a formidable challenge. Clearly, an improved understanding of PC genesis and progression along with the development of new targeted therapies are warranted. Animal models, especially, transgenic immunocompetent mouse models, have proven to be the best ally in this respect. A series of models have been developed by modulation of expression of genes implicated in cancer-genesis and progression; mainly, modulation of expression of oncogenes, steroid hormone receptors, growth factors and their receptors, cell cycle and apoptosis regulators, and tumor suppressor genes have been used. Such models have contributed significantly to our understanding of the molecular and pathological aspects of PC initiation and progression. In particular, the transgenic mouse models based on multiple genetic alterations can more accurately address the inherent complexity of PC, not only in revealing the mechanisms of tumorigenesis and progression but also for clinically relevant evaluation of new therapies. Further, with advances in conditional knockout technologies, otherwise embryonically lethal gene changes can be incorporated leading to the development of new generation transgenics, thus adding significantly to our existing knowledge base. Different models and their relevance to PC research are discussed.

Low level HER2 overexpression is associated with rapid tumor cell proliferation and poor prognosis in prostate cancer

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.

Molecular markers of prostate cancer outcome

Molecular markers have the potential to serve not only as prognostic factors but may be targets for new therapeutic strategies and predictors of response in a range of cancers. Prostate cancer development and progression is predicated on a series of genetic and epigenetic events within the prostate cell and its milieu. Within this review, we identify candidate molecules involved in diverse processes such as cell proliferation, death and apoptosis, signal transduction, androgen receptor (AR) signalling, cellular adhesion and angiogenesis that are linked to outcome in prostate cancer. Current markers with potential prognostic value include p53, Bcl-2, p16INK4A, p27Kip1, c-Myc, AR, E-cadherin and vascular endothelial growth factor. Evolving technology permits the identification of an increasing number of molecular markers with prognosis and predictive potential. We also review the use of gene microarray analysis in gene discovery as a means of identifying and cosegregating novel markers of prostate cancer outcome. By integrating selected markers into prospective clinical trials, there is potential for us to provide specific targeted therapy tailored for an increasing number of patients.

Expression of nuclear factor-kappa B and I kappa B alpha proteins in prostatic adenocarcinomas: correlation of nuclear factor-kappa B immunoreactivity with disease recurrence

PURPOSE

The nuclear transcription factor nuclear factor-kappa B (NF kappa B) and its inhibitor, I kappa B, regulate the transcription of various genes involved in cell proliferation, adhesion, and survival. The NF kappa B transcription factor complex plays a role in cancer development and progression through its influence on apoptosis. More recently, NF kappa B has been shown to be activated in human and androgen-independent prostate cancer cells. To our knowledge, this is the first study demonstrating the prognostic significance of NF kappa B immunoreactivity in prostate adenocarcinomas (PACs).

EXPERIMENTAL DESIGN

Using prostatectomy specimens, we performed immunohistochemical staining for NF kappa B and I kappa B alpha (Santa Cruz Biotechnology) on formalin-fixed, paraffin-embedded sections obtained from 136 patients with PAC. Cytoplasmic and nuclear immunoreactivity was scored for intensity and distribution, and results were correlated with preoperative serum prostate-specific antigen, tumor grade, stage, DNA ploidy (Feulgen spectroscopy), and biochemical disease recurrence.

RESULTS

Forty-nine percent of PACs overexpressed cytoplasmic NF kappa B, and 63% showed decreased I kappa B expression. Cytoplasmic NF kappa B overexpression correlated with advanced tumor stage (P = 0.048), aneuploidy (P = 0.022), and biochemical disease recurrence (P = 0.001). When we compared the means for the NF kappa B-positive and -negative subgroups, NF kappa B overexpression correlated with preoperative serum prostate-specific antigen (P = 0.04) and DNA index (P = 0.05). Fifteen percent of PACs expressed nuclear NF kappa B, which correlated with high tumor grade (P = 0.001) and advanced stage (P = 0.05). Decreased I kappa B alpha expression correlated with high tumor grade (P = 0.015). On multivariate analysis, tumor stage (P = 0.043) and NF kappa B overexpression (P = 0.006) were independent predictors of biochemical recurrence.

CONCLUSION

These results support a role for NF kappa B pathway proteins in the tumorigenesis of PACs. The findings are also consistent with reported experimental studies suggesting a new strategy of combined chemotherapy and specific NF kappa B blockade in decreasing the rate of disease relapse.

Trastuzumab plus docetaxel in HER2/neu-positive non-small-cell lung cancer: a California Cancer Consortium screening and phase II trial

HER2 is reported to be overexpressed in 20% of cases of non-small-cell lung cancer (NSCLC), principally adenocarcinoma. Trastuzumab is a monoclonal antibody against HER2 that, when combined with a taxane, improves survival compared with chemotherapy alone in advanced breast cancer. In view of these observations, we conducted a phase II HER2 screening and efficacy trial of trastuzumab plus weekly docetaxel in cases of advanced NSCLC in which primary platinum-based therapy had failed. Patients with advanced or metastatic NSCLC were screened for HER2 overexpression by immunohistochemistry. Patients with HER2-positive tumors (2+ or 3+) were initially randomized to either single-agent trastuzumab or docetaxel. After completing 2 treatment cycles, all patients went on to receive the trastuzumab/docetaxel combination regardless of response to the single agents. Treatment consisted of docetaxel 30 mg/m2 weekly for 6 weeks followed by a 2-week break and trastuzumab 4 mg/kg intravenously on week 1 followed by 2 mg/kg per week thereafter. Cycle length was 8 weeks. Sixty-nine patients with NSCLC (33 men, 36 women) were screened between August 1999 and March 2001. Only 13 patients (19%) had HER2-positive disease; all 13 enrolled in the efficacy trial. Of 9 patients receiving docetaxel alone, 1 partial response (PR) was seen. None responded to trastuzumab alone. The overall outcomes to the sequence of single-agent therapy followed by combination therapy included a PR rate in 8% of cases, stable disease in 23%, progression in 46%, and nonassessable disease in 23%. Estimated event-free and overall survival times were 4.3 and 5.7 months, respectively. Treatment was well tolerated. The screening component of this trial demonstrated that the target population for trastuzumab therapy in NSCLC is relatively small. Because of the limited clinical activity of trastuzumab-based therapy in this cohort and the similar disappointing reports from other studies of trastuzumab in NSCLC, this trial was closed to further accrual. In view of the limited target population for HER2 inhibition, future efforts and resources should be directed toward molecular targets other than HER2 in NSCLC.

Trastuzumab plus docetaxel in HER-2/neu-positive prostate carcinoma: final results from the California Cancer Consortium Screening and Phase II Trial

BACKGROUND

Overexpression of the HER-2/neu oncoprotein has been reported to occur in </= 60% of patients with prostate carcinoma and to correlate with shortened survival. Trastuzumab is a humanized monoclonal antibody to the HER-2 receptor and has activity against HER-2-positive breast carcinoma, more so when combined with a taxane. The authors screened for HER-2 overexpression in patients developing hormone-refractory prostate carcinoma (HRPC) and conducted a Phase II trial of trastuzumab plus docetaxel in HER-2-positive patients.

