Best practices in contemporary diagnostic immunohistochemistry: panel approach to hematolymphoid proliferations

Immunocytochemistry on frozen-embedded cell block for the diagnosis of hematolymphoid cytology specimen: a straightforward alternative to the conventional cell block

Agarose-based cell block (CB) technique can be modified to be combined with the frozen section technique for the preparation of a high-quality frozen-embedded CB (F-CB) from an effusion or fine-needle aspiration (FNA) cytology sample. This combined technique can be effectively used for the immunocharacterization of the hematolymphoid cells on F-CB. To demonstrate the applicability of performing diagnostic ICC on F-CB, we have analyzed the immunophenotype of the hematolymphoid cells in a series of eight cases of effusions and eight cases of FNA cytology specimens by using CB-ICC on sections cut from frozen-embedded CBs. The SurePathTM residue or cytologic material scraped off from the FNA cytology smear that was diagnostic for or suspicious of hematolymphoid malignancy was pelleted and pre-embedded in agarose. Half of the agarose-embedded pellet was frozen-embedded in OCT compound for the preparation of F-CB, while the other half was processed for the preparation of paraffin-embedded CB. Sections cut from the F-CB and P-CB were used for CB-ICC. Panels of ICC on the F-CBs could enable the immunocytochemical differential diagnosis of large cell hematologic malignancies that encompass anaplastic large cell lymphoma and other forms of large-cell hematolymphoid malignancies such as large B-cell lymphomas, anaplastic plasma cell myeloma, myeloid sarcoma, and T-lymphoblastic lymphoma. It also appeared that the small B-cell lymphomas in the effusions or FNAs could be differentially diagnosed with the aid of CB-ICC on the F-CB. A modified agarose-based CB technique can be combined with the frozen-embedded CB method for the preparation of F-CB that can be directly used for the immunocytochemical differential diagnosis of hematolymphoid cytology samples.

Transforming Diagnosis and Therapeutics Using Cancer Genomics

In past quarter of the century, much has been understood about the genetic variation and abnormal genes that activate cancer in humans. All the cancers somehow possess alterations in the DNA sequence of cancer cell's genome. In present, we are heading toward the era where it is possible to obtain complete genome of the cancer cells for their better diagnosis, categorization and to explore treatment options.

Enabling automated and reproducible spatially resolved transcriptomics at scale

Spatial information of tissues is an essential component to reach a holistic overview of gene expression mechanisms. The sequencing-based Spatial transcriptomics approach allows to spatially barcode the whole transcriptome of tissue sections using microarray glass slides. However, manual preparation of high-quality tissue sequencing libraries is time-consuming and subjected to technical variability. Here, we present an automated adaptation of the 10x Genomics Visium library construction on the widely used Agilent Bravo Liquid Handling Platform. Compared to the manual Visium library preparation, our automated approach reduces hands-on time by over 80% and provides higher throughput and robustness. Our automated Visium library preparation protocol provides a new strategy to standardize spatially resolved transcriptomics analysis of tissues at scale.

Immunohistochemical Analysis of Expression, Phosphorylation, and Nuclear Translocation of NF-κB Proteins in Human Tissues

Immunohistochemistry (IHC) is a technique aimed at detecting specific antigens on tissue sections by the use of targeting reagents labeled with reporter molecules. This technique allows a snapshot of the structure of tissue and determines the cellular and subcellular localization of a target antigen. This chapter describes how to identify and localize NF-κB proteins in human tissue using immunohistochemical staining on formalin-fixed paraffin-embedded and frozen tissue.

The diagnostic challenges of patients with carcinoma of unknown primary

INTRODUCTION

Cancer of unknown primary (CUP) is a disease entity encompassing heterogeneous malignancies without a clinically-detectable anatomical primary. It is usually a poor prognosis malignancy with dismal prognosis where molecular and genetic testing were expected to be a major breakthrough.

