Is triple immunostaining with 34betaE12, p63, and racemase in prostate cancer advantageous? A tissue microarray study

Cowper Glands Identified in Prostate and Urethral Specimens: A Comprehensive Immunohistochemical Characterization and Potential Diagnostic Pitfall

Cowper glands recognition remains one of the key histoanatomic benign mimics of prostatic adenocarcinoma. In most instances, these can be identified based on the dimorphic population of lobulated acini and duct(s). However, in the prostate biopsy setting with incomplete/distorted cores, this may not be immediately apparent and may warrant use of immunohistochemistry to argue against prostatic adenocarcinoma. Although immunohistochemical pitfalls in Cowper glands have been described, to our knowledge a comprehensive evaluation of both traditional and purportedly prostate-specific novel markers in Cowper glands has not been previously performed. Herein, we studied the clinicopathological and immunohistochemical features of 21 male patients (age range 39-81 years; mean = 63 years), including 15 prostate biopsies (7 of which also had prostate cancer in the same specimen set and 2 of which had both prostate cancer and Cowper glands in the same biopsy core). Immunohistochemistry showed the following results in Cowper glands: 100% positive for NKX3.1, 100% positive (basal cells) for both high molecular weight keratin and p63, 57% positive for PSAP, 25% positive for PSMA, 5% positive for AMACR, and 0% positive for PSA. In conclusion, for specimens lacking appreciable dimorphic morphology, caution should be rendered when using prostate-specific markers (PSA, PSAP, PSMA, and NKX3.1) as these can show considerable staining in Cowper glands and be a pitfall. Instead, findings from this cohort indicate relying on basal markers (high molecular weight keratin/p63; either individually or in a "cocktail" approach) and PSA are most useful in distinguishing Cowper glands (retained basal cell markers staining) from prostatic adenocarcinoma.

Glyoxalase 1 Expression as a Novel Diagnostic Marker of High-Grade Prostatic Intraepithelial Neoplasia in Prostate Cancer

Glyoxalase 1 (GLO1) is an enzyme involved in the detoxification of methylglyoxal (MG), a reactive oncometabolite formed in the context of energy metabolism as a result of high glycolytic flux. Prior clinical evidence has documented GLO1 upregulation in various tumor types including prostate cancer (PCa). However, GLO1 expression has not been explored in the context of PCa progression with a focus on high-grade prostatic intraepithelial neoplasia (HGPIN), a frequent precursor to invasive cancer. Here, we have evaluated GLO1 expression by immunohistochemistry in archival tumor samples from 187 PCa patients (stage 2 and 3). Immunohistochemical analysis revealed GLO1 upregulation during tumor progression, observable in HGPIN and PCa versus normal prostatic tissue. GLO1 upregulation was identified as a novel hallmark of HGPIN lesions, displaying the highest staining intensity in all clinical patient specimens. GLO1 expression correlated with intermediate-high risk Gleason grade but not with patient age, biochemical recurrence, or pathological stage. Our data identify upregulated GLO1 expression as a molecular hallmark of HGPIN lesions detectable by immunohistochemical analysis. Since current pathological assessment of HGPIN status solely depends on morphological features, GLO1 may serve as a novel diagnostic marker that identifies this precancerous lesion.

Delineating the breast cancer immune microenvironment in the era of multiplex immunohistochemistry/immunofluorescence

Breast cancer is the most common malignancy and the leading cause of cancer death in females worldwide. Treatment is challenging, especially for those who are triple-negative. Increasing evidence suggests that diverse immune populations are present in the breast tumour microenvironment, which opens up avenues for personalised drug targets. Historically, our investigations into the immune constitution of breast tumours have been restricted to analyses of one or two markers at a given time. Recent technological advances have allowed simultaneous labelling of more than 35 markers and detailed profiling of tumour-immune infiltrates at the single-cell level, as well as determining the cellular composition and spatial analysis of the entire tumour architecture. In this review, we describe emerging technologies that have contributed to the field of breast cancer diagnosis, and discuss how to interpret the vast data sets obtained in order to effectively translate them for clinically relevant use.

