Manzamine A reduces androgen receptor transcription and synthesis by blocking E2F8-DNA interactions and effectively inhibits prostate tumor growth in mice

The androgen receptor (AR) is the main driver in the development of castration-resistant prostate cancer, where the emergence of AR splice variants leads to treatment-resistant disease. Through detailed molecular studies of the marine alkaloid manzamine A (MA), we identified transcription factor E2F8 as a previously unknown regulator of AR transcription that prevents AR synthesis in prostate cancer cells. MA significantly inhibited the growth of various prostate cancer cell lines and was highly effective in inhibiting xenograft tumor growth in mice without any pathophysiological perturbations in major organs. MA suppressed the full-length AR (AR-FL), its spliced variant AR-V7, and the AR-regulated prostate-specific antigen (PSA; also known as KLK3) and human kallikrein 2 (hK2; also known as KLK2) genes. RNA sequencing (RNA-seq) analysis and protein modeling studies revealed E2F8 interactions with DNA as a potential novel target of MA, suppressing AR transcription and its synthesis. This novel mechanism of blocking AR biogenesis via E2F8 may provide an opportunity to control therapy-resistant prostate cancer over the currently used AR antagonists designed to target different parts of the AR gene.

Morphologic features of prostate cancer-encased native vessels: An image analysis study

BACKGROUND

Vasculature plays a crucial role in the progression of prostate cancer (PC). Changes to the prostatic native vessels have not been studied since 2000 when Garcia et al. demonstrated marked media hypercellularity and increased artery thickness in prostatic native arteries within PC. We aim to further evaluate and characterize prostatic native vessels with a more accurate method with the use of virtual slides and digital analysis.

DESIGN

Pathologist-annotated whole-mount digital slides from 96 entirely submitted prostatectomies were annotated for PC (color-coded by Gleason) using Omero platform. A subset of 44 cases met criteria for further analysis of media thickness, cellularity, and wall thickness to lumen ratio. Cases were included based on containing ≥5 native arteries (≥100 µm diameter) encased on at least 3 sides by PC, with vessels (≥100 µm diameter) designated as controls if they were ≥ 1000 µm away from PC. Annotated vessels were segmented and processed using Matlab 2023b. Mean media thickness (corrected for oblique sections), media: lumen ratio (based on numbers of pixels), and media cellularity (nuclei count) were studied by analysis with SPSS by linear mixed model with nested random effects for subject and slide to account for repeated measures.

RESULTS

Vessels encased by PC showed greater media thickness (p=0.02), cellularity (p=0.02) and wall thickness/lumen ratio (p= <0.001) compared to vessels away from PC. These values showed an increasing trend according to stage in cellularity (p=0.14), media thickness (p=0.12) and wall thickness/ lumen ratio (p= 0.33) with higher stage (pT3). A Gleason group comparison showed a borderline-significant gradewise trend when analyzing wall thickness/lumen ratio (p=0.06). Grade 5 emerged as significantly different (p=0.02) from grades 3 or 4 non-cribriform.

CONCLUSIONS

Similar to the 2000 study, increased media thickness and hypercellularity of vessels encased by PC were evident compared to controls. Borderline grade-dependent increased vessel cellularity changes were seen, suggesting a possible role in PC progression; the predictive value of these changes for outcome is uncertain. Whether the etiology of changes reflects locally increased intravascular pressure of vessels within tumor should be investigated.

Stat5 induces androgen receptor (AR) gene transcription in prostate cancer and offers a druggable pathway to target AR signaling

Androgen receptor (AR) drives prostate cancer (PC) growth and progression, and targeting AR signaling is the mainstay of pharmacological therapies for PC. Resistance develops relatively fast as a result of refueled AR activity. A major gap in the field is the lack of understanding of targetable mechanisms that induce persistent AR expression in castrate-resistant PC (CRPC). This study uncovers an unexpected function of active Stat5 signaling, a known promoter of PC growth and clinical progression, as a potent inducer of AR gene transcription. Stat5 suppression inhibited AR gene transcription in preclinical PC models and reduced the levels of wild-type, mutated, and truncated AR proteins. Pharmacological Stat5 inhibition by a specific small-molecule Stat5 inhibitor down-regulated Stat5-inducible genes as well as AR and AR-regulated genes and suppressed PC growth. This work introduces the concept of Stat5 as an inducer of AR gene transcription in PC. Pharmacological Stat5 inhibitors may represent a new strategy for suppressing AR and CRPC growth.

Addition of cribriform pattern 4 and intraductal prostatic carcinoma into the CAPRA-S tool improves post-radical prostatectomy patient stratification in a multi-institutional cohort

AIMS

Pre-surgical risk classification tools for prostate cancer have shown better patient stratification with the addition of cribriform pattern 4 (CC) and intraductal prostatic carcinoma (IDC) identified in biopsies. Here, we analyse the additional prognostic impact of CC/IDC observed in prostatectomies using Cancer of Prostate Risk Assessment post-surgical (CAPRA-S) stratification.

METHODS

A retrospective cohort of treatment-naïve radical prostatectomy specimens from three North American academic institutions (2010-2018) was assessed for the presence of CC/IDC. Patients were classified, after calculating the CAPRA-S scores, into low-risk (0-2), intermediate-risk (3-5) and high-risk (6-12) groups. Kaplan-Meier curves were created to estimate biochemical recurrence (BCR)-free survival. Prognostic performance was examined using Harrell's concordance index, and the effects of CC/IDC within each risk group were evaluated using the Cox proportional hazards models.

RESULTS

Our cohort included 825 prostatectomies (grade group (GG)1, n=94; GG2, n=475; GG3, n=185; GG4, n=13; GG5, n=58). CC/IDC was present in 341 (41%) prostatectomies. With a median follow-up of 4.2 years (range 2.9-6.4), 166 (20%) patients experienced BCR. The CAPRA-S low-risk, intermediate-risk and high-risk groups comprised 357 (43%), 328 (40%) and 140 (17%) patients, and discriminated for BCR-free survival (p<0.0001). For CAPRA-S scores 3-5, the addition of CC/IDC status improved stratification for BCR (HR 2.27, 95% CI 1.41 to 3.66, p<0.001) and improved the overall c-index (0.689 vs 0.667, analysis of variance p<0.001).

CONCLUSION

The addition of CC/IDC into the CAPRA-S classification significantly improved post-radical prostatectomy patient stratification for BCR among the intermediate-risk group (CAPRA-S scores 3-5). The reporting of CC and IDC should be included in future prostate cancer stratification tools for improved outcome prediction.

Addition of Cribriform and Intraductal Carcinoma Presence to Prostate Biopsy Reporting Strengthens Pretreatment Risk Stratification Using CAPRA and NCCN Tools

BACKGROUND

Pretreatment stratification tools can help in clinical decision making in prostate cancer. To date, none incorporates well-established routinely reported adverse prognostic pathologic features such as intraductal carcinoma of prostate (IDC) or cribriform pattern 4 (CC).

OBJECTIVE

To assess the impact of addition of CC and/or IDC on the Cancer of Prostate Risk Assessment (CAPRA) and National Cancer Comprehensive Network (NCCN) tools for predicting biochemical recurrence free survival (BCR-FS) and event-free survival (EFS) across multiple patient cohorts.

DESIGN, SETTING, AND PARTICIPANTS

Matched prostate biopsies and radical prostatectomies from institutions in Toronto, Wisconsin and Rotterdam. The presence/absence of CC/IDC was recorded on all biopsies.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Relationship to outcome was assessed using Cox proportional hazard models, ANOVA and Harrell's concordance index.

RESULTS AND LIMITATIONS

We included 1326 patients (Toronto- 612, Wisconsin- 542, Rotterdam- 172) with median follow up of 4.2 years (IQR 2.9-6.4 years); 306 (23.1%) had CC/IDC on biopsy with 207 (20.9%) BCR and 154 (11.6%) events (metastases/death). Addition of CC/IDC improved stratification in CAPRA scores 3 to 5 for BCR-FS (c-index increase 0.633-0.658, P < .001) and scores 6-10 for EFS (c-index increase 0.653-0.697, P < .001). For NCCN, all risk groups apart from score 1 to 2 showed improvement in BCR-FS (c-index increase 0.599-0.636, P < 0.001) and EFS prediction (c-index increase 0.648-0.697, P < .001). Sub-analysis of grade group (GG) 2 biopsies showed similar findings. The retrospective nature and inclusion of cases only reported by genitourinary pathologists are study limitations.

CONCLUSIONS

The clinical benefit of the addition of CC/IDC to both CAPRA and NCCN pretreatment tools was validated in 3 cohorts, including the subset of biopsy GG2 prostate cancer patients.

PATIENT SUMMARY

Including additional pathologic features to existing pretreatment, clinical decision making tools improves the ability to predict prostate cancer recurrence, cancer spread and death of disease.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer: Working Group 3: Subcategorization of T1 Bladder Cancer

Emerging data on T1 bladder cancer subcategorization (aka substaging) suggests a correlation with oncological outcomes. The International Society of Urological Pathology (ISUP) organized the 2022 consensus conference in Basel, Switzerland to focus on current issues in bladder cancer and tasked working group 3 to make recommendations for T1 subcategorization in transurethral bladder resections. For this purpose, the ISUP developed and circulated a survey to their membership querying approaches to T1 bladder cancer subcategorization. In particular, clinical relevance, pathological reporting, and endorsement of T1 subcategorization in the daily practice of pathology were surveyed. Of the respondents of the premeeting survey, about 40% do not routinely report T1 subcategory. We reviewed literature on bladder T1 subcategorization, and screened selected articles for clinical performance and practicality of T1 subcategorization methods. Published literature offered evidence of the clinical rationale for T1 subcategorization and at the conference consensus (83% of conference attendants) was obtained to report routinely T1 subcategorization of transurethral resections. Semiquantitative T1 subcategorization was favored (37%) over histoanatomic methods (4%). This is in line with literature findings on practicality and prognostic impact, that is, a shift of publications from histoanatomic to semiquantitative methods or by reports incorporating both methodologies is apparent over the last decade. However, 59% of participants had no preference for either methodology. They would add a comment in the report briefly stating applied method, interpretation criteria (including cutoff), and potential limitations. When queried on the terminology of T1 subcategorization, 34% and 20% of participants were in favor of T1 (microinvasive) versus T1 (extensive) or T1 (focal) versus T1 (nonfocal), respectively.

