Diagnostic utility of a p63/alpha-methyl-CoA-racemase (p504s) cocktail in atypical foci in the prostate

Emerin mislocalization during chromatin bridge resolution can drive prostate cancer cell invasiveness in a collagen-rich microenvironment

Micronuclei (MN) can form through many mechanisms, including the breakage of aberrant cytokinetic chromatin bridges. The frequent observation of MN in tumors suggests that they might not merely be passive elements but could instead play active roles in tumor progression. Here, we propose a mechanism through which the presence of micronuclei could induce specific phenotypic and functional changes in cells and increase the invasive potential of cancer cells. Through the integration of diverse in vitro imaging and molecular techniques supported by clinical samples from patients with prostate cancer (PCa) defined as high-risk by the D'Amico classification, we demonstrate that the resolution of chromosome bridges can result in the accumulation of Emerin and the formation of Emerin-rich MN. These structures are negative for Lamin A/C and positive for the Lamin-B receptor and Sec61β. MN can act as a protein sinks and result in the pauperization of Emerin from the nuclear envelope. The Emerin mislocalization phenotype is associated with a molecular signature that is correlated with a poor prognosis in PCa patients and is enriched in metastatic samples. Emerin mislocalization corresponds with increases in the migratory and invasive potential of tumor cells, especially in a collagen-rich microenvironment. Our study demonstrates that the mislocalization of Emerin to MN results in increased cell invasiveness, thereby worsening patient prognosis.

Clinical-Grade Validation of an Autofluorescence Virtual Staining System With Human Experts and a Deep Learning System for Prostate Cancer

The tissue diagnosis of adenocarcinoma and intraductal carcinoma of the prostate includes Gleason grading of tumor morphology on the hematoxylin and eosin stain and immunohistochemistry markers on the prostatic intraepithelial neoplasia-4 stain (CK5/6, P63, and AMACR). In this work, we create an automated system for producing both virtual hematoxylin and eosin and prostatic intraepithelial neoplasia-4 immunohistochemistry stains from unstained prostate tissue using a high-throughput hyperspectral fluorescence microscope and artificial intelligence and machine learning. We demonstrate that the virtual stainer models can produce high-quality images suitable for diagnosis by genitourinary pathologists. Specifically, we validate our system through extensive human review and computational analysis, using a previously validated Gleason scoring model, and an expert panel, on a large data set of test slides. This study extends our previous work on virtual staining from autofluorescence, demonstrates the clinical utility of this technology for prostate cancer, and exemplifies a rigorous standard of qualitative and quantitative evaluation for digital pathology.

AMACR Expression is a Potential Diagnostic Marker in Apocrine Lesions of Breast, and is Associated with High Histologic Grade and Lymph Node Metastases in Some Invasive Apocrine Breast Cancers

BACKGROUND

Carcinoma with apocrine differentiation (AC) is a subtype of breast carcinoma with apocrine features in >90% of the tumor. Molecular studies demonstrate AC has high expression of androgen receptor (AR) mRNA. Pure AC lack estrogen receptor (ER), progesterone receptor (PR), and express AR, with variable human epidermal growth factor 2 (HER2) status. Currently, in triple negative AC, no targetable therapies or specific diagnostic markers exist.

MATERIALS AND METHODS

α-Methylacyl CoA racemase (AMACR) expression was investigated as a marker of apocrine differentiation using a single-plex immunoperoxidase stain, and a novel AMACR/p63 dual stain in a subset of cases, across 1) benign apocrine lesions (apocrine metaplasia, adenosis) 2) apocrine DCIS (ADCIS), 3) AC/ invasive ductal carcinoma (IDC) with apocrine features, 4) non-apocrine triple negative breast cancer (TNBC) and 5) IDC, no special type. A sub-set of cases were evaluated by tissue microarray.

RESULTS

AMACR expression was increased in both AC and ADCIS, with minimal expression in benign breast tissue, TNBC and IDC, NST cases. In invasive cases, those with positive AMACR (>5% positivity) were significantly associated with higher histologic grade (P = .006), initial N stage (chi squared 0.044), and lack of ER or PR expression (both P < .001), with no correlation with overall survival. Analysis of TCGA breast cancer datasets revealed AMACR expression was significantly higher in molecularly defined apocrine carcinomas relative to basal and luminal subtypes. Moreover, high AMACR expression predicted worse relapse-free and distant-metastasis free survival, among both ER-/PR-/Her2- and ER-/PR-/Her2+ breast cancer cohorts (log-rank P = .081 and .00011, respectively).

CONCLUSION

AMACR represents a promising diagnostic and prognostic marker in apocrine breast lesions. Further study is needed to determine the biologic and clinical significance of this protein in AC.

Carcinoma of Unknown Primary Origin: Application of Immunohistochemistry With Emphasis to Different Cytokeratin 7 and 20 Staining Patterns

BACKGROUND

Although the primary origin of some carcinomas may be obscure to clinicians, its identification is crucial as it affects prognosis and treatment (especially novel targeted therapies). Immunohistochemistry (IHC) may be helpful in identifying the primary origin of carcinomas. This retrospective survey aimed to evaluate the frequency and accuracy of each IHC marker used to determine the origin of carcinomas.

METHODS

The review of pathology department archives revealed 307 cases of cancer of unknown primary origin (CUP) between 2015 and 2020, which were accessible in the department archives. Demographic information, site of biopsy, clinical and pathologic diagnoses, and IHC results of the patients were collected.

