Titanium Implants Coated with Hydroxyapatite Used in Orbital Wall Reconstruction-A Literature Review.

With the increasing incidences of orbital wall injuries, effective reconstruction materials and techniques are imperative for optimal clinical outcomes. In this literature review, we delve into the efficacy and potential advantages of using titanium implants coated with nanostructured hydroxyapatite for the reconstruction of the orbital wall. Titanium implants, recognized for their durability and mechanical strength, when combined with the osteoconductive properties of hydroxyapatite, present a potentially synergistic solution. The purpose of this review was to critically analyze the recent literature and present the state of the art in orbital wall reconstruction using titanium implants coated with nanostructured hydroxyapatite. This review offers clinicians detailed insight into the benefits and potential drawbacks of using titanium implants coated with nanostructured hydroxyapatite for orbital wall reconstruction. The highlighted results advocate for its benefits in terms of osseointegration and provide a novel strategy for orbital reconstruction, though further studies are essential to establish long-term efficacy and address concerns.

Canadian Multicentric Pan-TRK (CANTRK) Immunohistochemistry Harmonization Study.

Tumor-agnostic testing for NTRK1-3 gene rearrangements is required to identify patients who may benefit from TRK inhibitor therapies. The overarching objective of this study was to establish a high-quality pan-TRK immunohistochemistry (IHC) screening assay among 18 large regional pathology laboratories across Canada using pan-TRK monoclonal antibody clone EPR17341 in a ring study design. TRK-fusion positive and negative tumor samples were collected from participating sites, with fusion status confirmed by panel next-generation sequencing assays. Each laboratory received: (1) unstained sections from 30 cases of TRK-fusion-positive or -negative tumors, (2) 2 types of reference standards: TRK calibrator slides and IHC critical assay performance controls (iCAPCs), (3) EPR17341 antibody, and (4) suggestions for developing IHC protocols. Participants were asked to optimize the IHC protocol for their instruments and detection systems by using iCAPCs, to stain the 30 study cases, and to report the percentage scores for membranous, cytoplasmic, and nuclear staining. TRK calibrators were used to assess the analytical sensitivity of IHC protocols developed by using the 2 reference standards. Fifteen of 18 laboratories achieved diagnostic sensitivity of 100% against next-generation sequencing. The diagnostic specificity ranged from 40% to 90%. The results did not differ significantly between positive scores based on the presence of any type of staining vs the presence of overall staining in ≥1% of cells. The median limit of detection measured by TRK calibrators was 76,000 molecules/cell (range 38,000 to >200,000 molecules/cell). Three different patterns of staining were observed in 19 TRK-positive cases, cytoplasmic-only in 7 samples, nuclear and cytoplasmic in 9 samples, and cytoplasmic and membranous in 3 samples. The Canadian multicentric pan-TRK study illustrates a successful strategy to accelerate the multicenter harmonization and implementation of pan-TRK immunohistochemical screening that achieves high diagnostic sensitivity by using laboratory-developed tests where laboratories used centrally developed reference materials. The measurement of analytical sensitivity by using TRK calibrators provided additional insights into IHC protocol performance.

Uroplakin-IIIb as a novel immunohistochemical marker for mesothelioma.

Distinguishing mesothelioma from non-small cell lung carcinoma often requires a battery of immunohistochemical stains, as many traditional markers used in mesothelioma lack sufficient specificity to allow them to be used alone. A recent large-scale TMA screen identified uroplakin-IIIb (UpIIIb; clone MSVA-736M) as a potentially specific marker for mesothelioma. We examined the performance of this antibody using tissue microarrays containing a panel of 48 epithelioid mesotheliomas, 26 sarcomatoid mesotheliomas, and 144 non-small cell lung carcinomas (NSCLCs). Here we show that UpIIIb has good sensitivity (37/47 evaluable cases positive, 79%) and excellent specificity for distinguishing epithelioid mesothelioma from NSCLC (0/140 evaluable cases positive). UPIIIb sensitivity for epithelioid mesotheliomas was only slightly inferior to the established highly specific mesothelioma marker HEG1 (41/46 evaluable cases positive on the same TMA, 89%). However, UpIIIb did not stain any sarcomatoid mesotheliomas (0/24 evaluable cases positive). We also found that UpIIIb stained a proportion of high-grade serous ovarian carcinomas, a perennial diagnostic confounder in the context of mesotheliomas. Taken together, our data suggest that UpIIIb can be used as a highly specific and sensitive mesothelial marker when the diagnostic question is epithelioid mesothelioma versus NSCLC; in particular, UpIIIb staining will pick up some number of epithelioid mesotheliomas that are HEG1 negative. Since UpIIIb is known to stain some proportion of urothelial carcinomas as well as gynecologic and a few pancreatic tumors, it should be used with caution in the peritoneal cavity or when the differential diagnosis includes carcinomas from these locations.