Racial differences in serum chemokines in prostate cancer patients

BACKGROUND

This study aimed to understand the differential levels of inflammatory chemokines in association with higher prostate cancer incidence and mortality in African American (AA) men than in Caucasians (CA).

METHODS

The authors used a chemokine assay to simultaneously measure 40 chemokines and cytokines levels in the serum of preoperative prostate cancer patients and healthy controls of AA and CA races. Selected chemokines (CXCL2, CXCL5, and CCL23) serum level was validated in 211 serum samples from prostate cancer patients and healthy controls. Differential expression of CXCL5 and CCL23 was analyzed using immunohistochemistry in a representative cohort of prostate tumor tissues of AA and CA races.

RESULTS

Race-specific comparisons from 211 serum samples showed significantly higher levels of CXCL2 (control: 3104.0 pg/mL vs. cancer: 2451.0 pg/mL) and CXCL5 (control: 5189.0 pg/mL vs. cancer: 5459.0 pg/mL) in AA men than in CAs (CXCL2; control: 1155.0 pg/mL vs. cancer: 889.3 pg/mL, and CXCL5; control: 1183.0 pg/mL vs. cancer: 977.5 pg/mL). CCL23 differed significantly within and between the races with a lower level in AA cancer cases (454.5 vs. 966.6 pg/mL) than healthy controls (740.5 vs. 1263.0 pg/mL). Patient age, prostate-specific antigen, or Gleason scores were not significantly associated with these chemokines. Immunostaining for CXCL5 and CCL23 in a representative cohort of archival prostate tissues displayed significantly higher CXCL5 in prostate tumors than in adjacent benign tissues, whereas CCL23 was nondetectable in most of the analyzed tumor tissues.

CONCLUSION

Lower levels of CCL23 in AA prostate cancer patient sera and tumor tissues and high CXCL2 and CXCL5 may contribute to aggressive prostate cancer, as often seen in AA men. The disproportionate levels of serum chemokines associated with race warrant further exploration to improve equitability in precision oncology to benefit prostate cancer patients.

Quantitative Histomorphometric Features of Prostate Cancer Predict Patients Who Biochemically Recur Following Prostatectomy

Prostate cancer is the most commonly diagnosed cancer in men, accounting for 27% of the new male cancer diagnoses in 2022. If organ-confined, removal of the prostate through radical prostatectomy is considered curative; however, distant metastases may occur, resulting in a poor patient prognosis. This study sought to determine whether quantitative pathomic features of prostate cancer differ in patients who biochemically experience biological recurrence after surgery. Whole-mount prostate histology from 78 patients was analyzed for this study. In total, 614 slides were hematoxylin and eosin stained and digitized to produce whole slide images (WSI). Regions of differing Gleason patterns were digitally annotated by a genitourinary fellowship-trained pathologist, and high-resolution tiles were extracted from each annotated region of interest for further analysis. Individual glands within the prostate were identified using automated image processing algorithms, and histomorphometric features were calculated on a per-tile basis and across WSI and averaged by patients. Tiles were organized into cancer and benign tissues. Logistic regression models were fit to assess the predictive value of the calculated pathomic features across tile groups and WSI; additionally, models using clinical information were used for comparisons. Logistic regression classified each pathomic feature model at accuracies >80% with areas under the curve of 0.82, 0.76, 0.75, and 0.72 for all tiles, cancer only, noncancer only, and across WSI. This was comparable with standard clinical information, Gleason Grade Groups, and CAPRA score, which achieved similar accuracies but areas under the curve of 0.80, 0.77, and 0.70, respectively. This study demonstrates that the use of quantitative pathomic features calculated from digital histology of prostate cancer may provide clinicians with additional information beyond the traditional qualitative pathologist assessment. Further research is warranted to determine possible inclusion in treatment guidance.

T2-Weighted MRI Radiomic Features Predict Prostate Cancer Presence and Eventual Biochemical Recurrence

Prostate cancer (PCa) is the most diagnosed non-cutaneous cancer in men. Despite therapies such as radical prostatectomy, which is considered curative, distant metastases may form, resulting in biochemical recurrence (BCR). This study used radiomic features calculated from multi-parametric magnetic resonance imaging (MP-MRI) to evaluate their ability to predict BCR and PCa presence. Data from a total of 279 patients, of which 46 experienced BCR, undergoing MP-MRI prior to surgery were assessed for this study. After surgery, the prostate was sectioned using patient-specific 3D-printed slicing jigs modeled using the T2-weighted imaging (T2WI). Sectioned tissue was stained, digitized, and annotated by a GU-fellowship trained pathologist for cancer presence. Digitized slides and annotations were co-registered to the T2WI and radiomic features were calculated across the whole prostate and cancerous lesions. A tree regression model was fitted to assess the ability of radiomic features to predict BCR, and a tree classification model was fitted with the same radiomic features to classify regions of cancer. We found that 10 radiomic features predicted eventual BCR with an AUC of 0.97 and classified cancer at an accuracy of 89.9%. This study showcases the application of a radiomic feature-based tool to screen for the presence of prostate cancer and assess patient prognosis, as determined by biochemical recurrence.

Whole slide imaging (WSI) scanner differences influence optical and computed properties of digitized prostate cancer histology

Purpose

Digital pathology is becoming an increasingly popular area of advancement in both research and clinically. Pathologists are now able to manage and interpret slides digitally, as well as collaborate with external pathologists with digital copies of slides. Differences in slide scanners include variation in resolution, image contrast, and optical properties, which may influence downstream image processing. This study tested the hypothesis that varying slide scanners would result in differences in computed pathomic features on prostate cancer whole mount slides.

Design

This study collected 192 unique tissue slides from 30 patients following prostatectomy. Tissue samples were paraffin-embedded, stained for hematoxylin and eosin (H&E), and digitized using 3 different scanning microscopes at the highest available magnification rate, for a total of 3 digitized slides per tissue slide. These scanners included a (S1) Nikon microscope equipped with an automated sliding stage, an (S2) Olympus VS120 slide scanner, and a (S3) Huron TissueScope LE scanner. A color deconvolution algorithm was then used to optimize contrast by projecting the RGB image into color channels representing optical stain density. The resulting intensity standardized images were then computationally processed to segment tissue and calculate pathomic features including lumen, stroma, epithelium, and epithelial cell density, as well as second-order features including lumen area and roundness; epithelial area, roundness, and wall thickness; and cell fraction. For each tested feature, mean values of that feature per digitized slide were collected and compared across slide scanners using mixed effect models, fit to compare differences in the tested feature associated with all slide scanners for each slide, including a random effect of subject with a nested random effect of slide to account for repeated measures. Similar models were also computed for tissue densities to examine how differences in scanner impact downstream processing.

Results

Each mean color channel intensity (i.e., Red, Green, Blue) differed between slide scanners (all P<.001). Of the color deconvolved images, only the hematoxylin channel was similar in all 3 scanners (all P>.05). Lumen and stroma densities between S3 and S1 slides, and epithelial cell density between S3 and S2 (P>.05) were comparable but all other comparisons were significantly different (P<.05). The second-order features were found to be comparable for all scanner comparisons, except for lumen area and epithelium area.

Conclusion

This study demonstrates that both optical and computed properties of digitized histological samples are impacted by slide scanner differences. Future research is warranted to better understand which scanner properties influence the tissue segmentation process and to develop harmonization techniques for comparing data across multiple slide scanners.

Malignant Mesothelioma of Tunica Vaginalis Testis: Update for 2022

Malignant mesothelioma of the testicular tunics is rare. About one third of cases are metastatic and carry a poor prognosis. This paper reviews the epidemiology, clinicopathologic features, treatment, and outcome of this entity.

The DACH1 gene is frequently deleted in prostate cancer, restrains prostatic intraepithelial neoplasia, decreases DNA damage repair, and predicts therapy responses

Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. The DACH1 gene encodes a winged helix/Forkhead DNA-binding protein that competes for binding to FOXM1 sites. Herein, DACH1 gene deletion within the 13q21.31-q21.33 region occurs in up to 18% of human PCa and was associated with increased AR activity and poor prognosis. In prostate OncoMice, prostate-specific deletion of the Dach1 gene enhanced prostatic intraepithelial neoplasia (PIN), and was associated with increased TGFβ activity and DNA damage. Reduced Dach1 increased DNA damage in response to genotoxic stresses. DACH1 was recruited to sites of DNA damage, augmenting recruitment of Ku70/Ku80. Reduced Dach1 expression was associated with increased homology directed repair and resistance to PARP inhibitors and TGFβ kinase inhibitors. Reduced Dach1 expression may define a subclass of PCa that warrants specific therapies.

Abstract 2598: The DACH1 gene is frequently deleted in prostate cancer, restrains prostatic intraepithelial neoplasia, augments DNA damage repair and predicts therapy responses

Background: Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. The DACH1 gene encodes a winged helix/Forkhead DNA-binding protein that competes for binding to FOXM1 sites.