Signature maps for automatic identification of prostate cancer from colorimetric analysis of H&E- and IHC-stained histopathological specimens

Prostate cancer (PCa) is a major cause of cancer death among men. The histopathological examination of post-surgical prostate specimens and manual annotation of PCa not only allow for detailed assessment of disease characteristics and extent, but also supply the ground truth for developing of computer-aided diagnosis (CAD) systems for PCa detection before definitive treatment. As manual cancer annotation is tedious and subjective, there have been a number of publications describing methods for automating the procedure via the analysis of digitized whole-slide images (WSIs). However, these studies have focused only on the analysis of WSIs stained with hematoxylin and eosin (H&E), even though there is additional information that could be obtained from immunohistochemical (IHC) staining. In this work, we propose a framework for automating the annotation of PCa that is based on automated colorimetric analysis of both H&E and IHC WSIs stained with a triple-antibody cocktail against high-molecular weight cytokeratin (HMWCK), p63, and α-methylacyl CoA racemase (AMACR). The analysis outputs were then used to train a regression model to estimate the distribution of cancerous epithelium within slides. The approach yielded an AUC of 0.951, sensitivity of 87.1%, and specificity of 90.7% as compared to slide-level annotations, and generalized well to cancers of all grades.

[What primary care physicians should know about new markers in prostate cancer]

The use of prostate-specific antigen as a diagnostic tool in the screening of prostate cancer is reflected in an increase in the incidence, an increase in diagnosis at initial stages, and an increase in radical therapies, even at the expense of over-treatment in some cases. It is known from the data collected in the literature that not every patient with high prostate-specific antigen needs a biopsy, and that not every patient diagnosed with prostate cancer needs treatment. With the new emerging prostate markers, we will try to improve the specificity of prostate-specific antigen in the grey area (4-10 ng/ml) should be improved. This should avoid unnecessary biopsies. The sensitivity in the detection of significant prostate cancer with low prostate-specific antigen should also be improved in an attempt to reduce the risk of over-treatment. On the other hand, prognostic biomarkers with genomic tests will help to choose the best therapeutic option for the patient.

Typing the atypical: Diagnostic issues and predictive markers in suspicious prostate lesions

As much as 5% of prostate biopsies yield findings equivocal for malignancy even for skilled uropathologist; such "grey zone" lesions have been addressed in many ways, although the acronym ASAP (atypical small acinar proliferation) is the most widely used when referring to an atypical focus suspicious, but not diagnostic, for malignancy. Since the introduction of this diagnostic category more than 20 years ago, debate has ensued over its histological characterization and clinical significance. Pathology reporting of ASAP, commonly based on strict morphological criteria and traditional immunohistochemical markers such as basal cell antibodies, has been improved by recent availability of novel immunohistochemical markers such as AMACR and ERG. Further pathological issues, such as the role of pre-analytical variables, number of tissue levels, interobserver variability, and association with prostatic intraepithelial neoplasia also play a role in the optimal assessment of ASAP. Apart from diagnostic issues, a major issue is ASAP predictive value for prostate cancer on repeat biopsy. Therefore, attempts have been made to identify clinical and biological parameters that could predict subsequent diagnosis of malignancy as well as define time and modality of repeat biopsy. Finally, pathological features of cancers detected after a previous ASAP diagnosis are compared with those diagnosed at first prostate biopsy.

Expression of proinflammatory cytokine interleukin-6 in tissue samples of human prostate obtained by needle biopsy

Interleukin-6 (IL-6) has been associated with the development of prostate cancer. The aim of the study was to clarify whether IL-6 expression in prostate tissue could be a useful marker in differentiation of prostate diseases in small foci by pathologist visual scoring. Archival paraffin-embedded specimens of benign prostate hyperplasia (BPH), high-grade prostatic intraepithelial neoplasia (PIN), prostatitis and prostate adenocarcinoma were studied by immunohistochemistry with a mouse monoclonal antibody IL-6 using the streptavidin-biotin method. Significantly, lower IL-6 immunoreactivity was observed in normal epithelial cells (p=0.000) and basal cells (p=0.000) in the samples of prostate adenocarcinoma in comparison to the samples with BPH, PIN and prostatitis. There was no significant difference in IL-6 expression in malignant and premalignant cells (p=0.814) as well as in stromal cells among the four diagnoses (p=0.22). IL-6 was expressed in normal epithelial cells, premalignant epithelial cells and malignant epithelial cells as well as in stromal cells. However, in our research IL-6 was of limited utility as a single marker for differential diagnosis of the prostate diseases in small foci needle biopsy by pathologist visual scoring. The standardization of immunohistochemical (IHC) staining protocol for IL-6 is required to determine IL-6 expression in order to avoid possible misinterpretation of the IHC results.

