Fusion of old and new: Employing touch imprint slides for next generation sequencing in solid tumors

BACKGROUND

Cytomorphological evaluation of tissue touch imprints during rapid on-site evaluation or intraoperative pathology consultation has crucial value. However, literature on their utility for molecular testing is limited. In this study, we emphasize a further benefit of touch imprint slides and scrutinize our institutional experience on their use in molecular testing, specifically next generation sequencing (NGS).

MATERIALS AND METHODS

NGS-based reports (2019-2023) of Koç University Hospital were retrospectively analyzed and circumstances in which sequencing was conducted on touch imprint slides were retrieved (n = 18). Type/location of the biopsy, diagnosis, results, and quality metrics were recorded.

RESULTS

Touch imprints were addressed when they harbored more neoplastic cells compared with permanent biopsies, when suboptimal fixation mitigated deoxyribonucleic acid/ribonucleic acid (DNA/RNA) yield in resections or when the sample was obtained from bone and required decalcification. Diagnoses were diverse, namely non-small-cell lung cancer, gastric adenocarcinoma, glial tumor, Ewing sarcoma, and carcinoma of unknown primary. The percentage of tumor cells on slides stretched between 15% and 70%. Molecular findings ranged from KRAS mutations to TRIM1::NTRK2 and EWSR::FLI1 fusions. For five cases, sequencing did not yield any alteration, one study was not completed because it did not yield high-quality RNA.

CONCLUSION

Touch imprint slides provide a reliable alternative, especially when neoplastic cells are scarce in permanent biopsies or decalcification deters nucleic acid quality. Based on our experience, we suggest making touch imprints on a routine basis, especially for every bone biopsy. Once digitally scanned duplicates are made, original slides can be safely used for DNA-/RNA-based molecular studies.

Large Language Models as a Rapid and Objective Tool for Pathology Report Data Extraction

Medical institutions continuously create a substantial amount of data that is used for scientific research. One of the departments with a great amount of archived data is the pathology department. Pathology archives hold the potential to create a case series of valuable rare entities or large cohorts of common entities. The major problem in creation of these databases is data extraction which is still commonly done manually and is highly laborious and error prone. For these reasons, we offer using large language models to overcome these challenges. Ten pathology reports of selected resection specimens were retrieved from electronic archives of Koç University Hospital for the initial set. These reports were de-identified and uploaded to ChatGPT and Google Bard. Both algorithms were asked to turn the reports in a synoptic report format that is easy to export to a data editor such as Microsoft Excel or Google Sheets. Both programs created tables with Google Bard facilitating the creation of a spreadsheet from the data automatically. In conclusion, we propose the use of AI-assisted data extraction for academic research purposes, as it may enhance efficiency and precision compared to manual data entry.

Novel ALK immunohistochemistry assay (clone OTI1A4, Dako) is a sensitive, reliable marker for identifying ALK rearrangements in lung adenocarcinomas: A validation study

OBJECTIVES

We present the first study validating the recent Dako ALK assay (clone OTI1A4, in vitro diagnostic) for detecting ALK rearrangements in lung adenocarcinoma.

METHODS

Lung adenocarcinoma cases between 2011 and 2023 were retrospectively collected to create a cohort of 203 samples. Cases were stained with Dako ALK OTI1A4 and Ventana ALK D5F3 and reviewed by 3 pathologists independently. Correlation between assays, including their sensitivity and specificity, was evaluated.

RESULTS

The cohort (n = 203) consisted of resections, core needle biopsies, and cell blocks. Agreement between Dako ALK OTI1A4 and Ventana ALK D5F3 assays was "almost perfect," with κ = 0.89. The sensitivity and specificity of the Dako ALK OTI1A4 assay were 93.3% and 96%, respectively, in a subgroup of 55 molecularly confirmed cases (n = 30 with and n = 25 without ALK rearrangement).

CONCLUSIONS

Immunohistochemistry-based assays provide a valid and reasonably priced alternative, especially in settings where molecular confirmatory tests are neither offered nor accessible. Given high interassay and molecular concordance, we propose that the novel Dako OTI1A4 assay can be reliably used to identify cases with ALK rearrangement.

Predicting Prostate Cancer Molecular Subtype With Deep Learning on Histopathologic Images

Microscopic examination of prostate cancer has failed to reveal a reproducible association between molecular and morphologic features. However, deep-learning algorithms trained on hematoxylin and eosin (H&E)-stained whole slide images (WSI) may outperform the human eye and help to screen for clinically-relevant genomic alterations. We created deep-learning algorithms to identify prostate tumors with underlying ETS-related gene (ERG) fusions or PTEN deletions using the following 4 stages: (1) automated tumor identification, (2) feature representation learning, (3) classification, and (4) explainability map generation. A novel transformer-based hierarchical architecture was trained on a single representative WSI of the dominant tumor nodule from a radical prostatectomy (RP) cohort with known ERG/PTEN status (n = 224 and n = 205, respectively). Two distinct vision transformer-based networks were used for feature extraction, and a distinct transformer-based model was used for classification. The ERG algorithm performance was validated across 3 RP cohorts, including 64 WSI from the pretraining cohort (AUC, 0.91) and 248 and 375 WSI from 2 independent RP cohorts (AUC, 0.86 and 0.89, respectively). In addition, we tested the ERG algorithm performance in 2 needle biopsy cohorts comprised of 179 and 148 WSI (AUC, 0.78 and 0.80, respectively). Focusing on cases with homogeneous (clonal) PTEN status, PTEN algorithm performance was assessed using 50 WSI reserved from the pretraining cohort (AUC, 0.81), 201 and 337 WSI from 2 independent RP cohorts (AUC, 0.72 and 0.80, respectively), and 151 WSI from a needle biopsy cohort (AUC, 0.75). For explainability, the PTEN algorithm was also applied to 19 WSI with heterogeneous (subclonal) PTEN loss, where the percentage tumor area with predicted PTEN loss correlated with that based on immunohistochemistry (r = 0.58, P = .0097). These deep-learning algorithms to predict ERG/PTEN status prove that H&E images can be used to screen for underlying genomic alterations in prostate cancer.

STRN-ALK rearranged malignant peritoneal mesothelioma-Presenting with bilateral extensive pelvic masses in a young woman: Mimicking low-grade serous ovarian carcinoma

Malignant peritoneal mesothelioma (MPM) is an exceptionally rare tumor type. Although some somatic/germline genetic alterations including BAP1 loss have been identified in some cases, the molecular properties of MPMs are remained poorly understood. In recent years, anaplastic lymphoma kinase (ALK) gene rearrangement was revealed in a subset of (3.4%) MPMs. Low-grade serous carcinomas (LGSCs) are a rare subtype of ovarian carcinoma and have some morphologic and immunophenotypic overlapping features with MPMs and this may cause misdiagnosis in daily practice. Here, we report a case of 18-year-old women with STRN-ALK-rearranged MPM and no previous exposure to asbestos. This case was presented with bilateral pelvic masses and histologically was displaying pure papillary morphology with mild-to-moderate nuclear atypia, psammoma bodies, and diffuse PAX8 expression as LGSCs. With the detection of ALK alteration in some of the MPMs, a targeted treatment option has emerged for these unusual tumor types.

Pathological perspectives in pilocytic astrocytomas: Extent of resection as the sole critical factor for recurrence-free survival, and the challenge of evaluating conclusions derived from limited data

Introduction: Pilocytic astrocytoma (PA) is one of the most common primary intracranial neoplasms in childhood with an overall favorable prognosis. Despite decades of experience, there are still diagnostic and treatment challenges and unresolved issues regarding risk factors associated with recurrence, most often due to conclusions of publications with limited data. We analyzed 499 patients with PA diagnosed in a single institution over 30 years in order to provide answers to some of the unresolved issues. Materials and Methods: We identified pilocytic astrocytomas diagnosed at the University of California, San Francisco, between 1989 and 2019, confirmed the diagnoses using the WHO 2021 essential and desirable criteria, and performed a retrospective review of the demographic and clinical features of the patients and the radiological, pathologic and molecular features of the tumors. Results: Among the patients identified from pathology archives, 499 cases fulfilled the inclusion criteria. Median age at presentation was 12 years (range 3.5 months - 73 years) and the median follow-up was 78.5 months. Tumors were predominantly located in the posterior fossa (52.6%). There were six deaths, but there were confounding factors that prevented a clear association of death to tumor progression. Extent of resection was the only significant factor for recurrence-free survival. Recurrence-free survival time was 321.0 months for gross total resection, compared to 160.9 months for subtotal resection (log rank, p <0.001). Conclusion: Multivariate analysis was able to identify extent of resection as the only significant variable to influence recurrence-free survival. We did not find a statistically significant association between age, NF1 status, tumor location, molecular alterations, and outcome. Smaller series with apparently significant results may have suffered from limited sample size, limited variables, acceptance of univariate analysis findings as well as a larger p value for biological significance. PA still remains a predominantly surgical disease and every attempt should be made to achieve gross total resection since this appears to be the most reliable predictor of recurrence-free survival.