The Unmet Diagnostic and Treatment Needs in Large Cell Neuroendocrine Carcinoma of the Lung.

Large cell neuroendocrine carcinoma of the lung (LCNEC) is currently classified as a rare lung cancer subtype, but given the high incidence of lung cancer, the overall number of cases is considerable. The pathologic diagnosis of LCNEC is mainly based on the microscopic appearance of the tumor cells, the mitotic rate, the amount of intra-tumoral necrosis, and the presence of positive neuroendocrine markers identified by immunohistochemistry. Recently, a subdivision into two main categories was proposed based on mutation signatures involving the RB1, TP53, KRAS, and STK11/LKB1 genes, into SCLC-like (small cell lung cancer-like) and NSCLC-like (non-small cell lung cancer-like) LCNEC. In terms of treatment, surgery is still the best option for resectable, stage I-IIIA cases. Chemotherapy and radiotherapy have conflicting evidence. Etoposide/platinum remains the standard chemotherapy regimen. However, based on the newly proposed LCNEC subtypes, some retrospective series report better outcomes using a pathology-driven chemotherapy approach. Encouraging outcomes have also been reported for immunotherapy and targeted therapy, but the real impact of these strategies is still being determined in the absence of adequate prospective clinical trials. The current paper scrutinized the epidemiology, reviewed the reliability of pathologic diagnosis, discussed the need for molecular subtyping, and reviewed the heterogeneity of treatment algorithms in LCNEC.

Canadian Consensus Recommendations on the Management of Extensive-Stage Small-Cell Lung Cancer.

Small-cell lung cancer (SCLC) is an aggressive, neuroendocrine tumour with high relapse rates, and significant morbidity and mortality. Apart from advances in radiation therapy, progress in the systemic treatment of SCLC had been stagnant for over three decades despite multiple attempts to develop alternative therapeutic options that could improve responses and survival. Recent promising developments in first-line and subsequent therapeutic approaches prompted a Canadian Expert Panel to convene to review evidence, discuss practice patterns, and reach a consensus on the treatment of extensive-stage SCLC (ES-SCLC). The literature search included guidelines, systematic reviews, and randomized controlled trials. Regular meetings were held from September 2022 to March 2023 to discuss the available evidence to propose and agree upon specific recommendations. The panel addressed biomarkers and histological features that distinguish SCLC from non-SCLC and other neuroendocrine tumours. Evidence for initial and subsequent systemic therapies was reviewed with consideration for patient performance status, comorbidities, and the involvement and function of other organs. The resulting consensus recommendations herein will help clarify evidence-based management of ES-SCLC in routine practice, help clinician decision-making, and facilitate the best patient outcomes.

Improving Time-to-Treatment for Advanced Non-Small Cell Lung Cancer Patients through Faster Single Gene EGFR Testing Using the Idylla™ EGFR Testing Platform.

INTRODUCTION: Patients with advanced-stage non-small cell lung cancer (NSCLC) may benefit from a short time-to-treatment (TTT). Predictive biomarker testing is performed prior to treatment, as recommended by various international expert consensus bodies. Genetic testing is more time-intensive than immunohistochemistry (IHC) and commonly contributes to prolonged TTT. For epidermal growth factor receptor-positive patients (EGFR+), further genetic testing may not be required due to the mutual exclusivity of actionable mutations. METHODS: The trial cohort (N = 238) received both BC Cancer NGS panel (Oncopanel) and Idylla EGFR testing. Data were also collected for a control cohort (N = 220) that received Oncopanel testing. For each patient, the time that the lab received the sample, the time taken to report the NGS and Idylla tests, the time of first treatment, and the final treatment regimen were recorded. RESULTS: A concordance frequency of 98.7% (232/235) was observed between the Idylla and NGS panel. The lab turnaround time (TAT) was faster for the Idylla test by an average of 12.4 days (N = 235, p < 0.01). Overall, the average TTT in the trial cohort (N = 114) was 10.1 days faster (p < 0.05) than the control (N = 114), leading to a 25% reduction in TTT. For patients treated based on EGFR positivity, the mean TTT was 16.8 days faster (p < 0.05) in the trial cohort (N = 33) than the control cohort (N = 28), leading to a 48% reduction in TTT. CONCLUSION: Using the Idylla EGFR test as part of the molecular testing repertoire in advanced-stage NSCLC patients could significantly reduce TTT.