RESULTS

The patients included 157 (51.15%) men and 150 (48.85%) women. The age of the patients ranged from 14 to 92 years, including 106 (34.5%) expired cases. In 27% of cases, the primary origin of carcinoma remained unknown. The agreement between pathologic and clinical diagnoses was 59%. The most common pattern of cytokeratin (CK) expression in CUP was CK7+/CK20- (55.3%), followed by CK7-/CK20- (19%), CK7+/CK20+ (15%), and CK7-/CK20+ (10.7%), respectively.

CONCLUSION

The IHC analysis may improve the diagnosis of CUPs. However, the origin of some cases remains unknown despite an IHC analysis, thereby necessitating the use of more diagnostic procedures or gene expression studies for reaching a definitive diagnosis.

Radiomics-Based Machine Learning Models for Predicting P504s/P63 Immunohistochemical Expression: A Noninvasive Diagnostic Tool for Prostate Cancer

Objective

To develop and validate a noninvasive radiomic-based machine learning (ML) model to identify P504s/P63 status and further achieve the diagnosis of prostate cancer (PCa).

Methods

A retrospective dataset of patients with preoperative prostate MRI examination and P504s/P63 pathological immunohistochemical results between June 2016 and February 2021 was conducted. As indicated by P504s/P63 expression, the patients were divided into label 0 (atypical prostatic hyperplasia), label 1 (benign prostatic hyperplasia, BPH) and label 2 (PCa) groups. This study employed T2WI, DWI and ADC sequences to assess prostate diseases and manually segmented regions of interest (ROIs) with Artificial Intelligence Kit software for radiomics feature acquisition. Feature dimensionality reduction and selection were performed by using a mutual information algorithm. Based on screened features, P504s/P63 prediction models were established by random forest (RF), gradient boosting decision tree (GBDT), logistic regression (LR), adaptive boosting (AdaBoost) and k-nearest neighbor (KNN) algorithms. The performance was evaluated by the area under the ROC curve (AUC) and accuracy.

Results

A total of 315 patients were enrolled. Among the 851 radiomic features, the 32 top features were derived from T2WI, in which the gray-level run length matrix (GLRLM) and gray-level cooccurrence matrix (GLCM) features accounted for the largest proportion. Among the five models, the RF algorithm performed best in general evaluations (microaverage AUC=0.920, macroaverage AUC=0.870) and provided the most accurate result in further sublabel prediction (the accuracies of label 0, 1, and 2 were 0.831, 0.831, and 0.932, respectively). In comparative sequence analyses, T2WI was the best single-sequence candidate (microaverage AUC=0.94 and macroaverage AUC=0.78). The merged datasets of T2WI, DWI, and ADC yielded optimal AUCs (microaverage AUC=0.930 and macroaverage AUC=0.900).

Conclusions

The radiomic-based RF classifier has the potential to be used to evaluate the presurgical P504s/P63 status and further diagnose PCa noninvasively and accurately.

Immunohistochemistry for Prostate Biopsy-Impact on Histological Prostate Cancer Diagnoses and Clinical Decision Making

BACKGROUND

To test the value of immunohistochemistry (IHC) staining in prostate biopsies for changes in biopsy results and its impact on treatment decision-making.

METHODS

Between January 2017-June 2020, all patients undergoing prostate biopsies were identified and evaluated regarding additional IHC staining for diagnostic purpose. Final pathologic results after radical prostatectomy (RP) were analyzed regarding the effect of IHC at biopsy.

RESULTS

Of 606 biopsies, 350 (58.7%) received additional IHC staining. Of those, prostate cancer (PCa) was found in 208 patients (59.4%); while in 142 patients (40.6%), PCa could be ruled out through IHC. IHC patients harbored significantly more often Gleason 6 in biopsy (p < 0.01) and less suspicious baseline characteristics than patients without IHC. Of 185 patients with positive IHC and PCa detection, IHC led to a change in biopsy results in 81 (43.8%) patients. Of these patients with changes in biopsy results due to IHC, 42 (51.9%) underwent RP with 59.5% harboring ≥pT3 and/or Gleason 7-10.

CONCLUSIONS

Patients with IHC stains had less suspicious characteristics than patients without IHC. Moreover, in patients with positive IHC and PCa detection, a change in biopsy results was observed in >40%. Patients with changes in biopsy results partly underwent RP, in which 60% harbored significant PCa.

Performance comparison of anti-p504s (SP116) Rabbit Monoclonal Primary Antibody vs. Monoclonal Rabbit Anti-Human AMACR clone 13H4 when duplexed with VENTANA Basal Cell Cocktail (34βE12+p63) as a diagnostic aid for prostatic adenocarcinoma using immunohistochemistry

Alpha-methylacyl-coenzyme A-racemase (AMACR), also known as p504s, is overexpressed in prostatic adenocarcinoma and is frequently used in combination with basal cell markers to aid in diagnosing difficult prostate adenocarcinoma cases. In this retrospective method comparison study, we examined the sensitivity and specificity of the ready-to-use anti-p504s (SP116) Rabbit Monoclonal Primary Antibody compared to the monoclonal rabbit anti-human AMACR clone 13H4 in prostatic adenocarcinoma samples. De-identified prostatic adenocarcinoma tissue samples were stained with either the SP116 or 13H4 antibody clone in combination with the VENTANA Basal Cell Cocktail (34βE12+p63) and scored as positive or negative for prostatic adenocarcinoma. The scoring pathologist was blinded to the known historical diagnosis of each sample. The scoring pathologist correctly diagnosed each sample regardless of which p504s clone was used. Both assays using either clone were 100% concordant in their sensitivity and specificity. This study demonstrates that the ready-to-use anti-p504s (SP116) Rabbit Monoclonal Primary Antibody is equivalent to clone 13H4 concentrate when used according to package insert instructions in combination with the VENTANA Basal Cell Cocktail (34βE12+p63) to aid pathologists in the diagnosis of prostatic adenocarcinoma.