Abstract 3772: Increased mitochondrial gene expression in prostate cancer

Warburg postulated that aerobic glycolysis, which is commonly observed in cancer, results from crippled mitochondrial function. Yet, most cancers and other rapidly proliferating cells rely on a functioning mitochondrial TCA cycle to generate important biosynthetic intermediates required for cell growth, and on the electron transport chain for pyrimidine synthesis and to recycle electron acceptors. Thus, increases in a number of mitochondrial activities have been proposed to be required for robust proliferation in most cancers. Mitochondrial function is regulated in part through mitochondrial biogenesis, which is influenced by mitochondrial DNA copy number (mtDNAcn). We previously developed an in situ hybridization method to quantify mtDNAcn in specific cell compartments in relation to normal physiological functioning and disease processes. We reported marked cell type heterogeneity across normal tissues including relatively higher mtDNAcn in a number of stem/proliferative compartments in humans and mice (PMID: 32304697). More recently, we combined this in situ approach with immunohistochemistry and reported increased mtDNAcn along with widespread heterogeneity in prostate cancer (DOI: 10.1158/1538-7445.AM2021-2404). We also found increased mtDNAcn in high grade prostatic intraepithelial neoplasia, the main precursor to prostate cancer, as well as precursor lesions in the large intestine and pancreas. To interrogate the functional significance of this mtDNAcn alteration, we sought to determine whether increased and heterogeneous mtDNAcn levels are accompanied by corresponding changes in its gene expression (mtRNA). To establish an initial survey of the landscape of steady state mtRNA levels, we used the RNAscope HiPlex system for multiplex in situ hybridization for 4 different mtRNAs along with in situ hybridization for mtDNA and combined this with immunofluorescence. In normal prostatic epithelium, we observed that the overall mtRNA expression pattern correlated with mtDNAcn, with higher levels in the basal cell layer compared with the luminal cell layer. We also found that, similar to changes in mtDNAcn in invasive prostate cancer, the 4 mtRNAs were upregulated yet heterogeneous in cancer lesions. Among the invasive tumors, cribriform prostate cancer showed distinct mtDNA and mtRNAs expression patterns, with higher signals in the peripheral cells than central cells, suggesting underlying biological differences in this unique histologic pattern. This spatial pattern in cribriform lesions correlated with the pattern of MYC protein expression, which is known to regulate mitochondrial biogenesis. Overall, we present a novel approach that advances the ability to quantify mtDNAcn and mtRNAs simultaneously in specific cell types while preserving the tissue spatial context. These findings suggest that increased mitochondrial function accompanies prostate cancer development and progression.

Citation Format: Jiayu Chen, Qizhi Zheng, Jessica L. Hicks, Levent Trabzonlu, Ibrahim Kulac, Alan K. Meeker, Srinivasan Yegnasubramanian, Angelo M. De Marzo. Increased mitochondrial gene expression in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3772.

Impact of the Amyotrophic Lateral Sclerosis Disease on the Biomechanical Properties and Oxidative Stress Metabolism of the Lung Tissue Correlated With the Human Mutant SOD1G93A Protein Accumulation

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease, and ALS incidence is increasing worldwide. Patients with ALS have respiratory failure at the disease’s end stages, leading to death; thus, the lung is one of the most affected organs during disease progression. Tissue stiffness increases in various lung diseases because of impaired extracellular matrix (ECM) homeostasis leading to tissue damage and dysfunction at the end. According to the literature, oxidative stress is the major contributor to ECM dysregulation, and mutant protein accumulation in ALS have been reported as causative to tissue damage and oxidative stress. In this study, we used SOD1^G93A and SOD1^WT rats and measured lung stiffness of rats by using a custom-built stretcher, where H&E staining is used to evaluate histopathological changes in the lung tissue. Oxidative stress status of lung tissues was assessed by measuring glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR), glutathione s-transferase (GST), catalase (CAT), and superoxide dismutase 1 (SOD1) levels. Western blot experiments were performed to evaluate the accumulation of the SOD1^G93A mutated protein. As a result, increased lung stiffness, decreased antioxidant status, elevated levels of oxidative stress, impaired mineral and trace element homeostasis, and mutated SOD1^G93A protein accumulation have been found in the mutated rats even at the earlier stages, which can be possible causative of increased lung stiffness and tissue damage in ALS. Since lung damage has altered at the very early stages, possible therapeutic approaches can be used to treat ALS or improve the life quality of patients with ALS.

Towards Development of a Standard Terminology of the World Health Organization Classification of Tumors of the Central Nervous System in the Turkish Language, and a Perspective on the Practical Implications of the WHO Classification for Low and Middle Income Countries

In our manuscript, we propose a common terminology in the Turkish language for the newly adopted WHO classification of the CNS tumors, also known as the WHO CNS 5th edition. We also comment on the applicability of this new scheme in low and middle income countries, and warn about further deepening disparities between the global north and the global south. This division, augmented by the recent COVID-19 pandemic, threatens our ability to coordinate efforts worldwide and may create significant disparities in the diagnosis and treatment of cancers between the "haves" and the "have nots".

EWSR1(22q12) Translocation Positive Pediatric Adrenal Tumor with Loss of 1p, 11q, and Unbalanced Gain of 17q: Neuroblastoma or Ewing Sarcoma?

Background Although neuroblastoma and Ewing sarcoma/Primitive neuroectodermal tumor are different clinical entities, they are both a member of small round blue cell tumors and can mimic each other's behavior in clinical and molecular aspects. Case report: A 3 year-old girl with an abdominal mass was found to have a small round blue cell tumor originating from the right adrenal gland. High level of neuron specific enolase, initial genetic test results (N-Myc amplification: negative, loss of 1p, 11q, and unbalanced gain of 17q) and characteristic radiological appearance of the tumor suggested a preliminary diagnosis of neuroblastoma but further analysis showed CD99 expression and presence of EWSR1 rearrangement, which are mostly observed in Ewing sarcoma. Conclusion: Adrenal gland tumors of childhood with complex immunophenotypic features requires distinguishing two discrete tumors in the small round blue cell tumor group, neuroblastoma and Ewing sarcoma. Although no exact diagnosis of the tumor was made, we reached a good response with neuroblastoma treatment protocol.

GSTP1 positive prostatic adenocarcinomas are more common in Black than White men in the United States

GSTP1 is a member of the Glutathione-S-transferase (GST) family silenced by CpG island DNA hypermethylation in 90-95% of prostate cancers. However, prostate cancers expressing GSTP1 have not been well characterized. We used immunohistochemistry against GSTP1 to examine 1673 primary prostatic adenocarcinomas on tissue microarrays (TMAs) with redundant sampling from the index tumor from prostatectomies. GSTP1 protein was positive in at least one TMA core in 7.7% of cases and in all TMA cores in 4.4% of cases. The percentage of adenocarcinomas from Black patients who had any GSTP1 positive TMA cores was 14.9%, which was 2.5 times higher than the percentage from White patients (5.9%; P < 0.001). Further, the percentages of tumors from Black patients who had all TMA spots positive for GSTP1 (9.5%) was 3-fold higher than the percentage from White patients (3.2%; P<0.001). In terms of association with other molecular alterations, GSTP1 positivity was enriched in ERG positive cancers among Black men. By in situ hybridization, GSTP1 mRNA expression was concordant with protein staining, supporting the lack of silencing of at least some GSTP1 alleles in GSTP1-positive tumor cells. This is the first report revealing that GSTP1-positive prostate cancers are substantially over-represented among prostate cancers from Black compared to White men. This observation should prompt additional studies to determine whether GSTP1 positive cases represent a distinct molecular subtype of prostate cancer and whether GSTP1 expression could provide a biological underpinning for the observed disparate outcomes for Black men.