Molecular markers for prostate cancer in formalin-fixed paraffin-embedded tissues

Prostate cancer (PCa) is the most frequently diagnosed type of cancer in developed countries. The decisive method of diagnosis is based on the results of biopsies, morphologically evaluated to determine the presence or absence of cancer. Although this approach leads to a confident diagnosis in most cases, it can be improved by using the molecular markers present in the tissue. Both miRNAs and proteins are considered excellent candidates for biomarkers in formalin-fixed paraffin-embedded (FFPE) tissues, due to their stability over long periods of time. In the last few years, a concerted effort has been made to develop the necessary tools for their reliable measurement in these types of samples. Furthermore, the use of these kinds of markers may also help in establishing tumor grade and aggressiveness, as well as predicting the possible outcomes in each particular case for the different treatments available. This would aid clinicians in the decision-making process. In this review, we attempt to summarize and discuss the potential use of microRNA and protein profiles in FFPE tissue samples as markers to better predict PCa diagnosis, progression, and response to therapy.

A-methylacyl-CoA racemase (AMACR) and prostate-cancer risk: a meta-analysis of 4,385 participants

Background

Alpha-methylacyl-CoA racemase (AMACR) is a mitochondrial and peroxisomal enzyme that is overexpressed in prostate cancer. The aim of this study was to confirm and expand the findings that the PCa risk increased in men associated with AMACR expression across various geographic regions.

Methods

A systematic search of databases was carried out and other relevant articles were also identified. Then the meta-analyses were conducted according to the standard guidelines.

Results

A total of 22 studies with 4,385 participants were included on the basis of inclusion criteria. AMACR by IHC was significantly associated with increased diagnosis of PCa (OR = 76.08; 95% CI, 25.53–226.68; P<0.00001). Subgroup-analysis showed that findings didn’t substantially change when only Caucasians or Asians (OR = 51.23; 95% CI, 19.41–135.24; P<0.00001) were considered. Expression of AMACR by PCR in relation to PCa risk suggested that AMACR was associated with PCa (OR = 33.60; 95% CI, 4.67–241.77; P<0.00001). There was also no significant publication bias observed.

Conclusions

Our findings provide further evidences that the expression of AMACR contribute to PCa risk. AMACR protein overexpression was found in prostate cancers, low expression in any of the normal tissues or in benign prostatic tissue. AMACR is potentially an important prostate tumor marker.

Clinical implications of current developments in genitourinary pathology

CONTEXT

Several developments in genitourinary pathology are likely to change our understanding and management of some genitourinary cancers considerably.

OBJECTIVE

To review 5 stories in genitourinary pathology: (1) fusion in the ETS (E26) gene family in prostatic adenocarcinoma; (2) insulin-like growth factor II messenger RNA-binding protein 3 (IMP3), an important prognostic biomarker for kidney and bladder cancers; (3) translocation renal cell carcinoma; (4) UroVysion fluorescence in situ hybridization test in urine cytology for detection of bladder cancer; and (5) the use of triple immunostaining for diagnosis of prostate cancer.

DATA SOURCES

Literature review and authors' personal experiences.

CONCLUSIONS

Many scientific findings have contributed recently to the understanding of the natural pathogenesis and progression of genitourinary cancers. This translational research helps in diagnosing, predicting, and potentially, treating genitourinary cancers.