AREAS COVERED

In this review, we provide an overview of the advances in the understanding of the carcinogenesis, biology, diagnosis and treatment of patients with CUP. This review focuses on the advantages and inconveniences of immunohistochemistry and CUP classifiers in assessing the progress in the management of CUP.

EXPERT OPINION

CUP classifiers were expected to gradually replace the classical multistep approach in identifying the culprit tumors to guide site-specific therapy. Immunohistochemistry staining led to the prediction of a single tissue of origin in 10.8-51%. CUP classifiers identified the primary site in 61-89% of these cases and were concordant with immunohistochemistry in 57.1-100%. Immunohistochemistry is cheap, fast and broadly available whereas CUP classifiers are less widely available and have not been validated in randomized control trials. The diagnostic recommendations consist of a standard pathology evaluation based on morphology and algorithmic immunohistochemistry assessment. Physicians should weigh in the input of the CUP classifier to the clinical picture and pathology investigations before performing additional investigations.

Multicentric MFI30 study: Standardization of flow cytometry analysis of CD30 expression in non-Hodgkin lymphoma

CD30 transmembrane receptor, a member of the tumor necrosis factor receptor family, is expressed in different lymphomas. Brentuximab vedotin (BV), a CD30 monoclonal antibody (Ab)-drug conjugate, is effective in CD30-positive lymphomas. However, the response to BV is not always correlated to CD30 expression detected by immunohistochemistry (IHC). The objectives of this study were to standardize and evaluate CD30 intensity by flow cytometry (FCM) in non-Hodgkin's lymphomas. Twelve centers analyzed 161 cases on standardized cytometers using normalized median fluorescence intensity (nMFI30) of three different Abs, of which one clone can recognize the same epitope as BV. FCM distinguished four groups of cases: negative group (n = 110) which showed no expression with the three clones; high positive group (n = 13) which gave nMFI30 > 5% with all tested clones; dim positive group (n = 17) which showed nMFI30 > 1% with all tested clones and <5% for at least one; discordant group (n = 21) with positive and negative expression of the different clones. In consistency with the literature, CD30 was positive in all anaplastic large cell lymphomas, in some diffuse large B-cell lymphomas (DLBCL), and in other rare lymphomas. FCM results were concordant with those of IHC in 77% of cases. Discrepancies could be explained by clones-related differences, microenvironment, or intracytoplasmic staining. Interestingly, FCM was more sensitive than IHC in 11% of cases, especially in DLBCL. Multicenter standardized FCM of specific CD30 could improve case detection and extend the treatment of BV to various CD30-positive lymphomas.

Image-guided core needle biopsy in the diagnosis of malignant lymphoma: comparison with surgical excision biopsy

PURPOSE

This study aimed to compare the efficacy and safety of image-guided core needle biopsy (CNB) with those of surgical excision biopsy (SEB) for the diagnosis of lymphoma, and to clarify the indication of CNB in clinical practice.

METHOD

This retrospective study included 263 image-guided CNB cases and 108 SEB cases that were performed at our institution between January 2014 and December 2018. The rate of patients with performance status of grade 1-4 was higher in the CNB group than in the SEB group (43.7% vs. 24.1%, P <  0.01). Waiting time to biopsy and diagnosis was shorter for CNB group than for SEB group (4 days vs. 7 days, 13 days vs. 15 days, P <  0.01). The rate of biopsy at the deep sites was higher in the CNB group than in the SEB group (53.2% vs. 8.3%, P <  0.01). Successful biopsy and complication rates were compared between the 2 groups.

RESULTS

There were no significant differences between the CNB and SEB groups in successful biopsy rates (89.0% vs. 93.5%, P =  0.25). The grade 3 complication rate was significantly lower for CNB group than for SEB group (0% vs. 4.6%, P <  0.01), although there was no significant difference in overall complication rates (4.9% vs. 6.5%, respectively, P =  0.61).