METHODS

Paraffin-embedded tumor specimens from potentially eligible patients were screened for HER-2 expression by immunohistochemistry (IHC) and/or amplification by fluorescent in situ hybridization (FISH). Shed HER-2 was also assessed by enzyme-linked immunoradsorbent assay (ELISA). Patients with HER-2-positive tumor specimens (IHC 2+ or 3+ or FISH ratio > 2) were initially randomized to receive either single-agent trastuzumab or docetaxel. After two treatment cycles, nonresponding patients received the trastuzumab/docetaxel combination. Treatment was comprised of 30 mg/m(2) of docetaxel weekly for 6 weeks followed by a 2-week break and 4 mg/kg of trastuzumab intravenously during Week 1 then 2 mg/kg per week thereafter. The cycle length was 8 weeks.

RESULTS

One hundred patients with HPRC were screened. IHC results were as follows: 3+ (n = 1), 2+ (n = 6), 1+ (n = 26), 0 (n = 39), and insufficient tissue specimen/not tested (n = 28). Only 3 of 37 patients had elevated shed HER-2 by ELISA (> 15 mg/mL). None overexpressed HER-2 by IHC. FISH amplification was found in 0 of 34 tissue samples. Of seven patients with IHC 3+ or 2+, four were tested by ELISA and two by FISH. None were abnormal. Age and Gleason score did not correlate with IHC status. Of the seven patients eligible for the Phase II study, only four agreed to participate. The trial was thus closed for nonfeasibility (the overall HER-2 positivity rate was < 20%). No patient responded to trastuzumab alone. The median survival was not reached and the median progression-free survival was 7 months.

CONCLUSIONS

HER-2 overexpression by IHC in archival prostate carcinoma specimens was infrequent. There was no apparent correlation among IHC, ELISA, and FISH, although the sample size was limited. Conclusions regarding the predictive value of HER-2 status on outcome after trastuzumab-based therapy were not reached and were only drawn after larger-scale screening efforts. The authors estimated that 1000 patients need to be screened to complete accrual to a 40-patient efficacy trial.

Survivin and Bcl-2 expression in prostatic adenocarcinomas

CONTEXT

Dysregulated cell proliferation caused by inhibitors of programmed cell death (apoptosis) contributes to tumor progression and spread. Aberrant expression of Bcl-2, the most notable inhibitor of apoptosis, has been well characterized in several human malignancies. Recent studies have described a novel apoptosis inhibitor, survivin, in human carcinomas, although its exact role remains to be characterized.

OBJECTIVE

The purpose of this study was to evaluate the immunohistochemical expression of Bcl-2 and survivin proteins in prostate cancer and to correlate the results with clinicopathologic variables.

DESIGN

Formalin-fixed, paraffin-embedded tissue sections from 138 cases of prostatic adenocarcinomas (PACs) were immunostained by an automated method using specific antibodies against survivin and Bcl-2. Staining was semiquantitatively scored based on both intensity and distribution, and results were correlated with morphologic and prognostic variables.

RESULTS

Of the 138 PACs tested, 113 (82%) expressed survivin. We found no correlation between survivin expression and prognostic variables, including grade, stage, DNA content (ploidy), and recurrence. Bcl-2 expression was positive in 95 (69%) of these 138 cases and correlated with nondiploid DNA content. Fourteen (50%) of 28 nondiploid PACs expressed Bcl-2, compared to 17 (25%) of 68 diploid tumors (P =.02). A trend for association of Bcl-2 expression with tumor stage was noted as follows: 21 (39%) of 54 advanced-stage PACs expressed Bcl-2, in comparison with 20 (24%) of 84 low-stage tumors (P =.07). On univariate analysis, 25 (48%) of the 52 PACs that recurred expressed Bcl-2, as compared with 16 (19%) of the 86 nonrecurrent PACs (P <.001). No correlation was noted between survivin and Bcl-2 expression.

CONCLUSION

Survivin is expressed in a majority of PACs and is not a prognosis-related marker, but may be a potential target for apoptosis-based therapy. Overexpression of Bcl-2 correlates with other prognostic variables and predicts disease recurrence of PACs. These data also suggest that survivin and Bcl-2 may regulate cell proliferation and cell death through different mechanisms.

Different mechanisms are implicated in ERBB2 gene overexpression in breast and in other cancers

The ERBB2 gene is overexpressed in 30% of breast cancers and this has been correlated with poor prognosis. ERBB2 is upregulated in other cancers such as prostate, pancreas, colon and ovary. In breast cancer cells, the mechanisms leading to ERBB2 gene overexpression are increased transcription and gene amplification. In these cancers, AP-2 transcription factors are involved in ERBB2 overexpression, and AP-2 levels are correlated with p185(c-)(erbB-2) levels. In this work, we wanted to know if the same molecular mechanisms are responsible for the ERBB2 upregulation in non-breast cancers. We compared ERBB2 gene copy number, p185(c-)(erbB-2) and mRNA levels with AP-2 levels in several ovary, prostate, colon and pancreas cancer cells. A moderate expression of erbB-2 mRNA and protein were observed in some cells without gene amplification. In contrast to breast cancer cells, AP-2 factors were absent or low in some non-breast cells which did express ERBB2. It is thus likely that AP-2 is not a major player in the increased levels of erbB-2 transcripts in non-breast cancer cells. The transcriptional activity of the ERBB2 promoter in colon and ovary cancer cells was estimated using reporter vectors. The results showed that the promoter regions involved in ERBB2 gene overexpression in breast cancer cells are different from those that lead to the gene upregulation in colon and ovary cancers. In conclusion, our results indicate that different transcriptional and post-transcriptional mechanisms are responsible for the increased levels of erbB-2 transcript and protein in breast and non-breast cancer cells.

Molecular and genetic prognostic factors of prostate cancer

Prostate cancer is the most commonly diagnosed cancer in Western males, responsible for 3% of all deaths in men over 55 years of age and second only to lung cancer as a cause of cancer death. Biomarkers have become an important diagnostic tool in prostate cancer. The discovery of the serum marker prostate-specific antigen (PSA) significantly facilitated the detection and management of prostate cancer. As we enter into the post-genomics era, novel biomarkers of prostate cancer of therapeutic significance will invariably emerge. Here we review a series of existing and emerging molecular-based prognostic markers particularly with radiotherapy.

Involvement of Growth Factor Receptors of the Epidermal Growth Factor Receptor Family in Prostate Cancer Development and Progression to Androgen Independence

The development of prostate cancer and the progression from a normal prostate epithelium to androgen-dependent cancer and eventually to hormone-refractory prostate cancer is a multistep process involving several changes in the function of different growth-regulatory signals. In the past 10 years, conflicting results on epidermal growth factor receptor (EGFR) family expression in prostate cancer have been reported. These differences may result from technical differences, lack of standardization of immunohistochemical assays, or different scoring methodologies. Recently, 4 studies have shown experimental evidence of a role of the EGFR family, particularly ErbB-2, in the development of prostate cancer and, more specifically, in the progression to hormone-refractory clinical behavior. These 4 studies were similar in some relevant aspects, such as the patient population. In fact, the patients in each study were divided into 3 groups that represent the progression of prostate cancer. In 3 of 4 studies, a statistically significant increase in ErbB-2 expression was detected by immunohistochemistry in the progression from hormone-dependent to hormone-independent disease. The expression of EGFR was also evaluated in 1 of the 4 studies. In a recent report from our group, a significant increase in EGFR expression was observed in patients treated with radical surgery, in patients who received hormonal therapy as primary therapy before radical prostatectomy, and, finally, in patients with metastatic and hormone-refractory disease. It has been proposed that EGFR family receptors and androgen receptors function synergistically in the absence of androgen suggesting cross-talk between the ErbB-2 and androgen receptor pathways, and that mitogen-activated protein kinase and phosphatidylinositol 3-kinase can be considered the transduction pathways. Finally, clinical trials are currently in progress in patients with prostate cancer testing novel agents that selectively interfere with these receptors, such as trastuzumab, an anti- ErbB-2 monoclonal antibody, and gefitinib (ZD1839, Iressa), a small-molecule selective EGFR tyrosine kinase inhibitor.

