A Pilot Validation Study Comparing Fluorescence-Imitating Brightfield Imaging, A Slide-Free Imaging Method, With Standard Formalin-Fixed, Paraffin-Embedded Hematoxylin-Eosin-Stained Tissue Section Histology for Primary Surgical Pathology Diagnosis.

Context.—: Digital pathology using whole slide images has been recently approved to support primary diagnosis in clinical surgical pathology practices. Here we describe a novel imaging method, fluorescence-imitating brightfield imaging, that can capture the surface of fresh tissue without requiring prior fixation, paraffin embedding, tissue sectioning, or staining.

The Biomarker Ki-67: Promise, Potential, and Problems in Breast Cancer.

Ki-67 is a nuclear protein serendipitously discovered by monoclonal antibody selection in the early 1980s. While it has been applied for decades in the context of breast cancer as a putative prognostic and, more recently, predictive, biomarker, even after all this time there is incomplete agreement as to the validity of the immunohistochemical assays employed for Ki-67 assessment, given possible effects of the disparate methodologies employed and possible confounding preanalytical, analytical, and interpretive variables. In this brief review, the history of Ki-67 and the problems, particularly with the analytical and interpretive variables, are highlighted through a selective review of the published literature.

Phosphorylated transducer and activator of transcription-3 (pSTAT3) immunohistochemical expression in paired primary and metastatic colorectal cancer.

Background: Signal Transducer and Activator of Transcription-3 (STAT3) mediates cellular functions. We assessed the IHC expression of phosphorylated STAT3 (pSTAT3) in paired primary tumors and liver metastases in patients with advanced stage colorectal cancer (CRC).

Methods: We included patients with tissue blocks available from both the primary CRC and a surgically resected liver metastasis.

SATB2 protein expression by immunohistochemistry is a sensitive and specific marker of appendiceal and rectosigmoid well differentiated neuroendocrine tumours.

Aims: Neuroendocrine neoplasms (NNs) range from well to poorly differentiated and indolent to highly aggressive. The site of origin in metastatic NNs has therapeutic and prognostic implications. SATB2 is a transcriptional regulator involved in osteoblastic and neuronal differentiation and is a sensitive and specific marker of colorectal epithelium.

Quantitative assessment of PD-L1 as an analyte in immunohistochemistry diagnostic assays using a standardized cell line tissue microarray.

Programmed death 1 ligand 1 (PD-L1) Immunohistochemistry (IHC) is the key FDA-approved predictive marker to identify responders to anti-PD1 axis drugs. Multiple PD-L1 IHC assays with various antibodies and cut points have been used in clinical trials across tumor types. Comparative performance characteristics of these assays have been extensively studied qualitatively but not quantitatively.

Analytical validation of a standardised scoring protocol for Ki67 immunohistochemistry on breast cancer excision whole sections: an international multicentre collaboration.

Aims: The nuclear proliferation marker Ki67 assayed by immunohistochemistry has multiple potential uses in breast cancer, but an unacceptable level of interlaboratory variability has hampered its clinical utility. The International Ki67 in Breast Cancer Working Group has undertaken a systematic programme to determine whether Ki67 measurement can be analytically validated and standardised among laboratories. This study addresses whether acceptable scoring reproducibility can be achieved on excision whole sections.

Immunohistochemistry for TFE3 lacks specificity and sensitivity in the diagnosis of TFE3-rearranged neoplasms: a comparative, 2-laboratory study.

TFE3 rearrangements are characteristic of alveolar soft part sarcomas (ASPS), Xp11.2 translocation renal cell carcinomas (Xp11-RCC), and other rare tumors. Immunohistochemistry for TFE3 protein has been considered by some to be a reliable surrogate for TFE3 molecular studies, although others disagree.

Role of SATB2 in distinguishing the site of origin in glandular lesions of the bladder/urinary tract.

The differential diagnosis of glandular lesions of the bladder/urinary tract can be challenging because of significant morphologic and immunohistochemical overlap between primary lesions and metastasis/direct extension from adjacent organs. Special AT-rich sequence-binding protein 2 (SATB2), encoded on chromosome 2q32-33, is a recently described DNA-binding protein involved in osteoblast lineage commitment and expressed in colorectal and appendiceal neoplasms. In this study, we hypothesized that immunohistochemistry for SATB2 may be of value in distinguishing primary adenocarcinoma of the bladder/urinary tract and urothelial carcinoma with glandular differentiation from gastrointestinal and endocervical primaries.

Guidelines for Pathologic Diagnosis of Malignant Mesothelioma 2017 Update of the Consensus Statement From the International Mesothelioma Interest Group.

Context: - Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.

Objective: - To provide updated, practical guidelines for the pathologic diagnosis of MM.

Data Sources: - Pathologists involved in the International Mesothelioma Interest Group and others with an interest and expertise in the field contributed to this update.

Comparative Sensitivities and Specificities of Antibodies to Breast Markers GCDFP-15, Mammaglobin A, and Different Clones of Antibodies to GATA-3: A Study of 338 Tumors Using Whole Sections.

GATA-3 is a transcription factor that has recently been identified by immunohistochemistry to be highly expressed in urothelial and breast carcinomas (CAs). We sought to determine the potential utility of GATA-3 in identifying metastatic breast CA, and to compare its utility with the standard breast markers, GCDFP-15, and mammaglobin A. We identified an archival series of 338 formalin-fixed paraffin-embedded whole-tissue sections of various CAs.