Monocarboxylate transporter 2 (MCT2) as putative biomarker in prostate cancer

BACKGROUND

Monocarboxylate transporter 2 (MCT2) is a transmembrane protein involved in the transport of monocarboxylates such as pyruvate and lactate. In a previous study we described overexpression of MCT2 in prostate carcinoma raising the hypothesis of using MCT2 as a possible biomarker in prostate cancer. With the present study we aimed to compare the pattern of expression of MCT2 and alpha-methylacyl-CoA racemase (AMACR), in prostate carcinoma, PIN lesions, non-neoplastic prostate tissue, and normal prostate and compare their sensitivity and specificity. Also, we wanted to evaluate the value of using MCT2 in combination with AMACR and the negative markers 34βE12 or p63 to detect prostate cancer.

METHODS

A total of 349 cases, including prostate carcinoma, non-neoplastic prostate tissue and PIN lesions, from radical prostatectomies were examined by immunohistochemistry for AMACR, MCT2, p63, and 34βE12, using tissue microarrays (TMAs). Normal prostate from radical cystoprostatectomy was also studied.

RESULTS

Our study revealed that MCT2, similarly to AMACR, was consistently expressed in prostate cancer regardless of the Gleason score. In combination with AMACR and p63 or 34βE12, MCT2 helped to improve the diagnosis of prostate carcinoma. Also, overexpression of MCT2 as well as AMACR in PIN lesions may indicate the involvement of these two proteins in prostate cancer initiation.

CONCLUSIONS

We provided evidence for the presence of MCT2 in prostate cancer, selectively labeling malignant glands. Importantly, assessment of MCT2 together with AMACR, along with the negative markers, highly increases the accuracy in prostate cancer diagnosis.

SULT2B1b sulfotransferase: induction by vitamin D receptor and reduced expression in prostate cancer

An elevated tumor tissue androgen level, which reactivates androgen receptor in recurrent prostate cancer, arises from the intratumor synthesis of 5α-dihydrotestosterone through use of the precursor steroid dehydroepiandrosterone (DHEA) and is fueled by the steroidogenic enzymes 3β-hydroxysteroid dehydrogenase (3β-HSD1), aldoketoreductase (AKR1C3), and steroid 5-alpha reductase, type 1 (SRD5A1) present in cancer tissue. Sulfotransferase 2B1b (SULT2B1b) (in short, SULT2B) is a prostate-expressed hydroxysteroid SULT that converts cholesterol, oxysterols, and DHEA to 3β-sulfates. DHEA metabolism involving sulfonation by SULT2B can potentially interfere with intraprostate androgen synthesis due to reduction of free DHEA pool and, thus, conversion of DHEA to androstenedione. Here we report that in prostatectomy specimens from treatment-naive patients, SULT2B expression is markedly reduced in malignant tissue (P < .001, Mann-Whitney U test) compared with robust expression in adjacent nonmalignant glands. SULT2B was detected in formalin-fixed specimens by immunohistochemistry on individual sections and tissue array. Immunoblotting of protein lysates of frozen cancer and matched benign tissue confirmed immunohistochemistry results. An in-house-developed rabbit polyclonal antibody against full-length human SULT2B was validated for specificity and used in the analyses. Ligand-activated vitamin D receptor induced the SULT2B1 promoter in vivo in mouse prostate and increased SULT2B mRNA and protein levels in vitro in prostate cancer cells. A vitamin D receptor/retinoid X receptor-α-bound DNA element (with a DR7 motif) mediated induction of the transfected SULT2B1 promoter in calcitriol-treated cells. SULT2B knockdown caused an increased proliferation rate of prostate cancer cells upon stimulation by DHEA. These results suggest that the tumor tissue SULT2B level may partly control prostate cancer growth, and its induction in a therapeutic setting may inhibit disease progression.

The diagnostic utility of the minimal carcinoma triple stain in breast carcinomas