Methods: Analysis of DACH1 gene deletion and gene expression was conducted from public data bases and human prostate cancer samples. Transgenic mice were generated in which the Dach1 gene was deleted in the prostate of prostate Oncomice. Cells derived from Dach1 gene deletion mice and human prostate cancer cell lines with Dach1 knockdown were analyzed for DNA damage repair responses.

Results: DACH1 gene deletion within the 13q21.31-q21.33 region, occurred in up to 18% of human PCa, and was associated with increased AR activity, and poor prognosis. DACH1 homozygous deletions more frequent in the metastatic site than in the primary tumors (Mich: 10% vs. 18%, N=59; FHCRC: 4% vs.11%, N= 54, SU2C: not profiled vs. 3.3, N=150). The prevalence of DACH1 heterozygous deletions was higher in the metastatic lesions than in primary tumors within a given cohort for three of six cohorts (Mich: 27.3% vs. 36%, N=59; FHCRC: 15% vs. 59%, N=54; SU2C: 0% vs. 26%, N=150, respectively). The patients with homozygous DACH1 deletions had reduced overall survival (medians of 84 vs. 120 months, N=667, log rank test P=9.3x10-3). Low DACH1 gene expression (expressed as a z-score with a z-score threshold of -1.25) was significantly correlated with earlier biochemical recurrence (BCR, log rank p value = 4.7x10-4, n=79). In prostate OncoMice, prostate-specific deletion of the Dach1 gene enhanced prostatic intraepithelial neoplasia (PIN) and was associated with increased DNA damage. Reduced Dach1 increased DNA damage in responses to genotoxic stresses. DACH1 was recruited to sites of DNA damage, augmenting recruitment of Ku70/Ku80. Reduced Dach1 expression was associated with resistance to TGFβ kinase and PARP inhibitors.

Conclusions: Reduced Dach1 expression may define a subclass of PCa that warrants specific therapies.

Citation Format: Zhiping Li, Xuanmao Jiao, Gordon Robertson, Gabriele Di Sante, Anthony W. Ashton, Agnese DiRocco, Min Wang, Jun Zhao, Sankar Addya, Chenguang Wang, Peter A. McCue, Andrew P. South, Carlos Cordon-Cardo, Runzhi Liu, Kishan Patel, Rasha Hamid, Jorim Parmar, James B. DuHadaway, Nikolaus Schultz, Andrew Kossenkov, Lai Yee Phoon, Hao Chen, Li Lan, Yunguang Sun, Kenneth A. Iczkowski, Hallgeir Rui, Richard G. Pestell. The DACH1 gene is frequently deleted in prostate cancer, restrains prostatic intraepithelial neoplasia, augments DNA damage repair and predicts therapy responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2598.

Zinc finger protein‑like 1 is a novel neuroendocrine biomarker for prostate cancer

Prostate‑derived calcitonin (CT) and its receptor induce tumorigenicity and increase metastatic potential of prostate cancer (PC). CT‑inducible genes in human prostate were identified by subtraction hybridization. Among these genes, zinc finger protein like 1 (ZFPL1) protein was interesting since it was abundantly expressed in malignant prostates but was almost absent in benign prostates. ZFPL1 expression was upregulated by CT and androgens, and ZFPL1 protein was secreted by prostate tumor cells through exosomal secretion. Serum levels of ZFPL1 in cancer patients were at least 4‑fold higher than those in the sera of cancer‑free individuals. Cell biology of ZFPL1 suggests its localization in Golgi bodies and exosomes, and its colocalization with chromogranin A and CD44. These results suggested that ZFPL1 is secreted by tumor cells of neuroendocrine (NE)/stem cell phenotype. The knockdown of endogenous ZFPL1 in (PC) cells led to a remarkable decrease in cell proliferation, and invasion while increasing their apoptosis. As expected, the overexpression of ZFPL1 in prostate cells had an opposite effect on these functions. The knockdown of ZFPL1 in PC cells also decreased Akt phosphorylation, suggesting the actions of ZFPL1 may be mediated through the PI3K‑Akt pathway. Moreover, the present results revealed that ZFPL1 is released by tumors cells of NE or androgen‑independent phenotype and its serum levels are significantly higher in cancer patients, suggesting that it may serve as a blood‑based non‑invasive biomarker of aggressive PC.

Interobserver reproducibility of cribriform cancer in prostate needle biopsies and validation of International Society of Urological Pathology criteria

AIMS

There is strong evidence that cribriform morphology indicates a worse prognosis of prostatic adenocarcinoma. Our aim was to investigate its interobserver reproducibility in prostate needle biopsies.

METHODS AND RESULTS

A panel of nine prostate pathology experts from five continents independently reviewed 304 digitised biopsies for cribriform cancer according to recent International Society of Urological Pathology criteria. The biopsies were collected from a series of 702 biopsies that were reviewed by one of the panellists for enrichment of high-grade cancer and potentially cribriform structures. A 2/3 consensus diagnosis of cribriform and noncribriform cancer was reached in 90% (272/304) of the biopsies with a mean kappa value of 0.56 (95% confidence interval 0.52-0.61). The prevalence of consensus cribriform cancers was estimated to 4%, 12%, 21%, and 20% of Gleason scores 7 (3 + 4), 7 (4 + 3), 8, and 9-10, respectively. More than two cribriform structures per level or a largest cribriform mass with ≥9 lumina or a diameter of ≥0.5 mm predicted a consensus diagnosis of cribriform cancer in 88% (70/80), 84% (87/103), and 90% (56/62), respectively, and noncribriform cancer in 3% (2/80), 5% (5/103), and 2% (1/62), respectively (all P < 0.01).

CONCLUSION

Cribriform prostate cancer was seen in a minority of needle biopsies with high-grade cancer. Stringent diagnostic criteria enabled the identification of cribriform patterns and the generation of a large set of consensus cases for standardisation.

The DACH1 gene is frequently deleted in prostate cancer, restrains prostatic intraepithelial neoplasia, decreases DNA damage repair, and predicts therapy responses

Prostate cancer (PCa), the second leading cause of death in American men, includes distinct genetic subtypes with distinct therapeutic vulnerabilities. The DACH1 gene encodes a winged helix/Forkhead DNA-binding protein that competes for binding to FOXM1 sites. Herein, DACH1 gene deletion within the 13q21.31-q21.33 region occurs in up to 18% of human PCa and was associated with increased AR activity and poor prognosis. In prostate OncoMice, prostate-specific deletion of the Dach1 gene enhanced prostatic intraepithelial neoplasia (PIN), and was associated with increased TGFb activity and DNA damage. Reduced Dach1 increased DNA damage in response to genotoxic stresses. DACH1 was recruited to sites of DNA damage, augmenting recruitment of Ku70/Ku80. Reduced Dach1 expression was associated with increased homology directed repair and resistance to PARP inhibitors and TGFb kinase inhibitors. Reduced Dach1 expression may define a subclass of PCa that warrants specific therapies.

Computational pathology in 2030: a Delphi study forecasting the role of AI in pathology within the next decade

BACKGROUND

Artificial intelligence (AI) is rapidly fuelling a fundamental transformation in the practice of pathology. However, clinical integration remains challenging, with no AI algorithms to date in routine adoption within typical anatomic pathology (AP) laboratories. This survey gathered current expert perspectives and expectations regarding the role of AI in AP from those with first-hand computational pathology and AI experience.

METHODS

Perspectives were solicited using the Delphi method from 24 subject matter experts between December 2020 and February 2021 regarding the anticipated role of AI in pathology by the year 2030. The study consisted of three consecutive rounds: 1) an open-ended, free response questionnaire generating a list of survey items; 2) a Likert-scale survey scored by experts and analysed for consensus; and 3) a repeat survey of items not reaching consensus to obtain further expert consensus.

FINDINGS

Consensus opinions were reached on 141 of 180 survey items (78.3%). Experts agreed that AI would be routinely and impactfully used within AP laboratory and pathologist clinical workflows by 2030. High consensus was reached on 100 items across nine categories encompassing the impact of AI on (1) pathology key performance indicators (KPIs) and (2) the pathology workforce and specific tasks performed by (3) pathologists and (4) AP lab technicians, as well as (5) specific AI applications and their likelihood of routine use by 2030, (6) AI's role in integrated diagnostics, (7) pathology tasks likely to be fully automated using AI, and (8) regulatory/legal and (9) ethical aspects of AI integration in pathology.

INTERPRETATION

This systematic consensus study details the expected short-to-mid-term impact of AI on pathology practice. These findings provide timely and relevant information regarding future care delivery in pathology and raise key practical, ethical, and legal challenges that must be addressed prior to AI's successful clinical implementation.

FUNDING

No specific funding was provided for this study.

Comparison of a machine and deep learning model for automated tumor annotation on digitized whole slide prostate cancer histology

One in eight men will be affected by prostate cancer (PCa) in their lives. While the current clinical standard prognostic marker for PCa is the Gleason score, it is subject to inter-reviewer variability. This study compares two machine learning methods for discriminating between cancerous regions on digitized histology from 47 PCa patients. Whole-slide images were annotated by a GU fellowship-trained pathologist for each Gleason pattern. High-resolution tiles were extracted from annotated and unlabeled tissue. Patients were separated into a training set of 31 patients (Cohort A, n = 9345 tiles) and a testing cohort of 16 patients (Cohort B, n = 4375 tiles). Tiles from Cohort A were used to train a ResNet model, and glands from these tiles were segmented to calculate pathomic features to train a bagged ensemble model to discriminate tumors as (1) cancer and noncancer, (2) high- and low-grade cancer from noncancer, and (3) all Gleason patterns. The outputs of these models were compared to ground-truth pathologist annotations. The ensemble and ResNet models had overall accuracies of 89% and 88%, respectively, at predicting cancer from noncancer. The ResNet model was additionally able to differentiate Gleason patterns on data from Cohort B while the ensemble model was not. Our results suggest that quantitative pathomic features calculated from PCa histology can distinguish regions of cancer; however, texture features captured by deep learning frameworks better differentiate unique Gleason patterns.