Diagnostic approach in TFE3-rearranged renal cell carcinoma: a multi-institutional international survey

Transcription factor E3-rearranged renal cell carcinoma (TFE3-RCC) has heterogenous morphologic and immunohistochemical (IHC) features.131 pathologists with genitourinary expertise were invited in an online survey containing 23 questions assessing their experience on TFE3-RCC diagnostic work-up.Fifty (38%) participants completed the survey. 46 of 50 participants reported multiple patterns, most commonly papillary pattern (almost always 9/46, 19.5%; frequently 29/46, 63%). Large epithelioid cells with abundant cytoplasm were the most encountered cytologic feature, with either clear (almost always 10/50, 20%; frequently 34/50, 68%) or eosinophilic (almost always 4/49, 8%; frequently 28/49, 57%) cytology. Strong (3+) or diffuse (>75% of tumour cells) nuclear TFE3 IHC expression was considered diagnostic by 13/46 (28%) and 12/47 (26%) participants, respectively. Main TFE3 IHC issues were the low specificity (16/42, 38%), unreliable staining performance (15/42, 36%) and background staining (12/42, 29%). Most preferred IHC assays other than TFE3, cathepsin K and pancytokeratin were melan A (44/50, 88%), HMB45 (43/50, 86%), carbonic anhydrase IX (41/50, 82%) and CK7 (32/50, 64%). Cut-off for positive TFE3 fluorescent in situ hybridisation (FISH) was preferably 10% (9/50, 18%), although significant variation in cut-off values was present. 23/48 (48%) participants required TFE3 FISH testing to confirm TFE3-RCC regardless of the histomorphologic and IHC assessment. 28/50 (56%) participants would request additional molecular studies other than FISH assay in selected cases, whereas 3/50 participants use additional molecular cases in all cases when TFE3-RCC is in the differential.Optimal diagnostic approach on TFE3-RCC is impacted by IHC and/or FISH assay preferences as well as their conflicting interpretation methods.

Use of Aspirin and Statins in Relation to Inflammation in Benign Prostate Tissue in the Placebo Arm of the Prostate Cancer Prevention Trial

Aspirin and statin use may lower the risk of advanced/fatal prostate cancer, possibly by reducing intraprostatic inflammation. To test this hypothesis, we investigated the association of aspirin and statin use with the presence and extent of intraprostatic inflammation, and the abundance of specific immune cell types, in benign prostate tissue from a subset of men from the placebo arm of the Prostate Cancer Prevention Trial. Men were classified as aspirin or statin users if they reported use at baseline or during the 7-year trial. Presence and extent of inflammation were assessed, and markers of specific immune cell types (CD4, CD8, FoxP3, CD68, and c-KIT) were scored, in slides from end-of-study prostate biopsies taken irrespective of clinical indication, per trial protocol. Logistic regression was used to estimate associations between medication use and inflammation measures, adjusted for potential confounders. Of 357 men included, 61% reported aspirin use and 32% reported statin use. Prevalence and extent of inflammation were not associated with medication use. However, aspirin users were more likely to have low FoxP3, a T regulatory cell marker [OR, 5.60; 95% confidence interval (CI), 1.16-27.07], and statin users were more likely to have low CD68, a macrophage marker (OR, 1.63; 95% CI, 0.81-3.27). If confirmed, these results suggest that these medications may alter the immune milieu of the prostate, which could potentially mediate effects of these medications on advanced/fatal prostate cancer risk.

High Extratumoral Mast Cell Counts Are Associated with a Higher Risk of Adverse Prostate Cancer Outcomes

BACKGROUND

Given our previous findings that low intratumoral and high extratumoral mast cell numbers are associated with higher risk of biochemical recurrence after radical prostatectomy, we now assessed this relationship with race and the development of metastases.

METHODS

We stained for mast cell tryptase via IHC and fluorescent immunolabeling in 885 men across multiple tissue microarray sets designed to assess biomarkers in association with race and prostate cancer outcomes (median follow-up, 7.0 years).

RESULTS

Intratumoral and extratumoral mast cell counts were significantly lower in tissues from African-American compared with European-American men, but not within strata of cancer grade. There was no association between mast cell counts and ERG positivity, PTEN loss, or TP53 missense mutation. Higher minimum extratumoral mast cells were associated with an increased risk of biochemical recurrence [comparing highest with lowest tertiles: HR, 1.61; 95% confidence interval (CI), 1.12-2.29; P trend = 0.01]; this pattern was similar among European-American and African-American men and by grade of disease. There was no significant association between minimum intratumoral mast cell count and biochemical recurrence, overall or within strata of race and grade. Finally, high minimum number of extratumoral mast cells was associated with prostate cancer metastases (comparing highest with lowest tertiles: HR, 2.12; 95% CI, 1.24-3.63; P trend = 0.01).

CONCLUSIONS

High extratumoral mast cell numbers are associated with biochemical recurrence and the development of metastases after radical prostatectomy.

IMPACT

Higher numbers of benign tissue mast cells are associated with a higher risk of adverse outcomes after radical prostatectomy, including metastatic prostate cancer.

Clinical and histopathological comparative study of two equine-derived bone graft: a human study

OBJECTIVE

To compare the performance of collagenated bone graft substances with different collagen ratios after sinus floor augmentation.

METHODS

The cross-sectional study was conducted at Hacettepe University, Ankara, Turkey, from September 2011 to September 2013. Sinus floor augmentation was done with two different equinederived xenografts in patients before dental implant application. Of the two randomised groups, one was treated with 100% collagenated bone mix (Group A), and the other half with 90% collagenated bone mix + 10% collagen gel (Group B).Six months after sinus augmentation, prior to dental implant surgery, a specimen was taken from the implant socket with trephine drill for histopathological evaluation of new bone, connective tissue and residual graft material at each augmented site. SPSS 19 was used for data analysis.

RESULTS

Of the 19 patients, 12(63%) were females and 7(37%) were males. The overall mean age was 51.68±11,96 years (range: 24-69 years). A total of 30 sinus floor augmentations were done. New bone formation was significantly better in Group A(15 sinus floor augmentation) than in Group B (the other 15 sinus floor augmentation) (p<0.05), but there was no significant difference in connective tissue formation and residual graft materials between the groups (p>0.05).

CONCLUSIONS

Collagenated bone mix was found to be a suitable graft material for sinus floor augmentation, but increased collagen ratio did not improve new bone formation over the 6-month healing process.

Lactoferrin CpG Island Hypermethylation and Decoupling of mRNA and Protein Expression in the Early Stages of Prostate Carcinogenesis

Lactoferrin (LTF) is an iron-binding protein canonically known for its innate and adaptive immune functions. LTF may also act as a tumor suppressor with antiproliferative action. LTF is inactivated genetically or epigenetically in various cancers, and a CpG island spanning the transcriptional start site of LTF is hypermethylated in prostate cancer cell lines. We, therefore, hypothesized that LTF expression is silenced via CpG island hypermethylation in the early stages of prostate tumorigenesis carcinogenesis. Targeted methylation analysis was performed using a combination of methylated-DNA precipitation and methylation-sensitive restriction enzymes, and laser-capture microdissection followed by bisulfite sequencing on DNA isolated from prostate tissue samples, including both primary and metastatic disease. LTF mRNA in situ hybridization and LTF protein immunohistochemistry were also performed. We report that the LTF CpG island is frequently and densely methylated in high-grade prostatic intraepithelial neoplasia, primary prostate carcinoma, and metastases. We further report a decoupling of lactoferrin mRNA and protein expression, including in lesions where LTF mRNA has presumably been silenced via CpG island methylation. We conclude that LTF mRNA expression is silenced in prostate tumorigenesis via hypermethylation, supporting a role for LTF as a prostate cancer tumor suppressor gene. Likewise, the frequency at which the LTF CpG island is methylated across samples suggests it is an important and conserved step in prostate cancer initiation.

Molecular Pathology of High-Grade Prostatic Intraepithelial Neoplasia: Challenges and Opportunities

A better understanding of the early stages of prostate cancer initiation, potentially arising from precursor lesions, may fuel development of powerful approaches for prostate cancer prevention or interception. The best-known candidate for such a precursor lesion has been referred to as high-grade prostatic intraepithelial neoplasia (HGPIN). Although there is significant evidence supporting the notion that such HGPIN lesions can give rise to invasive adenocarcinomas of the prostate, there are also numerous complicating considerations and evidence that cloud the picture in many instances. Notably, recent evidence has suggested that some fraction of such lesions that are morphologically consistent with HGPIN may actually be invasive carcinomas masquerading as HGPIN-a state that we term "postinvasive intraepithelial carcinoma" (PIC). Although the prevalence of such PIC lesions is not fully understood, this and other factors can confound the potential of identifying prostate precursors that can be targeted for disease prevention, interception, or treatment. Here, we review our current understanding of the morphological and molecular pathological features of prostate cancer precursor lesions.

