Immunhistochemistry by Means of Widely Agreed-Upon Markers (Cytokeratins 5/6 and 7, p63, Thyroid Transcription Factor-1, and Vimentin) on Small Biopsies of Non-small Cell Lung Cancer Effectively Parallels the Corresponding Profiling and Eventual Diagnoses on Surgical Specimens

Metastatic Lung Cancer to the Head and Neck: A Clinico-Pathological Study on 21 Cases with Narrative Review of the Literature

Metastases from lung cancer to the oral cavity and to the head and neck generally are very infrequent and usually manifest in advanced stages of the disease. Even more rarely, they are the first sign of an unknown metastatic disease. Nevertheless, their occurrence always represents a challenging situation both for clinicians, in the management of very unusual lesions, and for pathologists, in the recognition of the primary site. We retrospectively studied 21 cases of metastases to the head and neck from lung cancer (sixteen males and five females, age range 43-80 years; eight cases localized to the gingiva [two of these to the peri-implant gingiva], seven to the sub-mandibular lymph nodes, two to the mandible, three to the tongue, one case to the parotid gland; in eight patients, metastasis was the first clinical manifestation of an occult lung cancer) and proposed a wide immunohistochemical panel for a proper identification of the primary tumor histotype, including CK5/6, CK8/18, CK7, CK20, p40, p63, TTF-1, CDX2, Chromogranin A, Synaptophysin, GATA-3, Estrogen Receptors, PAX8, PSA. Furthermore, we collected data from previously published studies and narratively reviewed the relevant literature.

Clinicopathological features of cytokeratin 5-positive pulmonary adenocarcinoma

Cytokeratin 5 (CK5) is a marker for pulmonary squamous cell carcinoma; however, CK5 is sometimes present in pulmonary adenocarcinoma (ADC), and there is insufficient information regarding the clinicopathological features of CK5-positive ADC. We aimed to explore the clinicopathological characteristics of CK5-positive ADC using immunohistochemistry. We prepared the following two cohorts: a resected cohort containing 220 resected tumours for primarily studying the detailed morphological characteristics, and a tissue microarray (TMA) cohort containing 337 samples for investigating the associations of CK5 expression with other protein expressions, genetic and prognostic findings. CK5-positive ADC was defined to have ≥ 10% tumour cells and presence of CK5-positive tumour cells in the resected and TMA cohorts, respectively. CK5-positive ADCs were identified in 91 (16.3%) patients in the combined cohort. CK5-positive ADCs had male predominance (P = 0.012), smoking history (P = 0.001), higher stage (P < 0.001), histological high-grade components (P < 0.001), vascular invasion (P < 0.001), mucinous differentiation (P < 0.001), spread through airspaces (P < 0.001), EGFR wild-type (P < 0.001), KRAS mutations (P < 0.001), ALK rearrangement (P < 0.001) and ROS1 rearrangement (P = 0.002). In the resected cohort, more than half the CK5-positive ADCs (19 cases, 65.5%) showed mucinous differentiation; the remaining cases harboured high-grade components. In the TMA cohort, CK5-positive ADCs correlated with TTF-1 negativity (P = 0.002) and MUC5B, MUC5AC and HNF4alpha positivity (P < 0.001, 0.048, < 0.001). Further, CK5-positive ADCs had significantly lower disease-free and overall survival rates than CK5-negative ADCs (P < 0.001 for each). Additionally, multivariate analysis revealed that CK5 expression was an independent poor prognostic factor. CK5-positive ADCs showed aggressive clinical behaviour, with high-grade morphology and mucinous differentiation.