Germ cell neoplasms of the testis: Update for 2022

Germ cell neoplasia in situ (GCNIS) is the precursor of both seminomatous and non-seminomatous germ cell tumors. It consists of distended tubules that may have either intratubular seminoma or intratubular embryonal carcinoma cells. Many invasive non-seminomatous tumors contain a mixture of tumor types, which are reviewed here. Morphology, aided by a panel of immunostains, can determine the presence and percent of embryonal carcinoma, yolk sac tumor, choriocarcinoma, or teratoma in such tumors. Use of immunostains, required for diagnosis in perhaps 25% of testicular neoplasms, is reviewed. Changes of classification in the AJCC (8^th edition) in 2016 are discussed, including the partitioning of two tumor types: the central role of chromosome 12p amplification allows both teratoma and yolk sac tumor to be divided into prepubertal types (lacking amplification) and post-pubertal types. Occasionally, sex cord-stromal tumors, hematolymphoid tumors, or epididymal adenomatoid tumors enter the differential diagnosis of germ cell neoplasms.

Trends in disagreement with outside genitourinary pathology diagnoses at an academic center

AIMS

To evaluate the frequencies and types of disagreements in a contemporary urological second-opinion consult service in order to improve pathologist awareness.

METHODS

For 7 years ending 30 October 2021, records were kept of our department's total urologic outside consultation and disagreed-upon cases. Disagreements were categorized according to specimen type and nature of conflict. All grading and staging assignments used International Society of Urological Pathology (ISUP) criteria. Statistical analyses for each specimen type included the percent disagreement. Cohen's kappa analysis was done to measure interrater reliability on the prostate biopsies, prostatectomies, and the bladder biopsies/resections. In addition, for the prostate biopsies, the potential for change in treatment candidacy calculation (CTC), was assessed as sum of changes from cancer to non-malignant tissue or the reverse, plus changes from Gleason Grade group (GG)1 to GG ≥ 2 (3 +4 =7) or the reverse.

RESULTS

Overall mean disagreement rate for all specimens was 15.2%. The highest rate was among 1545 prostate biopsy cases, where 410 contained disagreements (26.5%). 118 (7.6%) met criteria for CTC: 10 cases were altered from cancer to non-cancer, 38 cases downgraded from GG≥ 2 to GG1, and 70 upgraded from GG1 to GG≥ 2. Second opinion downgraded the overall highest GG more often than it upgraded it, with downgrade:upgrade ratios of 64:37 for the GG1/GG2 threshold, 79:67 for the GG2/GG3, and 14:0 for the GG3/GG4. 146 specimen parts had disagreements as to cancer vs. suspicious vs. benign, with 85 undercalled and 61 overcalled. Other rates of disagreement included: prostatectomy 34/198 (17.2%); bladder resection or biopsy 68/591 (11.5%); kidney 27/175 (15.4%); and orchiectomy 9/82 (11.0%). In bladder specimens, overgrading was 6X more frequent than undergrading; and overstaging muscularis propria invasion was 6X more frequent than understaging.

CONCLUSIONS

The review of uropathologic materials before definitive therapy can lead to changes that impact clinical decisions significantly. As an example, for prostate biopsies, candidacy for active surveillance versus definitive treatment hinges on GG1 versus 2 and this distinction constituted most CTC cases. The above findings highlight aspects of urological pathology to be emphasized to residents in training, and pathologists in practice.

Multi-Site Concordance of Diffusion-Weighted Imaging Quantification for Assessing Prostate Cancer Aggressiveness

BACKGROUND

Diffusion-weighted imaging (DWI) is commonly used to detect prostate cancer, and a major clinical challenge is differentiating aggressive from indolent disease.

PURPOSE

To compare 14 site-specific parametric fitting implementations applied to the same dataset of whole-mount pathologically validated DWI to test the hypothesis that cancer differentiation varies with different fitting algorithms.

STUDY TYPE

Prospective.

POPULATION

Thirty-three patients prospectively imaged prior to prostatectomy.

FIELD STRENGTH/SEQUENCE

3 T, field-of-view optimized and constrained undistorted single-shot DWI sequence.

ASSESSMENT

Datasets, including a noise-free digital reference object (DRO), were distributed to the 14 teams, where locally implemented DWI parameter maps were calculated, including mono-exponential apparent diffusion coefficient (MEADC), kurtosis (K), diffusion kurtosis (DK), bi-exponential diffusion (BID), pseudo-diffusion (BID*), and perfusion fraction (F). The resulting parametric maps were centrally analyzed, where differentiation of benign from cancerous tissue was compared between DWI parameters and the fitting algorithms with a receiver operating characteristic area under the curve (ROC AUC).

STATISTICAL TEST

Levene's test, P < 0.05 corrected for multiple comparisons was considered statistically significant.

RESULTS

The DRO results indicated minimal discordance between sites. Comparison across sites indicated that K, DK, and MEADC had significantly higher prostate cancer detection capability (AUC range = 0.72-0.76, 0.76-0.81, and 0.76-0.80 respectively) as compared to bi-exponential parameters (BID, BID*, F) which had lower AUC and greater between site variation (AUC range = 0.53-0.80, 0.51-0.81, and 0.52-0.80 respectively). Post-processing parameters also affected the resulting AUC, moving from, for example, 0.75 to 0.87 for MEADC varying cluster size.

DATA CONCLUSION

We found that conventional diffusion models had consistent performance at differentiating prostate cancer from benign tissue. Our results also indicated that post-processing decisions on DWI data can affect sensitivity and specificity when applied to radiological-pathological studies in prostate cancer.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 3.

PLK4 is upregulated in prostate cancer and its inhibition reduces centrosome amplification and causes senescence

BACKGROUND

Identification of novel molecular target(s) is important for designing newer mechanistically driven approaches for the treatment of prostate cancer (PCa), which is one of the main causes of morbidity and mortality in men. In this study, we determined the role of polo-like kinase 4 (PLK4), which regulates centriole duplication and centrosome amplification (CA), in PCa.

MATERIALS AND METHODS

Employing human PCa tissue microarrays, we assessed the prevalence of CA, correlated with Gleason score, and estimated major causes of CA in PCa (cell doubling vs. centriole overduplication) by staining for mother/mature centrioles. We also assessed PLK4 expression and correlated it with CA in human PCa tissues and cell lines. Further, we determined the effects of PLK4 inhibition in human PCa cells.

RESULTS

Compared to benign prostate, human PCa demonstrated significantly higher CA, which was also positively correlated with the Gleason score. Further, most cases of CA were found to arise by centriole overduplication rather than cell doubling events (e.g., cytokinesis failure) in PCa. In addition, PLK4 was overexpressed in human PCa cell lines and tumors. Moreover, PLK4 inhibitors CFI-400945 and centrinone-B inhibited cell growth, viability, and colony formation of both androgen-responsive and androgen-independent PCa cell lines. PLK4 inhibition also induced cell cycle arrest and senescence in human PCa cells.

CONCLUSIONS

CA is prevalent in PCa and arises predominantly by centriole overduplication as opposed to cell doubling events. Loss of centrioles is cellular stress that can promote senescence and suggests that PLK4 inhibition may be a viable therapeutic strategy in PCa.

Histologically resolved small RNA maps in primary focal segmental glomerulosclerosis indicate progressive changes within glomerular and tubulointerstitial regions

Pathological heterogeneity is common in clinical tissue specimens and complicates the interpretation of molecular data obtained from the specimen. As a typical example, a kidney biopsy specimen often contains glomeruli and tubulointerstitial regions with different levels of histological injury, including some that are histologically normal. We reasoned that the molecular profiles of kidney tissue regions with specific histological injury scores could provide new insights into kidney injury progression. Therefore, we developed a strategy to perform small RNA deep sequencing analysis for individually scored glomerular and tubulointerstitial regions in formalin-fixed, paraffin-embedded kidney needle biopsies. This approach was applied to study focal segmental glomerulosclerosis (FSGS), the leading cause of nephrotic syndrome in adults. Large numbers of small RNAs, including microRNAs, 3'-tRFs, 5'-tRFs, and mitochondrial tRFs, were differentially expressed between histologically indistinguishable tissue regions from patients with FSGS and matched healthy controls. A majority of tRFs were upregulated in FSGS. Several small RNAs were differentially expressed between tissue regions with different histological scores in FSGS. Notably, with increasing levels of histological damage, miR-21-5p was upregulated progressively and miR-192-5p was downregulated progressively in glomerular and tubulointerstitial regions, respectively. This study marks the first genome scale molecular profiling conducted in histologically characterized glomerular and tubulointerstitial regions. Thus, substantial molecular changes in histologically normal kidney regions in FSGS might contribute to initiating tissue injury or represent compensatory mechanisms. In addition, several small RNAs might contribute to subsequent progression of glomerular and tubulointerstitial injury, and histologically mapping small RNA profiles may be applied to analyze tissue specimens in any disease.

Development and Validation of an Artificial Intelligence-Powered Platform for Prostate Cancer Grading and Quantification

IMPORTANCE

The Gleason grading system has been the most reliable tool for the prognosis of prostate cancer since its development. However, its clinical application remains limited by interobserver variability in grading and quantification, which has negative consequences for risk assessment and clinical management of prostate cancer.