Increased oxidative stress and cancer biomarkers in the ventral prostate of older rats submitted to maternal malnutrition

The concept of Developmental Origins of Health and Disease (DOHaD) states that exposure to malnutrition early in life increase the incidence of non-communicable chronic diseases throughout the lifespan. In this study, a reduction in serum testosterone and an increase in estrogen levels were shown in older rats born to protein malnourished dams (6% protein in the diet) during gestation and lactation. Intraprostatic levels of reduced glutathione were decreased, while tissue expression of glutathione S-transferase pi and sulfiredoxin-1 were increased in these animals. Strong immunostaining for alfametilacil CoA racemase (AMACR), vascular endothelial growth factor-A (VEGF-A), and aquaporin-1 (AQP1) was also observed. In silico analysis confirmed commonly deregulated proteins in the ventral prostate of old rats and patients with prostate cancer. In conclusion, the increase in oxidative stress associated with an imbalance of sex hormones may contribute to prostate carcinogenesis in offspring, highlighting early-life malnutrition as a key risk factor for this malignance.

Diagnostic utility of triple antibody (AMACR, HMWCK and P63) stain in prostate neoplasm

Aims and Objective:

In recent period, basal cell markers high molecular weight cytokeratin (HMWCK), P63 and prostate biomarker AMACR have been used as adjuvant to morphology in diagnostically challenging cases with a very high sensitivity and specificity.

Materials and Methods:

In this prospective study, total of 80 cases including 40 cases of malignant lesions and 40 cases of benign lesions of the prostate were taken. Tumor grade was determined according to Gleason's grading system. AMACR, HMWCK, P63 expressions were determined by immunohistochemical staining.

Results:

This study showed AMACR had a sensitivity of 90%, specificity of 100%. AMACR was not expressed in any of the 40 cases of benign lesions of the prostate while in malignant lesions of prostate it was expressed in 36 of 40 (90%) cases; 15 of 16 (93%) of well-differentiated carcinoma were positive for AMACR expression; 17 of 19 (89.47%) moderately differentiated and 4 of 5 (80%) cases of poorly differentiated tumors were positive for AMACR. There was statistically significant difference in expression of AMACR between benign and malignant lesions of the prostate (P = 0.001). In benign lesions, HMWCK and P63 were expressed in all the 40 (100%) cases, while in malignant lesions of prostate it was not expressed in any of the (0%) case. AMACR expression was not seen in any of the benign lesion. Out of 40 malignant cases, 4 cases were negative for AMACR, HMWCK and P63, 36 cases were positive only for AMACR, but no case was positive for HMWCK and P63.

Conclusions:

As an adjunct to biopsy, AMACR, HMWCK and P63 have potential for combating diagnostically challenging cases.

RNA-based markers in biopsy cores with atypical small acinar proliferation: Predictive effect of T2E fusion positivity and MMP-2 upregulation for a subsequent prostate cancer diagnosis

BACKGROUND

Atypical small acinar proliferation (ASAP) is a precursor lesion of prostate cancer (PC), and PC develops from this suspicious focus or an unsampled malignant gland nearby. However, PC-related molecular alterations that could guide the timing of repeat biopsies and help monitor PC risk in ASAP-diagnosed patients have not been investigated. The purpose of this study was to first investigate the expression of seven different PC-related RNAs that included serine 2 (TMPRSS2): erythroblastosis virus E26 oncogene homolog (ERG) gene (TMPRSS2-ERG, T2E) fusion, alpha-methylacyl-CoA racemase (AMACR), kallikrein related peptidase 3 (KLK3), androgen receptor (AR), prostate cancer specific antigen 3 (PCA3), and matrix metalloproteinases (MMP)-2 and 9.

METHODS

PC-related RNAs were evaluated using a real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) system in pathologically ASAP-diagnosed prostate biopsy cores from 55 patients presenting with a normal digital rectal examination and a PSA level of 4-10 ng/mL.

RESULTS

We detected that positive T2E fusion status (P = 0.013) and the expression of AMACR (P = 0.016), AR (P = 0.016) and MMP-2 (P = 0.013) were independently and significantly associated with PC risk in ASAP patients. There were also several statistically significant correlations between expression levels. Additionally, we demonstrated that T2E fusion positive ASAP patients with higher MMP-2 expression were more likely to be diagnosed with PC at a subsequent biopsy during the follow-up period (P = 0.003).

CONCLUSIONS

Although, more clinical validations are needed for the stratification of PC risk in ASAP-diagnosed biopsy cores, our current results indicate that the coexistence of T2E fusion positivity with MMP-2 upregulation may help clinicians adjust their biopsy timetable and/or assessment of PC risk in ASAP-diagnosed patients with a PSA level of 4-10 ng/mL.

