Assessment of a computerized quantitative quality control tool for whole slide images of kidney biopsies.

Inconsistencies in the preparation of histology slides and whole-slide images (WSIs) may lead to challenges with subsequent image analysis and machine learning approaches for interrogating the WSI. These variabilities are especially pronounced in multicenter cohorts, where batch effects (i.e. systematic technical artifacts unrelated to biological variability) may introduce biases to machine learning algorithms. To date, manual quality control (QC) has been the de facto standard for dataset curation, but remains highly subjective and is too laborious in light of the increasing scale of tissue slide digitization efforts. This study aimed to evaluate a computer-aided QC pipeline for facilitating a reproducible QC process of WSI datasets. An open source tool, HistoQC, was employed to identify image artifacts and compute quantitative metrics describing visual attributes of WSIs to the Nephrotic Syndrome Study Network (NEPTUNE) digital pathology repository. A comparison in inter-reader concordance between HistoQC aided and unaided curation was performed to quantify improvements in curation reproducibility. HistoQC metrics were additionally employed to quantify the presence of batch effects within NEPTUNE WSIs. Of the 1814 WSIs (458 H&E, 470 PAS, 438 silver, 448 trichrome) from n = 512 cases considered in this study, approximately 9% (163) were identified as unsuitable for subsequent computational analysis. The concordance in the identification of these WSIs among computational pathologists rose from moderate (Gwet's AC1 range 0.43 to 0.59 across stains) to excellent (Gwet's AC1 range 0.79 to 0.93 across stains) agreement when aided by HistoQC. Furthermore, statistically significant batch effects (p < 0.001) in the NEPTUNE WSI dataset were discovered. Taken together, our findings strongly suggest that quantitative QC is a necessary step in the curation of digital pathology cohorts. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Prognostic marker analysis in pediatric intracranial ependymomas.

Histologic grading methods dependent upon H&E staining review have not been shown to reliably predict survival in children with intracranial ependymomas due to the subjectivity of the analytical methods. We hypothesized that the immunohistochemical detection of MIB-1, Tenascin C, CD34, VEGF, and CA IX may represent objective markers of post-operative survival (Progression Free and Overall Survival; PFS, OS) in these patients. Intracranial ependymomas from patients aged 22 years or less were studied. The original histologic grade was recorded, H&E sections were reviewed for vascular proliferation status, and immunohistochemistry was used to determine MIB-1, Tenascin C, CD34, VEGF, and CA IX status. Based upon the World Health Organization (WHO) grading system, 3 Grade I, 18 Grade II and 9 Grade III ependymomas were studied. Median follow-up time was 9.0 years; median PFS was, 6.1 years. Original WHO grade did not correlate with PFS or OS. Peri-necrotic CA IX localization correlated with PFS (Log rank = 0.0181) and OS (Log rank p = 0.0015). All patients with a CA IX ≤ 5 % total area localization were alive at last follow-up. Perinecrotic CA IX staining was also associated with vascular proliferation (p = 0.006), though not with VEGF expression score. MIB-1 labeling index (LI) correlated with OS (HR 1.06, 95 % CI 1.01, 1.12) and PFS (HR 1.08, 95 % CI 1.02, 1.14). MIB-1 LI and perinecrotic CA IX individually correlated with PFS. The effect of perinecrotic CA IX remained when grade was added to a Cox model predicting PFS. Immunodetection of CA IX and MIB-1 expression are predictive biomarkers for survival in children with posterior fossa ependymomas. These markers represent objective indicators of survival that supplement H&E grading alone.

Pre-existing Castration-resistant Prostate Cancer-like Cells in Primary Prostate Cancer Promote Resistance to Hormonal Therapy.