CONCLUSIONS

CNB showed high diagnostic yield comparable to SEB for suspected lymphoma. CNB was especially recommended to the cases with low-PS, lesions in the deep sites, and requiring early pathological diagnosis.

Diffuse Large B-Cell Lymphoma in Kenya: MYC, BCL2, and the Cell of Origin

PURPOSE

Diffuse large B-cell lymphoma (DLBCL) is the most commonly diagnosed non-Hodgkin lymphoma in adults in Kenya. Cell of origin (COO) and double expression of MYC and BCL2 are two important prognostic factors for DLBCL. A small subset (5% to 10%) of DLBCL cases show positivity for CD5 and are associated with poor prognosis, whereas CD30 antigen, seen in up to 10% of cases, may be a useful target for therapy. We sought to determine the prevalence of MYC/BCL2 double expression, COO, and proportion of Epstein-Barr virus positivity among patients with DLBCL diagnosed at a tertiary referral laboratory in Kenya.

PATIENTS AND METHODS

All cases of DLBCL diagnosed from 2012 through 2015 in our pathology department were analyzed. Tumor tissue microarray sections were stained with CD20, CD3, CD5, CD30, BCL2, BCL6, CD10, MUM1, MYC, and Ki67, classified for COO on the basis of the Hans algorithm, and subjected to Epstein-Barr virus-encoded small RNAs in situ hybridization.

RESULTS

Among 165 DLBCL cases, the median age was 50 years, and there was no sex predilection. Only 18 (10.9%) cases showed double expression for MYC and BCL2. Germinal center B (GCB)-cell type DLBCL accounted for 67 cases (40.6%) and 97 cases (59.4%) were classified as non-GCB. The mean Ki67 proliferation index was significantly higher in the double-expressing (45%) and non-GCB groups (36%) compared with the non-double-expressing group (29%) and GCB group (26%). Sixteen cases (9.7%) were Epstein-Barr virus-encoded small RNAs positive, 12 (75%) of which were non-GCB.

CONCLUSION

DLBCL in Kenya is seen in much younger patients with the poor prognostic non-GCB-type accounting for 59.4% of cases. MYC and BCL2 double expression was seen in fewer tumors than reported in the literature and in significantly older patients.

Evaluating breast lymphoplasmacytic infiltrates: a multiparameter immunohistochemical study, including assessment of IgG4

Lymphoplasmacytic infiltrates in the breast, a modified skin appendage, include lymphocytic lobulitis, other nonspecific benign proliferations, and mucosa-associated lymphoid tissue (MALT)-type lymphoma. Distinguishing these entities, all of which may be B-cell rich and may have associated sclerosis, can be difficult. In addition, the proportion that represents IgG4-related disease is unknown, and the similarity of MALT lymphomas to primary cutaneous marginal zone lymphoma is uncertain. To address these questions, the clinical, histologic, and immunohistochemical features of 50 benign and malignant breast lymphoplasmacytic infiltrates (10 lymphocytic lobulitis, 1 granulomatous, 19 not otherwise specified, 20 MALT lymphomas) were evaluated. Compared with the MALT lymphomas, benign cases had a less dense infiltrate (P < .001), fewer but more histologically apparent germinal centers (P < .001), and more marked fibrosis (P < .0001). Greater than 60% B cells were present in 23% (7/30) benign cases versus 75% (15/20) MALT lymphomas (P = .0003). Plasma cells were predominantly IgG+ in 83% (24/29) benign cases and predominantly IgM+ in 73% (14/19) MALT lymphomas (P < .0001). None of the benign cases had greater than 50 IgG4+ plasma cells/high-power field, and only 1 lymphocytic lobulitis case had an IgG4/IgG ratio exceeding 40% and no clinical evidence for extramammary IgG4-related disease. Although there may be some overlapping features, routine histopathology together with limited immunohistochemical stains can distinguish benign from neoplastic lymphoplasmacytic infiltrates in the breast. Despite frequent sclerosis, the breast is not a common site of unrecognized IgG4-related sclerosing disease. Although there are similarities, breast MALT lymphomas can be separated from cutaneous marginal zone lymphoma.