Immunohistochemical Pitfalls in Genitourinary Pathology: 2018 Update

Immunohistochemistry may be a very useful adjunct to morphologic diagnosis in many areas of surgical pathology, including genitourinary pathology. In this review, we address common diagnostic dilemmas where immunophenotypic analysis may be utilized and we highlight pitfalls specific to each scenario. For prostate, we review the diagnosis of limited prostatic adenocarcinoma and the distinction of high-grade prostatic adenocarcinoma from urothelial carcinoma. We also cover markers of urothelial lineage in the diagnosis of metastatic carcinoma of unknown primary site. In the kidney, distinction of poorly differentiated renal cell carcinoma from urothelial carcinoma and epithelioid angiomyolipoma, adjuncts to the recognition of hereditary renal neoplasia, and the diagnosis of metastatic renal cell carcinoma are discussed. Finally, for testis we address distinction of germ cell tumors from sex cord-stromal tumors, as well as the diagnosis of metastatic germ cell tumors.

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.

Evaluation of Combined Quantification of PCA3 and AMACR Gene Expression for Molecular Diagnosis of Prostate Cancer in Moroccan Patients by RT-qPCR

Prostate cancer (PCa) remains one of the most widespread and perplexing of all human malignancies. Assessment of gene expression is thought to have an important impact on cancer diagnosis, prognosis and therapeutic decisions. In this context, we explored combined expression of PCa related target genes AMACR and PCA3 in 126 formalin fixed paraffin embedded prostate tissues (FFPE) from Moroccan patients, using quantitative real time reverse transcription-PCR (RT-qPCR). This quantification required data normalization accomplished using stably expressed reference genes (RGs). A panel of twelve RG was assessed, data being analyzed using GenEx V6 based on geNorm, NormFinder and statistical methods. Accordingly, the hnRNP A1 gene was identified and selected as the most stably expressed RG for reliable and accurate gene expression quantification in prostate tissues. The ratios of both PCA3 and AMACR gene expression relative to that of the hnRNP A1 gene were calculated and the performance of each target gene for PCa diagnosis was evaluated using receiver-operating characteristics. PCA3 and AMACR mRNA quantification based on RT-qPCR may prove useful in PCa diagnosis. Of particular interesting, combining PCA3 and AMACR quantification improved PCa prediction by increasing sensitivity with retention of good specificity.

Atypical Adenomatous Hyperplasia (Adenosis) of the Prostate: DNA Ploidy Analysis and Immunophenotype

Atypical adenomatous hyperplasia (AAH) of the prostate is a microscopic proliferation of small acini that may be mistaken for adenocarcinoma. Although some data suggest that AAH is associated with adenocarcinoma arising in the transition zone, the clinical significance of this lesion is uncertain. Therefore we studied the DNA ploidy pattern and immunophenotype of AAH as compared with nodular hyperplasia and well-differentiated adenocarcinoma in 23 formalin-fixed, paraffin-embedded, whole-mounted retropubic prostatectomies. Representative sections were immunostained for keratin 34β-E12, chromogranin, bcl-2, c-erbB-2, ki67-MIB1, and factor VIII (microvessel density). DNA ploidy was determined by image analysis and Feul gen-stained sections. There were rare scattered immunoreactive cells for chromogranin, bcl-2, and c-erbB-2 in nodular hyperplasia and AAH (mainly in the basal cell compartment) and in carcinoma. The ki67-MIB1 labeling index was different between nodular hyperplasia and AAH (p<0.001) and carcinoma (p=0.003) but not between AAH and carcinoma (p=0.203). Microvessel density was different between AAH and carcinoma (p=0.001) but not between nodular hyperplasia and AAH (p=0.105) or carcinoma (p=0.0820). All foci of nodular hyperplasia, AAH, and carcinoma were diploid. Ploidy status and our selected panel of antibodies did not discriminate among these 3 entities reliably.

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

Is atypical adenomatous hyperplasia of the prostate a precursor lesion?

BACKGROUND

Alpha-methylacyl-CoA racemase (AMACR) is highly expressed in prostatic adenocarcinoma. The precursor nature of atypical adenomatous hyperplasia (AAH) is uncertain.

METHODS

One hundred twenty-one AAH foci from 101 patients who underwent transurethral prostatic resection or prostatectomy were immunohistochemically analyzed for AMACR, high molecular weight cytokeratin 34βE12, and p63 expression by a triple antibody (PIN4) cocktail stain.

RESULTS

Sixty-eight foci (56%) of AAH showed no AMACR immunostaining. Fourteen cases (12%) showed weak AMACR immunoreactivity in 1-9% of lesional cells. Sixteen cases (13%) showed strong immunopositivity for AMACR in >50% of lesional cells. AMACR expression in AAH was significantly higher in cases in which coexisting PCA was present, compared with its expression in AAH foci without coexisting PCA (P = 0.03). Strong diffuse AMACR positivity in over 50% of lesional cells was seen almost exclusively in AAH foci with coexisting PCA (P = 0.002). AMACR expression in AAH showed no correlation with patient age (P = 0.38), specimen type (P = 0.35), prostate weight (P = 0.80), zonal location (P = 0.50), distance to cancer (P = 0.28), Gleason score (P = 0.06), or pathologic stage (P = 0.23). Increased AMACR expression showed a negative correlation with the size of AAH foci (P = 0.03). All AAH lesions showed fragmented basal cell layers, highlighted by p63 and high molecular weight cytokeratin staining.

CONCLUSIONS

A significant percentage of AAH cases show stronger and more extensive AMACR expression when associated with prostatic adenocarcinoma, as compared to AAH foci found without coexisting prostate cancer. Our data provide additional evidence linking AAH to prostatic adenocarcinoma.