OBJECTIVE

To examine the impact of an artificial intelligence (AI)-assisted approach to prostate cancer grading and quantification.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted at the University of Wisconsin-Madison from August 2, 2017, to December 30, 2019. The study chronologically selected 589 men with biopsy-confirmed prostate cancer who received care in the University of Wisconsin Health System between January 1, 2005, and February 28, 2017. A total of 1000 biopsy slides (1 or 2 slides per patient) were selected and scanned to create digital whole-slide images, which were used to develop and validate a deep convolutional neural network-based AI-powered platform. The whole-slide images were divided into a training set (n = 838) and validation set (n = 162). Three experienced academic urological pathologists (W.H., K.A.I., and R.H., hereinafter referred to as pathologists 1, 2, and 3, respectively) were involved in the validation. Data were collected between December 29, 2018, and December 20, 2019, and analyzed from January 4, 2020, to March 1, 2021.

MAIN OUTCOMES AND MEASURES

Accuracy of prostate cancer detection by the AI-powered platform and comparison of prostate cancer grading and quantification performed by the 3 pathologists using manual vs AI-assisted methods.

RESULTS

Among 589 men with biopsy slides, the mean (SD) age was 63.8 (8.2) years, the mean (SD) prebiopsy prostate-specific antigen level was 10.2 (16.2) ng/mL, and the mean (SD) total cancer volume was 15.4% (20.1%). The AI system was able to distinguish prostate cancer from benign prostatic epithelium and stroma with high accuracy at the patch-pixel level, with an area under the receiver operating characteristic curve of 0.92 (95% CI, 0.88-0.95). The AI system achieved almost perfect agreement with the training pathologist (pathologist 1) in detecting prostate cancer at the patch-pixel level (weighted κ = 0.97; asymptotic 95% CI, 0.96-0.98) and in grading prostate cancer at the slide level (weighted κ = 0.98; asymptotic 95% CI, 0.96-1.00). Use of the AI-assisted method was associated with significant improvements in the concordance of prostate cancer grading and quantification between the 3 pathologists (eg, pathologists 1 and 2: 90.1% agreement using AI-assisted method vs 84.0% agreement using manual method; P < .001) and significantly higher weighted κ values for all pathologists (eg, pathologists 2 and 3: weighted κ = 0.92 [asymptotic 95% CI, 0.90-0.94] for AI-assisted method vs 0.76 [asymptotic 95% CI, 0.71-0.80] for manual method; P < .001) compared with the manual method.

CONCLUSIONS AND RELEVANCE

In this diagnostic study, an AI-powered platform was able to detect, grade, and quantify prostate cancer with high accuracy and efficiency and was associated with significant reductions in interobserver variability. These results suggest that an AI-powered platform could potentially transform histopathological evaluation and improve risk stratification and clinical management of prostate cancer.

Characterization of the Peritumoral Atrophic Band and Nonneoplastic Renal Parenchyma in Radical Nephrectomy Specimens

OBJECTIVES

Pathologic evaluation of nonneoplastic renal parenchyma in nephrectomy specimens is important for identifying chronic kidney disease and diabetic nephropathy, but increasing utilization of partial nephrectomies has led to less-sampled nonneoplastic parenchyma. The sampled tissue is often composed predominantly of the peritumoral atrophic band (PAB) directly adjacent to the tumor. We sought to determine the characteristics of the PAB and whether it could be used to reliably assess kidney pathology, including diabetic nephropathy.

METHODS

We investigated 59 radical nephrectomies to determine the PAB characteristics, whether the PAB is representative of distant nonneoplastic parenchyma, and if diabetic nephropathy could be reliably detected in the PAB.

RESULTS

Mesangial sclerosis was detected within the PAB in 100% of cases with mesangial sclerosis in the distant parenchyma. Eighty percent had a history of diabetes. The PAB exhibited increased glomerular sclerosis (51% vs 13%, P < .001) and interstitial fibrosis and tubular atrophy (83% vs 13%, P < .001) compared with distant parenchyma.

CONCLUSIONS

Diabetic nephropathy can be reliably detected in the PAB, which is important in partial nephrectomies or renal mass biopsies without ample distant renal parenchyma. The degree of glomerular and tubulointerstitial scarring within the PAB does not reflect the overall degree of chronic kidney disease.

Anti-melanoma effects of concomitant inhibition of SIRT1 and SIRT3 in BrafV600E/PtenNULL mice

Novel therapeutic strategies are required for the effective and lasting treatment of metastatic melanoma, one of the deadliest skin malignancies. In this study, we determined the anti-melanoma efficacy of 4'-bromo-resveratrol (4'-BR), which is a small molecule dual inhibitor of SIRT1 and SIRT3 in a Braf^V600E/Pten^NULL mouse model that recapitulates human disease, including metastases. Tumors were induced by topical application of 4-hydroxy-tamoxifen on shaved backs of 10-week-old mice, and the effects of 4'-BR (5-30 mg/kg b.wt.; intraperitoneally; 3d/week for 5 weeks) were assessed on melanoma development and progression. We found that 4'-BR at a dose of 30 mg/kg significantly reduced size and volume of primary melanoma tumors, as well as lung metastasis, with no adverse effects. Further, mechanistic studies on tumors showed significant modulation in markers of proliferation, survival and melanoma progression. As SIRT1 and SIRT3 are linked to immunomodulation, we performed differential gene expression analysis via NanoString PanCancer Immune Profiling panel (770 genes). Our data demonstrated that 4'-BR significantly downregulated genes related to metastasis-promotion, chemokine/cytokine-regulation, and innate/adaptive immune functions. Overall, inhibition of SIRT1 and SIRT3 by 4'-BR is a promising anti-melanoma therapy with anti-metastatic and immunomodulatory activities warranting further detailed studies, including clinical investigations.

ISUP Consensus Definition of Cribriform Pattern Prostate Cancer

The presence of a cribriform pattern is now recognized as a clinically important, independent adverse prognostic indicator for prostate cancer. For this reason the International Society of Urological Pathology (ISUP) recently recommended its inclusion in standard reporting. In order to improve interobserver agreement as to the diagnosis of cribriform patterns, the ISUP assembled an international panel of 12 expert urogenital pathologists for the purpose of drafting a consensus definition of cribriform pattern in prostate cancer, and provide their opinions on a set of 32 images and on potential diagnostic criteria. These images were selected by the 2 nonvoting convenors of the study and included the main categories where disagreement was anticipated. The Delphi method was applied to promote consensus among the 12 panelists in their review of the images during 2 initial rounds of the study. Following a virtual meeting, convened to discuss selected images and diagnostic criteria, the following definition for cribriform pattern in prostate cancer was approved: "A confluent sheet of contiguous malignant epithelial cells with multiple glandular lumina that are easily visible at low power (objective magnification ×10). There should be no intervening stroma or mucin separating individual or fused glandular structures" together with a set of explanatory notes. We believe this consensus definition to be practical and that it will facilitate reproducible recognition and reporting of this clinically important pattern commonly seen in prostate cancer. The images and the results of the final Delphi round are available at the ISUP website as an educational slide set (https://isupweb.org/isup/blog/slideshow/cribriform-slide-deck/).

Growth and differentiation factor 15 and NF-κB expression in benign prostatic biopsies and risk of subsequent prostate cancer detection

Growth and differentiation factor 15 (GDF‐15), also known as macrophage inhibitory cytokine 1 (MIC‐1), may act as both a tumor suppressor and promotor and, by regulating NF‐κB and macrophage signaling, promote early prostate carcinogenesis. To determine whether expression of these two inflammation‐related proteins affect prostate cancer susceptibility, dual immunostaining of benign prostate biopsies for GDF‐15 and NF‐κB was done in a study of 503 case‐control pairs matched on date, age, and race, nested within a historical cohort of 10,478 men. GDF‐15 and NF‐κB expression levels were positively correlated (r = 0.39; p < 0.0001), and both were significantly lower in African American (AA) compared with White men. In adjusted models that included both markers, the odds ratio (OR) for NF‐κB expression was statistically significant, OR =0.87; p = 0.03; 95% confidence interval (CI) =0.77–0.99, while GDF‐15 expression was associated with a nominally increased risk, OR =1.06; p = 0.27; 95% CI =0.96–1.17. When modeling expression levels by quartiles, the highest quartile of NF‐κB expression was associated with almost a fifty percent reduction in prostate cancer risk (OR =0.51; p = 0.03; 95% CI =0.29–0.92). In stratified models, NF‐κB had the strongest negative association with prostate cancer in non‐aggressive cases (p = 0.03), older men (p = 0.03), and in case‐control pairs with longer follow‐up (p = 0.02). Risk associated with GDF‐15 expression was best fit using nonlinear regression modeling where both first (p = 0.02) and second (p = 0.03) order GDF‐15 risk terms were associated with significantly increased risk. This modeling approach also revealed significantly increased risk associated with GDF‐15 expression for subsamples defined by AA race, aggressive disease, younger age, and in case‐control pairs with longer follow‐up. Therefore, although positively correlated in benign prostatic biopsies, NF‐κB and GDF‐15 expression appear to exert opposite effects on risk of prostate tumor development.

Cribriform prostate cancer: Morphologic criteria enabling a diagnosis, based on survey of experts

Among four sub-patterns of Gleason grade 4 prostate cancer, voluminous evidence supports that the cribriform pattern holds an unfavorable prognostic impact, as compared with poorly-formed, fused, or glomeruloid. The International Society of Urological Pathology (ISUP) recommends specifying whether invasive grade 4 cancer is cribriform. Recently, ISUP experts published a consensus definition of cribriform pattern highlighting criteria that distinguish it from mimickers. The current study aimed to analyze morphologic features separately to identify those that define the essence of the cribriform pattern. Thirty-two selected photomicrographs were classified by 12 urologic pathologists as: definitely cribriform cancer, probably cribriform, unsure, probably not cribriform, or definitely not cribriform. Consensus was defined as 9/12 agree or disagree, with ≤1 strongly supporting the opposite choice. Final consensus was achieved in 21 of 32 cases. Generalized estimating equation (GEE) model with logit link was fitted to estimate effect of multiple morphologic predictors. Fisher exact test was used for categorical findings. Presence of intervening stroma precluded calling cribriform cancer (p = 0.006). Mucin presence detracted (p = 0.003) from willingness to call cribriform cancer (only 3 cases had mucin). Lumen number was associated with cribriform consensus (p = 0.0006), and all consensus cases had ≥9 lumens. Predominant papillary pattern or an irregular outer boundary detracted (p = NS). Invasive cribriform carcinoma should have absence of intervening stroma, and usually neither papillary pattern, irregular outer boundary, nor very few lumens. Setting the criteria for cribriform will help prevent over- or undercalling this important finding.