If this is true, what does it imply? How end-user antibody validation facilitates insights into biology and disease

Antibodies are employed ubiquitously in biomedical sciences, including for diagnostics and therapeutics. One of the most important uses is for immunohistochemical (IHC) staining, a process that has been improving and evolving over decades. IHC is useful when properly employed, yet misuse of the method is widespread and contributes to the "reproducibility crisis" in science. We report some of the common problems encountered with IHC assays, and direct readers to a wealth of literature documenting and providing some solutions to this problem. We also describe a series of vignettes that include our approach to analytical validation of antibodies and IHC assays that have facilitated a number of biological insights into prostate cancer and the refutation of a controversial association of a viral etiology in gliomas. We postulate that a great deal of the problem with lack of accuracy in IHC assays stems from the lack of awareness by researchers for the critical necessity for end-users to validate IHC antibodies and assays in their laboratories, regardless of manufacturer claims or past publications. We suggest that one reason for the pervasive lack of end-user validation for research antibodies is that researchers fail to realize that there are two general classes of antibodies employed in IHC. First, there are antibodies that are "clinical grade" reagents used by pathologists to help render diagnoses that influence patient treatment. Such diagnostic antibodies, which tend to be highly validated prior to clinical implementation, are in the vast minority (e.g. < 500). The other main class of antibodies are "research grade" antibodies (now numbering >3 800 000), which are often not extensively validated prior to commercialization. Given increased awareness of the problem, both the United States, National Institutes of Health and some journals are requiring investigators to provide evidence of specificity of their antibody-based assays.

Mesenchymal stem cell infiltration during neoplastic transformation of the human prostate

Mesenchymal Stem Cells (MSCs) have been identified in prostate cancer, raising the critical question of their physical and temporal source. Therefore, MSCs were quantified and characterized in benign and malignant prostate tissue representing different disease states and a wide range of age groups from fetal development through adult death using analytical and functional methodologies. In contrast to lineage-restricted Mesenchymal Progenitor Cells (MPCs) found in normal prostate tissue, MSCs with tri-lineage differentiation potential (adipogenesis, osteogenesis, and chondrogenesis) are identified in prostate tissue from a subset of men with prostate cancer, consistent with an influx of more stem-like progenitors (i.e. MSCs) from the bone marrow. Additionally, prostate tissue from a subset of these patients is highly enriched in MSCs, suggesting their enumeration may have prognostic value for identifying men with aggressive disease. This influx is an ongoing process continuing throughout disease progression as documented by the presence of MSCs in metastatic lesions from multiple organ sites harvested at the time of death in metastatic castration-resistant prostate cancer (mCRPC) patients. This infiltration of MSCs from systemic circulation provides the rationale for their use as a cell-based vector to deliver therapeutic agents.

Profiling the Urinary Microbiome in Men with Positive versus Negative Biopsies for Prostate Cancer

PURPOSE

Studies demonstrating bacterial DNA and cultivable bacteria in urine samples have challenged the clinical dogma that urine is sterile. Furthermore, studies now indicate that dysbiosis of the urinary microbiome is associated with pathological conditions. We propose that the urinary microbiome may influence chronic inflammation observed in the prostate, leading to prostate cancer development and progression. Therefore, we profiled the urinary microbiome in men with positive vs negative biopsies for prostate cancer.

MATERIALS AND METHODS

Urine was collected from men prior to biopsy for prostate cancer. DNA was extracted from urine pellet samples and subjected to bacterial 16S rDNA Illumina® sequencing and 16S rDNA quantitative polymerase chain reaction. We determined the association between bacterial species and the presence or absence of cancer, cancer grade, and type and degree of prostate inflammation.

RESULTS

Urine samples revealed diverse bacterial populations. There were no significant differences in α or β diversity and no clear hierarchical clustering of benign or cancer samples. We identified a cluster of pro-inflammatory bacteria previously implicated in urogenital infections in a subset of samples. Many species, including known uropathogens, were significantly and differentially abundant among cancer and benign samples, in low vs higher grade cancers and in relation to prostate inflammation type and degree.

CONCLUSIONS

To our knowledge we report the most comprehensive study to date of the male urinary microbiome and its relationship to prostate cancer. Our results suggest a prevalence of pro-inflammatory bacteria and uropathogens in the urinary tract of men with prostate cancer.

A Prospective Study of Chronic Inflammation in Benign Prostate Tissue and Risk of Prostate Cancer: Linked PCPT and SELECT Cohorts

Background: We leveraged two trials to test the hypothesis of an inflammation-prostate cancer link prospectively in men without indication for biopsy.Methods: Prostate Cancer Prevention Trial (PCPT) participants who had an end-of-study biopsy performed per protocol that was negative for cancer and who subsequently enrolled in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) were eligible. We selected all 100 cases and sampled 200 frequency-matched controls and used PCPT end-of-study biopsies as "baseline." Five men with PSA > 4 ng/mL at end-of-study biopsy were excluded. Tissue was located for 92 cases and 193 controls. We visually assessed inflammation in benign tissue. We estimated ORs and 95% confidence intervals (CI) using logistic regression adjusting for age and race.Results: Mean time between biopsy and diagnosis was 5.9 years. In men previously in the PCPT placebo arm, 78.1% of cases (N = 41) and 68.2% of controls (N = 85) had at least one baseline biopsy core (∼5 evaluated per man) with inflammation. The odds of prostate cancer (N = 41 cases) appeared to increase with increasing mean percentage of tissue area with inflammation, a trend that was statistically significant for Gleason sum <4+3 disease (N = 31 cases; vs. 0%, >0-<1.8% OR = 1.70, 1.8-<5.0% OR = 2.39, ≥5% OR = 3.31, P_trend = 0.047). In men previously in the finasteride arm, prevalence of inflammation did not differ between cases (76.5%; N = 51) and controls (75.0%; N = 108).Conclusions: Benign tissue inflammation was positively associated with prostate cancer.Impact: This first prospective study of men without biopsy indication supports the hypothesis that inflammation influences prostate cancer development. Cancer Epidemiol Biomarkers Prev; 26(10); 1549-57. ©2017 AACR.

Abstract 5324: ERG expression and PTEN loss by BMI and weight change in men with prostate cancer

Background: Obesity and weight gain are associated with poor prostate cancer outcome; underlying mechanisms are unknown. Obesity has been more strongly associated with lethal disease in men positive for the TMPRSS2:ERG gene fusion than negative for this fusion. PTEN loss is associated with increased risk of lethal progression; its association with obesity has not been explored. We evaluated whether prevalence of ERG expression and PTEN loss in prostate tumors differs by BMI and weight change.

Methods: From a retrospective cohort study of 1,337 men with clinically-localized prostate cancer who underwent prostatectomy at Johns Hopkins (1993-2006), we sampled 291 men by combination of BMI at 1 year after surgery (normal, overweight, obese) and weight change from 5 years before to 1 year after surgery (loss, maintenance, gain). Within each category, men were frequency-matched on age, Gleason sum, organ confinement, and surgery year. We used genetically validated immunohistochemistry assays to assess ERG positivity and heterogeneous PTEN loss. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association of BMI and weight change (adjusted for height, starting weight) with ERG positivity and heterogeneous PTEN loss.

Results: Mean age was 56.1 years and mean Gleason sum was 6.2; 73% had organ-confined disease. Prevalence of ERG positivity did not statistically significantly differ by BMI or weight change. However, when jointly categorized by BMI and weight change, overweight/obese men who maintained (OR=2.5; 95%CI 1.1-5.7) or gained weight (OR=2.5; 95%CI 1.1-5.8), and normal weight men who gained weight (OR=4.7; 95%CI 1.4-15.2) were significantly more likely to have ERG positive tumors compared with normal weight men who maintained weight. Overweight/obese men were also significantly more likely (OR=2.4; 95%CI 1.3-4.7) to have PTEN loss compared with normal weight men. When stratified by ERG status, this association appeared to be stronger for men with ERG positive tumors (OR=2.9; 95%CI 1.3-6.8) than for men with ERG negative tumors (OR=1.6; 95%CI 0.6-4.9). Prevalence of PTEN loss did not differ by weight change. When jointly categorized by BMI and weight change, overweight/obese men who maintained (OR=2.0; 95%CI 0.8-5.3) or gained weight (OR=1.9; 95%CI 0.7-5.1) appeared to be more likely to have PTEN loss compared with normal weight men who maintained weight.