Evaluation of HER-2/neu expression in prostatic adenocarcinoma: a requested for a standardized, organ specific methodology

BACKGROUND

Some evidence suggests a role for HER-2/neu overexpression in prostate carcinoma progression. Reported rates of HER-2/neu overexpression in patients with prostate carcinoma vary greatly.

METHODS

The authors studied radical prostatectomy specimens from 38 patients who had biochemical failure after undergoing radical prostatectomy for prostate carcinoma. Immunohistochemistry for HER-2/neu overexpression using the HercepTest kit (Dako Corporation, Carpenteria, CA) was employed. Two different antigen-retrieval techniques were used: 1) the standard U.S. Food and Drug Administration (FDA)-approved HercepTest assay and 2) a modified HercepTest, which employed an alkaline citrate buffer, pH 9.0, for antigen retrieval and a 1-hour primary antibody incubation time. The level of HER-2/neu expression was evaluated on a scale from 0 (no staining) to 3+ according to the published guidelines. Fluorescent in situ hybridization for gene amplification was performed on all specimens.

RESULTS

With the standard technique, only one specimen had 2+ staining, and no specimens had 3+ staining. With the modified technique, 10 specimens (26%) had 2+ staining, and 9 specimens (24%) had 3+ staining. There was a significant association between the level of HER-2/neu expression shown with the modified technique and tumor stage (P = 0.03) as well as Gleason grade (P = 0.01). None of the specimens had HER-2/neu gene amplification.

CONCLUSIONS

The authors report a simple modification of the HercepTest that resulted in an increased rate of HER-2/neu expression, which was correlated with poor-risk pathologic findings. The findings suggest that adenocarcinoma of the prostate should be evaluated for HER-2/neu expression with a prostate specific immunohistochemical procedure that differs from the FDA-approved standard procedure.

HER-2/neu is overexpressed infrequently in patients with prostate carcinoma. Results from the California Cancer Consortium Screening Trial

BACKGROUND

The overexpression of HER-2/neu is found in 20-30% of patients with breast carcinoma and is an adverse prognostic factor. HER-2 overexpression also has been reported in up to 60% of patients with hormone-refractory prostate carcinoma (HRPC) and was correlated with shortened survival. Trastuzumab (Herceptin) is a humanized monoclonal antibody that binds to the HER-2 receptor and has antitumor activity in patients with HER-2-overexpressing breast carcinoma. The authors report the results of HER-2 screening from a Phase II trial of chemotherapy with trastuzumab and docetaxel in patients with HER-2-overexpressing prostate carcinoma.

METHODS

Archival paraffin embedded tumor tissue was obtained from potentially eligible patients and was screened for HER-2 expression by immunohistochemistry (IHC) using a specialized test kit. Shed HER-2 antigen in serum also was determined using an enzyme-linked immunosorbent assay (ELISA). HER-2 gene amplification was assessed by fluorescent in situ hybridization (FISH). Patients with IHC scores of 2+ or 3+ were considered to have HER-2 overexpression and were eligible for the trial. To date, 62 patients with HRPC have been screened.

RESULTS

The median patient age was 72 years, and Gleason scores were < 5 in 1 patients, 5-7 in 24 patients, > 7 in 23 patients, and not specified in 14 patients. IHC HER-2 expression was 0 in 28 patients, 1+ in 14 patients, 2+ in 4 patients, and 3+ in 1 patients. Fifteen patients had either suboptimal tissue (13 patients) for interpretation or had pending results (2 patients). Therefore, 8% of all patients screened (5 of 62 patients) had HER-2 overexpression by IHC. Quantitative ELISA for shed HER-2 was available in 32 patients; this level was elevated (> 15 ng/mL) in only 2 patients, and neither had HER-2 expression by IHC. Of the 5 patients with 2+ or 3+ HER-2 expression by IHC, none had elevated shed HER-2 antigen levels by ELISA. FISH for HER-2 amplification was performed on 12 specimens; 5 of these specimens were uninterpretable due to specimen artifact, and none of the remaining 7 specimens had HER-2 amplification, defined as a ratio > 1. Patient age and Gleason score were not correlated with HER-2 status.

CONCLUSIONS

Unlike breast carcinoma and contrary to prior reports, HER-2 overexpression by IHC in archival prostate tissue from patients who eventually developed hormone-refractory disease was infrequent. There did not appear to be any correlation between HER-2 overexpression by IHC and shed HER-2 antigen levels in serum by ELISA in this tumor type. Whether trastuzumab possesses single-agent activity or modulates chemotherapy response in tumor types other than breast carcinoma remains to be determined.

The significance of immunohistochemistry in the diagnosis and therapy of neoplasms

This review article details the diagnostical significance of immunohistochemistry, which has developed during the last quarter of the century. Certainly, the advancement of monoclonal antibody technology has been of great significance in assuring the place of immunohistochemistry in the modern accurate microscopic diagnosis of human neoplasms, as a method of choice in histopathology. The fact still remains that in order to properly assess any immunohistochemical reactivity used for differential diagnostic purposes, the target cells have to be identified as neoplastically transformed cells by routine histopathological techniques. Selected groups of target molecules of great significance in cancer biology are discussed. The discovery of neoplasm-associated antigens has not only made the more accurate diagnosis of human cancer feasible but has also shed light on the extensive immunophenotypical heterogeneity of even the most closely linked human malignancies. The identification of disseminated neoplastically transformed cells by immunohistochemistry has allowed for a clearer picture of cancer invasion and metastasis, as well as the evolution of the tumour cell associated immunophenotype towards increased malignancy. Some possibilities of neoplasm-associated antigen targeted, receptor-directed immunotherapy are discussed and reviewed in this manuscript. Future antineoplastic therapeutical approaches should see the inclusion of a variety of immunotherapies, in the form of an individualised 'cocktail' specific for the particular immunophenotypical pattern associated with each individual patient's neoplastic disease.

Morphologic and molecular prognostic markers in prostate cancer

In this review, a series of traditional morphology-based measurements, relatively well-documented ancillary biomarkers, and emerging molecular assays are evaluated for their relative ability to predict prognosis in prostate cancer. Prognostic factors that have achieved widespread use and are classified as category I by the College of American Pathologists' Solid Tumor Prognostic Factor Consensus Conference are compared with newer tests that are beginning to be used in clinical practice (category II) and emerging molecular-based assays that have yet to be widely validated in the published literature or in clinical trials (category III).

Her-2/neu oncogene amplification in clinically localised prostate cancer

AIM

To examine the incidence of Her-2/neu oncogene amplification in clinically localised prostate cancer using in situ hybridisation.

METHODS

One hundred and seventeen patients, who had undergone radical prostatectomy, were identified and in situ hybridisation was performed on formalin fixed, paraffin wax embedded tissue using the Quantum Appligene probe for Her-2/neu. The enzyme peroxidase was used to detect the probe because this enabled a permanent record to be kept. Tumours in which there were five or more signals in each nucleus in > 20% of the tumour cells were considered to have a significantly increased copy number. A serial section from these tumours was then hybridised with the chromosome 17 alpha satellite probe. The ratio of the percentage of cells showing an increase in Her-2/neu copy number to the number showing polysomy for chromosome 17 was calculated. A ratio above 2 was considered amplified.

