The utility of a novel triple marker (combination of TTF1, napsin A, and p40) in the subclassification of non-small cell lung cancer

Comparative Analysis of Transcriptomic and Proteomic Expression between Two Non-Small Cell Lung Cancer Subtypes

Non-small cell lung cancer (NSCLC) is frequently diagnosed late and has poor survival. The two predominant subtypes of NSCLC, adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC), are currently differentially diagnosed using immunohistochemical markers; however, they are increasingly recognized as very different cancer types suggestive of potential for new, more targeted therapies. There are extensive efforts to find more precise and noninvasive differential diagnostic tools. Here, we examined these two NSCLC subtypes for differences that may inform treatment and identify potential novel therapeutic pathways. We presented a comparative analysis of transcriptomic and proteomic expression in tumors from a cohort of 22 NSCLC patients: 8 LUSC and 14 LUAD. Comparing NSCLC subtypes, we found differential gene expression related to cell differentiation for LUSC and cellular structure and immune response regulation for LUAD. Differential protein expression between NSCLC subtypes was related to extracellular structure for LUSC and metabolic processes, including glucose metabolism for LUAD. This direct comparison was more informative about subtype-specific pathways than between each subtype and control (nontumor) tissues. Many of our observations between NSCLC subtypes support and inform existing observations and reveal differences that may aid research seeking to identify and validate novel subtype biomarkers or druggable targets.

Neuroanatomical location of lung cancer brain metastases in 234 patients with a focus on cancer subtyping and biomarkers

Brain metastases are frequent in neuropathology practices; however, the literature on their distribution is frequently derived from imaging studies. This work examined metastases of lung cancer to the brain through the lens of pathology specimens. All brain surgical pathology cases accessioned from 2011-2020 were retrieved from a regional laboratory. Specimens were classified by neuroanatomical location, diagnostic category, and diagnosis with a hierarchical free text string-matching algorithm. All reports classified as probable metastasis per algorithm were reviewed by a pathologist. Lung biomarkers and selected immunostains were retrieved with text parsing and reviewed. Among 4,625 cases of brain surgical resection specimens, 854 were classified as probable metastasis by the algorithm. On report review, 538/854 cases were confirmed as metastasis with a known primary site. The 538 cases were from 511 patients and 234/511 patients had lung primaries. Small cell lung cancer lesions were most frequently found in the cerebellum (17/30). Lesions from lung adenocarcinoma (59/164) and non-small cell carcinoma-not otherwise specified (NSCLC-NOS) (15/34) were most commonly found in the frontal lobe. Squamous cell carcinoma lesions were most commonly found in the frontal and occipital lobes (8/27). 72/234 cases were reported as NSCLC-NOS and could be further subclassified using immunostaining (41/72). Lung biomarker data were retrieved in ~38% of cases. PD-L1 positivity was dependent on neuroanatomical distribution (p = 0.04); other examined biomarkers were not. The distribution of lung tumours metastatic to the brain is dependent on the lung cancer subtype (p<0.001). The reporting of histologic subtype could be further optimized in the local environment.

Lung Cancer Subtyping: A Short Review

As of 2022, lung cancer is the most commonly diagnosed cancer worldwide, with the highest mortality rate. There are three main histological types of lung cancer, and it is more important than ever to accurately identify the subtypes since the development of personalized, type-specific targeted therapies that have improved mortality rates. Traditionally, the gold standard for the confirmation of histological subtyping is tissue biopsy and histopathology. This, however, comes with its own challenges, which call for newer sampling techniques and adjunctive tools to assist in and improve upon the existing diagnostic workflow. This review aims to list and describe studies from the last decade (n = 47) that investigate three such potential omics techniques-namely (1) transcriptomics, (2) proteomics, and (3) metabolomics, as well as immunohistochemistry, a tool that has already been adopted as a diagnostic adjunct. The novelty of this review compared to similar comprehensive studies lies with its detailed description of each adjunctive technique exclusively in the context of lung cancer subtyping. Similarities between studies evaluating individual techniques and markers are drawn, and any discrepancies are addressed. The findings of this study indicate that there is promising evidence that supports the successful use of omics methods as adjuncts to the subtyping of lung cancer, thereby directing clinician practice in an economical and less invasive manner.

Characterization of Nonsmall Cell Lung Carcinoma in Limited Biopsy Samples and Identifying Optimal Immunohistochemical Marker Combinations in Resource-Constrained Setup: An Institutional Experience

Background  The incorporation of immunohistochemical markers in the analysis of small biopsy samples, as outlined in the fourth edition of the World Health Organization Blue books, represents a noteworthy advancement in the diagnosis of advanced-stage lung carcinoma. This improved the histological classification for poorly differentiated nonsmall cell lung carcinomas (NSCLCs), especially in small biopsy specimens. Despite challenges in obtaining viable cells from diminutive tumor samples, a focused immunohistochemical panel effectively distinguishes histological types in most NSCLC. This preserves tissue for subsequent molecular testing. Material and Methods  This study examined 130 consecutive lung biopsy cases initially diagnosed as NSCLC, including various biopsy types (transbronchial, endobronchial, ultrasound-guided, computed tomography-guided). Carcinomas were categorized based on specific characteristics, such as glands and/or mucin for adenocarcinomas, keratinization and/or intercellular bridges for squamous cell carcinomas, and recognition of poorly differentiated NSCLC. Cases lacking clear morphological attributes underwent reclassification using immunohistochemical markers (TTF1, Napsin A, p63, and p40). Results  TTF1 exhibited superior sensitivity (97.56%) and specificity (96.77%) for adenocarcinoma compared with Napsin A, with sensitivity and specificity at 90.24 and 93.3%, respectively. p63 and p40 demonstrated 100% sensitivity for squamous cell carcinoma, with p40 being more specific than p63 (100% vs. 82.92%). Using TTF1 and p63 as a conventional panel, 87% of cases were subtyped. However, the combination of TTF1 and p40 achieved accurate classification in 94.66% (71/75) of cases, and all four markers allowed subtype identification in 97.2% (73/75) of cases. Conclusion  In a resource-constrained setting, subtyping NSCLC in small biopsy can be effectively accomplished using a minimal panel consisting of TTF1 and p40 immunohistochemical markers.

Evolving Precision First-Line Systemic Treatment for Patients with Unresectable Non-Small Cell Lung Cancer

First-line systemic therapy for patients with advanced or metastatic non-small cell lung cancer (NSCLC) has rapidly evolved over the past two decades. First, molecularly targeted therapy for a growing number of gain-of-function molecular targets has been shown to improve progression-free survival (PFS) and overall survival (OS) with favorable toxicity profiles compared to platinum-containing chemotherapy and can be given as first-line systemic therapy in ~25% of patients with NSCLC. Actionable genetic alterations include EGFR, BRAF V600E, and MET exon 14 splicing site-sensitizing mutations, as well as ALK-, ROS1-, RET-, and NTRK-gene fusions. Secondly, inhibitors of programmed cell death protein 1 or its ligand 1 (PD-1/L1) such as pembrolizumab, atezolizumab, or cemiplimab monotherapy have become a standard of care for ~25% of patients with NSCLC whose tumors have high PD-L1 expression (total proportion score (TPS) ≥50%) and no sensitizing EGFR/ALK alterations. Lastly, for the remaining ~50% of patients who are fit and whose tumors have no or low PD-L1 expression (TPS of 0-49%) and no sensitizing EGFR/ALK aberrations, platinum-containing chemotherapy with the addition of a PD-1/L1 inhibitor alone or in combination of a cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitor improves PFS and OS compared to chemotherapy alone. The objectives of this review are to summarize the current data and perspectives on first-line systemic treatment in patients with unresectable NSCLC and propose a practical algorithm for implementing precision biomarker testing at diagnosis.