Consensus Recommendations to Optimize Testing for New Targetable Alterations in Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) has historically been associated with a poor prognosis and low 5-year survival, but the use of targeted therapies in NSCLC has improved patient outcomes over the past 10 years. The pace of development of new targeted therapies is accelerating, with the associated need for molecular testing of new targetable alterations. As the complexity of biomarker testing in NSCLC increases, there is a need for guidance on how to manage the fluid standard-of-care in NSCLC, identify pragmatic molecular testing requirements, and optimize result reporting. An expert multidisciplinary working group with representation from medical oncology, pathology, and clinical genetics convened via virtual meetings to create consensus recommendations for testing of new targetable alterations in NSCLC. The importance of accurate and timely testing of all targetable alterations to optimize disease management using targeted therapies was emphasized by the working group. Therefore, the panel of experts recommends that all targetable alterations be tested reflexively at NSCLC diagnosis as part of a comprehensive panel, using methods that can detect all relevant targetable alterations. In addition, comprehensive biomarker testing should be performed at the request of the treating clinician upon development of resistance to targeted therapy. The expert multidisciplinary working group also made recommendations for reporting to improve clarity and ease of interpretation of results by treating clinicians and to accommodate the rapid evolution in clinical actionability of these alterations. Molecular testing of all targetable alterations in NSCLC is the key for treatment decision-making and access to new therapies. These consensus recommendations are intended as a guide to further optimize molecular testing of new targetable alterations.

Classifying Pulmonary and Urinary High-grade Neuroendocrine Carcinoma by CK7 Immunohistochemistry.

High-grade neuroendocrine carcinoma (HGNEC) is subclassified into small cell carcinoma (SmCC) and large cell neuroendocrine carcinoma (LCNEC). Although both are clinically aggressive, the SmCC and LCNEC need to have different treatment strategies, and accurate pathologic diagnosis is challenging. We studied a large retrospective cohort (186 cases) of HGNEC of bladder and lung to investigate the abundance of cytokeratin (CK) 7 expression and staining pattern in SmCC and LCNEC. Overall, the pulmonary and urinary HGNEC exhibited several different CK7 staining patterns, including negative staining (n=28), dot-like staining (n=73), partial membranous staining (n=26), and complete membranous staining (n=60). Overall, 88.9% (44/49) of pulmonary SmCC and 88.0% (44/50) of urinary SmCC showed negative or dot-like patterns for CK7, while 90.8% (59/65) of pulmonary LCNEC and 72.7% (16/22) of urinary LCNEC showed partial or complete membranous patterns for CK7 (χ 2 =105.05, P <0.0001). The distinct staining patterns were also present in those mixed SmCC and LCNEC. In addition, the specimen types or fixation did not affect CK7 staining patterns. In conclusion, CK7 has a high differential value for SmCC and LCNEC and could help guide personalized treatment for patients.

The impact of whole genome and transcriptome analysis (WGTA) on predictive biomarker discovery and diagnostic accuracy of advanced malignancies.