Investigation of PD-L1 Biomarker Testing Methods for PD-1 Axis Inhibition in Non-squamous Non-small Cell Lung Cancer.

Inhibitors of the programmed cell death 1 (PD-1) signaling axis have recently demonstrated efficacy and are rapidly being incorporated into the treatment of non-small cell lung cancers (NSCLCs). Despite clear benefits to certain patients, the association of these responses with a predictive biomarker remains uncertain. Several different biomarkers have been proposed, with differing results and conclusions.

Diagnostic Immunohistochemistry: What Can Go Wrong and How to Prevent It.

Context: -There are a number of critical factors that can lead to incorrect results if the diagnostic pathologist performing immunohistochemistry is unaware of, or not vigilant about, their influence.

Objective: -To highlight 3 arenas in which errors may be introduced.

Data Sources: -For choosing the correct primary antibody, selection of the most appropriate antibodies for a given clinical application can be aided by obtaining information from the vendor; however, this can yield incomplete information.

Analytical validation of a standardized scoring protocol for Ki67: phase 3 of an international multicenter collaboration.

Pathological analysis of the nuclear proliferation biomarker Ki67 has multiple potential roles in breast and other cancers. However, clinical utility of the immunohistochemical (IHC) assay for Ki67 immunohistochemistry has been hampered by unacceptable between-laboratory analytical variability. The International Ki67 Working Group has conducted a series of studies aiming to decrease this variability and improve the evaluation of Ki67.

BAP1 Immunohistochemistry and p16 FISH in the Diagnosis of Sarcomatous and Desmoplastic Mesotheliomas.

The separation of sarcomatous and desmoplastic mesotheliomas from benign organizing pleuritis can be morphologically very difficult. Deletion of p16 (CDKN2A) by fluorescence in situ hybridization (FISH) testing appears to be a reliable marker of malignancy in mesothelial proliferations, and more recently it has been reported that, in this setting, loss of BAP1 by immunohistochemistry is only seen in malignant mesotheliomas. To determine how useful these tests are with sarcomatous and desmoplastic mesotheliomas, we examined 20 such tumors.

Evaluation of Human Epidermal Growth Factor Receptor 2 (HER2) Gene Status in Human Breast Cancer Formalin-Fixed Paraffin-Embedded (FFPE) Tissue Specimens by Fluorescence In Situ Hybridization (FISH).

Current standard of care requires that HER2 gene testing be performed on all newly diagnosed invasive breast cancers in order to determine eligibility for anti-HER2 antibody therapy and should be performed in accordance with current ASCO-CAP guidelines (Hammond et al., J Clin Oncol 29(15):e458, 2011; Wolff et al., J Clin Oncol 31(31):3997-4013, 2013).

Markers of metastatic carcinoma of breast origin.

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging.

Vascular mesangial channels in human nodular diabetic glomerulopathy.

The presence of vascular mesangial channels has been reported in idiopathic nodular glomerulosclerosis and diabetic glomerulopathy. However, only limited information on the morphology and immunohistochemical phenotype of these channels is available. This study aims to describe the light and electron microscopic features of these channels and delineate their immunohistochemical phenotype.

Practical Applications in Immunohistochemistry: Carcinomas of Unknown Primary Site.

Context: -Identification of the site of origin of carcinoma of unknown primary using immunohistochemistry is a frequent requirement of anatomic pathologists. Diagnostic accuracy is crucial, particularly in the current era of targeted therapies and smaller sample sizes.

Objectives: -To provide practical guidance and suggestions for classifying carcinoma of unknown primary using both proven and new antibodies, as well as targeting panels based on integration of morphologic and clinical features.

Utility of BAP1 Immunohistochemistry and p16 (CDKN2A) FISH in the Diagnosis of Malignant Mesothelioma in Effusion Cytology Specimens.

The diagnosis of malignant mesothelioma in effusion cytology specimens is controversial. BAP1 immunohistochemistry and p16 fluorescence in situ hybridization (FISH) have recently been reported as reliable markers of malignancy in biopsies of mesothelioma. To determine whether these markers, singly or in combination, might also be useful in effusion cytology specimens, we examined 15 biopsies of epithelial mesotheliomas and 3 benign mesothelial reactions and corresponding effusion cytology paraffin-embedded cell blocks.

Personalized oncogenomics: clinical experience with malignant peritoneal mesothelioma using whole genome sequencing.

Peritoneal mesothelioma is a rare and sometimes lethal malignancy that presents a clinical challenge for both diagnosis and management. Recent studies have led to a better understanding of the molecular biology of peritoneal mesothelioma. Translation of the emerging data into better treatments and outcome is needed.

An international study to increase concordance in Ki67 scoring.

Although an important biomarker in breast cancer, Ki67 lacks scoring standardization, which has limited its clinical use. Our previous study found variability when laboratories used their own scoring methods on centrally stained tissue microarray slides. In this current study, 16 laboratories from eight countries calibrated to a specific Ki67 scoring method and then scored 50 centrally MIB-1 stained tissue microarray cases.

BAP1 immunohistochemistry and p16 FISH to separate benign from malignant mesothelial proliferations.

A variety of immunohistochemical (IHC) stains have been proposed to mark either benign or malignant mesothelial proliferations. Loss of the p16 tumor suppressor (CDKN2A), through homozygous deletions of 9p21, is a good marker of mesotheliomas but lacks sensitivity. Recent reports indicate that some mesotheliomas are associated with loss of BRCA-associated protein 1 (BAP1) expression.