Virtual multiplex immunohistochemistry: Application on cell block of effusion and aspiration cytology

Comparison of Claudin-4, BerEP4, Carcinoembryonic Antigen and MOC31 in Serous Fluids Metastases Demonstrate High Sensitivity of Claudin-4 at Low Cellularity

INTRODUCTION

Claudin-4 has been described as a highly sensitive immunocytochemical marker for detection of metastatic carcinoma cells in effusion cytology specimens. This study aims to challenge the performance of claudin-4 in different types of malignancies and low cellularity specimens, by comparison with other markers in a large cohort of carcinomatous effusion specimens.

METHODOLOGY

Cell block preparations from peritoneal and pleural fluid specimens were retrieved, with malignant (carcinoma) diagnoses confirmed by review of hospital diagnosis code and pathology reports. Claudin-4, BerEP4, CEA, and MOC31 immunocytochemistry were performed and scored by expression proportion and intensity. Tumor cellularity was assessed for subgroup analysis of low cellularity specimens.

RESULTS

Totally 147 specimens (70 pleural, 77 peritoneal) of 68 lung, 62 breast, 9 gynecological, and 7 gastrointestinal carcinomas were retrieved. The average proportion expression of claudin-4 was highest (89.6%, vs. CEA 40.5%, BerEp4 18.6%, MOC31 16.8%) and the percentage of strong expression was highest for claudin-4 (72.1%). Expression levels of claudin-4 were consistently higher than other markers in subgroups of all primary sites. The difference was more significant for low cellularity specimens. High (≥50%) proportion expression was seen for 96.61% of cases for claudin-4 (vs. BerEp4 8.77%, CEA 46.55%, MOC31 8.77%, p < 0.001). These factors contributed to a low concordance between claudin-4 and BerEp4, CEA and MOC31 (K = 0.010-0.043).

CONCLUSION

Claudin-4 is more sensitive than CEA, BerEp4 and MOC31, suitable for low cellularity specimens of most types of metastatic carcinoma and is a robust immunocytochemical marker for carcinoma that can be used solitarily.

Single-cell multiplex immunocytochemistry in cell block preparations of metastatic breast cancer confirms sensitivity of GATA-binding protein 3 over gross cystic disease fluid protein 15 and mammaglobin

BACKGROUND

Metastatic breast cancers are frequently encountered in cytology and require immunocytochemistry (ICC). In this study, traditional and multiplex ICC (mICC) for GATA-binding protein 3 (GATA3), gross cystic disease fluid protein 15 (GCDFP15), and mammaglobin (MMG) were performed with the aim of validating mICC in cell blocks, with further single-cell expression pattern analysis to identify the single markers and combinations of markers most sensitive in subtypes of breast cancer.

METHODS

GATA3, GCDFP15, and MMG were paired with OptiView 3,3'-diaminobenzidine and Ventana DISCOVERY Purple and Blue, respectively, with cyclical and serial staining. Bright-field imaging was performed with the Mantra 2 system and analyzed with the inForm Tissue Finder (Akoya Biosciences). Cell detection and phenotyping were further confirmed by two pathologists.

RESULTS

In the 36 cases studied, traditional ICC and mICC demonstrated good concordance (kappa coefficient, >0.5; p < .01) at three cutoffs (1%, 5%, and 50%), except for GATA3 at the 1% cutoff. Single-marker positivity outnumbered double-marker positivity and the exceedingly rare triple-marker positivity (<3%). GATA3 was the leading single marker-positive phenotype in all breast cancer subtypes, except for MMG in estrogen receptor-positive, progesterone receptor-positive, and human epidermal growth factor receptor 2-positive (ER+/PR+/HER2+) breast cancers. Limited to two markers, GATA3/MMG included the greatest number of tumor cells for luminal breast cancers (ER+/PR+/HER2+, 60.6%; ER+/PR+/HER2+, 31.4%), whereas HER2-overexpressed breast cancers (27.4%) and triple-negative breast cancers (26.4%) favored the combination of GATA3/GCDFP15.

CONCLUSIONS

For a single marker, GATA3 displayed the highest sensitivity. The addition of MMG for hormone receptor-positive breast cancers and GCDFP15 for hormone receptor-negative breast cancers further increased sensitivity. The low proportion of multimarker-positive cells suggested that the coexpression observed with traditional ICC is attributable to intratumoral heterogeneity, not genuine coexpression.