Non B Cell-Derived Immunoglobulins in Lung Epithelial Cells and Lung Cancer

As the locus for air exchange, lung tissue is perpetually exposed to a significant quantity of foreign pathogens. Consequently, lung has developed a refined and intricate immune system. Beyond their physical and chemical barrier roles, lung epithelial cells can contribute to immune defence through the expression of Toll-like receptors (TLRs) and other pattern recognition receptors, along with the secretion of cytokines. Emerging evidence demonstrates that lung epithelial cells can generate and secrete immunoglobulins (Igs), including IgM, IgA, or IgG, thus performing antibody function. Moreover, malignantly transformed lung epithelial cells have been discovered to produce high levels of Ig, predominantly IgG, which do not fulfill the role of antibodies, but instead carries out tumour-promoting activity. Structural analysis has indicated that the biological activity of IgG produced by lung cancer cells differs from that of Igs produced by normal lung epithelial cells due to the unique glycosylation modification. Specifically, the sialylated IgG (SIA-IgG), characterised by a non-traditional N-glycosylation modification at the Asn162 site of Igγ CH1, is highly expressed in tumour stem cells. It has been demonstrated that SIA-IgG relies on this unique sialylation modification to promote tumorigenesis, metastasis, and immune evasion. Current results have proven that the Ig produced by lung epithelial cells has multifaceted biological activities, including immune defence functions under physiological conditions, while acquiring tumour-promoting activity during malignant transformation. These insights possess potential for the diagnosis and treatment of lung cancer as novel biomarkers and targets.

Shared features of metaplasia and the development of adenocarcinoma in the stomach and esophagus

Introduction: Plasticity is an inherent property of the normal gastrointestinal tract allowing for appropriate response to injury and healing. However, the aberrancy of adaptable responses is also beginning to be recognized as a driver during cancer development and progression. Gastric and esophageal malignancies remain leading causes of cancer-related death globally as there are limited early disease diagnostic tools and paucity of new effective treatments. Gastric and esophageal adenocarcinomas share intestinal metaplasia as a key precancerous precursor lesion.

Methods: Here, we utilize an upper GI tract patient-derived tissue microarray that encompasses the sequential development of cancer from normal tissues to illustrate the expression of a set of metaplastic markers.

Results: We report that in contrast to gastric intestinal metaplasia, which has traits of both incomplete and complete intestinal metaplasia, Barrett's esophagus (i.e., esophageal intestinal metaplasia) demonstrates hallmarks of incomplete intestinal metaplasia. Specifically, this prevalent incomplete intestinal metaplasia seen in Barrett's esophagus manifests as concurrent development and expression of both gastric and intestinal traits. Additionally, many gastric and esophageal cancers display a loss of or a decrease in these characteristic differentiated cell properties, demonstrating the plasticity of molecular pathways associated with the development of these cancers.

Discussion: Further understanding of the commonalities and differences governing the development of upper GI tract intestinal metaplasias and their progression to cancer will lead to improved diagnostic and therapeutic avenues.

The Correlation Between Histologic, Immunophenotypic, and Molecular Characteristics of Pulmonary Sarcomatoid Carcinoma Reveals That Sarcomatoid Change Is Potentially Derived From Epithelial Carcinoma Cells Undergoing Epithelial-Mesenchymal Transition

Pulmonary sarcomatoid carcinoma (PSC) is characterized by biphasic tumors with epithelial and mesenchymal phenotype. Little is known about the correlation between histologic, immunophenotypic features and the genetic profile of PSC. We analyzed the expression of epithelial-mesenchymal transition-related markers, adenocarcinoma (ADC) and squamous cell carcinoma lineage-specific markers of 205 PSC cases. The alteration of 5 targeted genes was detected by amplification-refractory mutation system-polymerase chain reaction. The intensity of cytokeratin staining was stronger in epithelial carcinoma (EC) than that of the sarcomatoid component (SC) of pleomorphic carcinoma, while vimentin was positive in only 16.3% (17/104) of EC of pleomorphic carcinoma. There is no significant difference between thyroid transcription factor 1 (TTF-1) expression in the SC (46.5%, 33/71) of pleomorphic carcinoma with ADC components and pure PSC (44.2%, 42/95) without p40 expression ( P =0.858). Four cases with ALK rearrangement were confirmed to co-express ALK fusion protein in both the SC and EC. The incidence of EGFR/ALK/KRAS mutation was similar between pleomorphic carcinoma with ADC components (40.6%, 26/64) and TTF-1 + pure PSC (38.2%, 13/34) ( P =0.583). However, higher proportions of TTF-1 + /p40 - PSC patients (44.8%, 39/87) had EGFR/ALK/KRAS mutation than those with TTF-1 - /p40 - PSC (16.7%, 4/24) ( P =0.031). The incidence of EGFR mutation was significantly higher in TTF-1-positive (18.4%, 16/87) than TTF-1-negative (2.7%, 2/74) PSC ( P =0.002). No EGFR and ALK abnormality were observed in 24 pleomorphic carcinoma cases with squamous cell carcinoma components or pure PSC with p40 expression. Our study reveals a close correlation between SC and EC components of pleomorphic carcinoma in terms of immunophenotypic and genetic features, which suggests that pleomorphic carcinoma is potentially derived from the sarcomatoid change of EC cells undergoing epithelial-mesenchymal transition.

A targeted expression panel for classification, gene fusion detection and PD-L1 measurements - Can molecular profiling replace immunohistochemistry in non-small cell lung cancer?

The histological classification of non-small-cell lung cancer (NSCLC) and identification of possible therapeutic targets are important for disease management. However, as biopsies are often small, with a limited amount of tumor cells, it can be challenging to obtain enough tissue for the needed number of diagnostic immunohistochemical stains and molecular analyses. In this study, we combined a small custom designed targeted expression panel with a commercial fusion transcript assay by which we were able to perform both a histological classification (transcribing the expression of the genes encoding TTF1, Napsin A, CK5/6, and the truncated P63 isoform ΔNp63 (p40) into either adenocarcinoma or squamous cell carcinoma) and an identification of fusion genes involving ALK, RET, and ROS1. The expression panel also included the PD-L1 encoding gene, CD274, in order to evaluate the PD-L1 mRNA potential for identification of patients who will benefit from immune checkpoint inhibitor treatment. We evaluated the panel using 42 NSCLC patient samples. The molecular profiling agreed with the original immunohistochemistry (IHC)-based classification in 93% of the cases. For ten of the patients, being fusion gene positive, the fusion transcripts were detected in 100%. The molecular assessment of PD-L1 also showed agreement with the original assessment made by IHC. In conclusion, this study presents a small, targeted expression panel with the potential to perform both a molecularly based histological classification and a fusion gene identification in NSCLC patients as well as identifying PD-L1 status from a very limited amount of starting material.

Real-World Diagnostic Accuracy and Use of Immunohistochemical Markers in Lung Cancer Diagnostics

OBJECTIVES

Accurate and reliable diagnostics are crucial as histopathological type influences selection of treatment in lung cancer. The aim of this study was to evaluate real-world accuracy and use of immunohistochemical (IHC) staining in lung cancer diagnostics.

MATERIALS AND METHODS

The diagnosis and used IHC stains for small specimens with lung cancer on follow-up resection were retrospectively investigated for a 15-month period at two major sites in Sweden. Additionally, 10 pathologists individually suggested diagnostic IHC staining for 15 scanned bronchial and lung biopsies and cytological specimens.

RESULTS

In 16 (4.7%) of 338 lung cancer cases, a discordant diagnosis of potential clinical relevance was seen between a small specimen and the follow-up resection. In half of the cases, there was a different small specimen from the same investigational work-up with a concordant diagnosis. Diagnostic inaccuracy was often related to a squamous marker not included in the IHC panel (also seen for the scanned cases), the case being a neuroendocrine tumor, thyroid transcription factor-1 (TTF-1) expression in squamous cell carcinomas (with clone SPT24), or poor differentiation. IHC was used in about 95% of cases, with a higher number of stains in biopsies and in squamous cell carcinomas and especially neuroendocrine tumors. Pre-surgical transthoracic samples were more often diagnostic than bronchoscopic ones (72-85% vs. 9-53% for prevalent types).