[The role of pathology in the diagnostics of CUP syndrome]

Cancers of unknown primary (CUP) origin account for 2-3 % of all malignancies in Germany and represent a heterogeneous, often aggressive and clinically challenging group of tumors with early metastatic dissemination for which a standardized diagnostic work-up initially fails to identify the primary site of origin at the time of diagnosis. This article reviews the options and challenges of tissue-based conventional as well as molecular diagnostic procedures to categorize this heterogeneous group of neoplasms. The role of pathology in the diagnostics of CUP syndrome is described as part of a multidisciplinary effort involving oncologists, surgeons and radiologists with the ultimate goal of assisting clinical reasoning and decision-making.

Developments in the immunophenotypic analysis of haematological malignancies

Immunophenotyping is the method by which antibodies are used to detect cellular antigens in clinical samples. Although the major role is in the diagnosis and classification of haematological malignancies, applications have expanded over the past decade. Immunophenotyping is now used extensively for disease staging and monitoring, to detect surrogate markers of genetic aberrations, to identify potential immuno-therapeutic targets and to aid prognostic prediction. This expansion in applications has resulted from developments in antibodies, methodology, automation and data handling. In this review we describe recent advances in both the technology and applications for the analysis of haematological malignancies. We highlight the importance of the expanding repertoire of testing capability for diagnostic, prognostic and therapeutic applications. The impact and significance of immunophenotyping in the assessment of haematological neoplasms are evident.

Topologies of amyloidogenic proteins in Congo red-positive sliced sections of formalin-fixed paraffin embedded tissues by MALDI-MS imaging coupled with on-tissue tryptic digestion

OBJECTIVES

Matrix-assisted laser desorption time-of flight ionization (MALDI)-imaging MS (IMS) with MSMS analysis using on-tissue tryptic digests is a powerful tool for identification of disease-related proteins in formalin-fixed paraffin-embedded (FFPE) tissue sections. We applied this novel IMS technique, not only to identify tryptic peptides of deposited amyloidogenic proteins but also to clarify topologies of these proteins in amyloidosis tissue sections.

METHODS

Sequence determinations of tryptic peptides derived from amyloidogenic proteins were performed using MALDI-MSMS analysis directly from Congo red positive regions in tissue sections with/without procedure for retrieval of epitopes before on-tissue digestion.

RESULTS

Tryptic peptides, m/z=1073.5 and 1924.3 were identified with the sequences, from 48th to 56th and 1st to 19th positions of Ig lambda V-III region, respectively. Other peptides, m/z=1365.5 and 1523.5 were with the sequences, from 22nd to 34th and 36th to 48th positions of TTR, respectively. Heat-map images of all four tryptic peptides were overlapped with Congo red positive regions. Immunohistochemistry of FFPE tissue sections was confirmed to only react with anti-λ chain antibody in a case of AL-type amyloidosis or anti-TTR antibody in two cases of TTR-type amyloidosis.

CONCLUSION

IMS with MSMS analysis using on-tissue tryptic digestion enables us not only to identify amyloidogenic molecule in a sliced tissue section but also to play a complementary role with the conventional pathological examination.