In this study, we evaluate the impact of whole genome and transcriptome analysis (WGTA) on predictive molecular profiling and histologic diagnosis in a cohort of advanced malignancies. WGTA was used to generate reports including molecular alterations and site/tissue of origin prediction. Two reviewers analyzed genomic reports, clinical history, and tumor pathology. We used National Comprehensive Cancer Network (NCCN) consensus guidelines, Food and Drug Administration (FDA) approvals, and provincially reimbursed treatments to define genomic biomarkers associated with approved targeted therapeutic options (TTOs). Tumor tissue/site of origin was reassessed for most cases using genomic analysis, including a machine learning algorithm (Supervised Cancer Origin Prediction Using Expression [SCOPE]) trained on The Cancer Genome Atlas data. WGTA was performed on 652 cases, including a range of primary tumor types/tumor sites and 15 malignant tumors of uncertain histogenesis (MTUH). At the time WGTA was performed, alterations associated with an approved TTO were identified in 39 (6%) cases; 3 of these were not identified through routine pathology workup. In seven (1%) cases, the pathology workup either failed, was not performed, or gave a different result from the WGTA. Approved TTOs identified by WGTA increased to 103 (16%) when applying 2021 guidelines. The histopathologic diagnosis was reviewed in 389 cases and agreed with the diagnostic consensus after WGTA in 94% of non-MTUH cases (n = 374). The remainder included situations where the morphologic diagnosis was changed based on WGTA and clinical data (0.5%), or where the WGTA was non-contributory (5%). The 15 MTUH were all diagnosed as specific tumor types by WGTA. Tumor board reviews including WGTA agreed with almost all initial predictive molecular profile and histopathologic diagnoses. WGTA was a powerful tool to assign site/tissue of origin in MTUH. Current efforts focus on improving therapeutic predictive power and decreasing cost to enhance use of WGTA data as a routine clinical test.

A Case of ALK-Rearranged Combined Lung Adenocarcinoma and Neuroendocrine Carcinoma with Diffuse Bone Metastasis and Partial Response to Alectinib.

We report a rare case of stage IV pulmonary combined large-cell neuroendocrine carcinoma (LCNEC) and adenocarcinoma (ACA), both demonstrating anaplastic lymphoma kinase (ALK) rearrangement by IHC and FISH. This 61-year-old lifelong nonsmoking Asian woman presented with a cough, and after diagnosis and surgical treatment, completed four cycles of adjuvant cisplatin and etoposide chemotherapy. She subsequently developed recurrence with bony metastases of exclusively ALK-positive LCNEC. Alectinib was started, and the patient experienced a partial response.

Bacterial Cellulose-A Remarkable Polymer as a Source for Biomaterials Tailoring.

Nowadays, the development of new eco-friendly and biocompatible materials using 'green' technologies represents a significant challenge for the biomedical and pharmaceutical fields to reduce the destructive actions of scientific research on the human body and the environment. Thus, bacterial cellulose (BC) has a central place among these novel tailored biomaterials. BC is a non-pathogenic bacteria-produced polysaccharide with a 3D nanofibrous structure, chemically identical to plant cellulose, but exhibiting greater purity and crystallinity. Bacterial cellulose possesses excellent physicochemical and mechanical properties, adequate capacity to absorb a large quantity of water, non-toxicity, chemical inertness, biocompatibility, biodegradability, proper capacity to form films and to stabilize emulsions, high porosity, and a large surface area. Due to its suitable characteristics, this ecological material can combine with multiple polymers and diverse bioactive agents to develop new materials and composites. Bacterial cellulose alone, and with its mixtures, exhibits numerous applications, including in the food and electronic industries and in the biotechnological and biomedical areas (such as in wound dressing, tissue engineering, dental implants, drug delivery systems, and cell culture). This review presents an overview of the main properties and uses of bacterial cellulose and the latest promising future applications, such as in biological diagnosis, biosensors, personalized regenerative medicine, and nerve and ocular tissue engineering.

Histological subtype is associated with PD-L1 expression and CD8+ T-cell infiltrates in triple-negative breast carcinoma.