BACKGROUND: Hormonal therapy targeting the androgen receptor inhibits prostate cancer (PCa), but the tumor eventually recurs as castration-resistant prostate cancer (CRPC). OBJECTIVE: To understand the mechanisms by which subclones within early PCa develop into CRPC. DESIGN, SETTING, AND PARTICIPANTS: We isolated epithelial cells from fresh human PCa cases, including primary adenocarcinoma, locally recurrent CRPC, and metastatic CRPC, and utilized single-cell RNA sequencing to identify subpopulations destined to become either CRPC-adeno or small cell neuroendocrine carcinoma (SCNC). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We revealed dynamic transcriptional reprogramming that promotes disease progression among 23226 epithelial cells using single-cell RNA sequencing, and validated subset-specific progression using immunohistochemistry and large cohorts of publically available genomic data. RESULTS AND LIMITATIONS: We identified a small fraction of highly plastic CRPC-like cells in hormone-naïve early PCa and demonstrated its correlation with biochemical recurrence and distant metastasis, independent of clinical characteristics. We show that progression toward castration resistance was initiated from subtype-specific lineage plasticity and clonal expansion of pre-existing neuroendocrine and CRPC-like cells in early PCa. CONCLUSIONS: CRPC-like cells are present early in the development of PCa and are not exclusively the result of acquired evolutionary selection during androgen deprivation therapy. The lethal CRPC and SCNC phenotypes should be targeted earlier in the disease course of patients with PCa. PATIENT SUMMARY: Here, we report the presence of pre-existing castration-resistant prostate cancer (CRPC)-like cells in primary prostate cancer, which represents a novel castration-resistant mechanism different from the adaptation mechanism after androgen deprivation therapy (ADT). Patients whose tumors harbor increased pre-existing neuroendocrine and CRPC-like cells may become rapidly resistant to ADT and may require aggressive early intervention.

PD-L1 Assay Concordance in Metastatic Renal Cell Carcinoma and Metastatic Urothelial Carcinoma.

BACKGROUND: Immune checkpoint inhibitors are now standard of care for many patients with metastatic renal cell carcinoma (mRCC) and metastatic urothelial carcinoma (mUC). Given real-world limitations in programmed death-ligand 1 (PD-L1) testing, concordance studies between PD-L1 assays are needed. We undertook comparisons of Dako 28-8 and Ventana SP142 assays in mRCC and Dako 22C3 and Ventana SP263 assays in mUC. PATIENTS AND METHODS: Thirty-two patients with mRCC and 18 patients with mUC who had received immune checkpoint inhibitor therapy were identified. Formalin-fixed paraffin-embedded tumor samples for patients with mRCC were evaluated with Dako 28-8 and Ventana SP142 PD-L1 immunohistochemistry assays. For patients with mUC, formalin-fixed paraffin-embedded tumor samples were evaluated with Dako 22C3 and Ventana SP263 PD-L1 immunohistochemistry assays. RESULTS: The majority (29/32; 91%) of mRCC cases were concordant between assays. The majority (17/18; 94%) of mUC cases were also concordant between assays. CONCLUSIONS: There was strong concordance between PD-L1 assays chosen for comparison in both mRCC and mUC, with similar performance characteristics. One limitation is the small number of cases in this study; larger comparison studies are needed for this biomarker in mRCC and mUC.

MGMT: Immunohistochemical Detection in High-Grade Astrocytomas.

Glioma therapeutic resistance to alkylating chemotherapy is mediated via O6-methylguanine-DNA methyltransferase (MGMT). We hypothesized that a CD45/HAM56/MGMT double-stained cocktail would improve MGMT discrimination in tumor cells versus inflammatory and endothelial cells (IEC). Total MGMT protein was quantified by IHC on 982 glioblastomas (GBM) and 199 anaplastic astrocytomas. Correcting for IEC was done by a CD45/HAM56/MGMT 2-color cocktail. Lowest IEC infiltrates (IEC "cold spots") were identified to quantitate MGMT as well as the percentage of IEC% in the IEC cold spots. MGMT promoter methylation (PM) was also determined. Among the GBM biopsies, mean uncorrected and corrected MGMT% were 19.87 (range 0-90) and 16.67; mean IEC% was 18.65 (range 1-80). Four hundred and fifty one (45.9%) GBM biopsies were positive MGMT PM. Both uncorrected and corrected MGMT% positivity correlated with PM. All 3 MGMT scores correlated with overall survival (OS) in GBM's. Cold spot IEC% was also positively associated with OS. These effects remained in a multivariate model after adjusting for age and disease status. Prognosis determined by correcting MGMT% score for IEC% is not improved in this analysis. However, IEC COLD SPOT score does provide additional prognostic information that can be gained from this correction method.

Overexpression of SOX11 and TFE3 in Solid-Pseudopapillary Neoplasms of the Pancreas.