Pathologists are expected to accurately diagnose increasingly smaller breast carcinomas. Correct classification (ie, lobular vs ductal or in situ vs invasive) directly affects subsequent management, especially when the focus is near a surgical margin or present in a needle core biopsy and is further challenging if the lesion is morphologically ambiguous. We assessed the diagnostic utility of a multiplex, trichromogen immunostain of 3 commonly employed antibodies (CK7, p63, and E-cadherin) developed in our laboratory to evaluate these small lesions. Of the 147 specimens containing minimal (defined as ≤3 mm in size) invasive carcinoma, 81 also contained in situ carcinoma. In each case, the Minimal Carcinoma Triple Stain was prepared with a parallel H&E-stained slide. Observations of staining characteristics in the focus of interest were recorded. The Minimal Carcinoma Triple Stain was diagnostically useful in all but 1 case. In a case of invasive lobular carcinoma in an excisional biopsy, the Minimal Carcinoma Triple Stain stained only the surrounding breast tissue (appropriately) and not the focus of interest. Also, a subset of 29 of 81 excisional biopsies had minimal invasive carcinoma located 2 mm or less from the inked surgical margin, in which in all cases the Minimal Carcinoma Triple Stain was fully interpretable despite morphologic distortion due to concomitant cautery artifact and tissue disruption in some cases. The Minimal Carcinoma Triple Stain offers an accurate and tissue-conserving method to diagnose small, morphologically problematic foci of breast carcinoma while ideally leaving more tissue for additional adjunctive studies.

Use of immunohistochemistry in routine workup of prostate needle biopsies: a tertiary academic institution experience

CONTEXT

Diagnostic use of immunohistochemistry has been extensively studied in prostate needle biopsy, but its use in routine practice and the quality assurance and associated cost have not been previously addressed.

OBJECTIVE

To examine the routine use of immunohistochemistry in prostate biopsies in a tertiary academic institution.

DESIGN

We reviewed reports of 748 consecutive prostate biopsies and we evaluated the turnaround times, the final diagnosis on individual specimens, the intradepartmental consultation rates, and the associated costs.

RESULTS

Immunohistochemistry evaluation was required for 39.4% of biopsies and 12% of blocks (average 1.8 blocks/case). The biopsies with immunohistochemistry were signed out 1.7 workdays later (8.6 versus 6.9 days). The diagnostic breakdown for individual blocks evaluated by immunohistochemistry was Cancer 47.7%; Atypical, Suspicious 10.8%; Small Atypical Glands Adjacent to High-Grade Prostatic Intraepithelial Neoplasia 6.9%; High-Grade Prostatic Intraepithelial Neoplasia 12.4%; and Benign 22.2%. Diagnoses of Cancer or Atypical, Suspicious (Atypical, Suspicious + Small Atypical Glands Adjacent to High-Grade Prostatic Intraepithelial Neoplasia) were rendered in 65.4% of individual blocks assessed by immunohistochemistry. Immunohistochemistry aided in establishing limited cancer (≤10% of core) in 69.3% of cases and in 74% of single-core-positive biopsies. Departmental consultation was performed in 18.3% of biopsies and immunohistochemistry was used in 68% of these cases. Both immunohistochemistry and consultation were performed in 55.8% of Atypical, Suspicious cases. The average immunohistochemistry cost per biopsy was $22.34 and the estimated annual cost for prostate biopsy immunohistochemistry in our laboratory was $33 420.64.

CONCLUSIONS

Immunohistochemistry is frequently used in our prostate biopsy practice to establish or confirm a limited Cancer diagnosis, to better resolve diagnostic ambiguity, or for quality assurance. The data provided herein can be used for comparisons with other prostate biopsy practices.

Comparative analysis of three- and two-antibody cocktails to AMACR and basal cell markers for the immunohistochemical diagnosis of prostate carcinoma

Background

Immunohistochemistry using antibody cocktails against basal cell specific and cancer-associated markers is important in the diagnosis of prostate carcinoma in needle biopsies. We compared the usefulness for detecting prostate carcinoma of a three-marker cocktail of antibodies to α-methylacyl-CoA racemase (AMACR), p63 and cytokeratin (CK) 5 with a traditional two-marker cocktail of AMACR and p63.

Methods

Sixty-six prostate needle biopsies were analysed prospectively. Serial sections were immunostained with the two- and three- antibody cocktails. Blinded slides were assessed individually by two pathologists and sensitivity, specificity and kappa statistics were calculated.

Results

Both antibody cocktails contributed to the detection of prostate carcinoma in needle biopsies. There was an acceptable level of agreement between the pathologists for both the cocktails. Sensitivity was similar for one pathologist comparing both the cocktails (76.4% and 75.7%), but was slightly lower comparing the three-antibody with the two-antibody cocktail for the other pathologist (66.6% vs. 77.4%, respectively). Higher specificity values of 90.3% were achieved by both pathologists using three-antibody as compared with two-antibody cocktails (68.7% and 71.8%).