Assessment of programmed death-ligand 1 (PD-L1) expression and CD8+ lymphocyte infiltrates in triple-negative breast carcinoma (TNBC) can provide valuable prognostic and predictive information. Knowledge of clinical and pathological factors that predict the status of these two markers is needed to better select patients likely to respond to immunotherapy. We aim to assess the association between histological subtypes of TNBC and tumor microenvironment type, defined here as each tumor's PD-L1 status and the percentage of CD8+ cells in its tumor-associated lymphocyte population. Tissue microarrays consisting of 72 TNBC cases (28 conventional invasive ductal carcinomas (IDCs), 21 basal-like IDCs, 18 apocrine carcinomas, and five metaplastic carcinomas) were evaluated for PD-L1 expression using the SP142 and 22C3 immunohistochemical (IHC) assays. The percentages of CD8+ and CD4+ intra-tumoral stromal lymphocytes in each case were analyzed using QuPath (open-source software platform) on CD8 and CD4 IHC-stained digital slides of the TMAs. Tumor-infiltrating lymphocytes (TILs) were also assessed on representative H&E-stained whole-tissue sections and compared to CD8+ and CD4+ lymphocyte percentages, and to the CD4/CD8 ratio of intra-tumoral lymphocytes for each case. Cases were then separated into four tumor microenvironment groups (PD-L1+/CD8+, PD-L1+/CD8-, PD-L1-/CD8+, and PD-L1-/CD8-). Basal-like IDCs were most often PD-L1-/CD8- (71.4%/61.9% of cases with SP142/22C3, respectively), while conventional IDCs were more distributed among PD-L1+ and PD-L1- microenvironments (35.7% PD-L1+/CD8+ and 42.9% PD-L1-/CD8- with the 22C3 assay). Apocrine carcinomas tended to be PD-L1-/CD8- (83.3% of cases with both SP142 and 22C3 antibodies). Metaplastic carcinomas were PD-L1-/CD8- in 60% of cases with both 22C3 and SP142. A CD8+ lymphocyte percentage ≥5% strongly predicted PD-L1 positivity (positive predictive value using the 22C3 assay: 0.75). Our data suggest that some histological subtypes of TNBC are predictive of PD-L1 status and CD8+ T-cell infiltrate levels.

Canadian ROS proto-oncogene 1 study (CROS) for multi-institutional implementation of ROS1 testing in non-small cell lung cancer.

Patients with non-small cell lung cancer (NSCLC) harboring ROS proto-oncogene 1 (ROS1) gene rearrangements show dramatic response to the tyrosine kinase inhibitor (TKI) crizotinib. Current best practice guidelines recommend that all advanced stage non-squamous NSCLC patients be also tested for ROS1 gene rearrangements. Several studies have suggested that ROS1 immunohistochemistry (IHC) using the D4D6 antibody may be used to screen for ROS1 fusion positive lung cancers, with assays showing high sensitivity but moderate to high specificity. A break apart fluorescence in situ hybridization (FISH) test is then used to confirm the presence of ROS1 gene rearrangement. The goal of Canadian ROS1 (CROS) study was to harmonize ROS1 laboratory developed testing (LDT) by using IHC and FISH assays to detect ROS1 rearranged lung cancers across Canadian pathology laboratories. Cell lines expressing different levels of ROS1 (high, low, none) were used to calibrate IHC protocols after which participating laboratories ran the calibrated protocols on a reference set of 24 NSCLC cases (9 ROS1 rearranged tumors and 15 ROS1 non-rearranged tumors as determined by FISH). Results were compared using a centralized readout. The stained slides were evaluated for the cellular localization of staining, intensity of staining, the presence of staining in non-tumor cells, the presence of non-specific staining (e.g. necrosis, extracellular mater, other) and the percent positive cells. H-score was also determined for each tumor. Analytical sensitivity and specificity harmonization was achieved by using low limit of detection (LOD) as either any positivity in the U118 cell line or H-score of 200 with the HCC78 cell line. An overall diagnostic sensitivity and specificity of up to 100% and 99% respectively was achieved for ROS1 IHC testing (relative to FISH) using an adjusted H-score readout on the reference cases. This study confirms that LDT ROS1 IHC assays can be highly sensitive and specific for detection of ROS1 rearrangements in NSCLC. As NSCLC can demonstrate ROS1 IHC positivity in FISH-negative cases, the degree of the specificity of the IHC assay, especially in highly sensitive protocols, is mostly dependent on the readout cut-off threshold. As ROS1 IHC is a screening assay for a rare rearrangements in NSCLC, we recommend adjustment of the readout threshold in order to balance specificity, rather than decreasing the overall analytical and diagnostic sensitivity of the protocols.

Automated PD-L1 Scoring for Non-Small Cell Lung Carcinoma Using Open-Source Software.