OBJECTIVES: To characterize the expression of SOX11 and TFE3 proteins in solid-pseudopapillary neoplasms (SPNs) and their histologic mimickers. METHODS: Immunohistochemistry for SOX11, TFE3, and ß-catenin was performed on 31 cases of surgically resected SPNs. Neuroendocrine tumors, acinar cell carcinomas, and pancreatoblastomas served as controls. RESULTS: Nuclear immunoreactivity for SOX11 was detected in all SPNs and five of 31 control tumors. Nuclear immunoreactivity for TFE3 was detected in 30 SPNs and three control tumors. Nuclear immunoreactivity for ß-catenin was detected in all SPNs and four control tumors. The combination of three markers as immunohistochemical panels resulted in optimal sensitivity and specificity. CONCLUSIONS: Both SOX11 and TFE3 were overexpressed in SPNs and may be involved in the pathogenesis. Clinically, SOX11 and TFE3 can be potentially used as diagnostic markers in distinguishing indeterminate SPNs from their histologic mimickers.

Validation of an Immunohistochemistry Assay for Detection of CD155, the Poliovirus Receptor, in Malignant Gliomas.

CONTEXT: - The oncolytic polio-rhinovirus recombinant (PVSRIPO) has demonstrated promise in currently ongoing phase I/II clinical trials against recurrent glioblastoma and was granted breakthrough therapy designation by the Food and Drug Administration/Center for Biologics Evaluation and Research. A reliable clinical assay to document expression of the poliovirus receptor, CD155, in routinely available patient tumor samples is needed for continued clinical development of PVSRIPO oncolytic immunotherapy in primary brain tumors and beyond. OBJECTIVES: - To validate a novel anti-CD155 antibody for immunohistochemistry and develop a robust, reliable, and specific protocol for detecting CD155 expression in glioblastoma formalin-fixed, paraffin-embedded (FFPE) tissue samples. To characterize the expression of CD155 in human glioblastoma cells as well as to evaluate the influence of CD155 expression levels on tumor cell susceptibility to PVSRIPO infection and killing. DESIGN: - Immunohistochemical staining on glioblastoma FFPE tissue sections and immunoblot of corresponding frozen tissues were performed. Positive controls were confirmed sites of poliovirus propagation, spinal cord anterior horn, and tonsils; negative controls were vascular smooth muscle in patient samples and FFPE sections from a confirmed CD155-negative Burkitt lymphoma line (Raji). RESULTS: - We succeeded in developing a reliable assay to specifically detect CD155 by immunohistochemistry in glioblastoma FFPE sections. Our data suggest widespread, virtually universal expression of CD155 in glioblastoma cells at levels commensurate with susceptibility to PVSRIPO infection and killing. CONCLUSIONS: - Anti-CD155 antibody D3G7H achieves monospecific detection of CD155 in immunoblots of tumor homogenates and immunohistochemistry of tumor FFPE sections. Our assay has utility in defining appropriate use of PVSRIPO in oncolytic immunotherapy against malignant glioma and other cancer histotypes.

Mixed Adenoneuroendocrine Carcinoma, Amphicrine Type, of the Small Bowel.

OBJECTIVES: Amphicrine-type mixed adenoneuroendocrine carcinomas are exceedingly rare lesions of the gastrointestinal tract, comprising tumor cells simultaneously demonstrating both neuroendocrine and exocrine features. To date, only 14 cases of amphicrine carcinoma have been reported; here we report the first definitive case of amphicrine carcinoma in the small bowel. METHODS: A 72-year-old woman who sought treatment for nonspecific abdominal complaints was found to have a duodenojejunal junction tumor and underwent radical surgical resection. RESULTS: Morphologically, the tumor consisted of areas of moderately differentiated adenocarcinoma intermingled with areas characteristic of neuroendocrine tumor. The entire tumor showed strong, diffuse immunoreactivity for synaptophysin. Coexpression of exocrine and neuroendocrine features by neoplastic cells indicates bivalent differentiation, and therefore the tumor was classified as an amphicrine carcinoma of the small bowel. CONCLUSIONS: Demonstration of amphicrine carcinoma in the small bowel carries implications with regard to the common origin of exocrine and neuroendocrine cells in the gastrointestinal tract.

Bilateral diffuse uveal melanocytic proliferation associated with pancreatic carcinoma: a case report and literature review of this paraneoplastic syndrome.