RESULTS

Biochemical recurrence occurred in 50 (43%) patients and 24 (21%) had clinical recurrence. In situ hybridisation for Her-2/neu was accessible in 114 (97%) patients. A significant increase in copy number was present in two patients (1.75 %), but chromosome 17 hybridisation showed that the increase was the result of polysomy rather than true amplification. Both these patients had a Gleason score of 7 and stage T3; they also had recurrent clinical disease with distal metastasis within two and 19 months.

CONCLUSIONS

Increased Her-2/neu oncogene copy number appears to be rare in clinically localised prostatic adenocarcinoma and is related to chromosome 17 polysomy rather than true amplification. As a result, it would not be a useful biomarker for identifying those patients who will have recurrences after radical prostatectomy.

Reversion of the malignant phenotype of gastric cancer cell SGC7901 by c-erbB-2-specific hammerhead ribozyme

The c-erbB-2/neu-encoded protein p185 is closely related to the growth and metastasis of adenocarcinoma. We sought to reverse the malignant phenotype of gastric cancer cell line SGC7901 with c-erbB-2-specific ribozyme. We designed the ribozyme and generated the in vitro transcription vectors of the ribozyme and its substrate. In vitro cleavage reaction indicated that the ribozyme catalyzed 79.3% target RNA in 1 hour at 37 degrees C. Then, we generated the eucaryotic expression vectors of the ribozyme and transfected them into SGC7901 cells, which highly express p185. Analyses showed that the c-erbB-2 mRNA and p185 were reduced remarkably in the ribozyme-transfected cells. The growth rate of the ribozyme-transfected cells was much lower than that of the control group. Tumorigenicity was also decreased dramatically in nude mice. The results demonstrated that c-erbB-2-specific ribozyme may inhibit the malignancy of gastric cancer cells SGC7901.

HER2 protein expression and gene amplification in androgen-independent prostate cancer

The role of the HER2 receptor remains uncertain in the pathogenesis and progression of human prostate cancer. Previous studies have reported widely divergent rates for HER2 expression in primary prostate tumors, probably owing to significant methodologic differences in the studies. Few data exist about the frequency of HER2 protein overexpression and gene amplification in androgen-independent prostate cancer (AIPC), although recent xenograft models suggest HER2 expression may be up-regulated in the transition from androgen-dependent to androgen-independent disease. We studied the role of HER2 protein in AIPC by immunohistochemical and fluorescence in situ hybridization (FISH) analyses on AIPC specimens using well-characterized and validated reagents. Fourteen (36%) of 39 specimens expressed HER2; however, only 2 (5%) had moderate (2+) expression, and 2 (5%) had high-level (3+) expression. Two (6%) of 36 specimens had gene amplification by FISH. These data suggest that HER2 protein overexpression and gene amplification are relatively uncommon in AIPC.

A phase II study of the bispecific antibody MDX-H210 (anti-HER2 x CD64) with GM-CSF in HER2+ advanced prostate cancer

The proto-oncogene HER2 presents a novel therapeutic target. We report results in 25 patients with HER2+ advanced prostate cancer treated with the bispecific antibody MDX-H210 15 microg m(-2)by intravenous infusion plus GM-CSF 5 microg kg(-1)day(-1)by subcutaneous injection for 4 days repeated weekly for 6 weeks. Patients with stable disease or better received further cycles of treatment until disease progression or study withdrawal. 1 patient received no treatment and 4 received less than 1 cycle and are included in the toxicity analysis only. Median duration of follow up was 105+ (range 21-188) days. Toxicity was generally NCI-CTG 0-2. There were 2 grade 4 adverse events (heart failure and dyspnoea) and 1 grade 3 event (allergic reaction) resulting in discontinuation of the study medication. There were 9 further grade 3 events not resulting in trial withdrawal. There were no treatment-related deaths. 7/20 (35%) evaluable patients had a >50% PSA response of median duration 128 (range 71-184+) days. 7/12 (58%) patients with evaluable pain had improvements in pain scores. The PSA relative velocity on therapy decreased in 15/18 (83%) assessable patients compared to pre-study. GM-CSF and MDX-H210 is active in hormone refractory prostate carcinoma with acceptable toxicity; further studies are warranted.

Deletion (1)(q12) and double minutes in a metastatic adenocarcinoma of the prostate

Cytogenetic analysis after short-term cultures were performed on an invasive and moderately-differentiated prostatic adenocarcinoma. The results showed a normal male chromosomal complement in most metaphases examined. Furthermore, several abnormalities were found, including del(1)(q12), double minute and ring chromosomes, acentric fragments, triradial figures, and near-tetraploid cells.

Cell proliferation, apoptosis, oncogene, and tumor suppressor gene status in adenosis with comparison to benign prostatic hyperplasia, prostatic intraepithelial neoplasia, and cancer

There is scant information on the cell proliferation, apoptosis, oncogenes, and tumor suppressor genes status in adenosis. Forty-eight foci of adenosis were studied with immunohistochemistry for MIB-1; c-erbB-2, c-erbB-3, bcl-2 oncogenes; and p53. To evaluate apoptosis, the TdT dUTP nick end labeling (TUNEL) method was applied. Results were compared with the same studies on benign prostatic hyperplasia (BPH) (n = 20), low-grade prostatic intraepithelial neoplasia (PIN) (n = 10); high-grade PIN (n = 20), Gleason sum 2 to 6 cancer (n = 16); and Gleason sum 7 to 10 cancer (n = 22). MIB-1 proliferation index was lowest in BPH, followed by adenosis, low-grade prostatic intraepithelial neoplasia (PIN), low-grade cancer, high-grade PIN, and high-grade cancer. The apoptotic rate was generally low in all groups, although it was higher in PIN and cancer. In BPH and adenosis, bcl-2 was absent in luminal cells. In low- and high-grade PIN, both basal and luminal cells expressed bcl-2, whereas in cancer, expression was found in only 1 case (3%). C-erbB-2 showed absent or low values for cancer and adenosis, whereas it was commonly expressed in BPH and low- and high-grade PIN. Low expression in adenosis was also found with c-erbB-3 (6%) compared with all other groups. Expression of p53 was confined to cancer. Despite a significantly higher proliferation index rate compared with BPH, adenosis showed a markedly lower proliferating index when compared with low-grade PIN, high-grade PIN, and cancer. Expression of the oncogenes c-erbB-2 and cerbB-3 was very low in adenosis, and the staining pattern for bcl-2 was similar to that of BPH. These results provide additional evidence to that of prior studies that adenosis is a histological small acinar proliferation more akin to BPH than high-grade PIN or adenocarcinoma.