The use of immunohistochemistry for diagnosis of prostate cancer

PURPOSE

Atypical glands (ASAP) are diagnosed in 5.0% of prostate biopsies, and cancer identification in a rebiopsy is higher than 40.0%. The use of antibodies to mark basal cells is currently a common practice, in order to avoid rebiopsies. There has been no reported study that has reviewed characteristics of radical prostatectomies (RPs) when immunohistochemistry (IHC) was necessary for definitive diagnosis.

MATERIALS AND METHODS

Out of 4127 biopsies examined from 2004 to 2008, 144 (3.5%) were diagnosed with ASAP. IHC was performed using antibody anti-34ΒE12 and p63. The results of surgical specimens of 27 patients treated by RP after the diagnosis of prostate cancer (PC) was made using IHC (Group 1) were compared with 1040 patients where IHC was not necessary (Group 2).

RESULTS

IHC helped to diagnose PC in 103 patients (71.5%). Twenty-seven (26.2%) underwent RP. In Group 1, two (7.4%) adenocarcinomas were insignificant versus 29 (2.9%) for Group 2. Patients from Group 1 were younger (p = 0.039), had lower Gleason scores (GS) (p < 0.001), lower percentage of Gleason pattern 4 (p < 0.001), and smaller tumors (p < 0.001).

CONCLUSION

The use of IHC did not lead to diagnosis of insignificant tumors as illustrated by absence of differences in pathological stage or positive surgical margins in men submitted to RP. Therefore, our results suggest that this modality should be routinely used for a borderline biopsy and ASAP cases.

α-Methylacyl-CoA racemase spliced variants and their expression in normal and malignant prostate tissues

OBJECTIVES

To evaluate the possibility of using α-methylacyl-CoA racemase (AMACR) variants to improve the specificity of prostate cancer (CaP) detection. AMACR has been used as a diagnostic biomarker for CaP and is now a standard biomarker for needle biopsy specimens with ambiguous lesions.

METHODS

We used in silico analysis and molecular cloning to discover new AMACR variants and quantitative reverse transcription-polymerase chain reaction (RT-PCR) to measure the transcript levels of AMACR and its variants in 4 prostate cell lines and in 23 pairs of CaP and adjacent normal tissue.

RESULTS

We found 4 novel variants, IAs, IBL, IBLd, and IBLi. Transcript levels of most AMACR variants were significantly upregulated in CaP compared with its adjacent normal counterparts. A variants, the functional variants based on bioinformatic analysis, showed levels of transcript expression in CaP in this order: IA≫IAd=IIA≫IIAs>IAs. In contrast, the expression of the B variants, which appear to be nonfunctional due to the absence of exon 3, was lower than that of the A variants. IB was the most abundant form of B variant; and expression of IIB was negligible. More important, the difference between levels of variant IA, IAd, IIA, IIAs, IB, and IBLi in CaP and normal tissue was significantly higher than the difference in levels of total AMACR.

CONCLUSIONS

Our data suggest that AMACR variants have better power than total AMACR in discriminating between CaP and adjacent normal tissue. These findings may be useful for the development of future diagnostic assays.

Diagnostic utility of α-methylacyl CoA racemase (P504S) & HMWCK in morphologically difficult prostate cancer

Background

To evaluate the diagnostic utility of alpha-methylacyl CoA racemase (P504S) & HMWCK (34beta E12) in morphologically difficult prostate cancer.

Methods

A total of 1034 cases were reviewed and divided into benign (585) malignant (399) and suspicious (50). Immunohistochemistry with HMWCK and AMACR was done on the 50 suspicious cases along with controls.

Results

Forty nine suspicious cases were resolved by using both markers where as 1 case was resolved by further support with CD68. The original diagnosis was changed in 15 of 50 (30%) suspicious cases from benign to malignant, one case from benign to high grade PIN and in one case from malignant to benign. Change of diagnosis was seen in 17 of 50 (34%) suspicious cases with a significant p value of 0.002. The overall diagnosis was changed in 17 of 1034 cases (1.64%) of prostatic disease (p < 0.001).

Conclusions

A combination of HMWCK and AMACR is of great value in combating the morphologically suspicious cases and significantly increasing the diagnostic accuracy in prostate cancer. Although, in this study the sensitivity and specificity of HMWCK and AMACR were high, yet it should be used with caution, keeping in mind all their pitfalls and limitations.

Cancer biomarker discovery: the entropic hallmark

Background

It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods.

Methodology/Principal Findings

Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer.

Conclusions/Significance

We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-througput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases.

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.

Reliability of the 34βE12, keratin 5/6, p63, bcl-2, and AMACR in the diagnosis of prostate carcinoma

OBJECTIVE

In this study, we aimed to investigate which basal cell marker should be used with α-methylacyl coenzyme A racemase (AMACR) to increase diagnostic accuracy in the diagnosis of prostate carcinoma.

MATERIALS AND METHODS

A total of 98 cases of prostate biopsy, comprising 65 cases with prostate adenocarcinoma and 33 cases without adenocarcinoma, were included in this study. Prostate-specific antigen (PSA) serum levels before biopsies were obtained. The number of cores with malignant glands and Gleason scores for each case were determined. Paraffin sections were stained immunohistochemically with 34βE12, keratin 5/6, p63, bcl-2, and AMACR.