Comparative influence of cribriform growth and percent Gleason 4 in prostatic biopsies with Gleason 3+4 cancer

The International Society of Urological Pathology endorses specifying presence of cribriform architecture in Gleason (G)4 prostate cancer because of cribriform's aggressiveness. The relative effect of cribriform presence versus percentage G4 within grade group (GG)2 or 3 was uncertain. 194 men's biopsies with GG2 with or without cribriform (excluding glomeruloid from cribriform) and GG3 without cribriform (controls) from 4 years were reviewed. 173 cases had follow-up including 147 GG2 (15/147 or 10% had cribriform) and 26 GG3. Effects of total tumor specimen involvement, %Gleason 4, and cribriform were stratified into prostatectomy (n = 90), radiotherapy (n = 61), and watching waiting (n = 22) groups. Median follow-up duration was 3.32 years (range 1.90-6.18). Biochemical failures in the above 3 cohorts numbered 9 (9/90; 10%), 5 (5/61; 8%), and 13 (13/22; 59%) respectively. In all groups, (GG2+ GG3, n = 173), the HR for C pattern was 1.64. In GG2, cribriform presence (considering glomeruloid as non-cribriform) conferred a hazard ratio (HR) of 1.51 (p = 0.48). It was 1.38, excluding glomeruloid. In watchful waiting cohort only, presence of C conferred a HR of 2.62 (p = 0.086). All remaining comparisons including percent G4, remained not significant. Thus, only in WW group did cribriform pattern presence approach significance. Detection of differences otherwise was not feasible, probably because: 1) biochemical failure is too rare in GG2 cancer; 2) cribriform frequency was only 10% in GG2 (in current study), less than in higher-grade cancer. 3) Use of biopsy tissue is subject to sampling variation which may undersample cribriform pattern, though biopsy forms the basis of treatment decisions.

Paraganglioma of the Urinary Bladder Metastatic to the Lung in a Patient with SDHB Gene Mutation: A Case Report

Introduction/Objective

Paragangliomas are tumors originating from the neural crest. Most tumors are benign and arise from various locations in the body. Extra-adrenal paragangliomas arise as sporadic cases in most settings or as part of heredofamilial syndromes in about one-quarter of cases. Succinate dehydrogenase subunit B (SDHB) gene mutations are associated with an aggressive clinical disease course of pheochromocytoma/paraganglioma.

Methods

We present a 41-year-old male former smoker with a history of a growing right upper lung nodule on chest imaging. He had no cough or respiratory symptoms. Twenty-seven months prior the patient underwent a cystoprostatectomy due to paraganglioma of the bladder. Genetic testing identified a pathogenic mutation in SDHB gene, c.166_170delCCTCA (p.Pro56Tyrfs*5). He underwent a wedge resection of the lung nodule.

Results

Sectioning of the lung wedge revealed a well circumscribed, firm tan nodule. Microscopically there were nests of large neoplastic cells with round nuclei and eosinophilic granular cytoplasm. Tumor cells were positive for synaptophysin and chromogranin and negative for pan-cytokeratin. S100 highlighted sustentacular cells. The pulmonary neoplasm was morphologically similar to the prior tumor of the bladder. These features are consistent with a metastatic urothelial paraganglioma to the lung, in a background of a hereditary paraganglioma syndrome.

Conclusion

Extra-adrenal paraganglioma occurring in a setting of hereditary paraganglioma syndrome has a higher risk of metastasis. Lifelong surveillance even after prompt resection of primary tumor with negative margins is required to ensure early detection of metastasis and prevention of complications associated with it.

Accurate segmentation of prostate cancer histomorphometric features using a weakly supervised convolutional neural network

Purpose: Prostate cancer primarily arises from the glandular epithelium. Histomophometric techniques have been used to assess the glandular epithelium in automated detection and classification pipelines; however, they are often rigid in their implementation, and their performance suffers on large datasets where variation in staining, imaging, and preparation is difficult to control. The purpose of this study is to quantify performance of a pixelwise segmentation algorithm that was trained using different combinations of weak and strong stroma, epithelium, and lumen labels in a prostate histology dataset.

Approach: We have combined weakly labeled datasets generated using simple morphometric techniques and high-quality labeled datasets from human observers in prostate biopsy cores to train a convolutional neural network for use in whole mount prostate labeling pipelines. With trained networks, we characterize pixelwise segmentation of stromal, epithelium, and lumen (SEL) regions on both biopsy core and whole-mount H&E-stained tissue.

Results: We provide evidence that by simply training a deep learning algorithm on weakly labeled data generated from rigid morphometric methods, we can improve the robustness of classification over the morphometric methods used to train the classifier.

Conclusions: We show that not only does our approach of combining weak and strong labels for training the CNN improve qualitative SEL labeling within tissue but also the deep learning generated labels are superior for cancer classification in a higher-order algorithm over the morphometrically derived labels it was trained on.

Radio-pathomic mapping model generated using annotations from five pathologists reliably distinguishes high-grade prostate cancer

Purpose: Our study predictively maps epithelium density in magnetic resonance imaging (MRI) space while varying the ground truth labels provided by five pathologists to quantify the downstream effects of interobserver variability. Approach: Clinical imaging and postsurgical tissue from 48 recruited prospective patients were used in our study. Tissue was sliced to match the MRI orientation and whole-mount slides were stained and digitized. Data from 28 patients ( n = 33 slides) were sent to five pathologists to be annotated. Slides from the remaining 20 patients ( n = 123 slides) were annotated by one of the five pathologists. Interpathologist variability was measured using Krippendorff's alpha. Pathologist-specific radiopathomic mapping models were trained using a partial least-squares regression using MRI values to predict epithelium density, a known marker for disease severity. An analysis of variance characterized intermodel means difference in epithelium density. A consensus model was created and evaluated using a receiver operator characteristic classifying high grade versus low grade and benign, and was statistically compared to apparent diffusion coefficient (ADC). Results: Interobserver variability ranged from low to acceptable agreement (0.31 to 0.69). There was a statistically significant difference in mean predicted epithelium density values ( p < 0.001 ) between the five models. The consensus model outperformed ADC (areas under the curve = 0.80 and 0.71, respectively, p < 0.05 ). Conclusion: We demonstrate that radiopathomic maps of epithelium density are sensitive to the pathologist annotating the dataset; however, it is unclear if these differences are clinically significant. The consensus model produced the best maps, matched the performance of the best individual model, and outperformed ADC.

The 2019 International Society of Urological Pathology Consensus Conference on Prostate Cancer Grading

Modifications recommended by the International Society of Urological Pathology 2019 conference on prostate cancer grading include the mandatory reporting of cribriform pattern and intraductal carcinoma, inclusion of intraductal carcinoma grade in the Gleason score, and separate aggregate reporting for magnetic resonance imaging-targeted lesions.

Abstract 2918: Concomitant inhibition of SIRT1 and SIRT3 reduces melanoma growth and metastasis in BRAFV600E/PTENNULL transgenic mice

Metastatic melanoma, one of the most aggressive types of skin cancer, is extremely difficult to treat, with a median overall survival of less than one year. Despite recent advances in targeted- and immune- therapies, the treatment options have either failed to achieve &gt;25% response or the responses have been short-lived with the emergence of resistance. Therefore, newer approaches are needed for the management of this deadly neoplasm. 4′-bromo-resveratrol [5-(2-(4-hydroxyphenyl)vinyl)-1,3-benzenediol; 4′-BR], an analog of resveratrol, is a dual small molecule inhibitor of sirtuins 1 and 3 (SIRTs 1 & 3), which have pro-proliferative functions in melanoma. In a recently published study, we demonstrated that 4′-BR induced apoptosis and caused metabolic reprogramming in human melanoma cells, leading to reduced proliferation and growth of melanoma cells in vitro. In order to validate our in vitro findings to in vivo situations, in this study, we evaluated the therapeutic efficacy of 4′-BR on melanoma growth and metastasis in a genetically engineered transgenic (BRAFV600E/PTENNull) mouse model of melanoma. This mouse model shows melanoma's cardinal features and is an excellent model to test drug efficacy in pre-clinical settings. To induce melanoma tumors, 4-hydroxytamoxifen was applied on shaved backs of 10-week-old mice topically once per day for 3 consecutive days. Highly pigmented tumors appeared 10 days after tamoxifen application. At this point, treatment with 4′-BR (0, 5, 10, 20 and 30 mg/kg b.wt.; intraperitoneal; 3d/week; n=6 mice/group) was started. Body weight, tumor size and volume were measured weekly. At the termination of the study (~17 weeks of age), we observed significant reduction in tumor volume and tumor weight in mice treated with 30 mg/kg 4'-BR with no noticeable adverse effects. Further, we analyzed markers for cell proliferation and survival (Ki67, PCNA, and Survivin), metastasis (Vimentin), oxidative stress (Nrf2 and Keap1) and growth factor signaling (IGF1 and IGFBP5) using immunohistochemistry (IHC) or real-time quantitative PCR (RT-qPCR) in tumors. IHC analysis revealed that 4′-BR treatment markedly decreased Ki67 positive tumor cells. RT-qPCR analysis showed that 4'-BR treatments significantly decreased expression of PCNA, Survivin, and IGF1 (a melanoma promoting growth factor), as well as significantly increased expression of IGFBP5, a tumor suppressor gene. Furthermore, we observed that 4'-BR treatment significantly decreased the ratio of Nrf2/Keap1. In addition, our data demonstrated a significant decrease in lung metastasis and the levels of metastasis marker Vimentin in 4'-BR treatment group. Overall, these data show the ability of 4′-BR to exert anti-proliferative, anti-tumorigenic, and anti-metastatic effects in a human-relevant melanoma mouse model, thus warranting further pre-clinical and clinical investigations in this direction.