CONCLUSIONS

Although a high overall diagnostic accuracy of small specimens was seen, small changes in routine practice (such as consequent inclusion of p40 and TTF-1 clone 8G7G3/1 in the IHC panel for non-small cell cancer with unclear morphology) may lead to improvement, while reducing the number of IHC stains would be preferable from a time and cost perspective.

Precise pathological classification of non-small cell lung adenocarcinoma and squamous carcinoma based on an integrated platform of targeted metabolome and lipidome

BACKGROUND

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are the most common subtypes of NSCLC. Despite genetic differences between LUAD and LUSC have been clarified in depth, the metabolic differences of these two subtypes are still unclear.

METHODS

Totally, 128 plasma samples of NSCLC patients were collected before initial treatments, followed by determination of LC-ESI-Q TRAP-MS/MS. Differentially expressed metabolites were screened based on a strict standard.

RESULTS

Based on the integrated platform of targeted metabolome and lipidome, a total of 1141 endogenous metabolites (including 809 lipids) were finally detected in the plasma of NSCLC patients, including 16 increased and 3 decreased endogenous compounds in LUAD group when compared with LUSC group. Thereafter, a logistic regression model integrating four differential metabolites [2-(Methylthio) ethanol, Cortisol, D-Glyceric Acid, and N-Acetylhistamine] was established and could accurately differentiate LUAD and LUSC with an area under the ROC curve of 0.946 (95% CI 0.886-1.000). The cut-off value showed a satisfactory efficacy with 92.0% sensitivity and 92.9% specificity. KEGG functional enrichment analysis showed these differentially expressed metabolites could be further enriched in riboflavin metabolism, steroid hormone biosynthesis, prostate cancer, etc. The endogenous metabolites identified in this study have the potential to be used as novel biomarkers to distinguish LUAD from LUSC.

CONCLUSIONS

Our research might provide more evidence for exploring the pathogenesis and differentiation of NSCLC. This research could promote a deeper understanding and precise treatment of lung cancer.

Recommendations for immunocytochemistry in lung cancer typing: An update on a resource-efficient approach with large-scale comparative Bayesian analysis

OBJECTIVES

The majority of lung cancer cases are of advanced stage and diagnosis is usually made using minimally invasive small biopsies and cytological specimens. The WHO 2015 classification recommends limiting immunocytochemistry (ICC) to lung cancer typing and molecular testing drives for personalised therapies. An algorithm using Bayes' theorem could be useful for defining antibody profiles. This study aims to assess the impact of different antibody profiles for cytological samples on the accuracy of lung cancer typing with a large-scale Bayesian analysis.

METHODS

A retrospective examination of 3419 consecutive smears and/or cytospins diagnosed over 2011-2016 found 1960 primary lung cancer tumours: 972 adenocarcinomas (ADC), 256 squamous carcinomas (SQC), 268 neuroendocrine tumours (NET), and 464 non-small cell cancer-not otherwise specified (NSCC-NOS). The a priori and a posteriori probabilities, before and after ICC using antibodies singly or in combination, were calculated for different lung cancer types.

RESULTS

TTF-1 or CK7 alone improved the a posteriori probabilities of correct cytological typing for ADC to 86.5% and 95.8%, respectively. For SQC, using p40 (∆Np63) or CK5/6 together with CK5/14 led to comparable results (78.3% and 90.3%). With synaptophysin or CD56 alone, improvements in a posteriori probabilities to 87.5 and 90.3% for the correct recognition of NET could be achieved.

CONCLUSIONS

Based on morphological and clinical data, the use of two antibodies appears sufficient for reliable detection of the different lung cancer types. This applies to diagnoses that were finalised following ICC both on a clinical or cytological basis and on a histological basis.

Lung adenocarcinoma and lung squamous cell carcinoma cancer classification, biomarker identification, and gene expression analysis using overlapping feature selection methods

Lung cancer is one of the deadliest cancers in the world. Two of the most common subtypes, lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), have drastically different biological signatures, yet they are often treated similarly and classified together as non-small cell lung cancer (NSCLC). LUAD and LUSC biomarkers are scarce, and their distinct biological mechanisms have yet to be elucidated. To detect biologically relevant markers, many studies have attempted to improve traditional machine learning algorithms or develop novel algorithms for biomarker discovery. However, few have used overlapping machine learning or feature selection methods for cancer classification, biomarker identification, or gene expression analysis. This study proposes to use overlapping traditional feature selection or feature reduction techniques for cancer classification and biomarker discovery. The genes selected by the overlapping method were then verified using random forest. The classification statistics of the overlapping method were compared to those of the traditional feature selection methods. The identified biomarkers were validated in an external dataset using AUC and ROC analysis. Gene expression analysis was then performed to further investigate biological differences between LUAD and LUSC. Overall, our method achieved classification results comparable to, if not better than, the traditional algorithms. It also identified multiple known biomarkers, and five potentially novel biomarkers with high discriminating values between LUAD and LUSC. Many of the biomarkers also exhibit significant prognostic potential, particularly in LUAD. Our study also unraveled distinct biological pathways between LUAD and LUSC.

A deep learning model for the classification of indeterminate lung carcinoma in biopsy whole slide images

The differentiation between major histological types of lung cancer, such as adenocarcinoma (ADC), squamous cell carcinoma (SCC), and small-cell lung cancer (SCLC) is of crucial importance for determining optimum cancer treatment. Hematoxylin and Eosin (H&E)-stained slides of small transbronchial lung biopsy (TBLB) are one of the primary sources for making a diagnosis; however, a subset of cases present a challenge for pathologists to diagnose from H&E-stained slides alone, and these either require further immunohistochemistry or are deferred to surgical resection for definitive diagnosis. We trained a deep learning model to classify H&E-stained Whole Slide Images of TBLB specimens into ADC, SCC, SCLC, and non-neoplastic using a training set of 579 WSIs. The trained model was capable of classifying an independent test set of 83 challenging indeterminate cases with a receiver operator curve area under the curve (AUC) of 0.99. We further evaluated the model on four independent test sets-one TBLB and three surgical, with combined total of 2407 WSIs-demonstrating highly promising results with AUCs ranging from 0.94 to 0.99.

The Diagnostic and Prognostic Roles of Combined Expression of Novel Biomarkers in Lung Adenocarcinoma and Lung Squamous Cell Carcinoma: An Immunohistochemical Study

Background & Objective:

Diagnosis and discrimination of lung adenocarcinoma (LUAD) from lung squamous cell carcinoma (LUSC) is critical to select the appropriate treatment regimen as recently targeted therapies require accurate subtyping of nonsmall-cell lung carcinoma (NSCLCs). There are currently several biomarkers that could be used for differentiation between LUAD and LUSC, but they have less sensitivity, specificity, and clinical applicability. The aim of this study was to assess the diagnostic and prognostic values of CLCA2, SPATS2, ST6GALNAC1, and Adipophilin tissue expression in the tissues retrieved from LUAD and LUSC patients using immunohistochemistry.

Methods:

The current study was performed on the samples retrieved from sixty primary lung masses that were diagnosed as LUAD and LUSC. Immunohistochemistry was performed by using a panel of CLCA2, SPATS2, and ST6GALNAC1. We assessed the diagnostic roles of the studied markers in the discrimination between LUAD and LUSC and their prognostic values.

Results:

SPATS2 and CLCA2 were expressed higher in LUSC than LUAD. ST6GALNAC1 and Adipophilin showed higher expression in LUAD than LUSC (P<0.001). The sensitivity and specificity of CLCA2, SPATS2, ST6GALNAC1 and Adipophilin in adequate subtyping and reaching the accurate diagnosis was 100%. We found only significant difference in survival rate between the patients with negative and positive CLCA2 expression (P=0.038 and P=0.019, respectively).

Conclusion:

The combination of biomarkers of CLCA2, SPATS2, ST6GALNAC1, and Adipophilin may lead to an appropriate subtyping of lung cancer and reaching accurate diagnosis with the highest sensitivity and specificity.