Analysis of protooncogene c-erbB-2 in benign and malignant human prostate

In this report, we characterized the c-erbB-2 gene and its product in prostatic cancer cells. Three prostatic cancer cell lines (PC3, DU145 and TSU-Pr1), one primary prostatic cancer and four benign prostatic hyperplasias (BPH) were studied. In reverse transcribed polymerase chain reaction, c-erbB-2 mRNA was demonstrated in all three cell lines and prostatic cancer tissues as well as BPH. The c-erbB-2 protein was expressed higher in prostatic cancer cells and tissues as compared with benign tissue by enzyme immunoassay, but it was not statistically significant. Immunohistochemical study, with the monoclonal antibody SV2-61gamma that recognizes the extracellular domain of c-erbB-2, showed that all the prostatic tissues and cells had reactivity. Antigenicity was mainly in the cytoplasm. Analysis of genomic DNA failed to disclose gene amplifications or rearrangements of c-erbB-2 in both prostatic cancer and BPH. The sequence of amplified c-erbB-2, which corresponds to transmembrane domain, disclosed wild type in all prostatic cancer cells. These results demonstrate that although the number is limited, c-erbB-2 gene and protein are expressed in prostatic cancers and benign prostates. In the previous studies on c-erbB-2 expression in prostatic tissue, mainly conducted by immunohistochemistry, its frequency varies among each study, ranging from less than 0% to 100%. Therefore, to evaluate the c-erbB-2 in prostatic tissue precisely, it is also necessary to detect mRNA of c-erbB-2 as demonstrated in our study.

Fluorescence in situ hybridization study of HER-2/neu oncogene amplification in prostate cancer

Prostate cancer is a serious disease affecting men worldwide and treatment compromises the quality of life of prostate cancer patients. We conducted a study of 88 cases of prostate cancer in an attempt to identify prognostic biomarkers that can distinguish aggressive cases that must be treated immediately. HER-2/neu oncogene amplification was initially studied because amplification of this gene has been reported in many other cancers, including those studied in this laboratory. Fluorescence in situ hybridization (FISH) using a HER-2/neu gene probe with a chromosome 17 centromere control probe was performed on formalin-fixed, paraffin-embedded tissues. Of a total of 86 cases successfully analyzed, only 8 (9.3%) were found to be amplified. This frequency was lower than the frequency of amplification found in other cancers studied. Furthermore, no case was found where the level of amplification can be considered high. Only one case was found to have moderate amplification. The rest of the positive cases can all be classified as low amplification. Thus, while we have demonstrated that FISH is a sensitive technique for detecting oncogene amplification, the frequency and level of HER-2/neu amplification detected in prostate cancer seem to be lower than those in most cancers that we studied. In view of the fact that HER-2/neu amplification does not seem to play as significant a role, exploration of other biomarkers in prostate cancer is warranted.

The prognostic significance of proliferation-associated nucleolar protein p120 expression in prostate adenocarcinoma: a comparison with cyclins A and B1, Ki-67, proliferating cell nuclear antigen, and p34cdc2

BACKGROUND

In this study, the authors evaluated the prognostic significance of the expression of nucleolar antigen p120, along with other cell proliferation-associated proteins, in prostate adenocarcinomas (PACs) and compared the results with previously reported data on p34cdc2 cyclin-dependent kinase (p34 cdk).

METHODS

Archival sections from 132 PACs were immunostained with monoclonal antibodies against p120, cyclin A, cyclin B1, Ki-67, and proliferating cell nuclear antigen (PCNA). The DNA content of each tumor was determined by the Feulgen method using image analysis. The immunohistochemistry (IHC) results were correlated with tumor grade, stage, margin positivity, metastasis, ploidy, and postsurgical disease recurrence.

RESULTS

The overall positivity for the various proteins follows: p120, 36%; cyclin A, 35%; cyclin B1, 43%; Ki-67, 46%; and PCNA, 32%. p120 correlated with grade (P = 0.004), stage (P = 0.01), ploidy (P = 0.02), margin positivity (P = 0.03), and metastasis (P = 0.004). Cyclin B1 correlated with ploidy (P = 0.04) and grade (P = 0.05), Ki-67 with grade (P = 0.02) and margins (P = 0.03), and PCNA with grade (P = 0.01). Significant coexpression among these proteins was noted, as was a significant association between the expression of these markers and that previously reported for p34 cdk. In univariate analysis, p120 (P = 0.01), cyclin A (P = 0.01) and p34 cdk (P = 0.002) correlated with disease recurrence. In multivariate analysis of all these proteins, only p34 cdk independently predicted postsurgical recurrence (P = 0.05).

CONCLUSIONS

Nucleolar antigen p120 expression appears to be an additional marker of aggressiveness in PACs. The significant coexpression of the various cell cycle regulatory proteins support their collective role in tumor cell proliferation, with p34 cdk positivity being an independent predictor of postsurgical recurrence.

Needle biopsy DNA ploidy status predicts grade shifting in prostate cancer

DNA ploidy analysis of prostate needle biopsy specimens was performed to determine whether ploidy status could predict tumor grade shifting at radical prostatectomy. The paired needle biopsy and radical prostatectomy specimens from 111 randomly selected men with prostate cancer were obtained from the surgical pathology files of the Albany Medical Center Hospital. The original tumor grades were assigned by a staff of 12 surgical pathologists according to the Gleason system. Tumors with original Gleason scores < or = 6 were classified as low grade, and tumors with scores of > or = 7 were considered high grade. DNA ploidy analysis was performed on the needle biopsy specimens using the CAS 200 image analyzer (Becton Dickinson Immunocytometry Systems, Mountain View, CA, USA) on Feulgen stained 5-microm tissue sections. There were 88 diploid and 23 nondiploid cases. Thirty-eight of 111 (34%) of cases had grade shifting from needle biopsy to radical prostatectomy specimens. Of 89 low-grade needle biopsy cases, 28 (31%) were upgraded at radical prostatectomy. Of 22 high-grade needle biopsy cases, 10 (45%) were downgraded to low grade at radical prostatectomy. Of the 28 low-grade needle biopsy specimens that were upgraded at radical prostatectomy, 19 (68%) featured an aneuploid histogram and 9 (32%) were diploid. Nineteen of 28 (68%) of aneuploid low-grade tumors on needle biopsy became high-grade at radical prostatectomy. Nine of 10 (90%) diploid high-grade tumors at needle biopsy became low-grade at radical prostatectomy. Of the 38 cases in which ploidy and grade were incongruous, 28 (74%) had grade shifting. In a multivariate regression analysis, a high-grade Gleason score on radical prostatectomy specimens correlated significantly with needle biopsy ploidy (p = 0.0001) but not with needle biopsy grade (p = 0.15). The sensitivity of the needle biopsy grade in the detection of high-grade tumors on radical prostatectomy was 30%, and the specificity was 86%. The sensitivity of ploidy status in the prediction of high grade at radical prostatectomy was 78%, and the specificity was 96%. With a prostate-specific antigen (PSA) level of >0.4 ng/ml as the indicator of post-radical prostatectomy disease recurrence on a subset of 106 patients, on univariate analysis, disease recurrence was predicted by needle biopsy ploidy (p = 0.001) and radical prostatectomy grade (p = 0.04) but not by needle biopsy grade (p = 0.39). On multivariate analysis, needle biopsy DNA ploidy status independently predicted disease recurrence (p = 0.002), whereas needle biopsy and prostatectomy grade did not. These results indicate that DNA ploidy analysis of needle biopsy specimens of prostate cancer predicts grade shifting, that it is a more sensitive and specific indicator of final tumor grade at radical prostatectomy than is the original needle biopsy grade, and that ploidy status independently predicts postoperative disease recurrence.

p34cdc2 in invasive breast cancer: relationship to DNA content, Ki67 index and c-erbB-2 expression

AIMS

One-hundred and eighty-eight cases of human mammary carcinoma were examined immunohistochemically for their expression of Ki67, p34cdc2 and c-erbB-2. DNA image cytometry was performed to evaluate DNA ploidy, Auer type, S-phase fraction (SPF), 5c exceeding rate (5cER) and 2c deviation index (2cDI).