PSC subtyping based on TTF-1 and p40 expression reveals distinct molecular characteristics and therapeutic strategies

Pulmonary sarcomatoid carcinoma (PSC) is a unique form of poorly differentiated non-small cell lung cancer (NSCLC) and is notorious for its highly malignant nature and dismal prognosis. To introduce effective treatment for PSC patients, precise subtyping of PSC is demanding. In our study, TTF-1 and P40 immunohistochemistry (IHC) staining were applied to 56 PSC patients with multi-omics data. According to IHC results, we categorized these patients into three subgroups and profiled their molecular contexture using bioinformatic skills. IHC results classified these patients into three subgroups: TTF-1 positive subgroup (n=27), P40 positive subgroup (n=15), and double-negative subgroup (n=14). Spindle cell samples accounted for 35.71% (5/14) of double-negative patients, higher than others (p=0.034). The three subgroups were heterogeneous in the genomic alteration spectrum, showing significant differences in the RTK/RAS pathway (p=0.004) and the cell cycle pathway (p=0.030). The methylation profile of the double-negative subgroup was between the other two subgroups. In similarity analysis, the TTF-1 and p40 subgroups were closely related to LUAD and LUSC, respectively. The TTF-1 positive subgroup had the highest leukocyte fraction (LF) among several cancer types, and the tumor mutation burden (TMB) of the p40 positive subgroup ranked third in the TMB list, suggesting the applicability of immunotherapy for PSC. The study established a new subtyping method of PSC based on IHC results and reveals 3 subgroups with distinct molecular features, providing evidence for refined stratification in the treatment of PSC. This article is protected by copyright. All rights reserved.

Non-small cell lung carcinoma subtyping in conventional cytology: Results of the IASLC Cytology Working Group survey to determine specific cytomorphological criteria for adenocarcinoma and squamous cell carcinoma

INTRODUCTION

Accurate subtyping of non-small cell lung carcinomas (NSCLC) into lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) is the cornerstone of NSCLC diagnosis. Cytology samples show higher rates of classification failures, i.e., subtyping as non-small cell carcinoma, not otherwise specified (NSCC-NOS), as compared to histology. This study aims to identify specific algorithms based on known cytomorphological features that aid accurate and successful subtyping of NSCLC on cytology.

METHODS

Thirteen expert cytopathologists participated anonymously in an online survey to subtype 119 NSCLC cytology cases (gold standard diagnoses being LUAD in 80 and LUSC in 39) enriched for non-keratinising LUSC. They selected from 23 pre-defined cytomorphological features that they used in subtyping. Data were analysed using machine learning algorithms based on Random Forest Method and regression trees.

RESULTS

From 1474 responses recorded, concordant cytology typing was achieved in 53.7% (792/1474) responses. NSCC-NOS rates on cytology were similar among gold standard LUAD (36%) and LUSC (38%) cases. Misclassification rates were higher in gold standard LUSC (17.6%) than gold standard LUAD (5.5%; P<0.0001). Keratinisation, when present, recognised LUSC with high accuracy. In its absence, the ML algorithms developed based on experts' choices were unable to reduce cytology NSCC-NOS rates without increasing misclassification rates.

CONCLUSION

Suboptimal recognition of LUSC in the absence of keratinisation remains the major hurdle in improving cytology subtyping accuracy with such cases either failing classification (NSCC-NOS) or misclassifying as LUAD. NSCC-NOS appears to be an inevitable morphological diagnosis emphasizing that ancillary IC is necessary to achieve accurate subtyping on cytology.

A Subset of Large Cell Neuroendocrine Carcinomas in the Gastroenteropancreatic Tract May Evolve from Pre-existing Well-Differentiated Neuroendocrine Tumors

In the gastro-entero-pancreatic (GEP) tract, neuroendocrine neoplasms (NENs) include well differentiated neuroendocrine tumors (NETs) and high-grade NE carcinomas (NECs), which are thought to make up separate and mutually exclusive tumor entities. Little is known, however, as to whether there may be any pathogenetic link between them. Clustering analysis of a 10-gene panel generated from a previously reported next-generation sequencing analysis on 48 GEP-NENs with clinical annotations was used in the study. Unsupervised cluster analysis showed three histology-independent clusters, namely, C1, C2, and C3, which accounted for 44% of patients but the entire array of mutations. All but two NECs fell into the clusters, yet with different prevalence rates (p < 0.0001). A model was devised according to which NETs were likely to evolve into NECs upon progression of C3 into C1 and C2, despite different morphology. The median Ki-67 labeling index was 5% in C3 showing better prognosis and 50% in C1 and C2 experiencing worse prognosis, with an impressive intra-tumor heterogeneity of diversely proliferating tumor areas. This study suggests that a subset of large cell NECs in the gastroenteropancreatic tract may evolve from pre-existing well-differentiated NETs.