RESULTS

According to staining pattern, extensiveness, and intensity of basal cell markers in benign glands, 34βE12 gave the best results. As negative markers for prostate adenocarcinoma, the best markers were p63 and 34βE12. According to the AUC values in ROC curves for both extensiveness and intensity, the arrangement from the best to the worst was 34βE12, p63, bcl-2, and keratin 5/6. The 34βE12 had the best sensitivity and specificity values (95% and 98%, respectively). Staining extensiveness and intensity of keratin 5/6 in malignant glands, and those of bcl-2 in benign glands had statistically significant positive correlation with serum PSA levels. Even though AMACR is a negative marker for benignity, some of the benign glands also had positive immune reaction with AMACR. However, AMACR positivity was usually focal and weak. Nevertheless, intensively stained subjects were also present. No correlation was present between AMACR and basal cell markers.

CONCLUSIONS

As a result, we suggest that keratin 5/6 and bcl-2 should not be used to identify benign glands in prostate biopsy since they show high positivity in malignant glands and high negativity in benign glands. 34βE12 should be the first choice as a basal cell marker. p63 can be used together with 34βE12, but it may not give additional diagnostic information. When we evaluated the correlation of basal cell markers, we did not find any complementary staining results among basal cell markers. Our study showed that 34βE12 is the most appropriate negative marker to combine with AMACR as a positive marker for the diagnosis of prostate adenocarcinoma.

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.

Best practice in diagnostic immunohistochemistry: prostate carcinoma and its mimics in needle core biopsies

CONTEXT

The unrelenting challenge encountered when differentiating limited-volume prostate carcinoma and sometimes subtle variants from its many morphologic mimics has increased the use of ancillary immunohistochemistry in routine prostate needle biopsies. The availability of prostate cancer-associated and basal cell-associated markers has been an invaluable addition to diagnostic surgical pathology.

OBJECTIVE

To review commonly used immunohistochemical stains, including innovative combinations, for confirmation or differential diagnosis of prostate carcinoma, and to propose appropriately constructed panels using morphologic patterns in prostate needle biopsies.

DATA SOURCES

These best practices are based on our experience with routine and consultative case sign-outs and on a review of the published English-language literature from 1987 through 2008.

CONCLUSIONS

Basal cell-associated markers p63, high-molecular-weight cytokeratin 34 beta E12, cytokeratin 5/6 or a cocktail containing p63 and high-molecular-weight cytokeratin 34 beta E12 or cytokeratin 5/6 and prostate carcinoma-specific marker alpha-methylacyl coenzyme A (coA) racemase alone or in combination are useful adjuncts in confirming prostatic carcinoma that either lacks diagnostic, qualitative or quantitative features or that has an unusual morphologic pattern (eg, atrophic, pseudohyperplastic) or is in the setting of prior treatment. The combination of alpha-methylacyl coA racemase positivity with negative staining for basal cell-associated markers supports a malignant diagnosis in the appropriate morphologic context. Dual chromogen basal cell- associated markers (p63 [nuclear] and high-molecular-weight cytokeratin 34 beta E12/cytokeratin 5/6 [cytoplasmic]) and alpha-methylacyl coA racemase in an antibody cocktail provide greater sensitivity for the basal cell layer, easing evaluation and minimizing loss of representation of the focal area interest because the staining is performed on one slide. In the posttreatment setting, pancytokeratin facilitates detection of subtle-treated cancer cells. Prostate-specific antigen and prostatic acid phosphatase markers are helpful in excluding secondary malignancies involving the prostate, such as urothelial carcinoma, and occasionally in excluding nonprostatic benign mimickers, such as nephrogenic adenoma, mesonephric gland hyperplasia, and Cowper glands. There is no role for ordering immunohistochemistry prospectively in all cases of prostatic needle biopsies.

[The pathologist's perspective on the PCPT trial]

The PCPT (Prostate Cancer Prevention Trial) trial which compared 5 mg/d of finastéride to placebo in men over 55 years old showed that active treatment reduced the incidence of prostate cancer from 24.4 to 18.4%. Paradoxically, the incidence of high grade cancers (Gleason score > or = 7) was higher in the finasteride group (6.4%) than in the placebo group (5.1%). Histological interpretation of the radical prostatectomy specimens showed an overestimation of Gleason score on biopsy both in the finasteride and placebo group. The high grade cancers on total prostatectomy specimens were not more aggressive in the finasteride arm than in the placebo arm. There is no argument to suggest that long term finasteride may promote the development of highly aggressive cancer. Urologists must clearly be aware that finasteride treatment may result in morphological changes in order to inform the pathologist that this drug is being taken. If a prostate cancer with a Gleason score > or = 7 is diagnosed in a treated patient, the pathologist will perform a double reading of the slides to confirm the score.

p63 in prostate biology and pathology

The identification of stem cells and differentiation programs regulating the development and maintenance of the normal prostate epithelium is essential for the identification of the cell type(s) and molecular alterations involved in the development and propagation of prostate cancer (CaP). The p53-homologue p63 is highly expressed in normal prostate basal cells and is a clinically useful biomarker for the diagnosis of CaP. Importantly, p63 has been shown to play a critical role in prostate development. Recent experimental evidence also suggests that this gene is essential for normal stem cell function in the prostate as well as other epithelial organs. Future studies aimed at better defining the role of p63 in the renewal of the adult prostate epithelium are likely to shed new light on the mechanisms involved in prostate carcinogenesis.