METHODS AND RESULTS

One-hundred and sixty-eight cases were invasive ductal carcinomas, 20 were of invasive lobular type. Routinely assessed oestrogen and progesterone receptor scores were available. The results were analysed statistically in comparison to tumour type, histopathological grade, lymph node status, menopausal status, patient age and overall survival. Ki67 (P < 0.002) and c-erbB-2 (P < 0.0001) correlated well with overall survival (P < 0.0008) and grade (P < 0.038) but not with lymph node status and tumour type. p34cdc2 showed a trend towards a positive correlation with Ki67 (P < 0.058) and a significant negative correlation with receptor status (P < 0.008) but with none of the other parameters examined.

CONCLUSIONS

No association between the DNA measured parameters (Auer type, SPF, 5cER and 2cDI) and survival was found. Our results suggest that c-erbB-2 and Ki67 are parameters which might, in combination with receptor status, help to define subgroups with different outcomes.

Adrenocorticotropin-Producing Pituitary Carcinoma with Expression of c-erbB-2 and High PCNA Index: A Comparative Study with Pituitary Adenomas and Normal Pituitary Tissues

Pituitary carcinomas are very rare neoplasms with a poor prognosis. We report a case of Cushing's disease resulting from a pituitary carcinoma in a 22-yr old female, who died of massive hepatic failure. At autopsy, there was invasion of the parasellar structures and vasculature by the tumor, which stained positively only for ACTH. There were two metastatic nodules in the liver, which also stained positively for ACTH. When compared to other cases of Cushing's disease (n = 52), other pituitary adenomas (n = 292). and normal pituitary tissues (n = 21), the pituitary carcinoma was the only one with c-erbB-2 membrane staining in both the sellar-located tissue and liver metastasis. C-erbB-2 staining was present in the cytoplasm of a variable number of cells in 40% of the invasive adenomas (n = 103), while only 1.2% of the noninvasive tumors (n = 241) expressed this protein (p < 0.001). No particular immunohistological type preferentially expressed this protein. In normal pituitary tissues, 10% of the cells expressed cytoplasmic c-erbB-2. A higher index of proliferating cell nuclear antigen (PCNA) in the primary tumor and liver metastasis (10%) was also found compared to other ACTH-secreting adenomas (invasive, 3.4 -t 1 S% vs 1 ii +/- 1.5% in noninvasive) and other pituitary tumors (invasive, 2.9 +/- 1.5% vs 1.5 +/- 1.3% in noninvasive). The PCNA index was significantly higher in invasive tumors than in noninvasive adenomas (p = 0.004). PCNA staining was negative in normal pituitary tissues. Staining for p53, pRB and p(2ras) was negative in the carcinoma and liver metastasis. We suggest that the c-erbB-2 membrane pattern and a higher PCNA index may indicate a worse prognosis in adenohypophyseal neoplasia.

The prognostic significance of p34cdc2 and cyclin D1 protein expression in prostate adenocarcinoma

BACKGROUND

Cyclin-dependent kinases (CDK) and cyclins constitute the subunits of the maturation-promoting factor that controls the process of cell division. High levels of these proteins have been reported in human malignancies of the stomach, colon, breast, and lung, and have been implicated in aberrant cell division and dysregulated tumor growth.

METHODS

p34cdc2 CDK and cyclin D1 (D1) protein expression were evaluated in 140 radical prostatectomy specimens harboring adenocarcinoma (PAC), using the respective monoclonal antibodies on archival tissue sections. In each case, slides stained with hematoxylin and eosin were examined for evaluation of Gleason's grade and pathologic stage. The DNA content of the tumors was determined by the Feulgen method with the CAS200 Image Analyzer (Cell Analysis Systems, Lombard, IL). Nuclear immunoreactivity for the two proteins was semiquantitatively scored, and results were correlated with Gleason's grade, stage, ploidy, metastatic status, and disease recurrence after radical prostatectomy.

RESULTS

p34cdc2 was expressed in 84 of 140 PACs (60%) and correlated with high Gleason's grade (P = 0.0001), advanced pathologic stage (P = 0.01), nondiploid DNA content (P = 0.0001), and metastases (P = 0.04). On multivariate analysis using the Cox proportional hazards model, p34cdc2 immunoreactivity (P = 0.0001) and high Gleason's grade (P = 0.01) each independently predicted disease recurrence. When tumors were of low Gleason's grade and lacked p34cdc2 expression, 4 of 39 PACs (10%) recurred, as compared with 18 of 47 (38%) that recurred when tumors were of high Gleason's grade and expressed p34cdc2 protein. D1 was positive in 31 of 140 PACs (22%) and showed a trend (P = 0.07) of high Gleason's grade, but it did not reach statistical significance with any of the prognostic variables. In the majority of PACs expressing both p34cdc2 and D1 proteins, the adjacent benign prostate acini showed focal, scattered nuclear positivity of the basal and secretory epithelial cells.

CONCLUSIONS

p34cdc2 is expressed in a majority of PACs and correlates with high Gleason's grade, advanced pathologic stage, nondiploid DNA content, and metastases. On multivariate analyses high Gleason's grade and p34cdc2 immunoreactivity predict disease recurrence independently of the pathologic stage. Thus, p34cdc2 appears to play a critical role in the evolution, proliferation, and spread of PACs and may be of prognostic value when applied to initial prostate tissue samples taken by needle biopsy.

Telomerase activity in human benign prostate tissue and prostatic adenocarcinomas

Telomerase adds a hexanucleotide telomeric sequence to the chromosomal ends during replication and is postulated to play a role in cellular senescence and immortalization. Thirty-four human prostate tissues (18 malignant; 16 benign) were analyzed for telomerase activity by a sensitive nonradioactive polymerase chain reaction (PCR)-based method using the TRAP-eze telomerase detection kit (Oncor, Inc., Gaithersburg, MD). Telomerase activity in the homogenized tissue extracts was correlated with tumor grade, pathologic stage, and DNA ploidy. Specimens that exhibited the 36 bp internal control band and a ladder of products with 6-base increments starting with 50 nucleotides were considered positive. Fourteen (78%) of 18 prostatic adenocarcinomas (PACs) and only 2 (13%) of 16 benign prostate tissues exhibited telomerase activity. Our results indicate that, in contrast to most benign prostate tissues, telomerase activity can be detected in the majority of PACs and appears to be independent of tumor grade, stage, or DNA ploidy. Telomerase expression is occasionally detected in benign prostatic tissues bordering PACs and may result from either the presence of undetected tumor foci in these stored specimens or the proliferative response of the benign elements to adjacent cancer.