SOX2 and squamous cancers

SOX2 is a pleiotropic nuclear transcription factor with major roles in stem cell biology and in development. Over the last 10 years SOX2 has also been implicated as a lineage-specific oncogene, notably in squamous carcinomas but also neurological tumours, particularly glioblastoma. Squamous carcinomas (SQCs) comprise a common group of malignancies for which there are no targeted therapeutic interventions. In this article we review the molecular epidemiological and laboratory evidence linking SOX2 with squamous carcinogenesis, explore in detail the multifaceted impact of SOX2 in SQC, describe areas of uncertainty and highlight areas for potential future research.

Immunohistochemistry Profile Predicts EGFR Mutation Status in Lung Adenocarcinoma

Significant advances in targeted therapy have been made in recent years for patients with lung adenocarcinoma. These targeted therapies have made molecular testing of paramount importance to drive therapeutic decisions. Material for testing is often limited, particularly in cytology specimens and small core biopsies. A reliable screening tool is invaluable in triaging limited tissue and selection for epidermal growth factor receptor ( EGFR) mutation testing. We hypothesized that the immunohistochemistry (IHC) profile of lung adenocarcinoma predicts EGFR mutation status. In this retrospective study, we evaluated the thyroid transcription factor-1 (TTF-1)/napsin A IHC profile and EGFR mutation status in 339 lung adenocarcinomas at our academic institution. In our cohort, we found that 92.3% of cases were positive for TTF-1 and/or napsin A by IHC with an EGFR positivity rate of 17.3%. Importantly, 7.7% of the cases were dual TTF-1/napsin A negative, and none of these cases contained EGFR mutations. This finding supports the use of TTF-1 and napsin A IHC to identify cases where EGFR mutation status will be negative, thus preserving limited tissue for other ancillary testing.

Validation of Superiority of p40 over p63 in Differentiating Squamous Cell Carcinoma and Adenocarcinoma Lung

In this era of targeted therapy, it is important to distinguish the various subtypes of nonsmall cell lung carcinoma (NSCC). Diagnosis based on morphology alone is challenging in poorly differentiated carcinomas and core biopsies. Immunohistochemistry (IHC) helps in specifying the lineage for the subtype of NSCC. Till date, p63 is the most frequently used and sensitive marker for squamous cell carcinoma (SQCC). However, it is not specific and stains a subset of adenocarcinoma (ADC). Thus, a more reliable and specific marker is required for the diagnosis of SQCC.

The objective of the study was to validate the diagnostic utility of p40 over p63 in differentiating pulmonary SQCC from ADC and NSCC-not otherwise specified (NOS).

A total of 123 cases of NSCC were initially reviewed and subtyped blinded to the results of IHC. This was followed by a review of IHC slides which included p63, p40, thyroid transcription factor 1, Napsin-A, cytokeratin (CK) 5/6, and CK7.

There were 64 ADC, 19 SQCC, and 40 NSCC-NOS. IHC helped to confirm the morphological diagnosis in 62/64 ADCs and19/19 SQCCs. IHC classified the cases of NSCC-NOS into NSCC favoring ADC – 12 cases, NSCC favoring SQCC – 10 cases, and NSCC favoring AD-SQCC – 4 cases. Both p63 and p40 showed near equal sensitivity for SQCC (100% and 97%, respectively), whereas p63 showed far lower specificity when compared to p40 (51.3% vs. 100%).

The present study confirms and validates that p40 is equally sensitive but highly specific than p63 in detecting SQCC. Hence, we recommend the routine use of p40 instead of p63 for the definite categorization of NSCC of the lung.

Subtyping and EGFR mutation testing from blocks of cytological materials, based on liquid-based cytology for lung cancer at bronchoscopic examinations

BACKGROUND

Liquid-based cytology (LBC) allows immunohistochemistry (IHC), fluorescence in situ hybridization, and molecular testing to be performed in fixed cell materials. We examined the feasibility of subtyping and EGFR mutation testing of bronchoscopic samples from patients with lung cancer using cell blocks (CB) based on LBC fixation (LBC-CB).

METHODS

We included 35 consecutive patients with peripheral lung nodules who underwent endobronchial ultrasonography with a guide sheath in our hospital. Thirty of these patients were diagnosed with lung cancer by obtaining cytological samples. Cytological subtyping was performed with IHC using LBC-CB, and the Cobas EGFR Mutation Test ver. 2 was performed using extracted genomic DNA from the LBC-CB, formalin-fixed paraffin-embedded (FFPE) tissue, and matched plasma.

RESULTS

Of the 30 cases, 25 were classified cytomorphologically as adenocarcinoma (ADC, n = 17) and squamous-cell carcinoma (SQCC, n = 8). The remaining five cases were classified by IHC as favor ADC (n = 3) and favor SQCC (n = 2) according to the WHO criteria. In the final ADC group (n = 20), EGFR mutations on the LBC-CB were identified in eight cases (40%; 1 exon 19 deletion, 6 L858R, and 1 L861Q). Mutations in FFPE samples were identified in seven cases (35%) at the same site in each case. Plasma EGFR mutations were identified in four cases (20%) at the same site. The CB detection rate was higher than for FFPE and plasma.

CONCLUSION

LBC-CB is suitable for subtyping and EGFR mutation testing in lung cancers.

Successful lung cancer EGFR sequencing from DNA extracted from TTF-1 immunohistochemistry slides: a new means to extend insufficient tissue

Lung cancer biopsy material is limited and is used for morphologic diagnosis and immunohistochemical and molecular testing. This can lead to tissue exhaustion, resulting in repeat biopsies (when clinically possible), delayed testing, and increased risks. Consequently, there is a need to optimize preanalytical specimen use for molecular testing. Although hematoxylin/eosin can be used for as a DNA source for molecular testing, little is known regarding the potential use of immunohistochemistry (IHC) slides, as these are subject to harsh conditions that can lead to DNA degradation. Our aim was to evaluate whether DNA extracted from TTF-1 IHC slides, a common stain for lung adenocarcinoma, can be tested for EGFR mutations. Twenty-two lung adenocarcinoma samples (11 EGFR wild type and 11 mutated) were selected. Slides were stained for TTF-1 IHC. Following TTF-1 staining, tissue underwent DNA extraction. Pyrosequencing for mutations in exons 18, 19, 20, and 21 of EGFR was performed, and results were compared to clinical EGFR testing data. All 22 TTF-1 samples produced successful results, and 21 were concordant. Of the 11 originally EGFR-mutated cases, 10 TTF-1 samples showed identical mutations in all exons of interest. One case with an L858R mutation on original testing was negative on sequencing of the TTF-1 sample, possibly due to lower tumor burden on the TTF-1 stained slide. All 11 originally EGFR wild-type cases showed identical results on the TTF-1 samples. TTF-1 IHC slides can be a viable DNA source for molecular testing, especially important in lung biopsies with insufficient material following diagnostic evaluation.

Chromogenic immunohistochemical quadruplex provides accurate diagnostic differentiation of non-small cell lung cancer

Lung cancer is the most common cancer worldwide and has the highest mortality rate. Carcinomas comprise 95% of all lung malignancies, the vast majority of which are non-small cell lung carcinomas (NSCLC). Increasingly, the diagnosis of lung cancer is established by examination of small tissue specimens obtained by minimally invasive techniques. It is critical to employ these tissues at maximum efficiency in order to render an accurate pathologic diagnosis and to perform theranostic studies, either genomic or by immunohistochemistry, to demonstrate genetic mutations that make patients eligible for molecularly targeted agents. Currently Thyroid Transcription Factor-1 (TTF-1) and Napsin A are the most commonly used immunohistochemical (IHC) stains to identify primary lung adenocarcinoma, and p40 and cytokeratin 5/6 (CK5/6) are used for squamous cell carcinoma. IHC stains for these markers, are performed either individually (IHC brown staining) or in combination as dual immunostains (i.e. TTF-1 + Napsin A and p40 + CK5/6, utilizing brown and red chromogens). Here we present a novel, truly multiplex immunohistochemical approach that combines staining with the above four antibodies on a single tissue section utilizing four different chromogens to accurately diagnose primary lung adenocarcinomas, squamous cell carcinomas, and combined adenosquamous carcinomas of the lung. Each marker is represented by a distinct color that can be read by a pathologist, using standard, bright field microscopy. We evaluated the ability of pathologists to differentiate NSCLCs using the multiplexed assay as compared to standard, single marker per slide diaminobenzidine (DAB)-based IHC. All cases in a cohort of 264 NSCLCs showed concordance of information (including positivity of stain, intensity of stain and coverage) between single IHC stains and the multiplex assay. This new multiplex IHC offers the capability to accurately diagnose and sub-classify primary lung NSCLCs, while conserving precious tissue for additional testing.