Conclusions: Overweight/obese men who maintained or gained weight circa diagnosis and normal weight men who gained weight were more likely to have ERG positive tumors. Overweight/obese men were more likely to have tumors with PTEN loss; this association was stronger among overweight/obese men who also had ERG positive tumors. The TMPRSS2:ERG gene fusion and PTEN loss may contribute to the increased risk of poor prostate cancer outcomes among overweight/obese men. Funding: Prostate Cancer Foundation

Citation Format: Janelle S. Ho, Ibrahim Kulac, Tamara L. Lotan, John R. Barber, Patrick C. Walsh, Misop Han, Angelo M. De Marzo, Elizabeth A. Platz, Corinne E. Joshu. ERG expression and PTEN loss by BMI and weight change in men with prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5324. doi:10.1158/1538-7445.AM2017-5324

Low Intratumoral Mast Cells Are Associated With a Higher Risk of Prostate Cancer Recurrence

BACKGROUND

Mast cells are of interest in prostate cancer because they possess both pro- and anti-tumorigenic properties and are present in the tumor microenvironment. We studied the association of mast cell count and densities with prostate cancer recurrence using tissue microarrays (TMAs) for 462 men who recurred (cases) and 462 controls that were matched to the cases nested in a cohort of radical prostatectomy patients.

METHODS

Dual-immunostaining for mast cell tryptase and epithelial cytokeratin-8 and whole slide image analysis were used to assess total mast cell number, mast cell density (mast cell number/tissue area), and mast cell number per epithelial or stromal area in TMA spots containing tumor (up to 4 per man). We used conditional logistic regression to estimate the odds ratio (OR) and 95% confidence interval of recurrence for the mean, minimum, and maximum mast cell parameters in tumor tissue among each man's TMA spots.

RESULTS

After taking into account matching factors of age, race, Gleason sum, and pathologic stage, higher minimum mast cell density in the tumor (comparing highest to lowest quartiles: OR = 0.58, 95% CI 0.40-0.86; P-trend = 0.004) was associated with a lower risk of recurrence. Patterns for mast cell number and ratio of mast cell number to epithelial or stromal area were similar to those for mast cell density.

CONCLUSIONS

Our results suggest that intratumoral mast cells may be protective against prostate cancer recurrence and could potentially serve as a prognostic biomarker after prostatectomy. Prostate 77: 412-424, 2017. © 2016 Wiley Periodicals, Inc.

Novel Assay to Detect RNA Polymerase I Activity In Vivo

This report develops an analytically validated chromogenic in situ hybridization (CISH) assay using branched DNA signal amplification (RNAscope) for detecting the expression of the 5' external transcribed spacer (ETS) of the 45S ribosomal (r) RNA precursor in formalin-fixed and paraffin-embedded (FFPE) human tissues. 5'ETS/45S CISH was performed on standard clinical specimens and tissue microarrays (TMA) from untreated prostate carcinomas, high-grade prostatic intraepithelial neoplasia (PIN), and matched benign prostatic tissues. Signals were quantified using image analysis software. The 5'ETS rRNA signal was restricted to the nucleolus. The signal was markedly attenuated in cell lines and in prostate tissue slices after pharmacologic inhibition of RNA polymerase I (Pol I) using BMH-21 or actinomycin D, and by RNAi depletion of Pol I, demonstrating validity as a measure of Pol I activity. Clinical human prostate FFPE tissue sections and TMAs showed a marked increase in the signal in the presumptive precursor lesion (high-grade PIN) and invasive adenocarcinoma lesions (P = 0.0001 and P = 0.0001, respectively) compared with non-neoplastic luminal epithelium. The increase in 5'ETS rRNA signal was present throughout all Gleason scores and pathologic stages at radical prostatectomy, with no marked difference among these. This precursor rRNA assay has potential utility for detection of increased rRNA production in various tumor types and as a novel companion diagnostic for clinical trials involving Pol I inhibition.Implications: Increased rRNA production, a possible therapeutic target for multiple cancers, can be detected with a new, validated assay that also serves as a pharmacodynamic marker for Pol I inhibitors. Mol Cancer Res; 15(5); 577-84. ©2017 AACR.

Peripheral Zone Inflammation Is Not Strongly Associated With Lower Urinary Tract Symptom Incidence and Progression in the Placebo Arm of the Prostate Cancer Prevention Trial

BACKGROUND

Intraprostatic inflammation has been associated with lower urinary tract symptom (LUTS) progression. However, prior studies used tissue removed for clinical indications, potentially skewing inflammation extent or biasing the association. We, therefore, evaluated inflammation and LUTS incidence and progression in men who underwent biopsy of the prostate peripheral zone irrespective of indication.

MATERIALS AND METHODS

We developed nested case-control sets in men in the placebo arm of the Prostate Cancer Prevention Trial who were free of clinical BPH and had a protocol-directed year 7 biopsy. Cases had baseline IPSS <15 and year 7 IPSS of 8-14 (low, N = 47), 15-19 (incident moderate, N = 42), or ≥20 (incident high, N = 44). Controls had baseline and year 7 IPSS <8 (N = 41). For progression from IPSS <8, cases had baseline to year 7 IPSS slope >75th percentile (N = 46) and controls had a slope <25th percentile (N = 45). For progression from IPSS = 8-14, cases had a slope >75th percentile (N = 46) and controls had a slope <25th percentile (N = 46). We reviewed three H&E-stained biopsy cores per man to determine prevalence of ≥1 core with inflammation and mean extent (%) of tissue area with inflammation.

RESULTS

Inflammation prevalence in low cases (64%) was similar to controls (66%), but higher in moderate (69%) and high (73%) cases (P-trend = 0.4). Extent did not differ across LUTS categories (P-trend = 0.5). For progression from IPSS < 8, prevalence (65%, P = 0.9) and extent (2.5%, P = 0.8) in cases did not differ from controls (64%, 2.7%). For progression from IPSS 8-14, prevalence in cases (52%) was lower than in controls (78%, P = 0.009), while extent was higher in cases (5.3%) than controls (3.6%), especially in men with ≥1 core with inflammation (10.1% versus 4.6%, P = 0.06).

CONCLUSION

Peripheral zone intraprostatic inflammation is not strongly associated with LUTS incidence or progression. Prostate 76:1399-1408, 2016. © 2016 Wiley Periodicals, Inc.

Abstract LB-186: Development and validation of a novel RNA in situ hybridization assay to detect RNA polymerase I activity in vivo

Increased ribosome biogenesis is a critical process requisite for the cancer cell phenotype as it is required to doulbe protein levels for cell replication. Ribosome synthesis is a complex process that is stimulated by a number of well-studied oncogenic pathways (MYC, mTOR, RAS-RAF-ERK) and repressed by tumor suppressors (pRb, p53, PTEN, p14/ARF). A key first step in ribosome biogenesis is the increased synthesis by RNA Polymerase I (Pol I) of the precursor rRNA, referred to as 45S rRNA, that is later processed into the 28S, 5.8S and 18S mature rRNA forms. This process is compartmentalized into the nucleolus. As such, the pharmacological inhibition of RNA Pol I is becoming a potentially important therapeutic strategy in cancer (PMIDs 20055700, 23953479, 24434211). A validated assay that can reflect relative levels of Pol I activity in routinely obtained tissue specimens would be a useful tool. For example it would allow the pretreatment screening (as a predictive biomarker) for those tumors likely to respond to Pol I inhibition, and, could also serve as a pharmacodynamic biomarker of Pol I inhibition. The 5’ external transcribed spacer (5’ETS) of the nascent precursor 45S transcript is rapidly removed and degraded; thus, its levels can be used as a surrogate for new rRNA transcription.