Head and Neck Fine Needle Aspiration: Current and Future Impact on Patient Care

The discovery of multiple novel biomarkers in head and neck tumors has led to an increasing interest in utilizing head and neck cytology material as the primary specimens for testing diagnostic and prognostic biomarkers. Although human papillomavirus and programmed death ligand 1 are the most well-established biomarkers tested in cytology specimens, their utilization in cytology is limited by the absence of standardized protocols for specimen collection and fixation. This has led to a quest for innovative techniques to explore the genomic landscape in head and neck tumors and its application in cytology.

Liposarcoma Involving Serous Fluid Cavities-A Case Series Illustrating Clinical Implications and the Diagnostic Role of Exfoliative Cytology

Introduction: Cytological diagnosis of sarcomas requires detailed cytomorphological assessment and integration of immunocytochemistry and/or molecular testing. The role of exfoliative cytology, as compared to aspiration cytology, is less understood. This case series describes well-differentiated/dedifferentiated liposarcomas in effusions, with cytomorphological features, ancillary test results and clinical outcomes detailed. Methods: A computerized search of the department pathology archives was performed for sarcomatous effusions with histological diagnosis or clinical history of well-differentiated/dedifferentiated liposarcoma. Clinical progress, cytology slides, immunocytochemistry and molecular test results were reviewed. Results: Six patients were identified. In 5 patients with clinical follow up, 4 (80%) were deceased within 5 months of malignant effusion. One patient was alive with 12 years disease-free survival after radical resection with adjuvant radiotherapy. Three patients showed dedifferentiation on histology, and high-grade (dedifferentiated) tumor cells were present in effusion cytology of 2 patients. Two showed well-differentiated components only on biopsy, but high-grade (dedifferentiated) tumor cells were identified in cytology. The high-grade tumor cells displayed marked nuclear irregularity, enlargement, size variation, with macronucleoli and multinucleation. Well-differentiated lipomatous components were demonstrated in 4 patients (66.7%), comprising of multivacuolated lipoblasts and atypical lipocytes. CDK4 and MDM2 immunoreactivity in all 3 cases with cell blocks, and CDK4 and MDM2 amplification in one were successfully demonstrated. Conclusion: Lipomatous and dedifferentiated components can be sampled and cytomorphologically identified on effusion fluids of liposarcomas, with sufficient cellularity for immunocytochemistry and molecular testing. Although generally associated with poor prognosis, long disease-free survival with sarcomatous effusion is possible with radical surgery and adjuvant treatment.

Immunocytochemical markers, molecular testing and digital cytopathology for aspiration cytology of metastatic breast carcinoma

Fine-needle aspiration cytology (FNAC) is a versatile diagnostic procedure uniquely suited for tissue biopsy of breast carcinomas and axillary metastases and/or recurrences. With the expanding treatment options and accompanying theragnostic tests, it is crucial to recognize the developments on ancillary testing and digital cytopathology techniques related to aspiration cytology of metastatic breast carcinoma. In this review, we aim to summarize and update the evidence of immunocytochemistry, for the detection of carcinoma cells (epithelial markers), confirmation of breast primary (breast-specific markers), assessment of surrogate immunostains (hormone receptors, ki-67 proliferative index and HER2) and theragnostic biomarkers, with discussion on potential diagnostic pitfalls, followed by the application of molecular tests, and digital cytopathologic techniques for assessing metastatic breast carcinoma in cytology.

Image-based multiplex immune profiling of cancer tissues: translational implications. A report of the International Immuno-oncology Biomarker Working Group on Breast Cancer

Recent advances in the field of immuno-oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high-throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Comparison of consecutive and restained sections for image registration in histopathology

Significance

Although the registration of restained sections allows nucleus-level alignment that enables a direct analysis of interacting biomarkers, consecutive sections only allow the transfer of region-level annotations. The latter can be achieved at low computational cost using coarser image resolutions.

Purpose

In digital histopathology, virtual multistaining is important for diagnosis and biomarker research. Additionally, it provides accurate ground truth for various deep-learning tasks. Virtual multistaining can be obtained using different stains for consecutive sections or by restaining the same section. Both approaches require image registration to compensate for tissue deformations, but little attention has been devoted to comparing their accuracy.