Educational Case: Non-Small Cell Lung Cancer: Pathologic Diagnosis and Molecular Understanding

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.

The utility of TTF-1, napsin A, CK5 and p63 staining in the sub-classification of non-small cell carcinoma of the lung

BACKGROUND

The potentially curative and/or palliative therapy for non-resectable lung cancer has evolved significantly over the past 2 decades. With the availability of targeted therapies, the need for precise sub-typing of non-small cell lung carcinoma (NCSLC) has become paramount.

OBJECTIVES

As there are few data from South Africa, we aimed to determine utility of TTF-1, napsin A, p63 and CK5 immunostaining on fine needle aspiration (FNA) cell block and formalin-fixed paraffin-embedded tissue biopsy specimens in subtyping NSCLC as adenocarcinoma and squamous cell carcinomas.

METHODS

All cases of NSCLC diagnosed during a 3-year period were retrospectively identified. All FNA biopsy and formalin-fixed paraffin-embedded cases that were stained with TTF-1, napsin A, CK5 and p63 were collected. A lung cancer registry was used to access and correlate clinical and radiological data.

RESULTS

We included 271 cases with diagnoses of adenocarcinoma of the lung (n = 201), squamous cell carcinoma of the lung (n = 53), unspecified NSCLC (n = 8) and other carcinomas (n = 9). TTF-1 and napsin A had sensitivities of 99.0% and 91.9%, respectively, positive predictive values (PPVs) of 90.8% and 90.3%, respectively, and accuracies of 91.0% for adenocarcinoma of the lung. Napsin A had a higher specificity than TTF-1 (90.2% vs 62.8%). Both CK5 and P63 had high sensitivities (95.4% and 97.9%, respectively) and negative predictive values of 96.4% and 96.8%, respectively, for squamous cell carcinoma of the lung. CK5 had a higher specificity than p63 (84.4% and 61.2%, respectively), PPV (80.4% and 70.8%, respectively) and accuracy (88.8% and 79.2%, respectively) for squamous cell carcinoma.

CONCLUSION

All four immunostaining methods had high sensitivities. TTF-1 and napsin A both had high PPV and diagnostic accuracy for adenocarcinoma of the lung, whereas CK5 had an equally high PPV and accuracy for squamous cell carcinoma of the lung. The specificity of napsin A for adenocarcinoma was higher than that of TTF-1. The specificity of CK5 for squamous cell carcinoma was higher than p63.

Expression of p16 and p53 in non-small-cell lung cancer: clinicopathological correlation and potential prognostic impact

Aim: p16 and p53 are frequently altered intracellular pathways in cancers. We investigated the aberrant expression of p16 and its relationship with p53 and HPV status in primary non-small-cell lung carcinoma. Patients & methods: Lung tumor tissue microarray (n = 163), immunohistochemical study of p16 and p53, and HPV in-situ hybridization were analyzed. Results: p16 and p53 were detected in 50.7 and 57.3% of adenocarcinoma (ADCs; n = 75), and 35.2 and 63.6% of squamous cell carcinoma (n = 88). HPV was detected in 16 and 10.2% of ADC and squamous cell carcinoma. In ADCs, p16 positive tumors demonstrated a favorable median overall survival time of 60.9 months, compared with p16 negative tumors of 46.9 months (p < 0.05). Furthermore, we did not find significant relationships between p16 expression and HPV status, nor with p53 expression. Conclusion: p16 play an unique role in lung cancer survival. The mechanism of p16 needs to be further studied.

Agreement of CK5/6, p40, and p63 immunoreactivity in non-small cell lung cancer

Histological subtyping of non-small cell lung cancer (NSCLC) is of utmost importance for therapy stratification. Common immunohistochemical markers to identify squamous lineage are CK5/6, p40, and p63. Although p40 is considered the gold standard by current guidelines, the agreement of all three markers is an important aspect for tumours more difficult to classify. A total of 1244 NSCLC including 569 squamous cell carcinomas (SqCC) and 675 adenocarcinomas were assembled on a tissue microarray and stained with CK5/6, p40, p63, TTF-1, and Napsin-A. Sensitivity and specificity for squamous lineage markers as well as agreement of CK5/6, p40 and p63 were calculated. Sensitivity of CK5/6, p40, and p63 for SqCC was 93%, 94%, and 94% and specificity was 98%, 97%, and 84%, respectively. Positivity for two of these markers was found in at least in 90% of SqCC. Highest agreement was observed for p40 and p63 (Cohen's kappa 0.80). We report a similar sensitivity of CK5/6, p40, and p63, but a decreased specificity of p63 as compared to CK5/6 and p40 for the identification of squamous lineage. Our results support the use of either CK5/6 or p40 over p63 in the routine diagnostic setting.

Pulmonary sclerosing pneumocytoma, a rare tumor of the lung

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign pulmonary tumor. Usually diagnosed incidentally by chest X-ray or chest CT scan. We presented a case of PSP in a 50-year-old woman who was diagnosed with a nodular lesion in the right lung. Thoracotomy was used for the excision of the mass. Pathologic examination revealed no malignant cells. Immunohistochemical studies were performed. TTF-1 was (+), Napsin-A was found to be weakly (+). After surgical resection, the patient was followed up.

Dysbiosis of the Salivary Microbiome Is Associated With Non-smoking Female Lung Cancer and Correlated With Immunocytochemistry Markers

Background: Association between oral bacteria and increased risk of lung cancer have been reported in several previous studies, however, the potential association between salivary microbiome and lung cancer in non-smoking women have not been evaluated. There is also no report on the relationship between immunocytochemistry markers and salivary microbiota.

Method: In this study, we assessed the salivary microbiome of 75 non-smoking female lung cancer patients and 172 matched healthy individuals using 16S rRNA gene amplicon sequencing. We also calculated the Spearman's rank correlation coefficient between salivary microbiota and three immunohistochemical markers (TTF-1, Napsin A and CK7).

Result: We analyzed the salivary microbiota of 247 subjects and found that non-smoking female lung cancer patients exhibited oral microbial dysbiosis. There was significantly lower microbial diversity and richness in lung cancer patients when compared to the control group (Shannon index, P < 0.01; Ace index, P < 0.0001). Based on the analysis of similarities, the composition of the microbiota in lung cancer patients also differed from that of the control group (r = 0.454, P < 0.001, unweighted UniFrac; r = 0.113, P < 0.01, weighted UniFrac). The bacterial genera Sphingomonas (P < 0.05) and Blastomonas (P < 0.0001) were relatively higher in non-smoking female lung cancer patients, whereas Acinetobacter (P < 0.001) and Streptococcus (P < 0.01) were higher in controls. Based on Spearman's correlation analysis, a significantly positive correlation can be observed between CK7 and Enterobacteriaceae (r = 0.223, P < 0.05). At the same time, Napsin A was positively associated with genera Blastomonas (r = 0.251, P < 0.05). TTF-1 exhibited a significantly positive correlation with Enterobacteriaceae (r = 0.262, P < 0.05). Functional analysis from inferred metagenomes indicated that oral microbiome in non-smoking female lung cancer patients were related to cancer pathways, p53 signaling pathway, apoptosis and tuberculosis.