We employed branched DNA amplified RNA in situ hybridization using probes developed with Advanced Cellular Diagnostics (ACD RNAscope 2.0). The 5’ ETS/45S CISH signal was restricted to nucleoli. The signal was markedly attenuated in cell lines and in formalin fixed paraffin embedded (FFPE) prostate tissue slices after pharmacological inhibition of RNA Pol I using BMH-21 or actinomycin D, demonstrating validity as a measure of RNA Pol I transcriptional activity. In clinical human prostate FFPE tissue sections and TMAs there was a marked increase in the signal in the presumptive precursor lesion (high grade prostatic intraepithelial neoplasia/HGPIN, n = 25) and in invasive adenocarcinoma lesions (n = 72, Kruskal-Wallis, p = 0.0001 and p = 0.0001, respectively) compared with normal luminal epithelium. These results are consistent with prior work using RT-PCR showing an increase in 5’ ETS/45S rRNA levels in prostate cancer tissues. In adenocarcinomas, the increase in 5’ ETS/45S signal was present throughout all Gleason scores and pathological stages at radical prostatectomy, with no marked difference among these.

We developed and analytically validated a chromogenic in situ hybridization (CISH) protocol using RNAscope for detecting the 5’ external transcribed spacer (ETS) of the precursor 45S ribosomal RNA in FFPE human tissues. This novel assay was used to show increased rRNA transcription in human clinical samples of PIN and carcinoma, and should prove useful for detection of increased rRNA production in various tumor types and as a novel pharmacodynamic biomarker in clinical trials of RNA Pol I inhibitors.

Citation Format: Gunes Guner, Paul Sirajuddin, Qizhi Zheng, Hester Liu, Ibrahim Kulac, Marikki K. Laiho, Angelo M. De Marzo. Development and validation of a novel RNA in situ hybridization assay to detect RNA polymerase I activity in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-186.

Abstract C73: A relationship between mast cells and the racial disparity of prostate cancer

Prostate cancer afflicts African American men to a greater degree than European American men, with a 60% greater incidence and 2-3 times greater mortality. In addition, studies have shown that the incidence rate of distant metastasis is 4 times greater in African American men than in European American men, consistent with the notion that prostate cancer is more aggressive in African Americans. Of interest, African American men are also significantly more likely to present with inflammation in benign prostate biopsies, and studies have shown higher expression of a number of inflammatory markers in prostate cancer tissue from African Americans compared to European Americans. One immune cell type of particular interest in the context of prostate cancer are mast cells, which have the potential to play a number of roles in cancer, and have also been shown to increase in number in prostate cancer versus benign regions of the prostate. In the present study, immunohistochemistry (IHC) was used to directly visualize and localize mast cells in the prostate microenvironment of African American and European American men in a tissue microarray (TMA) containing tumor and benign tissues from 75 African American and 75 European American prostate cancer patients matched on tumor grade and stage. Automated counting of mast cell numbers as well as the calculation of mast cell-to-epithelial ratio (MC/Ep) and mast cell numbers per total tissue area (density) was aided by novel digital image analysis using a software framework integrating whole slide imaging, virtual microscopy, and ImageJ based analysis algorithms. Key results to date include the finding that mast cell density in prostate tumor tissues of African American men is significantly lower than that of Caucasian Americans (p &lt; 0.0001). This same trend was observed for total mast cell numbers and MC/Ep (p=0.001). These results suggest the intriguing possibility that a decrease in tumor-infiltrating mast cells may contribute to the racial disparity observed in association with prostate cancer and additional studies are underway to determine the biological function of mast cells in the prostate tumor microenvironment.

Citation Format: Heidi A. Hempel, Ibrahim Kulac, Nathan S. Cuka, Toby C. Cornish, Angelo M. De Marzo, Karen S. Sfanos. A relationship between mast cells and the racial disparity of prostate cancer. [abstract]. In: Proceedings of the Eighth AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 13-16, 2015; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2016;25(3 Suppl):Abstract nr C73.

Combined MYC Activation and Pten Loss Are Sufficient to Create Genomic Instability and Lethal Metastatic Prostate Cancer

Genetic instability, a hallmark feature of human cancers including prostatic adenocarcinomas, is considered a driver of metastasis. Somatic copy number alterations (CNA) are found in most aggressive primary human prostate cancers, and the overall number of such changes is increased in metastases. Chromosome 10q23 deletions, encompassing PTEN, and amplification of 8q24, harboring MYC, are frequently observed, and the presence of both together portends a high risk of prostate cancer-specific mortality. In extant genetically engineered mouse prostate cancer models (GEMM), isolated MYC overexpression or targeted Pten loss can each produce early prostate adenocarcinomas, but are not sufficient to induce genetic instability or metastases with high penetrance. Although a previous study showed that combining Pten loss with focal MYC overexpression in a small fraction of prostatic epithelial cells exhibits cooperativity in GEMMs, additional targeted Tp53 disruption was required for formation of metastases. We hypothesized that driving combined MYC overexpression and Pten loss using recently characterized Hoxb13 transcriptional control elements that are active in prostate luminal epithelial cells would induce the development of genomic instability and aggressive disease with metastatic potential. Neoplastic lesions that developed with either MYC activation alone (Hoxb13-MYC) or Pten loss alone (Hoxb13-Cre∣Pten(Fl/Fl)) failed to progress beyond prostatic intraepithelial neoplasia and did not harbor genomic CNAs. By contrast, mice with both alterations (Hoxb13-MYC∣Hoxb13-Cre∣Pten(Fl/Fl), hereafter, BMPC mice) developed lethal adenocarcinoma with distant metastases and widespread genome CNAs that were independent of forced disruption of Tp53 and telomere shortening. BMPC cancers lacked neuroendocrine or sarcomatoid differentiation, features uncommon in human disease but common in other models of prostate cancer that metastasize. These data show that combined MYC activation and Pten loss driven by the Hoxb13 regulatory locus synergize to induce genomic instability and aggressive prostate cancer that phenocopies the human disease at the histologic and genomic levels.

Molecular evidence that invasive adenocarcinoma can mimic prostatic intraepithelial neoplasia (PIN) and intraductal carcinoma through retrograde glandular colonization

Prostate cancer often manifests as morphologically distinct tumour foci and is frequently found adjacent to presumed precursor lesions such as high-grade prostatic intraepithelial neoplasia (HGPIN). While there is some evidence to suggest that these lesions can be related and exist on a pathological and morphological continuum, the precise clonal and temporal relationships between precursor lesions and invasive cancers within individual tumours remain undefined. Here, we used molecular genetic, cytogenetic, and histological analyses to delineate clonal, temporal, and spatial relationships between HGPIN and cancer lesions with distinct morphological and molecular features. First, while confirming the previous finding that a substantial fraction of HGPIN lesions associated with ERG-positive cancers share rearrangements and overexpression of ERG, we found that a significant subset of such HGPIN glands exhibit only partial positivity for ERG. This suggests that such ERG-positive HGPIN cells either rapidly invade to form adenocarcinoma or represent cancer cells that have partially invaded the ductal and acinar space in a retrograde manner. To clarify these possibilities, we used ERG expression status and TMPRSS2-ERG genomic breakpoints as markers of clonality, and PTEN deletion status to track temporal evolution of clonally related lesions. We confirmed that morphologically distinct HGPIN and nearby invasive cancer lesions are clonally related. Further, we found that a significant fraction of ERG-positive, PTEN-negative HGPIN and intraductal carcinoma (IDC-P) lesions are most likely clonally derived from adjacent PTEN-negative adenocarcinomas, indicating that such PTEN-negative HGPIN and IDC-P lesions arise from, rather than give rise to, the nearby invasive adenocarcinoma. These data suggest that invasive adenocarcinoma can morphologically mimic HGPIN through retrograde colonization of benign glands with cancer cells. Similar clonal relationships were also seen for intraductal carcinoma adjacent to invasive adenocarcinoma. These findings represent a potentially undervalued indicator of pre-existing invasive prostate cancer and have significant implications for prostate cancer diagnosis and risk stratification.

Abstract A70: Mast cells in prostate cancer race disparities: Are the minutemen of the microenvironment the key?