Aberrant diffuse expression of p63 in adenocarcinoma of the prostate on needle biopsy and radical prostatectomy: report of 21 cases

Aberrant diffuse expression of p63 in prostate carcinoma cells is a rare and poorly understood phenomenon. We studied 19 cases of prostate cancer with aberrant diffuse expression of p63 on needle biopsy and reviewed the subsequent radical prostatectomies in 6 cases. In 19/21 cases, 100% of the cancer nuclei stained intensely for p63, with 70% staining in the remaining 2 cases. Two additional radical prostatectomies with aberrant p63 staining with no needle biopsies available for review were also analyzed. On the hematoxylin and eosin-stained slides, 19/21 cases (90.5%) showed a distinctive morphology composed predominantly of glands, nests, and cords with atrophic cytoplasm, hyperchromatic nuclei, and visible nucleoli. Needle biopsy cases ranged from Gleason patterns 3 to 5 with tumor identified on one or more cores, ranging from a minute focus to 80% of the core. In all 8 radical prostatectomies p63 positive cancer was present, with in 2/8 cases both p63 positive cancer and usual p63 negative acinar prostate cancer. In all 8 cases, the tumors were organ confined with negative margins and there was no seminal vesicle involvement or lymph node metastasis. The presence of p63 positive atypical glands with an infiltrative pattern and perineural invasion on radical prostatectomy confirmed the needle biopsy diagnosis of carcinoma. Rarely, prostate cancer can aberrantly express diffuse p63 staining in a nonbasal cell distribution leading to the erroneous diagnosis of atrophy or atypical basal cell proliferation. The diagnosis of prostate cancer is based on the morphology and confirmed by the absence of high molecular weight cytokeratin staining and positivity for alpha-methylacyl-CoA racemase in the atypical glands. Pathologists need to be aware of this rare and unusual phenomenon, which is a potential pitfall in prostate cancer diagnosis.

[New markers in prostate biopsies]

The use of serum prostate-specific antigen screening to facilitate early detection of prostate cancer has resulted in a dramatic increase in the number of prostate needle core biopsies which pathologists must examine. This has been accompanied by a strong increase in the number of biopsies with ambiguous lesions, and an unequivocal diagnosis of malignancy is difficult to render, especially in the case of limited foci or in small atypical acinar lesions. When assessing small foci of atypical glands upon needle biopsy, the pathologist searches for differences between the benign glands and atypical glands in terms of usual morphological features and in such cases, immunohistochemical stains for basal cell markers such as 34betaE12 antibody or antibodies directed against cytokeratin 5 and 6 and more recently p63 may be a useful adjuvant to identify basal cells which are typically present in benign glands but absent in prostatic carcinoma. However several benign mimickers of prostate carcinoma, including atrophy, atypical adenomatous hyperplasia, nephrogenic adenoma can stain negatively with these antibodies and thus a negative basal cell marker immunostain alone does not exclude a diagnosis of benignancy. Alpha-methyl-coenzyme-A-racemase (AMACR) a new sensitive marker of prostate carcinoma, can be useful in confirming ambiguous lesion suspected for malignancy. Although, as with any immunohistochemical studies, problems exist in terms of both sensitivity and specificity. The aim of this review is to describe the histological features of prostatic carcinoma in case of small focus, and discuss the application of these new prostatic markers in the light of the current literature to highlight the best practice guidelines.

Dietary fat-gene interactions in cancer

Epidemiologic studies have suggested for decades an association between dietary fat and cancer risk. A large body of work performed in tissue culture and xenograft models of cancer supports an important role of various types of fat in modulating the cancer phenotype. Yet, the molecular mechanisms underlining the effects of fat on cancer initiation and progression are largely unknown. The relationships between saturated fat, polyunsaturated fat, cholesterol or phytanic acid with cancer have been reviewed respectively. However, few have considered the relationship between all of these fats and cancer. The purpose of this review is to present a more cohesive view of dietary fat-gene interactions, and outline a working hypothesis of the intricate connection between fat, genes and cancer.

Heterogeneous expression of alpha-methylacyl-CoA racemase in prostatic cancer correlates with Gleason score

AIMS

Alpha-methylacyl-CoA racemase (AMACR) is a sensitive and specific immunohistochemical marker of prostatic malignancy, staining 80-100% of prostatic cancers with absent staining in benign glands. However, positive staining in benign conditions as well as low rates of AMACR reactivity in prostatic cancer variants have been described. Preliminary use of AMACR immunohistochemistry in our institution has suggested lower specificity and sensitivity for prostatic cancer than initially proposed. The aim of this study was to establish true rates of AMACR reactivity in prostatic cancer and benign prostatic hyperplasia (BPH).

METHODS AND RESULTS

AMACR immunohistochemistry was performed on sections from 57 prostatic cancers and 44 BPH resections. Ninety-one percent of cancers were AMACR+, with diffuse (> 75%) tumour staining in 53% of cases. Thirty-eight percent of tumours showed heterogeneous expression (1-75% tumour staining). This was significantly correlated with increased Gleason score. High-grade prostatic intraepithelial neoplasia (PIN) was AMACR+ in 87% of cancers. Eleven percent of BPH showed moderate or strong staining in benign glands, focally mimicking the malignant staining pattern.

CONCLUSIONS

This study confirms heterogeneous AMACR expression in prostatic cancer and shows a correlation with Gleason score. Positive staining in BPH is also documented, thus emphasizing the importance of interpreting AMACR immunohistochemistry in the context of other findings in a diagnostic setting.

Atypical small acinar proliferation: biopsy artefact or distinct pathological entity?