Diagnostic patterns of non-small-cell lung cancer at Princess Margaret Cancer Centre

Background

Accurate classification of lung cancer subtypes has become critical in tailoring lung cancer treatment. Our study aimed to evaluate changes in diagnostic testing and pathologic subtyping of advanced non-small-cell lung cancer (nsclc) over time at a major cancer centre.

Methods

In a review of patients diagnosed with advanced nsclc at Princess Margaret Cancer Centre between 2007-2009 and 2013-2015, diagnostic method, sample type and site, pathologic subtype, and use of immunohistochemistry (ihc) staining and molecular testing were abstracted.

Results

The review identified 238 patients in 2007-2009 and 283 patients in 2013-2015. Over time, the proportion of patients diagnosed with adenocarcinoma increased to 73.1% from 60.9%, and diagnoses of nsclc not otherwise specified (nos) decreased to 6.4% from 18.9%, p < 0.0001. Use of diagnostic bronchoscopy decreased (26.9% vs. 18.4%), and mediastinal sampling procedures, including endobronchial ultrasonography, increased (9.2% vs. 20.5%, p = 0.0001). Use of ihc increased over time to 76.3% from 41.6% (p < 0.0001). Larger surgical or core biopsy samples and those for which ihc was performed were more likely to undergo biomarker testing (both p < 0.01).

Conclusions

Customizing treatment based on pathologic subtype and molecular genotype has become key in treating patients with advanced lung cancer. Greater accuracy of pathology diagnosis is being achieved, including through the routine use of ihc.

An Unusual Presentation of Aggressive Primary Invasive Adenocarcinoma of Lung

Bilateral diffuse infiltrates on chest imaging can present a diagnostic challenge due to a broader differential diagnosis which includes pulmonary and non-pulmonary causes. Malignancy is generally not considered under differential diagnosis at the time of initial presentation. Here we present a case of primary adenocarcinoma of lung manifesting as diffuse bilateral infiltrates on imaging. Our case is unique in regards to its acute presentation, rapid progression to respiratory failure, ultimately leading to the demise of the patient. This indicates the aggressive nature of this malignancy and its variable presentation, like male gender and young age, thus emphasizing the importance of entertaining malignancy in such presentations, especially if there is no response to conventional antibiotic therapy.

Histopathological Spectrum and Immunohistochemical Profile of Lung Carcinomas: A 9-Year Study from a Tertiary Hospital in North India

Background:

Lung cancer is the most common cancer worldwide and the leading cause of cancer-related death. Diagnostic bronchoscopic or percutaneous biopsies are usually small. However, judicious use of immunohistochemistry (IHC) helps in accurate subtyping, which forms the basis for molecular tests and treatment.

Aim:

The aim was to study the role of IHC in the diagnosis of various histological subtypes of lung cancer.

Methods:

This 9-year study from 2009 to 2017 included all cases diagnosed as lung carcinoma on tissue biopsies. IHC markers were selected based on histopathology, from a panel comprising CK7, CK20, CK5/6, p63, thyroid transcription factor 1 (TTF-1), napsin A, synaptophysin, chromogranin A, neuron-specific enolase, CD56, and CDX2. Metastatic cancers to the lung were excluded from the study.

Results:

There were 199 cases of lung carcinoma comprising squamous cell carcinoma (37.7% [n = 75]), adenocarcinoma (26.1% [n = 52]), small cell carcinoma (20.6% [n = 41]), non-small cell lung carcinoma-unclassified (10.1% [n = 20]), adenosquamous carcinoma (2.5% [n = 5]), and others (3% [n = 6]). IHC was done on 47.7% (95/199) of cases. Squamous cell carcinomas showed CK5/6 and p63 positivity in 13/13 (100%) and 12/13 (92.3%) cases, respectively. Adenocarcinomas were positive for napsin A in 12/13 (92.3%) and TTF-1 in 35/41 (85.4%) cases. Neuroendocrine markers were positive in all small cell carcinomas.