The goal of the current study is to establish the mechanism by which mast cells may serve as a prognostic factor in and possibly explain the racial disparity associated with prostate cancer. There is increasing evidence for a strong association between chronic inflammation and prostate cancer, and the role of mast cells in prostate cancer are of particular interest as they have been suggested to influence cancer progression and immune modulation. It is well established that prostate cancer presents with significant racial disparities, with African American (AA) men being 65% more likely to be diagnosed with prostate cancer than Caucasian American (CA) men and more than two times as likely to die as a result of prostate cancer. In addition, studies have shown AA men to be significantly more likely to present with inflammation in prostate biopsy samples negative for prostate cancer, while microarray data has suggested that inflammatory pathways are highly represented in the differentially expressed mRNA in the tumors of AA vs CA men. Complicating these results, it is probable that inflammatory cells play varied and multiple roles in different regions and grades within the same cancer. With this in mind, we are currently using immunohistochemistry (IHC) and in-situ hybridization techniques to directly visualize and localize mast cells in the prostate microenvironment. These studies are aided by novel digital image analysis using a software framework integrating whole slide imaging, virtual microscopy, and ImageJ based analysis algorithms. Our preliminary results in a 10 case tissue microarray (TMA) are consistent with other reports in the literature indicating that there are higher mast cell densities in better differentiated cancers; however, we are examining this further in a larger full slide cohort in relation to Gleason grade and stage. We are currently utilizing this image analysis technology on a TMA cohort designed to explore differences in mast cell density in AA vs CA men. Furthermore, we aim to examine differences in mast cell subtypes between benign and malignant regions of the prostate and between AA and CA men. Our goal is to establish the mechanism by which mast cells may serve as a prognostic factor in prostate cancer and may help to explain prostate cancer racial disparities.

Citation Format: Heidi A. Hempel, Ibrahim Kulac, Nathan S. Cuka, Toby C. Cornish, Angelo M. De Marzo, Karen S. Sfanos. Mast cells in prostate cancer race disparities: Are the minutemen of the microenvironment the key? [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr A70.

Abstract 2025: Inverse relation of Myc and p27 in cribriform pattern prostate cancer

Background: Prostate cancers composed exclusively of Gleason pattern 3 have an excellent prognosis,while those containing Gleason pattern 4 or higher are more aggressive. Gleason pattern 4 is composed of either fused glands, poorly formed glands or cribriform structures with cribriform structures being most readily recognized and shown to be of independent prognostic significance (PMIDS: 24145642;25189638). However, the biological properties of these cribriform structures have not been studied. There is a spectrum of nuclear features in cribriform glands with cells towards the perimeter containing enlarged nucleoli, and open chromatin as compared to cells towards the center. Since MYC overexpression drives nucleolar enlargement we examined the pattern of expression of MYC protein in these structures. Also, we examined p27 staining since it has been reported to be more intense in the nuclei in the center of these structures (PMID:9731735).

Design: Cases with cribriform Gleason score 7 were used for IHC for MYC, p27 and Ki67 as well as double label immunofluorescence staining for p27 and MYC. Slides were scanned and regions were selected containing cribriform glands (N = 18 total regions) and analyzed using image analysis software by Aperio Inc. We quantified the level of nuclear staining for MYC and p27 in relation to the outside/perimeter regions versus the inner aspect of the glands. Chromogenic in-situ hybridization for MYC mRNA was also performed.

Results: The increase in MYC staining in the perimeter aspects of the cribriform structures was highly significant as compared to the inner regions (P&lt;0.0001, rank sum). Conversely, p27 staining showed an increase in the central region as compared to the perimeter aspect (P = 0.0024). There was also a marked increase in staining for Ki67 (p&lt;0.0001) as well as MYC mRNA in the perimeter cells. Double label fluorescent staining showed a tight inverse correlation between MYC and nuclear p27 staining.

Conclusion: Two distinct populations of cancer cells comprise cribriform carcinomas of the prostate; the central aspect is composed of cells with relatively small nucleoli that are non-proliferating with high levels of nuclear p27, and an outer layer that is composed of metabolically more active cells with increased MYC, nucleolar size and proliferative fraction. These findings provide new biological insights into the unique structure of cribriform prostate cancer lesions and suggest a complex interplay between the two cell types. Future studies are needed to determine how and whether these findings relate to disease aggressiveness.

Citation Format: Ibrahim Kulac, Jessica Hicks, Qizhi Zheng, Helen Fedor, Toby C. Cornish, Angelo M. De Marzo. Inverse relation of Myc and p27 in cribriform pattern prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2025. doi:10.1158/1538-7445.AM2015-2025

Abstract 2342: Characterization of inflammatory markers and mast cells in association with prostate cancer

Evidence suggests that there is a strong association between chronic inflammation and prostate cancer development and/or progression. While chronic inflammation is known to serve as an “enabling characteristic” in many cancers, the mechanism whereby it contributes to carcinogenesis and progression is still very controversial. This is particularly true for cells of the innate immune system, such as mast cells, that have been shown to possess both pro- and anti-tumor properties. The role of mast cells in prostate cancer is of particular interest, as evidence suggests that they influence cancer progression and immune modulation. The current study seeks to characterize mast cell density and mast cell-to-epithelial ratio in relation to prostate cancer recurrence using a unique set of tissue microarrays (TMAs) from a case-control study nested in a cohort of prostate cancer patients who underwent radical prostatectomy. These studies are aided by novel digital image analysis using a software framework integrating whole slide imaging, virtual microscopy, and ImageJ based analysis algorithms. Our preliminary results, obtained via analysis of a prostate cancer TMA containing matched cancer and benign tissues from 727 cases of radical prostatectomy patients, correlated with the literature in that the mast cell density (mast cell number/total tissue area) was significantly higher in cancer versus benign (p = 0.0016). We will expanded this study to determine if mast cell number correlates with epithelial area in the same cohort and to examine mast cell density in correlation to the presence, grade, or progression of prostate cancer. Furthermore, we will be examining this in a large full tissue slide cohort in relation to Gleason grade and stage. Finally, we are expanding this study to explore a possible role for mast cells in the racial disparity in prostate cancer incidence and prognosis.

Citation Format: Heidi Hempel, Ibrahim Kulac, Nathan S. Cuka, Toby C. Cornish, Elizabeth A. Platz, Angelo M. DeMarzo, Karen S. Sfanos. Characterization of inflammatory markers and mast cells in association with prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2342. doi:10.1158/1538-7445.AM2015-2342

Should Gleason 6 be labeled as cancer?

PUPOSE OF REVIEW

The review covers arguments for and against removing the label of 'cancer' in Gleason score 6 prostate tumors.

RECENT FINDINGS

While there are a number of factors that determine whether men elect active surveillance, the most powerful predictor remains the Gleason score. Gleason grading remains a robust and powerful predictor of outcome in patients with prostate cancer. A pure Gleason score 6 (GS6) tumor is exceedingly unlikely to cause harm in the near term, and there have been discussions regarding whether the term cancer should still be applied. In this review, we update the largely clinico-pathological arguments that have led to the suggestion to remove the cancer label from GS6 tumors, and we provide counter arguments on the basis of practical matters of needle biopsy sampling, classical histopathology, and molecular biology findings.

SUMMARY

The implications are that by retaining the label of cancer and implementing the recently proposed concept of prognostic groups, with patients harboring GS6 tumors placed into the lowest category, there is still a strong rationale in support of the choice of active surveillance or watchful waiting for most patients with GS6 lesions.

Effects of intra-abdominal pressure on adrenal gland function and morphology in rats

Intra-abdominal hypertension and abdominal compartment syndrome (IAH/ACS) are life-threatening conditions and caused by several clinical status. Although there is insufficient data regarding its effects on adrenal glands. This study aimed to identify whether elevated intra-abdominal pressure (IAP) caused any alteration on the morphology and function of adrenal glands in a rat model. Twenty four Sprague-Dawley male rats were included in the study. Animals were allocated into 4 groups. IAP was elevated to 15 mmHg for one hour and four hours in group 2 and 4. Group 1 and 3 were sham groups. Blood samples were taken for the assessment of plasma adrenaline, noradrenaline, and corticosterone levels and adrenalectomies were performed to evaluate apoptosis. Blood adrenaline, noradrenaline and corticosterone levels were significantly higher in the study groups compared with the sham groups. However, there were no significant changes in apoptotic index scores in the study groups as compared to sham groups. These results support that increased IAH leads to discharge of catecholamine and corticosterone from the adrenal glands. Failure to demonstrate similar changes in apoptotic index score may be concluded as apoptosis is not a leading pathway for impairment of adrenal glands during IAH period.

Microscopic lesions of fallopian tubes in endometrioid carcinoma of the endometrium: How effective are the macroscopic tubal sampling techniques?