HER-2/neu gene amplification status in prostate cancer by fluorescence in situ hybridization

HER-2/neu expression has been established as a prognostic factor in breast and other cancers. In prostate cancer (PC), a similar predictive role has been hindered by variable immunohistochemical (IHC) results. The authors studied DNA amplification of the HER-2/neu gene on 4-microm sections obtained from 62 formalin-fixed, paraffin-embedded PCs by fluorescence in situ hybridization (FISH). The results were compared with HER-2/neu protein expression as determined by IHC and correlated by logistic regression analysis with Gleason tumor grade, DNA ploidy, serum prostate specific antigen (PSA), and pathological stage. The HER-2/neu gene was localized using the Oncor (Gaithersburg, MD) digoxigenin-labeled unique sequence probe. Amplified PCs had at least 20 malignant cells, with 5 or more copies of the sequence. Amplification of HER-2/neu correlated with Gleason score (P = .0001). The mean Gleason score of unamplified tumors was 5.7 and that of amplified tumors was 7.5. Nondiploid tumors had a significantly greater rate of HER-2/neu amplification compared with diploid tumors (P = .0003). Of the 62 cases evaluated by IHC and FISH, 18 cases (29%) were overexpressed by IHC, and 27 cases (44%) were amplified by FISH. A trend for similar HER-2/neu status in each PC by the two methods did not reach statistical significance (P = .23). HER-2/neu amplification by FISH was associated with advanced pathological stage; however, this relationship reached only near-statistical significance (P = .06). There was no correlation of HER-2/neu amplification by FISH with patient age or preoperative serum PSA levels. The authors conclude that HER-2/neu gene amplification status can be determined by FISH on archival prostate cancer specimens, significantly correlates with high tumor grade and nondiploid DNA content, and is more frequently encountered in tumors with advanced pathological stage. Also, FISH is more sensitive than IHC for detection of abnormalities in the HER-2/neu gene, and further studies should be undertaken to determine whether a FISH-based HER-2/neu detection method may prove of importance in the prediction of prognosis and planning of therapy in prostate cancer patients.

Prognostic significance of HER-2/neu gene amplification status by fluorescence in situ hybridization of prostate carcinoma

BACKGROUND

HER-2/neu gene amplification, established as a prognostic factor in breast carcinoma and other cancers, has not been correlated with outcome in prostate carcinomas (PCs).

METHODS

HER-2/neu gene amplification was determined by automated fluorescence in situ hybridization (FISH) using a unique sequence cosmid probe on 113 formalin fixed, paraffin embedded 4-microns tissue sections and the results compared with tumor grade, DNA ploidy, HER-2/neu protein expression by immunohistochemistry (IHC), serum prostate specific antigen, pathologic stage, and postoperative disease recurrence (mean follow-up of 44 months).

RESULTS

HER-2/neu gene amplification by FISH (41% of PCs) correlated with tumor grade (P = 0.001) and DNA ploidy status (P = 0.0003). HER-2/neu protein overexpression by IHC (29% of PCs) correlated with grade (P = 0.03), but not with DNA ploidy. A trend for similar HER-2/neu status in each PC by IHC and FISH did not reach statistical significance (P = 0.25). On univariate analysis, HER-2/neu amplification by FISH (P = 0.029), tumor grade (P = 0.013), and DNA ploidy (P = 0.016) correlated with postoperative disease recurrence. HER-2/neu expression by IHC did not correlate with outcome. On multivariate analysis, grade (P = 0.0001) and ploidy (P = 0.001) were independent outcome predictors; HER-2/neu amplification by FISH reached near-independent significance (P = 0.125).

CONCLUSIONS

HER-2/neu gene amplification by FISH on archival PCs significantly correlates with grade and DNA ploidy status, is more sensitive than IHC in detecting HER-2/neu gene abnormalities, predicts postoperative disease recurrence, and may prove important in planning therapy for patients with prostate carcinoma.

c-erbB-2 oncoprotein: a potential biomarker of advanced prostate cancer

BACKGROUND

Overexpression of the c-erbB-2 oncogene has been implicated in the development and/or prognosis of several human carcinomas, including that of the prostate. Recently, c-erbB-2 protein was found to be released in the circulation. The present study was undertaken to study the significance of serum c-erbB-2 protein determination in men with prostate cancer.

METHODS

Serum c-erbB-2 protein determination was performed via immunoradiometric assay using two monoclonal antibodies that react with the extracellular domain of the protein. The study population consisted of 71 untreated prostate cancer patients. Of those, 33 with stage D2 disease entered a follow-up study. As control, serum c-erbB-2 protein levels were determined in 92 patients with benign prostatic hypertrophy. In addition, elevations of c-erbB-2 protein were examined in patients with various disease statuses: clinically well controlled (28 patients), disease progression (24 patients), and end-stage disease (17 patients).

RESULTS

Elevation of serum c-erbB-2 protein level was observed in patients in advanced stages, such as stage D2 disease (30%), disease progression (42%), and end-stage disease (82.4%). In the follow-up study, patients with an elevated c-erbB-2 level had a significantly shorter interval to disease progression than did those with a normal level.

CONCLUSIONS

The results suggest that c-erbB-2 can be used as a biomarker to identify a malignant subgroup in prostate cancer.

Decreased levels of CD44 protein and mRNA in prostate carcinoma. Correlation with tumor grade and ploidy

BACKGROUND

CD44, a transmembrane protein, is associated with cell-cell and cell-matrix interaction and with tumor growth and metastasis. Expression of both standard form and variant isoforms of CD44 protein has been associated with aggressive behavior and metastasis in various tumors, but has not been characterized in prostate adenocarcinoma (PAC).

METHODS

The expression of CD44 standard (CD44s) and splice variant v3, v4/5, v6, v7/8, and v10 proteins were studied in 109 PACs and correlated with tumor grade, DNA ploidy, and mRNA levels. Monoclonal antibodies against the various CD44 proteins were applied to microwave irradiated, formalin fixed, paraffin embedded sections. The DNA content of the tumors was evaluated by the Feulgen method with the CAS200 Image Analyzer. Total RNA exhibiting 18s and 28s bands was derived from two benign prostatic tissues and 5 PACs exhibiting decreased levels of CD44 protein by immunohistochemistry. The RNA was analyzed with reverse transcriptase polymerase chain reaction using CD44 specific primers.

RESULTS

The basal cells of the benign prostatic acini revealed uniform membranous staining for CD44s, v3, and v6 in 95-97% of cases. Similar staining was observed for v4/5, v7/8, and v10 in 40%, 30%, and 2% of cases, respectively. Secretory epithelial cells of the benign prostatic acini showed predominant expression of CD44s (97% of cases). Staining for CD44 variant proteins (v3, v4/5, v6, v7/8, and v10) in this location ranged from 9-22% of cases. Approximately 70% of the PACs showed significant loss of CD44s expression, which correlated with high tumor grade (Gleason > or = 7) (P = 0.01) and aneuploid status (P = 0.002). In 93-98% of the PACS, there was a complete lack of membranous expression for all CD44 variant isoforms. The metastatic PACS did not show preferential expression of either the standard form or any variant isoform. The cDNA from the normal prostates yielded a prominent CD44 standard form polymerase chain reaction product at 482 base pair (bp) and variant isoforms at approximately 650 and 850 bp. No CD44 products could be amplified from the subset of five PAC cDNAs, even when present at four-fold excess.

CONCLUSIONS

PACS exhibit down-regulation of CD44 protein expression, which correlates with high tumor grade and aneuploidy. v6 and v3 isoforms were preferentially expressed in the basal cells of benign prostatic acini. Based on a subset of cases, loss of CD44 protein expression is associated with decreased abundance of CD44 mRNA.

Molecular biology of prostatic intraepithelial neoplasia

High-grade PIN is the most likely precursor of prostatic adenocarcinoma, according to virtually all available evidence to date. The clinical importance of recognizing PIN is based on its strong association with prostatic carcinoma. PIN has a high predictive value as a marker for adenocarcinoma. Its identification in biopsy specimens of the prostate warrants further search for concurrent invasive carcinoma. PIN is associated with progressive abnormalities of phenotype and genotype intermediate between normal prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. There is progressive gain or loss of a wide variety of biomarkers, including morphometric markers, differentiation markers, stromal markers, growth factors and associated receptors, oncogenes, tumor suppressor genes, and chromosomes. Abnormalities in expression of most biomarkers are amplified in the progression from high-grade PIN to localized cancer, metastatic cancer, and hormone-refractory cancer. Oncogenesis of prostatic carcinoma probably occurs through the selection of several genetic changes, each modifying the expression or function of genes controlling cell growth and differentiation. Further studies are needed to evaluate the function and prognostic value of oncogene expression in the normal, preneoplastic, and neoplastic prostate.