Approach

We compared affine and deformable variational image registration of consecutive and restained sections and analyzed the effect of the image resolution that influences accuracy and required computational resources. The registration was applied to the automatic nonrigid histological image registration (ANHIR) challenge data (230 consecutive slide pairs) and the hyperparameters were determined. Then without changing the parameters, the registration was applied to a newly published hybrid dataset of restained and consecutive sections (HyReCo, 86 slide pairs, 5404 landmarks).

Results

We obtain a median landmark error after registration of 6.5    μ m (HyReCo) and 24.1    μ m (ANHIR) between consecutive sections. Between restained sections, the median registration error is 2.2 and 0.9    μ m in the two subsets of the HyReCo dataset. We observe that deformable registration leads to lower landmark errors than affine registration in both cases (p < 0.001 ), though the effect is smaller in restained sections.

Conclusion

Deformable registration of consecutive and restained sections is a valuable tool for the joint analysis of different stains.

Cell Block-Based Two-Dimensional and Immunocytochemical Analyses Could Reduce Atypical/Indeterminate Case Frequency in Breast Fine-Needle Aspiration Cytology: A Retrospective Analysis

INTRODUCTION

In fine-needle aspiration of the breast (FNAB), the "atypical" category encompasses both benign and malignant lesions, particularly papillary proliferative lesions, as per the latest WHO classification. We aimed to reduce atypical cases and improve diagnostic accuracy by investigating the utility of cell block (CB) analysis.

METHODS

FNAB CB samples (2018-2022) were reviewed using smear only or CBs. CB-based diagnosis was performed with 2D morphological analysis and immunocytochemistry using ER, CK5/6, p63, SMA, and CD56. Samples were reclassified as "benign," "atypical," "suspicious of malignancy," "malignant," or "insufficient/inadequate." Atypical cases were reexamined. Diagnoses were validated histologically.

RESULTS

On examining the FNAB samples (n = 149; 32 atypical), 2D CB sectioning achieved a clearer definition of myoepithelial cells and fibrovascular cores than Papanicolaou staining. Immunocytochemistry was evaluated for 36 cases: estrogen receptor (ER)- and CK5/6+ tumors were reclassified as benign; ER+ and CK5/6- tumors as malignant; p63- tumors as invasive; papillary malignant tumors with a smooth muscle actin (SMA)+ fibrovascular core and p63- myoepithelial cells as encapsulated papillary carcinoma; and CD56+ carcinomas as neuroendocrine carcinoma. Diagnostic rates were as follows: benign (44% FNAB, 51% CB), atypical (21% FNAB, 3% CB), suspicious of malignancy and malignant (28% FNAB, 40% CB), and insufficient/inadequate (7% FNAB, 6% CB). CB achieved >85% sensitivity, specificity, and positive and negative predictive values.

CONCLUSION

CBs represent 3D FNA cell morphology using 2D sections, enabling adaption of pathology criteria to the cytological material. Immunocytochemical staining of CBs can predict low nuclear grade papillary tumors and reduce atypical case frequency, improving diagnostic accuracy.

EGFR testing in paraffin-embedded cell block cytology material is reliable with increased detection for effusion fluid

INTRODUCTION

Cytology is integral to lung cancer diagnosis. Aspiration and exfoliative fluid specimens represent valuable tumor material for molecular testing. In this study, a large retrospective cohort of EGFR tests was reviewed to address the adequacy, detection and discrepancy rate in tests performed with cytology material.

METHODS

EGFR tests performed from 2013 to 2022 were reviewed and classified by the modality of obtaining tissue and by tissue type. EGFR tests for tissue specimens were performed on unstained sections of paraffin-embedded material on glass slides. Adequacy and types of mutation(s) detected were analysed. Cases where multiple EGFR testing was performed on the same patient were reviewed for discordance.

RESULTS

There were 5,504 tests retrieved, with 1,855, 3,607 and 42 performed on cytology, surgical and blood specimens. Lung and excision specimens were more often adequate (p < 0.001). Cytology material showed lower adequacy rates (p < 0.01). EGFR detection (positive) rate was higher in pleural fluid compared to biopsy (59.8 % vs 50.7 %, p = 0.022), but similar between lung and lymph node cytology and non-cytology specimens. Effusion fluid specimens had the highest adequacy (81.5 %) and detection rate (59.3 %) among cytology specimens (p < 0.001). Four (4.4 %) cases showed discordant results in cytology specimens. Two were false negatives in the non-cytology material. Only in one case was cytology material genuinely discrepant. The remaining discordance was attributed to the interval treatment effect.