Lymphoma classification and the tools of our trade: an introduction to the 2012 USCAP Long Course

The 2012 USCAP Long Course 'Malignant Lymphomas-Building on the Past, Moving to the Future' began with an introduction to lymphoma classification over the last half century and a discussion of our current diagnostic armamentarium, together with a look toward the future. The Rappaport classification, originally published in 1956, was a morphologic classification with few categories. The early 1970s saw a great and tumultuous revolution in the field with the publication of two functional lymphoma classifications that related the malignant lymphomas to the cells of the normal immune system-the Lukes/Collins classification from the United States and the Kiel classification from Professor Lennert and the European Lymphoma Club. With discord abounding, the NCI working formulation, published in 1982, satisfied some but was a step back to a morphologic-based classification. In 1994, the International Lymphoma Study Group published the REAL classification, which reflected state-of-the-art practice for that time, and was shortly followed by preparations for the modern World Health Organization (WHO) classification published in 2001 and revised in 2008. The WHO classification, created by hematopathologists working with the advice and consent of clinical hematologist/oncologists, recognizes numerous distinct entities, defined based on their histopathological, immunophenotypical, molecular/cytogenetic and clinical features. The classification requires use of a multiparameter approach to lymphoma diagnosis although we still rely heavily on histopathology. Immunophenotypical studies, whether using paraffin section immunohistochemistry and/or flow cytometry, are also critical in almost all circumstances. Molecular/cytogenetic techniques that are constantly changing have an increasingly important role, even if not always required. The full impact of next-generation sequencing is yet to be felt but we are beginning to catch a glimpse of what is in our future. Finally, one must not forget the great importance of clinical data in arriving at a diagnosis that best serves the patient, our ultimate goal.

Diagnostic Workup of Small B Cell Lymphomas: A Laboratory Perspective

Small B cell lymphoma is a morphological designation to a group of B cell lymphomas which are composed of a clonal population of small lymphoid cells. The subtypes of this category have diagnostically distinct characteristics and different clinical behaviors and treatment. Correct diagnosis and classification of these subsets depend on the integration of morphologic, immunophenotypic, and molecular genetic features. In this paper, differential diagnosis of this category of tumors and a practical approach based on biomarker evaluation are discussed.

Applications of immunohistochemistry

Immunohistochemistry (IHC) is an important application of monoclonal as well as polyclonal antibodies to determine the tissue distribution of an antigen of interest in health and disease. IHC is widely used for diagnosis of cancers; specific tumor antigens are expressed de novo or up-regulated in certain cancers. This article deals with the various applications of IHC in diagnosis of diseases, with IHC playing an important role in diagnostic and research laboratories.

EUS-guided fine-needle tissue acquisition by using a 19-gauge needle in a selected patient population: a prospective study

BACKGROUND

The ability to obtain tissue samples for histological examination during EUS has theoretical advantages over cytology alone.

OBJECTIVE

To prospectively evaluate the feasibility and yield of EUS-guided fine-needle tissue acquisition (EUS-FNTA) with a large-gauge needle in patients in whom we expected histology to be more useful than cytology to reach a definitive diagnosis.

DESIGN

Prospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENTS

Consecutive patients with subepithelial lesions, esophagogastric wall thickening, mediastinal and abdominal masses/lymphadenopathy of unknown origin, or pancreatic lesions after nondiagnostic FNA.

INTERVENTIONS

EUS-FNTA with a 19-gauge needle.

MAIN OUTCOME MEASUREMENTS

Feasibility and yield of EUS-FNTA.

RESULTS

A total of 120 patients with a mean age of 61 ± 14.6 years and mean lesion size of 38 ± 25 mm (range 8-140 mm) were enrolled. FNTA was successfully performed in all but 1 patient (98.9%), and adequate samples for histological examination were obtained in 116 of the 119 patients (97.5%) in whom EUS-FNTA was technically successful. A mean of 2.8 ± 0.8 passes per patient were performed. At the time of current follow-up, a definitive diagnosis was available in 117 of the 120 patients (97.5%), with only 8 false-negative results. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of EUS-FNTA in the 117 patients with a definitive diagnosis were 91.8%, 100%, 100%, 71.4%, and 93.2%, respectively.

LIMITATIONS

Single-center study with limited power.

CONCLUSIONS

EUS-FNTA by using a large-gauge needle has a high yield and promising diagnostic accuracy and could be used when histology may be more useful than cytology to reach a definitive diagnosis.