OBJECTIVE

To determine if atypical small acinar proliferation (ASAP) represents minimally sampled prostate cancer not fully evaluated on a biopsy or a distinct pathological entity, by examining prostates removed at radical cystectomy, as a finding of ASAP of the prostate on needle-core biopsy is closely associated with the detection of cancer on subsequent biopsy.

PATIENTS AND METHODS

In all, 65 consecutive cystoprostatectomy specimens taken from June 1990 to March 2004 had prostatic material reviewed by one genitourinary pathologist (S.E.M.). The presence of high-grade prostatic intraepithelial neoplasia (HGPIN), ASAP, and adenocarcinoma was recorded. Foci of ASAP found in the absence of cancer were assessed with additional sectioning, high-molecular weight keratin (CK903), and alpha-methylacyl coenzyme A racemase (AMACR) immunohistochemistry.

RESULTS

In all, 24 of 65 specimens (37%) had adenocarcinoma. Of the 41 without cancer, 18 (44%) had neither HGPIN nor ASAP, 14 (34%) had HGPIN alone, three (7%) had ASAP alone (four foci), and six had both HGPIN and ASAP (15%). Two foci of ASAP were not present on any further sectioning. The remaining eight foci all lacked CK903 stain, indicating disruption of the basal cell layer. Of these eight, only five were present for the AMACR stain, all of which were positive. Two of these five developed into a lesion considered cancer on further sectioning.

CONCLUSION

ASAP identified in incidental prostates represented marginally sampled cancer in at least two of 10 foci assessed. The remainder could not be resolved as benign on further evaluation, and remained suspicious for malignancy.

Diagnosis of adenocarcinoma in prostate needle biopsy tissue

Prostate cancer is a major public health problem throughout the developed world. For patients with clinically localised prostate cancer, the diagnosis is typically established by histopathological examination of prostate needle biopsy samples. Major and minor criteria are used to establish the diagnosis, based on the microscopic appearance of slides stained using haematoxylin and eosin. Major criteria include an infiltrative glandular growth pattern, an absence of basal cells and nuclear atypia in the form of nucleomegaly and nucleolomegaly. In difficult cases, basal cell absence may be confirmed by immunohistochemical stains for high-molecular-weight cytokeratins (marked with antibody 34betaE12) or p63, which are basal cell markers. Minor criteria include intraluminal wispy blue mucin, pink amorphous secretions, mitotic figures, intraluminal crystalloids, adjacent high-grade prostatic intraepithelial neoplasia, amphophilic cytoplasm and nuclear hyperchromasia. Another useful diagnostic marker detectable by immunohistochemistry is alpha-methylacyl coenzyme A racemase (AMACR), an enzyme selectively expressed in neoplastic glandular epithelium. Cocktails of antibodies directed against basal cell markers and AMACR are particularly useful in evaluating small foci of atypical glands, and in substantiating a diagnosis of a minimal adenocarcinoma. Reporting of adenocarcinoma in needle biopsy specimens should always include the Gleason grade and measures of tumour extent in the needle core tissue. Measures of tumour extent are (1) number of cores positive for cancer in the number of cores examined, (2) percentage of needle core tissue affected by carcinoma and (3) linear millimetres of carcinoma present.

Atypical Small Acinar Proliferation in the Prostate: Clinical Significance in 2006

About 2% of contemporary prostate needle biopsy specimens contain collections of small acini that are suspicious for cancer but that fall below the diagnostic threshold and are reported as atypical small acinar proliferation suspicious for but not diagnostic of malignancy. Prostate cancer has been identified in specimens from subsequent biopsies in up to 60% of cases of atypical small acinar proliferation, indicating that this finding is a significant predictor of cancer. Identification of atypical small acinar proliferation warrants repeat biopsy for concurrent or subsequent invasive carcinoma.

Current prostate biopsy interpretation: criteria for cancer, atypical small acinar proliferation, high-grade prostatic intraepithelial neoplasia, and use of immunostains

CONTEXT

The past decade has brought major changes in prostate biopsy sampling, interpretation, and reporting.

OBJECTIVE

To summarize current information on diagnostic decision making, Gleason grading, "atypical" diagnoses, and use of immunostaining.

DATA SOURCES

Pertinent literature from 1985 to 2005 is reviewed, emphasizing recent findings.

CONCLUSIONS

Diagnosis begins by evaluating a focus of atypical single-cell layer lined acini according to the 3 minimal diagnostic criteria for cancer: an infiltrative pattern, nuclear enlargement and hyperchromasia, and prominent nucleoli. The Gleason score and linear extent or percent of each core containing cancer should be reported. Atypical small acinar proliferation suspicious for malignancy designates foci that have either qualitative or quantitative limitations in atypia precluding a definite cancer diagnosis. It has about a 3% incidence as an isolated finding. Contemporary studies indicate a 39% predictive value for cancer on repeat biopsy. Isolated high-grade prostatic intraepithelial neoplasia has a 3% to 14% incidence and predicts cancer on repeat biopsy in 23% of cases. Immunostaining for a marker of benign prostate (cytoplasmic keratin 34betaE12 or nuclear p63) and a marker of cancer (alpha-methylacyl coA racemase, clone P504S) may or may not resolve atypical small acinar proliferation diagnoses. Performance of 34betaE12 and P504S immunostains resolved 76% of atypical small acinar proliferation diagnoses per consensus of 3 urologic pathologists studied; a technical limitation is preservation of the focus in question on the levels used for immunostaining.