PD-L1 expression in non-small cell lung cancer (NSCLC) is predictive of response to immunotherapy, but scoring of PD-L1 immunohistochemistry shows considerable interobserver variability. Automated methods may allow more consistent and expedient PD-L1 scoring. We aimed to assess the technical concordance of PD-L1 scores produced using free open source QuPath software with the manual scores of three pathologists. A classifier for PD-L1 scoring was trained using 30 NSCLC image patches. A separate test set of 207 image patches from 69 NSCLC resection cases was used for comparison of automated and manual scores. Automated and average manual scores showed excellent correlation (concordance correlation coeffecient = 0.925), though automated scoring resulted in significantly more 1-49% scores than manual scoring (p = 0.012). At both 1% and 50% thresholds, automated scores showed a level of concordance with our 'gold standard' (the average of three pathologists' manual scores) similar to that of individual pathologists. Automated scoring showed high sensitivity (95%) but lower specificity (84%) at a 1% threshold, and excellent specificity (100%) but lower sensitivity (71%) at a 50% threshold. We conclude that our automated PD-L1 scoring system for NSCLC has an accuracy similar to that of individual pathologists. The detailed protocol we provide for free open source scoring software and our discussion of the limitations of this technology may facilitate more effective integration of automated scoring into clinical workflows.

Discordance in PD-L1 scores on repeat testing of non-small cell lung carcinomas.

INTRODUCTION: PD-L1 expression may be used as a biomarker predictive of non-small cell lung carcinoma (NSCLC) response to PD-L1 inhibitor treatment. Spatial and temporal heterogeneity in PD-L1 expression and variation in PD-L1 test interpretation may contribute to differences in PD-L1 test results between samples of the same patient's disease. METHODS: Retrospective chart review identified 77 NSCLC patients with 22C3 PharmDx PD-L1 assays performed on two different tumor samples. Patients clinically suspected to have two separate primaries were excluded. PD-L1 test results in different score categories (<1%, 1-49% and ≥50%) were considered discordant. Clinical and pathologic factors associated with discordance were assessed. RESULTS: 28 (36%) of the 77 cases had discordant PD-L1 scores between samples. Patients with an initial test result of 1-49% were most likely to have a discordant second test result. Specimen type (cytology, small biopsy or resection), specimen site (lung, lymph node, pleura/pleural effusion or distant metastasis), time between specimen collection, and treatment between specimen collection were not significantly associated with the rate of discordance. CONCLUSIONS: Repeat PD-L1 testing of the same patient's NSCLC results frequently resulted in discordant test results, independent of whether the samples differed in clinical or pathologic factors. This discordance rate underscores the extent to which PD-L1 levels are heterogeneous and difficult to accurately represent with a single test value. Further study of the predictive value of PD-L1 scores in cases with discordant results is needed.

Utility of SOX6 and DAB2 for the Diagnosis of Malignant Mesothelioma.

The separation of malignant mesothelioma from non-small cell lung carcinomas can be a difficult problem. Sex-determining region Y box 6 (SOX6) and disabled homolog 2 (DAB2) have recently been proposed as sensitive/specific markers of mesothelial lineage, but have not yet been independently tested for utility in mesothelioma diagnosis. Using tissue microarrays containing mesotheliomas (epithelioid: n=40, sarcomatoid: n=23) and non-small cell lung carcinomas (adenocarcinoma: n=52, squamous cell carcinoma: n=57, large cell carcinoma: n=12) we evaluated the performance of SOX6 and DAB2 by themselves, in conjunction with other established mesothelioma markers (calretinin, WT1, D2-40, CK5/6, HEG1) and combined with 3 broad-spectrum established carcinoma markers: claudin-4, MOC31, and BerEP4. For epithelioid mesothelioma, SOX6 and DAB2 had sensitivities of 85% and 98%, respectively. For sarcomatoid mesothelioma, SOX6 had a sensitivity of 13% and DAB2 could not be assessed due to background stromal staining. For SOX6 alone, specificity for mesothelioma versus adenocarcinoma, squamous cell carcinoma, and large cell carcinoma was 94%, 79%, and 92%, respectively, while for DAB2 specificity was 77%, 86%, and 67%. Combinations of SOX6 and established mesothelioma markers produced sensitivities of 95% or greater. A combination of SOX6 positive/claudin-4 negative staining was 95% to 100% specific for mesothelioma versus carcinoma with a sensitivity of 85%. SOX6 is a promising marker for the diagnosis of mesothelioma and potentially could be combined with other mesothelial markers or a broad-spectrum carcinoma marker to reach an accurate diagnosis with relatively few immunostains, The relatively low specificity and difficulty of interpreting DAB2 staining limits its utility for mesothelioma diagnosis.