Conclusions

Antibody cocktails are important in diagnosing prostate carcinoma in needle biopsies. Adding an extra basal cell marker to the traditional two-antibody cocktail improves the specificity of detecting prostate carcinoma in limited needle biopsy material, and should be considered for routine diagnostic use.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2492231327330327

Correlation of p63 Protein Expression With Histological Grade of Meningiomas

Prediction of tumor behavior in meningiomas based on morphological features alone remains difficult. Several immunohistochemical biomarkers have been proposed to assist conventional methods. However, no single immunohistochemical marker can unequivocally discriminate between benign and aggressive meningiomas. There is only 1 study available in the literature that correlates p63 expression with overall histological grade of the meningioma. The present study is undertaken to assess the correlation between p63 expression and histological grade of meningiomas. For this purpose, the authors studied and analyzed the immunohistochemical expression of p63 in 85 cases of meningioma, including WHO grade I (63), grade II (11), and grade III (11) cases. Correlation between histological grade and nuclear immunoreactivity to p63 antibody was performed. Furthermore, expression of p63 protein was correlated with short clinical follow-up and Ki-67 proliferation index. Among 85 patients analyzed, there were 61 women (71.7 %) and 24 men (28.2%) between 7 and 75 years old. Expression of p63 protein was found in 34.9% of grade I cases, but in grade II and III, 63.6% of cases each were immunoreactive. Correlation between histological grade and p63 immunoreactivity was significant ( P = .02). p63-positive grade I meningiomas did not show elevated Ki-67 index. The present study contradicts earlier reports because there are a considerable number of grade I meningiomas that express p63. Although p63 expression is significantly associated with higher histological grade of meningiomas, it may not be considered as a sole biomarker to assess aggressive behavior of the tumor.

Diagnostic utility of P504S/p63 cocktail, prostate-specific antigen, and prostatic acid phosphatase in verifying prostatic carcinoma involvement in seminal vesicles: a study of 57 cases of radical prostatectomy specimens of pathologic stage pT3b

CONTEXT

Seminal vesicle invasion by prostatic carcinoma is directly associated with tumor staging; verification is challenging when the tumor demonstrates cribriform or papillary growth patterns or there are back-to-back small-gland proliferations. P504S is overexpressed in prostatic carcinoma and high-grade prostatic intraepithelial neoplasia with cytoplasmic immunoreactivity. p63 has positive immunoreactivity in basal cell nuclei of benign prostatic glands. Many researchers use a combination of these antibodies and their different colors.

OBJECTIVE

To evaluate the usefulness of a single-color P504S/p63 cocktail immunostain in verifying prostatic carcinoma within the seminal vesicle.

DESIGN

Sections from 57 radical prostatectomy specimens of pathologic stage pT3b that contain seminal vesicle with prostatic carcinoma involvement were immunostained with primary antibodies against prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) and a cocktail of antibodies against P504S and p63.

RESULTS

Prostatic carcinoma cells from all 57 cases were diffusely positive for P504S, PSA, and PAP with cytoplasmic staining and no p63 nuclear staining. Seminal vesicle epithelium from all 57 cases was negative for all 3 markers with distinct p63 nuclear staining of the basal cells. Benign prostatic tissue was positive for PSA and PAP, as well as for p63, but negative for P504S.

CONCLUSIONS

The P504S/p63 one-color cocktail is a practical and cost-effective stain to differentiate prostatic carcinoma that involves the seminal vesicle from seminal vesicle epithelium. It is superior to PSA or PAP when sections contain both seminal vesicle and benign glands because PSA and PAP cannot distinguish benign from malignant glands.