OBJECTIVE

Extrauterine involvement of endometrial carcinoma has a significant effect on the patients' prognosis and treatment decision. In classical method, macroscopic section is taken from the fallopian tube sparing the fimbrial ends. Fimbrial end of fallopian tube may be involved by tumors and precursor lesions. This study aims to determine the importance of sampling of fimbrial ends of fallopian tube in endometrioid endometrial carcinoma specimens.

METHODS

We reevaluated the fallopian tubes of 200 cases of endometrioid endometrial carcinoma cases that have no macroscopic tubal lesion. A hundred cases were sampled with classical method, and the other 100 were sampled with a new method that includes the fimbrial ends. Statistical difference was examined by Fisher's exact test.

RESULTS

No microscopic tubal lesion lesion was detected in cases that were sampled with the classical method. In contrast, there were 4 cases with tubal lesions in patients sampled with the new technique; 3 of them were located in the fimbrial end. Of the 3, there was one microscopic invasive carcinoma and two proliferative endometrial glandular lesions. Endometriosis was detected in two of the 4 cases with tubal lesions.

CONCLUSION

Including the fimbrial end of fallopian tube to macroscopic sampling could detect more tubal lesions, which might provide additional prognostic and pathogenetic information of endometrioid endometrial carcinoma.

Occurrence of dysplasia and human papilloma virus typing in penile condylomas

OBJECTIVE

To determine the incidence of dysplasia as a preneoplastic change and high-risk human papilloma virus (HPV) infection in penile condylomas, which are common HPV-related lesions and considered a risk factor for penile cancer.

METHODS

Histologic analysis was done of 58 consecutive penile condylomas with tissue diagnosis. An immunohistochemical panel that included stains for p53, Ki-67, and p16INK4a was also used. HPV typing was successfully performed in 43 lesions. Genotyping was accomplished through polymerase chain reaction and flow-through hybridization with an HPV GenoArray Diagnostic Test kit.

RESULTS

Dysplasia was observed in 13 of the 58 condylomas (22%). High-risk HPV DNA was detected in 5 of 10 dysplastic lesions (50%) for which tissue blocks were available for study. High-risk HPV was not detected in the nondysplastic lesions (P<.001). Ki-67≥20% above the basal layer of epithelium and p53-positive immunostaining occurred more frequently in dysplastic lesions than in nondysplastic lesions; however, the difference was not statistically significance. Staining for p16INK4a was not helpful.

CONCLUSION

Anogenital condylomas in men are usually treated using destructive methods or with medication. We suggest that at least a part of the lesion must be removed and sent for histopathologic examination. If the histologic result shows significant dysplastic alteration, the lesion should be further investigated to determine the subtype of infective virus, because 50% of such lesions are associated with high-risk HPV. When oncogenic pathogens are found, careful patient follow-up for recurrences and counseling for the patient and his sexual partner(s) may be warranted.

Does androgen receptor have a prognostic role in patients with estrogen/progesterone-negative and c-erbB-2-positive breast cancer?

Recently, it has been shown that androgen and androgen receptor (AR) also have an important role in the pathogenesis and outcome of breast cancer. However, their significance in different subtypes of breast cancer is still under investigation. The aim of this study was to study the effects of AR on clinicopathological features and prognosis in patients with estrogen and progesterone receptor (ER/PR)-negative, HER2-positive breast cancer. Tumor paraffin-embedded blocks from archives were used for AR study. Data of patients with ER/PR-negative and HER2-positive breast cancer diagnosed at our institute between 1999 and 2010 were recorded and analyzed retrospectively. We studied 36 patients with ER/PR-negative and HER2-positive breast cancer for AR status. Sixteen of them (44.4%) showed AR positivity. The median age was 47 and 56 years for AR-negative and -positive patients, respectively (P = 0.03). The number of postmenopausal patients was higher in the AR-positive than -negative group (56 vs 30%) (P = 0.01). Other demographic data were similar in both group. Histopathological parameters and tumor and nodal stages were similar in both groups. Trastuzumab treatment was more frequently given to AR-positive than -negative patients (94 vs 44%) (P = 0.01). Median follow-up was 47.1 and 34.7 months in AR-negative and -positive groups, respectively (P = 0.03). Relapse occurred in six and four patients in AR-negative and -positive groups. Median progression-free survival (PFS) was similar in both groups (15.7 and 19.6 months in AR-negative and -positive patients, respectively; P = 0.56). Two patients died at 23.4 and 46 months of follow-up in the AR-negative group. There were no deaths in the AR-positive group. Overall survival analyses were not done as a result of an unmet number of events. Median PFS was similar in AR-positive and -negative in that group of patients with ER/PR-negative and HER2-positive breast cancer. However AR-positive patients were more frequently postmenopausal, older, and positive for lymphovascular space invasion. More frequently applied trastuzumab in the AR-positive group might have an effect on the similarity of PFS between the two groups. Studies with higher numbers in this subset of patients with breast cancer will give more robust data.

Does Androgen Receptor Have a Prognostic Role in Patients with Estrogen/Progesterone-Negative and c-erbB-2-Positive Breast Cancer?

Recently, it has been shown that androgen and androgen receptor (AR) also have an important role in the pathogenesis and outcome of breast cancer. However, their significance in different subtypes of breast cancer is still under investigation. The aim of this study was to study the effects of AR on clinicopathological features and prognosis in patients with estrogen and progesterone receptor (ER/PR)-negative, HER2-positive breast cancer. Tumor paraffin-embedded blocks from archives were used for AR study. Data of patients with ER/PR-negative and HER2-positive breast cancer diagnosed at our institute between 1999 and 2010 were recorded and analyzed retrospectively. We studied 36 patients with ER/PR-negative and HER2-positive breast cancer for AR status. Sixteen of them (44.4%) showed AR positivity. The median age was 47 and 56 years for AR-negative and -positive patients, respectively ( P = 0.03). The number of postmenopausal patients was higher in the AR-positive than -negative group (56 vs 30%) ( P = 0.01). Other demographic data were similar in both group. Histopathological parameters and tumor and nodal stages were similar in both groups. Trastuzumab treatment was more frequently given to AR-positive than -negative patients (94 vs 44%) ( P = 0.01). Median follow-up was 47.1 and 34.7 months in AR-negative and -positive groups, respectively ( P = 0.03). Relapse occurred in six and four patients in AR-negative and -positive groups. Median progression-free survival (PFS) was similar in both groups (15.7 and 19.6 months in AR-negative and -positive patients, respectively; P = 0.56). Two patients died at 23.4 and 46 months of follow-up in the AR-negative group. There were no deaths in the AR-positive group. Overall survival analyses were not done as a result of an unmet number of events. Median PFS was similar in AR-positive and -negative in that group of patients with ER/PR-negative and HER2-positive breast cancer. However AR-positive patients were more frequently postmenopausal, older, and positive for lymphovascular space invasion. More frequently applied trastuzumab in the AR-positive group might have an effect on the similarity of PFS between the two groups. Studies with higher numbers in this subset of patients with breast cancer will give more robust data.

A case of prostatic adenocarcinoma with aberrant p63 expression: presentation with detailed immunohistochemical study and FISH analysis

Prostate carcinomas showing aberrant diffuse-nuclear p63 expression are extremely rare, and there is only 1 article in the literature reporting a series of 21 such cases. We document an additional case of p63-positive prostatic adenocarcinoma in a 60-year-old man, whose diagnosis was difficult. The patient was found to have an elevated prostate-specific antigen (PSA) level at a general health check-up and was referred to the hospital. His serum PSA was 4.2 ng/mL. Digital rectal examination and transrectal ultrasonography did not reveal a lesion. Transrectal needle biopsy of the prostate detected atypical, small prostatic glands suspected for adenocarcinoma at 2 cores. However immunohistochemistry showed nuclear p63 expression in the suspicious glands. Repeat biopsy revealed only high-grade prostatic intraepithelial neoplasia. In the third transrectal biopsy, finding of the same atypical glands showing perineural invasion facilitated the diagnosis of malignancy. The patient underwent a radical prostatectomy. Five different small tumor foci were seen in the prostate after pathological evaluation, one of which was p63 positive and the others p63 negative. The largest of the classic p63-negative tumors showed a TMPRSS2-ERG translocation by fluorescent in situ hybridization while the p63-positive tumor did not. The authors submit that this subtype (p63-positive prostate adenocarcinoma) should be listed among the recognized rare variants of prostatic adenocarcinoma.