A case of a 64-year-old man with bilateral diffuse uveal melanocytic proliferation is presented. Bilateral diffuse uveal melanocytic proliferation is a rare paraneoplastic disorder where an underlying malignancy causes bilateral blindness by uveal thickening, serous retinal detachment, and rapid cataract formation. The ocular symptoms and signs herald the onset of this disease, which leads to death in most cases within about 1 year. Including the present case, our literature review reveals that a total of 28 cases of bilateral diffuse uveal melanocytic proliferation have now been reported. Several different malignancies have been associated with bilateral diffuse uveal melanocytic proliferation, but ovarian carcinoma in women and lung and suspected pancreatic carcinoma in men are the most common. Our case is the first to be proven at autopsy to be associated with pancreatic carcinoma. The underlying mechanism remains to be identified, as numerous endogenous factors may regulate the proliferation of uveal melanocytes. Consideration of this entity during clinical examination may lead to an earlier diagnosis of malignancy and an improved prognosis.

A single tube, four-color flow cytometry assay for evaluation of ZAP-70 and CD38 expression in chronic lymphocytic leukemia.

We describe a simple and robust flow cytometry assay for ZAP-70 and CD38 expression. The steps required to validate this assay in a clinical flow cytometry laboratory are described. Two criteria were used to characterize ZAP-70 expression into positive, negative, and indeterminate categories and applied to 111 cases of chronic lymphocytic leukemia (CLL) resulting in 29.7% positive, 56.8% negative, and 13.5% indeterminate cases. A sensitivity-specificity crossover plot between ZAP-70 and CD38 suggested a cutoff of 12.5% for defining CD38 positivity. ZAP-70+ cases were significantly more likely to be at a higher clinical stage and, together with CD38+ cases, were more likely to have unmutated IgV(H). However, for individual patients, the concordance between these markers was not perfect. It may be necessary to evaluate several prognostic markers simultaneously in CLL, and availability of convenient assays for ZAP-70 and CD38 is desirable for optimal clinical decision making.

Distinct expression patterns of CD123 and CD34 on normal bone marrow B-cell precursors ("hematogones") and B lymphoblastic leukemia blasts.

We compared the expression of CD123, the alpha chain of the interleukin-3 receptor, on normal B-cell precursors in bone marrow ("hematogones") from 75 specimens and on leukemic blasts in 45 newly diagnosed B-acute lymphoblastic leukemias (B-ALL) cases. We found that the less mature hematogones (dim CD45+) that express CD34 lack CD123 expression, whereas the more mature hematogones (moderate CD45+) lack CD34 but always express CD123. In contrast with this discordant pattern of CD34 and CD123 expression in hematogones, blasts in 41 (91%) of 45 cases of B-ALL showed concordant expression of the 2 antigens: 80% (36 of 45) cases expressed both antigens, whereas 11% (5 of 45) expressed neither. We found that these distinct patterns of CD34/CD123 expression on hematogones (discordant) and B-ALL blasts (concordant) remain stable after chemotherapy and are useful in differentiating small populations of residual blasts from hematogones that may be simultaneously present.

Second messenger systems in human gliomas.

CONTEXT: Patients with glioblastoma (astrocytoma, World Health Organization grade IV) exhibit 2-year survival rates of less than 20% despite significant advances in therapeutic options available to patients. Epidermal growth factor receptor (EGFR) hyperexpression is one of the most commonly encountered abnormalities in this tumor. However, EGFR expression, amplification, and mutations are poorly predictive of patient survival. Investigators have taken to exploiting the sensitivities of activated downstream targets in the EGFR second messenger pathways to certain inhibitory drugs to downregulate their neoplastic messages promoting cell growth and inhibiting cell death. OBJECTIVE: It is important to both gain some understanding of the functional significance of these pathways and to understand the role the pathologist might play in characterizing the activation status of certain downstream messenger proteins that are targeted in these brain tumor therapies. We have reviewed the literature regarding histologic assays that have been incorporated into trials of these new drugs and report on the methods used to study these proteins and the conclusions of these studies. DATA SOURCES: Literature review and primary material from Duke University (Durham, NC) Department of Pathology archives. CONCLUSIONS: To date, drug trial reports indicate that identification of the presence of the EGFR variant, EGFRvIII, and measurement of the activated downstream targets, phospho-Akt, phospho-S6, and phospho-MAPK, may be useful in predicting sensitivity to some of the EGFR kinase inhibitors. No studies to date have identified prognostic significance related to immunoreactivity status among any of these markers that is independent of histologic grade.