A tyrosine kinase profile of prostate carcinoma

Tyrosine kinases play central roles in the growth and differentiation of normal and tumor cells. In this study, we have analyzed the general tyrosine kinase expression profile of a prostate carcinoma (PCA) xenograft, CWR22. We describe here an improved reverse transcriptase-PCR approach that permits identification of nearly 40 different kinases in a single screening; several of these kinases are newly cloned kinases and some are novel. According to this, there are 11 receptor kinases, 9 nonreceptor kinases, and at least 7 dual kinases expressed in the xenograft tissue. The receptor kinases include erbB2, erbB3, Ret, platelet-derived growth factor receptor, sky, nyk, eph, htk, sek (eph), ddr, and tkt. The nonreceptor kinases are lck, yes, abl, arg, JakI, tyk2, and etk/bmx. Most of the dual kinases are in the mitogen-activating protein (MAP) kinase-kinase (MKK) family, which includes MKK3, MKK4, MEK5, and a novel one. As a complementary approach, we also analyzed by specific reverse transcriptase-PCR primers the expression profile of erbB/epidermal growth factor receptor family receptors in a variety of PCA specimens, cell lines, and benign prostatic hyperplasia. We found that erbB1, -2, and -3 are often coexpressed in prostate tissues, but not in erbB4. The information established here should provide a base line to study the possible growth and oncogenic signals of PCA.

Overexpression of her-2/neu in human prostate cancer and benign hyperplasia

Overexpression of the neu oncoprotein has been described in several tumor models including breast and prostate cancer. Overexpression of neu has been reported to have prognostic significance in certain tumors but controversy continues regarding the role and frequency of neu overexpression in prostatic cancer. The objectives of the study were twofold. First, to characterize neu expression in prostate cancer in comparison to benign prostatic hyperplasia. Second, to determine whether neu expression correlates with Gleason grade in prostate cancer. Thirty-nine prostate cancers obtained from radical prostatectomy specimens and 10 benign prostatic hyperplasia specimens were included in the study. Specimens were formalin fixed and paraffin-embodied. neu expression was studied by immunohistochemical staining using a monoclonal neu specific AB-3 antibody. All 39 specimens (100%) of prostate cancer showed positive immunostaining of variable degree while 2 (20%) benign prostatic hyperplasia specimens showed positive staining. Thus, neu oncogene is overexpressed in localized prostate cancer compared to benign prostatic hyperplasia. The degree of neu immunostaining did not correlate with Gleason grade and there appeared to be a tendency towards an inverse relationship. The prognostic significance of the varying overexpression is unknown.

Prostatic carcinoma: Study of C-erb B2, p53, morphological and clinical parameters in 44 radical prostatectomies

In literature it is estimated that only 20% of prostatic carcinoma are clinically important and indicators of biological aggressiveness of the neoplasm would therefore seem necessary. We considered 44 radical prostatectomies that were performed in our Division between 1989 and 1996. A histological section was selected for each patient on which the expression of C-erb B2 and p53 were tested with immunohistochemical methods. In these patients, who were homogeneous as far as surgical criteria are concerned, no subgroups with different progression were found.

Prediction of pathologic stage and postprostatectomy disease recurrence by DNA ploidy analysis of initial needle biopsy specimens of prostate cancer

BACKGROUND

DNA ploidy determination of carcinomas in radical prostatectomy specimens has shown significant correlation with patient outcome, but the predictive value of ploidy status of cancers obtained by transrectal ultrasound-guided needle biopsies has not been studied extensively.

METHODS

Eighty-nine paired needle biopsy specimens (NBX) and radical prostatectomy (RPX) specimens from patients with early clinical stage (A2-B2) prostate cancer were evaluated for DNA content by image analysis of Feulgen stained tissue sections. Findings were compared with Gleason grading on the same specimens by univariate and multivariate analyses for prediction of local tumor invasion, metastasis, disease recurrence, and serum prostate specific antigen concentration during a 0.9-6.0 year clinical follow-up period.

RESULTS

There was excellent correlation of ploidy status between NBX and RPX specimens (P < 0.0001); NBX and RPX grades did not correlate. On RPX specimens, aneuploid status correlated with high tumor grade (P < 0.0005). Aneuploidy in NBX specimens was associated with a twofold higher rate of extracapsular spread (ECS) (P = 0.04). Aneuploid NBX tumors featured a tenfold greater frequency of metastasis than did diploid NBX tumors (P < 0.005). Radical prostatectomy grade correlated with ECS (P < 0.001) and presence of metastatic disease (P = 0.04). On multivariate logistic regression analysis, aneuploidy in both NBX and RPX specimens was the most significant variable and independently predicted the presence of metastasis (P = 0.006 for NBX; P = 0.028 for RPX). Tumor grade of NBX and RPX specimens did not independently predict metastatic disease or disease recurrence, but RPX grade was associated independently with ECS (P = 0.005). Aneuploid NBX tumors recurred after RPX three times more often than did diploid cases, which was significant on univariate (P < 0.001) and multivariate (P = 0.018) analyses using the Cox proportional hazards model. There was no correlation with NBX or RPX Gleason score and disease recurrence. Preoperative serum PSA concentration did not correlate with tumor grade or ploidy status, but on multivariate analysis, when paired with ploidy status, independently contributed to the propensity for ECS, metastasis, and disease recurrence.

CONCLUSIONS

DNA content analysis of early clinical stage prostate carcinoma needle biopsy specimens by image analysis directly correlates with radical prostatectomy specimen ploidy status and is associated independently, with the presence of metastasis, postprostatectomy disease recurrence, and ECS. Needle biopsy tumor grading did not correlate with prostatectomy grade and did not predict disease outcome accurately.

Overexpression of human epidermal growth factor receptor and c-erbB-2 by neuroendocrine cells in normal prostatic tissue

OBJECTIVE

It has been suggested that prostatic neuroendocrine (NE) cells play an important role in the growth and differentiation of the prostate by secreting various neuropeptides and serotonin. However, the mechanism by which NE cells themselves are regulated is virtually unknown. In the present study we evaluated the expression of the human epidermal growth factor receptor (EGFR) family (HER) in prostatic NE cells.

METHODS

Formalin-fixed, paraffin-embedded tissue sections from twenty radical prostatectomy specimens were immunostained with validated rabbit polyclonal antibodies raised against human EGFR and c-erbB-2, using the streptavidin-peroxidase enzyme conjugate method.

RESULTS

A strong immunoreactivity was observed with both antibodies in the cytosol of a few epithelial cells. These cells frequently had a dendritic appearance and were located in the acini and ducts. The EGFR-positive cells were predominant in most cases. Double immunostaining revealed the colocalization of both antigens with chromogranin A, a polypeptide that is expressed by most NE cells. Moreover, EGFR and c-erbB-2 appeared to be colocalized as well as independently expressed by different subpopulations of NE cells.

CONCLUSIONS

The results suggest that prostatic NE cells might be regulated by the HER protein family, probably, in a ligand-specific fashion. This is the first report identifying a potential pathway regulating prostatic NE cells.