Citation Format: Gagan Chhabra, Chandra K. Singh, Mary A. Ndiaye, Kenneth A. Iczkowski, Nihal Ahmad. Concomitant inhibition of SIRT1 and SIRT3 reduces melanoma growth and metastasis in BRAFV600E/PTENNULL transgenic mice [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2918.

CRISPR/Cas9-mediated Knockout of SIRT6 Imparts Remarkable Antiproliferative Response in Human Melanoma Cells in vitro and in vivo

Melanoma is one of the most aggressive, potentially fatal forms of skin cancer and has been shown to be associated with solar ultraviolet radiation-dependent initiation and progression. Despite remarkable recent advances with targeted and immune therapeutics, lasting and recurrence-free survival remain significant concerns. Therefore, additional novel mechanism-based approaches are needed for effective melanoma management. The sirtuin SIRT6 appears to have a pro-proliferative function in melanocytic cells. In this study, we determined the effects of genetic manipulation of SIRT6 in human melanoma cells, in vitro and in vivo. Our data demonstrated that CRISPR/Cas9-mediated knockout (KO) of SIRT6 in A375 melanoma cells resulted in a significant (1) decrease in growth, viability and clonogenic survival and (2) induction of G1-phase cell cycle arrest. Further, employing a RT² Profiler PCR array containing 84 key transformation and tumorigenesis genes, we found that SIRT6 KO resulted in modulation of genes involved in angiogenesis, apoptosis, cellular senescence, epithelial-to-mesenchymal transition, hypoxia signaling and telomere maintenance. Finally, we found significantly decreased tumorigenicity of SIRT6 KO A375 cells in athymic nude mice. Our data provide strong evidence that SIRT6 promotes melanoma cell survival, both in vitro and in vivo, and could be exploited as a target for melanoma management.

Squamous Cell Carcinoma of the Bladder Is Not Associated With High-risk HPV

OBJECTIVE

To evaluate the clinical features, pathologic features, and prevalence of human papilloma virus (HPV) in squamous cell carcinoma (SCC) of the bladder. SCC of the bladder is known to be associated with conditions that cause chronic inflammation/irritation. The literature is inconsistent regarding the association of HPV with pure SCC of the bladder.

METHODS

A multi-institutional study identified cases of SCC of the bladder. Pure squamous histology and the absence of urothelial carcinoma in situ were required for inclusion. Clinical and pathologic features were collected, and tissues were evaluated for high-risk HPV using p16 immunohistochemistry and in situ hybridization.

RESULTS

We identified 207 cases of SCC of the bladder. Risk factors for bladder cancer included smoking (133/207, 64%) and chronic bladder irritation (83/207, 40%). The majority (155/207, 75%) of patients had > pT2 disease. Mean tumor size was 5.6 ± 3.0 cm and 36/207 (17%) patients had lymph node positive disease. p16 immunohistochemistry was positive in 52/204 (25%) cases but high-risk HPV was identified with in situ hybridization in only 1 (0.5%) case. Tumor size, stage, number of lymph nodes removed, number of positive lymph nodes, lymphovascular invasion, perineural invasion, and positive margins each were associated with cancer-specific mortality when adjusted for demographic factors. A multivariate analysis of variable importance further revealed sex and race as important factors in predicting cancer-specific mortality.

CONCLUSION

SCC of the bladder is an aggressive histologic subtype. Although bladder SCC can express p16, it is not typically associated with high-risk HPV, although rare cases can occur.

Corpora amylacea in benign prostatic acini are associated with concurrent, predominantly low-grade cancer

BACKGROUND

Corpora amylacea (CAM), in benign prostatic acini, contain acute-phase proteins. Do CAM coincide with carcinoma?

METHODS

Within 270 biopsies, 83 prostatectomies, and 33 transurethral resections (TURs), CAM absence was designated CAM 0; corpora in less than 5% of benign acini: CAM 1; in 5% to 25%: CAM 2; in more than 25%: CAM 3. CAM were compared against carcinoma presence, clinicopathologic findings, and grade groups (GG) 1 to 2 vs 3 to 5. The frequency of CAM according to anatomic zone was counted. A pilot study was conducted using paired initial benign and repeat biopsies (33 benign, 24 carcinoma).

RESULTS

A total of 68.9% of biopsies, 96.4% of prostatectomies, and 66.7% of TURs disclosed CAM. CAM ≥1 was common at an older age (P = .019). In biopsies, 204 cases (75%) had carcinoma; and CAM of 2 to 3 (compared to 0-1) were recorded in 25.0% of carcinomas but only 7.4% of benign biopsies (P = .005; odds ratio [OR] = 5.1). CAM correlated with high percent Gleason pattern 3, low GG (P = .035), and chronic inflammation (CI). CI correlated inversely with carcinoma (P = .003). CAM disclosed no association with race, body mass index, serum prostate specific antigen (PSA), acute inflammation (in biopsies), atrophy, or carcinoma volume. With CAM 1, the odds of GG 3 to 5 carcinoma, by comparison to CAM 0, decreased more than 2× (OR = 0.48; P = .032), with CAM 2, more than 3× (OR = 0.33; P = .005), and with CAM 3, almost 3× (OR = 0.39, P = .086). For men aged less than 65, carcinoma predictive model was: Score = (2 × age) + (5 × PSA) - (20 × degree of CAM); using our data, area under the ROC curve was 78.17%. When the transition zone was involved by cancer, it showed more CAM than in cases where it was uninvolved (P = .012); otherwise zonal distributions were similar. In the pilot study, CAM ≥1 predicted carcinoma on repeat biopsy (P < .05; OR = 8), as did CAM 2 to 3 (P < .0001; OR = 30). CI was not significant, and CAM retained significance after adjusting for CI.

CONCLUSION

CAM correlate with carcinoma. Whether abundant CAM in benign biopsies adds value amidst high clinical suspicion, warrants further study.

Gleason Probability Maps: A Radiomics Tool for Mapping Prostate Cancer Likelihood in MRI Space

Prostate cancer is the most common noncutaneous cancer in men in the United States. The current paradigm for screening and diagnosis is imperfect, with relatively low specificity, high cost, and high morbidity. This study aims to generate new image contrasts by learning a distribution of unique image signatures associated with prostate cancer. In total, 48 patients were prospectively recruited for this institutional review board–approved study. Patients underwent multiparametric magnetic resonance imaging 2 weeks before surgery. Postsurgical tissues were annotated by a pathologist and aligned to the in vivo imaging. Radiomic profiles were generated by linearly combining 4 image contrasts (T2, apparent diffusion coefficient [ADC] 0-1000, ADC 50-2000, and dynamic contrast-enhanced) segmented using global thresholds. The distribution of radiomic profiles in high-grade cancer, low-grade cancer, and normal tissues was recorded, and the generated probability values were applied to a naive test set. The resulting Gleason probability maps were stable regardless of training cohort, functioned independent of prostate zone, and outperformed conventional clinical imaging (area under the curve [AUC] = 0.79). Extensive overlap was seen in the most common image signatures associated with high- and low-grade cancer, indicating that low- and high-grade tumors present similarly on conventional imaging.

Artificial intelligence for diagnosis and grading of prostate cancer in biopsies: a population-based, diagnostic study

BACKGROUND

An increasing volume of prostate biopsies and a worldwide shortage of urological pathologists puts a strain on pathology departments. Additionally, the high intra-observer and inter-observer variability in grading can result in overtreatment and undertreatment of prostate cancer. To alleviate these problems, we aimed to develop an artificial intelligence (AI) system with clinically acceptable accuracy for prostate cancer detection, localisation, and Gleason grading.

METHODS

We digitised 6682 slides from needle core biopsies from 976 randomly selected participants aged 50-69 in the Swedish prospective and population-based STHLM3 diagnostic study done between May 28, 2012, and Dec 30, 2014 (ISRCTN84445406), and another 271 from 93 men from outside the study. The resulting images were used to train deep neural networks for assessment of prostate biopsies. The networks were evaluated by predicting the presence, extent, and Gleason grade of malignant tissue for an independent test dataset comprising 1631 biopsies from 246 men from STHLM3 and an external validation dataset of 330 biopsies from 73 men. We also evaluated grading performance on 87 biopsies individually graded by 23 experienced urological pathologists from the International Society of Urological Pathology. We assessed discriminatory performance by receiver operating characteristics and tumour extent predictions by correlating predicted cancer length against measurements by the reporting pathologist. We quantified the concordance between grades assigned by the AI system and the expert urological pathologists using Cohen's kappa.

FINDINGS

The AI achieved an area under the receiver operating characteristics curve of 0·997 (95% CI 0·994-0·999) for distinguishing between benign (n=910) and malignant (n=721) biopsy cores on the independent test dataset and 0·986 (0·972-0·996) on the external validation dataset (benign n=108, malignant n=222). The correlation between cancer length predicted by the AI and assigned by the reporting pathologist was 0·96 (95% CI 0·95-0·97) for the independent test dataset and 0·87 (0·84-0·90) for the external validation dataset. For assigning Gleason grades, the AI achieved a mean pairwise kappa of 0·62, which was within the range of the corresponding values for the expert pathologists (0·60-0·73).