Conclusions: The study identified distinct salivary microbiome profiles in non-smoking female lung cancer patients, revealed potential correlations between salivary microbiome and immunocytochemistry markers used in clinical diagnostics, and provided proof that salivary microbiota can be an informative source for discovering non-invasive lung cancer biomarkers.

TTF-1 and EGFR expression are related to EGFR mutation in lung adenocarcinoma

Thyroid transcription factor-1 (TTF-1) is routinely used in the diagnosis of lung carcinoma and the subclassification of non-small cell lung cancer (NSCLC) in combination with other markers. The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are particularly effective in NSCLC patients harboring active EGFR mutations. EGFR protein is a poor prognostic factor for NSCLC patients. The relationship between TTF-1 expression and EGFR mutation and EGFR expression has not been well documented. The aim of this study was to investigate the relationship between TTF-1 and EGFR expression and mutation, and the clinical significance in lung adenocarcinoma. We analyzed TTF-1 expression, EGFR expression and mutation in 213 cases of lung adenocarcinoma. TTF-1 and EGFR expression levels were detected by immunohistochemical staining with monoclonal antibodies. EGFR mutations in exon 18, 19, 20 and 21 were assayed by the scorpion amplification refractory mutation system (ARMS) method. Forty-eight patients with EGFR mutations in exon 19 or 21 were detected from 91 patients with TTF-1 strong positive expression (3+) (52.74%), and 35 patients were detected with either exon 19 or 21 mutations from 54 patients with both TTF1 and EGFR positive expression (64.81%). Our data indicate that TTF-1 expression was positively related to EGFR mutation (P < 0.001) and EGFR expression (P < 0.001). EGFR expression level was positively related to its mutation (P = 0.003). These results indicate TTF-1 and EGFR positive lung adenocarcinomas frequently harbor EGFR mutations.

p40 & thyroid transcription factor-1 immunohistochemistry: A useful panel to characterize non-small cell lung carcinoma-not otherwise specified (NSCLC-NOS) category

Background & objectives:

Accurate histopathological subtyping of non-small cell lung carcinoma (NSCLC) is essential for targeted therapeutic agents. Immunohistochemistry (IHC) is helpful in identification of different tumour subtypes. In this study two marker approaches, one each for glandular and squamous cell differentiation was applied to maximize the proportion of accurately subtyped NSCLC not otherwise specified (NOS) tumours on small biopsy samples.

Methods:

Two hundred and sixty three consecutive lung biopsies of primary lung carcinoma were prospectively studied. These were subtyped first morphologically and then by IHC for p40 and thyroid transcription factor-1 (TTF-1). The diagnosis of NSCLC-NOS before and after addition of IHC was evaluated. Results were correlated and validated with morphologically proven cases and matched surgical specimens.

Results:

Based on morphology, only 140 of the 263 (53.2%) cases of NSCLC were characterized, whereas 123 (46.7%) were classified as NSCLC-NOS type. With addition of IHC (p40 and TTF-1), the latter category reduced to 14.4 per cent and a sum of 225 (85.5%) cases were accurately subtyped into squamous cell carcinoma, adenocarcinoma and adenosquamous carcinoma. p40 showed 100 per cent sensitivity and specificity for squamous differentiation whereas TTF-1 showed sensitivity of 85.3 per cent and specificity of 98.1 per cent. Ninety per cent correlation of morphologic subtypes was achieved with matched resected specimens.

Interpretation & conclusions:

Our results showed that an approach of using only a two-antibody panel (p40 and TTF-1) might help in reduction of diagnostic category of NSCLC-NOS significantly and contribute in saving tissue for future molecular testing.

Current WHO guidelines and the critical role of immunohistochemical markers in the subclassification of non-small cell lung carcinoma (NSCLC): Moving from targeted therapy to immunotherapy

Recent large scale genomic studies from the Clinical Lung Cancer Genome Project have identified different driver gene mutations in the subtypes of non-small cell lung carcinoma (NSCLC). These findings not only lead to remarkable progress in targeted therapies for lung cancer patients, but also provide fundamental knowledge for the subclassification of NSCLC. More recently, the advancement and clinical application of immunotherapy have reinforced the need for the accurate subclassification of NSCLC. In 2015, the World Health Organization (WHO) and the International Association for the Study of Lung Cancer (IASLC) updated their guidelines for the subclassification of lung cancers. These guidelines emphasize: (1) the subclassification of NSCLC, (2) the critical role of molecular characterization of tumors for targeted therapy, (3) the unique terminology for subclassifying NSCLC using small biopsy specimens, and (4) the utility of IHC biomarkers in the accurate diagnosis and subclassification of lung cancer. The guidelines have significant prognostic impact on oncologic practice and patient care. In this review, we summarize the current WHO guidelines for the classification of lung cancer, discuss advancements of targeted therapy and immunotherapy, and address the utility and limitation of immunomarkers in the subclassification of NSCLC, as well as the prospective future of the field.

INSM1 Demonstrates Superior Performance to the Individual and Combined Use of Synaptophysin, Chromogranin and CD56 for Diagnosing Neuroendocrine Tumors of the Thoracic Cavity

Despite the importance of recognizing neuroendocrine differentiation when diagnosing tumors of the thoracic cavity, the sensitivity of traditional neuroendocrine markers is suboptimal, particularly for high-grade neuroendocrine carcinomas such as small cell lung carcinoma and large cell neuroendocrine carcinoma. To increase sensitivity, neuroendocrine markers are routinely ordered as panels of multiple immunostains where any single positive marker is regarded as sufficient evidence of neuroendocrine differentiation. Insulinoma-associated protein 1 (INSM1) is a well-validated transcription factor of neuroendocrine differentiation that has only recently been evaluated for diagnostic use. We performed INSM1 immunohistochemistry on a large series of thoracic neuroendocrine and non-neuroendocrine tumors and compared its performance to synaptophysin, chromogranin, and CD56. INSM1 was positive in 94.9% of small cell lung carcinomas and 91.3% of large cell neuroendocrine carcinomas, compared with 74.4% and 78.3% with the combined panel of traditional markers. INSM1 also stained all (100%) of the atypical carcinoids, typical carcinoids and mediastinal paragangliomas, but only 3.3% of adenocarcinomas and 4.2% of squamous cell carcinomas. Overall, INSM1 demonstrated a sensitivity of 96.4% across all grades of thoracic neuroendocrine tumors, significantly more than the 87.4% using the panel of traditional markers (P=0.02). INSM1 is sufficiently sensitive and specific to serve as a standalone first-line marker of neuroendocrine differentiation. A more restrained approach to immunohistochemical analysis of small thoracic biopsies is appropriate given the expanding demand on this limited material for therapeutic biomarker analysis.

Heterogeneous expression of PD-L1 in pulmonary squamous cell carcinoma and adenocarcinoma: implications for assessment by small biopsy

Predicting response to checkpoint blockade therapy for lung cancer has largely focused on measuring programmed death-ligand 1 (PD-L1) expression on tumor cells. PD-L1 expression is geographically heterogeneous within many tumors, however, and we questioned whether small tissue samples, such as biopsies, might be sufficiently representative of PD-L1 expression for evaluating this marker in lung cancer tumors. To evaluate the extent of variability of PD-L1 expression in small tissue samples, and how that variability affects accuracy of overall assessment of PD-L1 in lung cancer, we scored immunohistochemical staining for PD-L1 in tissue microarray cores from a series of 79 squamous cell lung cancers and 71 pulmonary adenocarcinomas. Our study found substantial inconsistencies for the percentages of cells staining positive for PD-L1 among different tissue microarray cores in many cases of both adenocarcinoma and squamous cell carcinoma. This variable scoring was seen at both high levels and low levels of PD-L1 expression, and by further evaluation of cases with discordant results on full-face sections to assess geographic distribution of staining, we found that discordant results among different tissue microarray cores reflected geographic variation of PD-L1 expression in those tumors. Moreover, we found that as a result of heterogeneous expression, the sensitivity of a single small tissue sample can be as low as 85% for detecting PD-L1 expression at scoring thresholds commonly used in clinical practice. Based on these studies, we conclude that many cases of lung cancer could be inaccurately or variably scored for PD-L1 expression with a single biopsy sample. Accordingly, lung cancer patients can be inconsistently classified for PD-L1 expression status, particularly when a threshold for the percentage of positive cells is used to determine eligibility for checkpoint blockade therapy.