Comparability of laboratory-developed and commercial PD-L1 assays in non-small cell lung carcinoma.

PD-L1 expression in non-small cell lung cancer (NSCLC) is predictive of response to treatment with PD-1 and PD-L1 inhibitors. Different inhibitors have been developed with different PD-L1 assays, which use different PD-1 antibody clones on different immunohistochemistry platforms. Depending on instrument and reagent availability, laboratory-developed tests with cross-platform use of PD-L1 antibodies may have practical benefits over commercial assays. The 22C3 pharmDx Assay (referred to as 22C3 DAKO), the VENTANA PD-L1 SP263 Assay (referred to as SP263 VENTANA) and a lab-developed test using the 22C3 antibody on the VENTANA BenchMark ULTRA IHC/ISH system (referred to as 22C3 VENTANA) were performed on whole sections of 85 NSCLC surgical resections. All sections were independently scored by three pathologists using tumor proportion scores. Correlation coefficients for continuous scores in pairwise comparisons between assays ranged from 0.976 to 0.978. When using a 1% positivity threshold (dichotomous scores), the 22C3 DAKO assay and 22C3 VENTANA assays showed the greatest agreement (93% agreement, κ = 0.86, 95% CI 0.75-0.97), and the 22C3 DAKO and SP263 VENTANA assays tended to show slightly less agreement (84% agreement, κ = 0.66, 95% CI 0.50-0.82). When using a 50% positivity threshold (dichotomous scores), all pairwise comparisons showed similar agreement (96-99% agreement, κ = 0.89-0.97). Overall, there was no significant difference between assays at 1% or 50% thresholds (P = .77). These data are consistent with potential interchangeability of these assays, which may widen the scope of PD-L1 assays available to laboratories and reduce logistical barriers to testing.

Comprehensive assessment of PD-L1 immunohistochemistry on paired tissue and cytology specimens from non-small cell lung cancer.

OBJECTIVES: PD-L1 staining assessed by immunohistochemistry (IHC) is a predictive biomarker used to select advanced stage non-small cell lung carcinoma (NSCLC) patients who are likely to respond to PD-1/PD-L1 inhibitors. Cytology specimens represent a significant percentage of the diagnostic samples and additional data are required to show that they provide reliable PD-L1 results when compared to tissue specimens. We aimed to compare PD-L1 staining obtained from patient-matched tissue and cytology specimens. We also want to assess the feasibility of PD-L1 testing on cell blocks with two assays by evaluating the intra- and inter-observer agreement and the level of difficulty for determining the percentage of stained tumor cells (TPS). MATERIALS AND METHODS: Forty-six patients with NSCLC were selected. Each patient provided a surgical specimen and a cytology sample (cell block) and/or a biopsy at diagnosis. PD-L1 staining using Agilent PD-L1 IHC 28-8 pharmDx and VENTANA PD-L1 (SP263) assays was evaluated by four pathologists using the TPS. Sixty slides were rescored to document intra-observer agreement. Pathologists were asked to score the level of difficulty for evaluating PD-L1 TPS for each slide. Fleiss's and Cohen's kappas (k) were used to assess the agreement between paired specimens as well as intra- and inter-observer agreement. RESULTS: The concordance in PD-L1 TPS between cell blocks and surgical specimens (k varying from 0.56 to 0.82) or biopsies (k from 0.43 to 0.81) was moderate to substantial, depending on the cut-off. On cell blocks, inter-observer agreement was substantial (k from 0.74 to 0.82) and intra-observer agreement was almost perfect (k from 0.85 to 0.93). The perceived difficulty of PD-L1 evaluation of cell blocks was not different from surgical specimens but more difficult than biopsy samples. CONCLUSION: PD-L1 TPS was concordant between cell blocks and tissue specimens, mainly at 10, 25 and 50 % cut-offs. PD-L1 evaluation on cell blocks was feasible and reproducible between different observers and assays.