CONCLUSION

The findings support that EGFR testing in cell block is reliable and complements tissue material. In addition, pleural fluid appears to be superior to pleural biopsies for molecular testing.

The role of cytokeratin 7/20 coordination revisited-Machine learning identifies improved interpretative algorithms for cell block immunohistochemistry in aspirates of metastatic carcinoma

BACKGROUND

Fine-needle aspiration (FNA) is a robust diagnostic technique often used for tissue diagnosis of metastatic carcinoma. For interpretation of FNA cytology, cell block immunohistochemistry (IHC) and clinicocytologic parameters are indispensable. In this review of a large cohort, the current report: 1) describes clinicocytologic parameters and immunoprofiles of aspirates of metastatic carcinoma, 2) compares the predictivity of immunostains and classical approaches for IHC interpretation, and 3) describes machine learning-based algorithms for IHC interpretation.

METHODS

Aspirates of metastatic carcinoma that had IHC performed were retrieved. Clinicocytologic parameters, IHC results, the corresponding primary site, and histologic diagnoses were recorded. By using machine learning, decision trees for predicting the primary site were generated, their performance was compared with 2 human-designed algorithms, and the primary site was suggested in the historical diagnosis.

RESULTS

In total, 1145 cases were identified. The 6 most populated groups were selected for machine learning and predictive analysis. With IHC input, the decision tree achieved a concordance rate of 94.5% and overall accuracy of 83.6%, which improved to 95.3% and 85.8%, respectively, when clinical data were incorporated and exceeded the human-designed IHC algorithms (P < .001). The historical diagnosis was more accurate unless indeterminate diagnoses were regarded as discordant (P < .001). CDX2 and TTF-1 immunostains had the highest weight in model accuracy, occupied the root of the decision trees, scored higher as features of importance, and outperformed the predictive power of cytokeratins 7 and 20.

CONCLUSIONS

Cytokeratins 7 and 20 may be superseded in immunostaining panels, including organ-specific immunostains such as CDX2 and TTF-1. Machine learning generates algorithms that surpasses human-designed algorithms but is inferior to expert assessment integrating clinical and cytologic assessment.

Tumor Microenvironment in Breast Cancer-Updates on Therapeutic Implications and Pathologic Assessment

The tumor microenvironment (TME) in breast cancer comprises local factors, cancer cells, immune cells and stromal cells of the local and distant tissues. The interaction between cancer cells and their microenvironment plays important roles in tumor proliferation, propagation and response to therapies. There is increasing research in exploring and manipulating the non-cancerous components of the TME for breast cancer treatment. As the TME is now increasingly recognized as a treatment target, its pathologic assessment has become a critical component of breast cancer management. The latest WHO classification of tumors of the breast listed stromal response pattern/fibrotic focus as a prognostic factor and includes recommendations on the assessment of tumor infiltrating lymphocytes and PD-1/PD-L1 expression, with therapeutic implications. This review dissects the TME of breast cancer, describes pathologic assessment relevant for prognostication and treatment decision, and details therapeutic options that interacts with and/or exploits the TME in breast cancer.

Advances in Imaging Modalities, Artificial Intelligence, and Single Cell Biomarker Analysis, and Their Applications in Cytopathology

Several advances in recent decades in digital imaging, artificial intelligence, and multiplex modalities have improved our ability to automatically analyze and interpret imaging data. Imaging technologies such as optical coherence tomography, optical projection tomography, and quantitative phase microscopy allow analysis of tissues and cells in 3-dimensions and with subcellular granularity. Improvements in computer vision and machine learning have made algorithms more successful in automatically identifying important features to diagnose disease. Many new automated multiplex modalities such as antibody barcoding with cleavable DNA (ABCD), single cell analysis for tumor phenotyping (SCANT), fast analytical screening technique fine needle aspiration (FAST-FNA), and portable fluorescence-based image cytometry analyzer (CytoPAN) are under investigation. These have shown great promise in their ability to automatically analyze several biomarkers concurrently with high sensitivity, even in paucicellular samples, lending themselves well as tools in FNA. Not yet widely adopted for clinical use, many have successfully been applied to human samples. Once clinically validated, some of these technologies are poised to change the routine practice of cytopathology.