The impact of immunohistochemistry on the classification of lung tumors

INTRODUCTION

To highlight the role of immunohistochemistry to lung cancer classification on the basis of existing guidelines and future perspectives.

AREAS COVERED

Four orienting key-issues were structured according to an extensive review on the English literature: a) cancer subtyping; b) best biomarkers and rules to follow; c) negative and positive profiling; d) suggestions towards an evidence-based proposal for lung cancer subtyping. A sparing material approach based on a limited number of specific markers is highly desirable. It includes p40 for squamous cell carcinoma ('no p40, no squamous'), TTF1 for adenocarcinoma, synaptophysin for neuroendocrine tumors and vimentin for sarcomatoid carcinoma. A close relationship between genotype and phenotype also supports a diagnostic role for negative profiles. Expert commentary: Highly specific and sensitive IHC markers according to positive and negative diagnostic algorithms seem appropriate for individual patients' lung cancer subtyping.

Expression of P40 and P63 in lung cancers using fine needle aspiration cases. Understanding clinical pitfalls and limitations

BACKGROUND

Fine-needle aspiration (FNA) biopsy of lung lesions is a highly accurate method for diagnosing and staging of lung cancers, particularly in patients with advanced cancer. Although, the majority of FNA cases of non-small cell lung carcinoma (NSCLC) can be subclassified by hematoxylin and eosin (H&E) sections, immunohistochemical (IHC) markers are usually necessary for difficult cases. Our previous study has shown that both P40 and P63 demonstrate differential sensitivity and specificity in the subclassification of squamous cell carcinoma (SqCC) using tumor tissue microarrays (TMA). In the present study, we further evaluated the utility of P40 and P63 and the potential pitfalls and limitations associated with the usefulness of these stains in FNA cases.

METHODS

By a computer search of pathology archives, 144 FNA biopsies with diagnoses of lung cancers and P40/P63 stains were identified, including 50 adenocarcinomas (ADCs), 56 SqCCs, 8 small cell lung carcinomas (SCLCs), and 12 cases of poorly differentiated carcinoma (PD CA). Ten benign FNA lung lesions and 8 other malignant neoplasms were also included as controls. Nuclear staining patterns of P40 and P63 were scored semi-quantitatively as 0 (negative), 1 (<10%, weak and focal), or 2 (>10%, strong and diffuse).

RESULTS

In lung SqCCs, P40 and P63 were positive in 77.3% and 89.5% cases, respectively. In ADCs, P40 was weakly and focally positive in 6.1% cases, and P63 was variably positive in 62.8% cases. In SCLCs, P40 and P63 were focally positive in 12.5% and 50% cases. In PD CAs, no P40 or P63 immunoreactivity was detected. In the group of other neoplasms (n=8) both P40 and P63 were positive in the case of metastatic non-seminomatous germ cell tumor (NSGCT) (n=1), and P63 was positive in the case of metastatic Merkel cell carcinoma (n=1). The sensitivity and specificity of P40 and P63 were 76.9%/93.3%, and 90.2%/50.7% in the lung SqCC.

CONCLUSIONS

P63 has a better sensitivity, and P40 has a better specificity for SqCC. A positive staining pattern with both markers was also found in certain non-SqCC cases. Recognizing limitations of these markers are particularly important in FNA cases.

Napsin A/p40 antibody cocktail for subtyping non-small cell lung carcinoma on cytology and small biopsy specimens

BACKGROUND

Subtyping non-small cell lung carcinomas (NSCLC) into adenocarcinoma (ACA) or squamous cell carcinoma (SQCC) is important for treatment and specimen triage for molecular studies. To preserve tissue for molecular studies in cytology/small biopsy specimens, a 2-antibody cocktail for NSCLC subtyping was developed.

METHODS

Markers for lung ACA (thyroid transcription factor 1 and napsin A) and SQCC (cytokeratin 5/6 and p40) were evaluated on tissue microarrays (TMAs) with 143 ACA and 98 SQCC specimens. The napsin A/p40 combination was selected for NSCLC subtyping and validated on the TMA as well as on a cohort of cell block/small biopsy specimens from 80 poorly differentiated NSCLCs.

RESULTS

Using TMA analysis, the napsin A-positive (+)/p40± immunophenotype identified ACA with 94% sensitivity and 100% specificity, whereas the napsin A (negative)-/p40+ immunophenotype identified SQCC with 100% sensitivity and specificity. On the validation cohort of 80 cell block and small biopsy specimens, the napsin A/p40 cocktail accurately subtyped 63 of 70 NSCLC (90%) as ACA or SQCC using the subsequent surgical resection as reference histology. Of the remaining 17 cases, 15 were classified as NSCLC-not otherwise specified based on a napsin A-/p40- immunophenotype; their corresponding resections were diagnosed as ACA (7 cases), large cell carcinoma (7 cases), or pleomorphic carcinoma (1 case). Two additional large cell carcinoma cases showed a napsin A-/p40+ or napsin A+/p40+ profile in the preoperative cell block/small biopsy sample.

CONCLUSIONS

A napsin A/p40 cocktail can accurately subtype NSCLC into ACA and SQCC in most cell block/small biopsy specimens of poorly differentiated NSCLC. In the minority of cases in which the napsin A/p40 immunophenotype is indeterminate, additional stains may be necessary for precise classification. Cancer Cytopathol 2016;124:472-84. © 2016 American Cancer Society.

The role of Napsin-A and Desmocollin-3 in classifying poorly differentiating non-small cell lung carcinoma

There is increased need for classification of non-small cell lung cancer (NSCLC) into its major subtypes, adenocarcinoma (AC) and squamous cell carcinoma (SCC). Such a classification is enabled in poorly differentiated tumours based on routine morphology due to overlapping morphologic features. In such cases, the use of immunohistochemistry (IHC) can differentiate between the two subtypes.

PURPOSE

To test the ability of the two markers; Napsin-A and Desmocollin-3, in differentiating poorly differentiated (AC) from poorly differentiated SCC in small biopsies.

PATIENTS AND METHODS

This is a retrospective study including 60 patients who presented with pulmonary nodules. Cases with biopsy specimens diagnosed as poorly differentiated non-small cell lung cancer, and had corresponding resection specimens were included. Cell blocks were stained with anti Napsin-A, and anti Desmocollin-3. Cytoplasmic immunoreactivity for both markers was considered specific. Sensitivity, specificity, positive and negative predictive values, total accuracy and combined accuracy of both markers were calculated.

RESULTS

Napsin A showed a sensitivity of 89.3%, a specificity of 96.9%, PPV of 96.2%, NPV of 91.2%, and a total accuracy of 93.3% for AC, while Desmocollin-3 achieved 90.6% sensitivity, 96.4% specificity, 96.7% PPV, 90% NPV, and 93.3% total accuracy. Both markers achieved a total accuracy of 90%.

CONCLUSION

Napsin-A, and Desmocollin-3 were sensitive and specific markers for the diagnosis of AC and SCC, respectively. Both markers allowed classification of 54/60 cases into either AC or SCC.