INTERPRETATION

An AI system can be trained to detect and grade cancer in prostate needle biopsy samples at a ranking comparable to that of international experts in prostate pathology. Clinical application could reduce pathology workload by reducing the assessment of benign biopsies and by automating the task of measuring cancer length in positive biopsy cores. An AI system with expert-level grading performance might contribute a second opinion, aid in standardising grading, and provide pathology expertise in parts of the world where it does not exist.

FUNDING

Swedish Research Council, Swedish Cancer Society, Swedish eScience Research Center, EIT Health.

Small Cell Variant of Metastatic Melanoma: A Mimicker of Lymphoblastic Leukemia/Lymphoma

It is well-known to pathologists that melanoma is "the great mimicker" and can look like anything. Despite this widespread awareness, the diagnosis remains a continuous challenge, especially when a metastatic melanoma with rare morphology is examined. We report a case of a 64-year-old man with a lung mass and right-sided pleural effusion who underwent video-assisted thoracoscopic surgery for pleural decortication. The history of melanoma was not reported to us. Microscopic examination revealed sheets of small round blue cells infiltrating into the adipose tissue in a lace-like pattern mimicking lymphoblastic lymphoma. Immunohistochemical stains for melanocytic markers, including S-100 protein, Mart-1, and HMB-45, highlighted the neoplastic cells. The tumor was also positive for CD56 and CD117, but negative for pancytokeratin, CD45, cytokeratin 8, TTF-1, WT1, CD34, chromogranin, synaptophysin, and neuron-specific enolase. The findings were most consistent with metastatic small cell melanoma, an uncommon variant of melanoma that closely resembles lymphoblastic lymphoma and other malignant small round blue cell tumors. To our knowledge, we are the first to describe a case of metastatic small cell melanoma to the pleura in an adult. Clinical and histological details are provided with a review of the literature.

Enzalutamide-Induced Feed-Forward Signaling Loop Promotes Therapy-Resistant Prostate Cancer Growth Providing an Exploitable Molecular Target for Jak2 Inhibitors

The second-generation antiandrogen, enzalutamide, is approved for castrate-resistant prostate cancer (CRPC) and targets androgen receptor (AR) activity in CRPC. Despite initial clinical activity, acquired resistance to enzalutamide arises rapidly and most patients develop terminal disease. Previous work has established Stat5 as a potent inducer of prostate cancer growth. Here, we investigated the significance of Jak2-Stat5 signaling in resistance of prostate cancer to enzalutamide. The levels of Jak2 and Stat5 mRNA, proteins and activation were evaluated in prostate cancer cells, xenograft tumors, and clinical prostate cancers before and after enzalutamide therapy. Jak2 and Stat5 were suppressed by genetic knockdown using lentiviral shRNA or pharmacologic inhibitors. Responsiveness of primary and enzalutamide-resistant prostate cancer to pharmacologic inhibitors of Jak2-Stat5 signaling was assessed in vivo in mice bearing prostate cancer xenograft tumors. Patient-derived prostate cancers were tested for responsiveness to Stat5 blockade as second-line treatment after enzalutamide ex vivo in tumor explant cultures. Enzalutamide-liganded AR induces sustained Jak2-Stat5 phosphorylation in prostate cancer leading to the formation of a positive feed-forward loop, where activated Stat5, in turn, induces Jak2 mRNA and protein levels contributing to further Jak2 activation. Mechanistically, enzalutamide-liganded AR induced Jak2 phosphorylation through a process involving Jak2-specific phosphatases. Stat5 promoted prostate cancer growth during enzalutamide treatment. Jak2-Stat5 inhibition induced death of prostate cancer cells and patient-derived prostate cancers surviving enzalutamide treatment and blocked enzalutamide-resistant tumor growth in mice. This work introduces a novel concept of a pivotal role of hyperactivated Jak2-Stat5 signaling in enzalutamide-resistant prostate cancer, which is readily targetable by Jak2 inhibitors in clinical development.

Eosinophilic Kidney Tumors: Old and New

Context.—

Eosinophilic cytoplasm is the most common finding of difficult-to-classify kidney tumors. Morphology, cytogenetics, and immunohistochemical stains are discriminatory. This review compares well-recognized tumors such as granular clear cell carcinoma, papillary variants, chromophobe renal cell carcinoma, and oncocytoma and introduces newly described entities of hybrid oncocytic tumors, carcinomas defined by translocations, and carcinomas with deficiencies in the tricarboxylic acid cycle. The focus is on immunostaining, clinical correlations, and differential diagnoses. Representative examples of some entities are presented with elaboration on their workup.

Objective.—

To provide a review of the differential diagnoses for renal neoplasms with eosinophilic cytoplasm and elaborate on methods that may assist with correct identification.

Data Sources.—

Review of current literature on kidney tumors with eosinophilic cytoplasm, as well as the authors' personal experience.

Conclusions.—

Eosinophilic cytoplasm is a feature shared by many kidney tumors. Understanding the morphologic differences and the role of ancillary studies is key when encountering such a tumor.

KIF3B protein expression loss correlates with metastatic ability of prostate cancer

Kinesin family member 3B (KIF3B) is a microtubule motor kinesin involved in mitotic progression and vasculotropism. A novel therapeutic target, it is overexpressed in several cancers [PMID 29904055]. Its significance in prostate cancer (PC) was uncertain.

METHODS

89 cases, including tissue microarrays from 70 prostatectomies comprising matched cancer and benign spots, 19 additional prostatectomy tissues, plus 16 prostate cancer metastases (7 nodal and 9 distant sites; 8 had matched primary PC) were stained with rabbit polyclonal KIF3B antibody. Cytoplasmic immunoreactivity was scored: 0 (negative) to 3+ (strong and diffuse). 39 patients had no nodal metastases, 31 had positive lymph nodes, and 19 had nodes not sampled. Gleason grade groups were 1 (9), 2 (28), 3 (39), 4 (1), and 5 (12). 15 cases had cribriform pattern. AJCC stages were 2 (48), 3 (29), unknown (12).

RESULTS

KIF3B in PC (mean 1.0) was higher than in benign prostate (mean 0.1, P<0.01, Student t-test). All 7 available nodal metastases of PC were negative. One-third of primary PCs with nodal metastases lost all expression, compared to retained expression in all but one PC without nodal metastasis (P<0.01, chi-square). The former group also had stronger staining (mean 1.0) than metastases (mean 0.3) (P<0.01, Student t-test) and had fewer cases with any positive (>0) expression compared to cases without metastases or with unsampled lymph nodes (P<0.01, chi-square test). Reactivity of paired metastatic tissue and primary PC correlated strongly (Pearson coefficient: +0.7). No significant trends were found by grade group, cribriform status, or stage.

CONCLUSIONS

KIF3B is a PC marker. Metastatic cancers showed less KIF3B expression than their primary PC counterparts, and primary cases with positive nodes demonstrated reduced positivity, suggesting use as a prognostic marker. It is possible that KIF3B protein becomes altered prior to metastases, preventing immunohistochemical detection.

Improving sensitivity of amyloid detection by Congo red stain by using polarizing microscope and avoiding pitfalls

Systemic amyloidosis is a devastating group of disorders for which there is no current cure. The treatment goal is to reduce the burden of amyloidogenic protein precursors. The treatment is only effective if applied early in the disease process before significant and irreversible end organ damage has taken place. Congo red is still the standard stain used in most histopathology laboratories to identify amyloid material in tissues. The identification of Congophilic amyloid material is challenging because of multiple interfering factors. Here we describe improved sensitivity of identifying Congophilic materials in histologic sections using a metallurgical polarized microscope specifically constructed for polarized microscopy. The microscope is equipped with strain-free optics, matching polarizers, dis-integrated compensators, and a circular mobile stage. Compared to a standard clinical microscope, this setup significantly improves sensitivity of identifying amyloid material in Congo red-stained slides. We also describe the deleterious effect of plastic coverslip which can interfere with the ability to examine the slides under polarized light. We present a series of 10 different patients who had cardiac, brain, and salivary gland biopsies that were either equivocal or deemed negative using a standard clinical microscope but were positive using the equipment described above. These samples were confirmed to be positive by other methods including electron microscopy. We conclude that use of the correct equipment is needed before ruling out amyloidosis in tissue sections.

Rete Testis Invasion Is Consistent With Pathologic Stage T1 in Germ Cell Tumors

OBJECTIVES

Rete testis invasion by germ cell tumors is frequently concomitant with lymphovascular or spermatic cord invasion (LVI/SCI); independent implications for staging are uncertain.

METHODS

In total, 171 seminomas and 178 nonseminomatous germ cell tumors (NSGCTs; 46 had 1%-60% seminoma component) came from five institutions. Metastatic status at presentation, as a proxy for severity, was available for all; relapse data were unavailable for 152. Rete direct invasion (ReteD) and rete pagetoid spread (ReteP) were assessed.

RESULTS

ReteP and ReteD were more frequent in seminoma than NSGCT. In seminoma, tumor size bifurcated at 3 cm or more or less than 3 cm predicted metastatic status. Tumors with ReteP or ReteD did not differ in size from those without invasions but were less than with LVI/SCI; metastatic status or relapse did not show differences. In NSGCT, ReteP/ReteD did not correlate with size, metastatic status, or relapse.

CONCLUSIONS

Findings support retaining American Joint Committee for Cancer pathologic T1 stage designation for rete testis invasion and pT1a/pT1b substaging of seminoma.