Computer-aided detection of prostate cancer on tissue sections

We report an automated computer technique for detection of prostate cancer in prostate tissue sections processed with immunohistochemistry. Two sets of color optical images were acquired from prostate tissue sections stained with a double-chromogen triple-antibody cocktail combining alpha-methylacyl-CoA racemase, p63, and high-molecular-weight cytokeratin. The first set of images consisted of 20 training images (10 malignant) used for developing the computer technique and 15 test images (7 malignant) used for testing and optimizing the technique. The second set of images consisted of 299 images (114 malignant) used for evaluation of the performance of the computer technique. The computer technique identified image segments of alpha-methylacyl-CoA racemase-labeled malignant epithelial cells (red), p63, and high-molecular-weight cytokeratin-labeled benign basal cells (brown), and secretory and stromal cells (blue) for identifying prostate cancer automatically. The sensitivity and specificity of the computer technique were 94% (16/17) and 94% (17/18), respectively, on the first (training and test) set of images, and 88% (79/90) and 97% (136/140), respectively, on the second (validation) set of images. If high-grade prostatic intraepithelial neoplasia, which is a precursor of cancer, and atypical cases were included, the sensitivity and specificity were 85% (97/114) and 89% (165/185), respectively. These results show that the novel automated computer technique can accurately identify prostatic adenocarcinoma in the triple-antibody cocktail-stained prostate sections.

Evaluation of routine application of P504S, 34betaE12 and p63 immunostaining on 250 prostate needle biopsy specimens

BACKGROUND

We aimed to determine whether a standard P504S, 34betaE12 and p63 immunostaining of prostate core needle biopsy specimens can optimize diagnostic accuracy of conventional staining methods.

MATERIALS AND METHODS

The staining properties of all three antibodies were evaluated on 250 prostate biopsies formerly diagnosed as benign.

RESULTS

Lack of basal cell staining in more than three glands for 34betaE12 and p63 occurred in 41 (27.5%) and 9 (6%) respective cases from the General Hospital pool. Respective figures from the Uropathology department specimens were 18 (18%) for 34betaE12 and 8 (8%) for p63. With the aid of P504S positivity, a case of prostate cancer as well as another of atypical small acinar proliferation was discovered.

CONCLUSION

Despite its potential for important aid in accurate diagnosis, standard application of immunohistochemistry in prostate biopsy is not justified and should be reserved for equivocal cases where conventional pathology fails to be conclusive.

Usefulness of cytokeratin 5/6 and AMACR applied as double sequential immunostains for diagnostic assessment of problematic prostate specimens

We evaluated the usefulness of double immunohistochemical staining for cytokeratin (CK)5/6 and alpha-methylacyl coenzyme A racemase (AMACR) applied sequentially on 1 slide by assessing 223 foci in 110 consecutive prostate specimens. Double-chromogen reaction was used to visualize the antibodies: brown for CK5/6 and red for AMACR. Staining was scored as diffuse, focal, or negative. To establish the diagnosis, CK5/6 and AMACR were correlated with the morphologic features. All cancers lacked CK5/6 staining (100% specificity). AMACR showed diffuse or focal positivity in cancer, high-grade prostatic intraepithelial neoplasia, and atypia in 96.8% (120/124), 85% (22/26), and 80% (16/20) of cases, respectively. In atypical cases, diagnosis was because of non-immunohistochemical staining reasons in 80% of cases. In adenosis (n = 14), AMACR was diffusely positive in 4 cases (29%). Double immunohistochemical staining for CK5/6 and AMACR is a simple assay to perform and may be used as an alternative to antibody cocktails for routine evaluation of problematic prostate specimens.

The role of tissue microarrays in prostate cancer biomarker discovery

Tissue microarrays (TMAs) offer the potential to rapidly translate genomics and basic science research findings to practical clinical application. This is particularly true in the field of cancer biomarker research, where TMAs can be used for candidate biomarker validation and association with patient clinical, pathologic, and outcomes parameters. In this review, we examine the effect of TMA use on prostate cancer biomarker research, focusing on the types of TMAs that have been used, and the biomarkers that have been examined. The results demonstrate that TMAs have been very effective in screening candidate biomarkers for subsequent, extended evaluation in large patient populations. In addition, the use of TMAs in multiple biomarker series allows for the statistical analysis of sets of biomarkers as diagnostic or prognostic tests. The processes used here can be applied to any tumor type to improve patient diagnosis, prognosis, and treatment response prediction.