Histomolecular profiling of pleomorphic, spindle cell, and giant cell carcinoma of the lung for targeted therapies

In pleomorphic, spindle cell, and giant cell carcinoma (PSCGC) of the lung, we wondered if an integrated diagnosis including morphological and immunohistochemical features could be related to molecular status. We performed immunohistochemistry on 35 PSCGCs against TTF1, napsin A, p40, ALK, ROS1, and c-MET. Mutational status regarding EGFR, KRAS, BRAF, HER2, and PIK3CA genes was established. Of 18 PSCGCs with adenocarcinomatous or "undifferentiated" carcinoma differentiation, 8 were mutated for EGFR (n = 1), KRAS (n = 2), BRAF (n = 1), HER2 (n = 3), and PIK3CA (n = 1). No PSCGC (0/4) with only squamous cell or adenosquamous (0/2) differentiation was mutated. c-MET overexpression was only seen in PSCGC with adenocarcinomatous or undifferentiated component (n = 5) without squamous cell component. ROS1 and ALK were negative. The presence of a "targetable mutation" was correlated to the presence of morphological or immunohistochemical adenocarcinomatous differentiation (P = .0137). Integrated diagnosis of an adenocarcinomatous component in PSCGC could be associated with the presence of targetable gene mutation. Because only PSCGC with adenocarcinomatous or undifferentiated carcinoma harbors mutations, whereas PSCGC with only squamous or adenosquamous differentiation does not in our study, this might represent a prescreening for patients with PSCGC to be tested for molecular targets. Our results emphasize that careful morphological examination and the use of immunohistochemistry might be useful for the selection of PSCGC tested for a mutational target.

Identification of immunohistochemical markers for distinguishing lung adenocarcinoma from squamous cell carcinoma

BACKGROUND

Immunohistochemical staining has been widely used in distinguishing lung adenocarcinoma (LUAD) from lung squamous cell carcinoma (LUSC), which is of vital importance for the diagnosis and treatment of lung cancer. Due to the lack of a comprehensive analysis of different lung cancer subtypes, there may still be undiscovered markers with higher diagnostic accuracy.

METHODS

Herein first, we systematically analyzed high-throughput data obtained from The Cancer Genome Atlas (TCGA) database. Combining differently expressed gene screening and receiver operating characteristic (ROC) curve analysis, we attempted to identify the genes which might be suitable as immunohistochemical markers in distinguishing LUAD from LUSC. Then we detected the expression of six of these genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) in lung cancer sections using immunohistochemical staining.

RESULTS

A number of genes were identified as candidate immunohistochemical markers with high sensitivity and specificity in distinguishing LUAD from LUSC. Then the staining results confirmed the potentials of the six genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) in distinguishing LUAD from LUSC, and their sensitivity and specificity were not less than many commonly used markers.

CONCLUSIONS

The results revealed that the six genes (MLPH, TMC5, SFTA3, DSG3, DSC3 and CALML3) might be suitable markers in distinguishing LUAD from LUSC, and also validated the feasibility of our methods for identification of candidate markers from high-throughput data.

The expression of TTF-1 and Napsin A in early-stage lung adenocarcinoma correlates with the results of surgical treatment

Non-small cell lung cancer (NSCLC) accounts for 80 % of lung cancers, and lung adenocarcinoma (ADC) is one of the main types of NSCLC. Although there are several studies on the relationship between lung ADC immunohistochemical diagnostic markers (thyroid transcription factor 1 (TTF-1) and Napsin A) and survival, some aspects of those studies could be improved. We examined the significance of the commonly used lung ADC diagnostic markers, including TTF-1, Napsin A, and CK7, in the prognosis of early-stage lung ADC. One hundred and nineteen cases of early-stage lung ADC (N0) were selected from the prospective database of lung cancer (Jan 2000 to Dec 2009). The expression levels of TTF-1, Napsin A, and CK7 in inventoried specimens were analyzed using tissue microarray (TMA) and immunohistochemical (IHC) analysis, and the effect of the expression level of each marker on patients' survival was examined. The diagnostic sensitivity and specificity of each marker for lung ADC were as follows: TTF-1, 87.0 and 90.1 %; Napsin A, 72.2 and 90.4 %; and CK7, 94.6 and 76.0 %, respectively. Patients with high expression levels of TTF-1 and Napsin A, and high co-expression levels of TTF-1/Napsin A had better survival rates than those with low levels of expression (P < 0.05). The expression levels of CK7 were not related to patients' survival. Multivariate analysis showed that the expression levels of Napsin A and TTF-1/Napsin A are independent prognostic factors for survival. The IHC detection of TTF-1 and Napsin A in specimens should be routinely performed in postoperative early-stage lung ADC patients. Its significance lies not only in the differential diagnosis, but also in determining the prognosis.

Utility of five commonly used immunohistochemical markers TTF-1, Napsin A, CK7, CK5/6 and P63 in primary and metastatic adenocarcinoma and squamous cell carcinoma of the lung: a retrospective study of 246 fine needle aspiration cases

BACKGROUND

Fine needle aspiration (FNA) biopsy plays a critical role in the diagnosis and staging of lung primary and metastatic lung carcinoma. Accurate subclassification of adenocarcinoma (ADC) and/or squamous cell carcinoma (SqCC) is crucial for the targeted therapy. However, the distinction between ADC and SqCC may be difficult in small FNA specimens. Here, we have retrospectively evaluated the utility of TTF-1, Napsin A, CK7, P63 and CK5/6 immunohistochemical (IHC) markers in the distinguishing and subclassification of ADC and SqCC.

METHODS

A total of 246 FNA cases were identified by a computer search over a two-year period, including 102 primary NSCLC and 144 primary NSCLC which had metastasized to other sites. The immunostaining patterns of TTF-1, Napsin A, CK7, P63 and CK5/6 were correlated with the histological diagnosis of the tumor.

RESULTS

In 72 primary ADCs, TTF-1, Napsin A and CK7 showed a sensitivity and specificity of 84.5%/96.4%, 92.0%/100%, and 93.8%/50.0%. In 30 primary SqCCs, CK5/6 and P63 showed a sensitivity and specificity of 100%/77.8% and 91.7%/78.3%. In 131 metastatic ADCs, Napsin A showed the highest specificity (100%), versus TTF-1 (87.5%) and CK7 (25%) but decreased sensitivity (67.8% versus 86.9% and 100%); whereas in 13 metastatic SqCCs, CK5/6 and P63 showed a sensitivity/specificity of 100%/84.6% and 100%/68.4%. Bootstrap analysis showed that the combination of TTF-1/CK7, TTF-1/Napsin A and TTF-1/CK7/Napsin A had a sensitivity/specificity of 0.960/0.732, 0.858/0.934, 0.972/0.733 for primary lung ADCs and 0.992/0.642, 0.878/0.881, 0.993/0.618 for metastatic lung ADCs.

CONCLUSIONS

Our study demonstrated that IHC markers had variable sensitivity and specificity in the subclassification of primary and metastatic ADC and SqCC. Based on morphological findings, an algorithm with the combination use of markers aided in the subclassification of NSCLCs in difficult cases.

Cytomorphology of sebaceous carcinoma with analysis of p40 antibody expression

BACKGROUND

Sebaceous carcinomas (SBCs) are aggressive tumors with the potential to cause great morbidity and mortality. Poorly-differentiated tumors may at times pose challenges for the correct diagnosis. p40, a new antibody that targets a short isoform of p63 has been shown as a promising squamous cell marker. In this study, we sought to evaluate cytomorphological features of SBC and p40 expression analysis.

METHODS

A total of 29 previously diagnosed cases of SBCs including fine-needle aspirates and histopathology specimens from various sites were reviewed and studied for p40 expression. p40 nuclear expression was semi-quantitatively assessed. Adequate positive and negative controls of non-small cell lung carcinoma were taken for comparison. Expression pattern of normal sebaceous glands was also analyzed.

RESULTS

Of the 29 cases, 13 (44.8%) were from the periocular region. The most common extraocular site was parotid gland. Morphologically tumors were categorized into well- and poorly-differentiated varieties based on extent of sebaceous differentiation. p40 positivity was seen in all cases of cytology aspirates and histology sections with similar intensity. No difference in percentage positivity of cells was recorded in well- and poorly-differentiated tumors.

CONCLUSION

p40 can be a valuable marker when evaluating tumors with possible sebaceous differentiation. Although p40 expression in SBCs is not as useful for the differential diagnosis that includes poorly-differentiated squamous cell carcinoma, this study, for the first time in the literature, highlights an important observation that p40 can be utilized as a marker for sebaceous lineage.