Conclusion:

Squamous cell carcinoma was the most common primary lung malignancy in the North Indian population, followed by adenocarcinoma and small cell carcinoma. IHC panel of TTF-1, napsin A, CK5/6, and p63 is very helpful to classify most non-small cell lung carcinomas.

Immune-enrichment of non-small cell lung cancer baseline biopsies for multiplex profiling define prognostic immune checkpoint combinations for patient stratification

Background

Permanence of front-line management of lung cancer by immunotherapies requires predictive companion diagnostics identifying immune-checkpoints at baseline, challenged by the size and heterogeneity of biopsy specimens.

Methods

An innovative, tumor heterogeneity reducing, immune-enriched tissue microarray was constructed from baseline biopsies, and multiplex immunofluorescence was used to profile 25 immune-checkpoints and immune-antigens.

Results

Multiple immune-checkpoints were ranked, correlated with antigen presenting and cytotoxic effector lymphocyte activity, and were reduced with advancing disease. Immune-checkpoint combinations on TILs were associated with a marked survival advantage. Conserved combinations validated on more than 11,000 lung, breast, gastric and ovarian cancer patients demonstrate the feasibility of pan-cancer companion diagnostics.

Conclusions

In this hypothesis-generating study, deepening our understanding of immune-checkpoint biology, comprehensive protein-protein interaction and pathway mapping revealed that redundant immune-checkpoint interactors associate with positive outcomes, providing new avenues for the deciphering of molecular mechanisms behind effects of immunotherapeutic agents targeting immune-checkpoints analyzed.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0544-x) contains supplementary material, which is available to authorized users.

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.

A Picture Tells 1000 Words (but Most Results Graphs Do Not): 21 Alternatives to Simple Bar and Line Graphs

Graphical representation of results are a central component of original research articles in sports medicine. There has been recent criticism in the scientific community of a heavy reliance on simple bar graphs and line graphs to illustrate results because they often fail to clearly represent the measures and changes to interventions of individual participants. This article aims to suggest alternatives to bar and line graphs, including those that emphasize the illustration of (1) individual subject measures and data set distribution, (2) magnitude of group differences, (3) the relationships between multiple variables, and (4) unique ways of displaying time series data.

Pulmonary Basaloid Squamous Cell Carcinoma in a Dog

A 9-year-old neutered male crossbred dog with a 4-week history of progressive vestibulocerebellar signs was presented for necropsy examination. Gross examination revealed neoplastic growth in the lungs, thoracic lymph nodes, left kidney and cerebellum. Microscopically, the tumour consisted of an infiltrative, densely cellular, basaloid epithelial neoplastic growth with extensive areas of abrupt keratinization. Immunohistochemically, neoplastic cells expressed p63 and partially expressed cytokeratins 5/6. Based on these findings, the tumour was diagnosed as a primary pulmonary basaloid squamous cell carcinoma (BSSC) with metastasis to regional lymph nodes, kidney and brain. As far as the authors are aware, this is the first description of BSCC in an animal species.

Roles of Thyroid Transcription Factor 1 in Lung Cancer Biology

Thyroid transcription factor 1 (TTF-1 or NKX2-1) is a transcription factor of fundamental importance in driving lung maturation and morphogenesis. In the last decade, scientists began to appreciate the functional roles of TTF-1 in lung tumorigenesis. This movement was triggered by the discoveries of genetic alterations of TTF-1 in the form of gene amplification in lung cancer. Many downstream target genes of TTF-1 relevant to the lung cancer biology of TTF-1 have been documented. One of the most surprising findings was that TTF-1 may exhibit either pro- or antitumorigenic activities, an outcome with the complexity exceeding the original anticipation purely based on the fact that TTF-1 undergoes gene amplification in lung cancer. In the coming decade, we believe, we will witness additional surprises as the research exploring the cancer roles of TTF-1 progresses.

[Non-small cell lung cancer. New biomarkers for diagnostics and therapy]

Although advances in targeted therapies have recently been achieved, lung cancer remains a major health burden worldwide. It is therefore pivotal to investigate the biology of lung cancers in order to design new therapeutic strategies. To address this a multi-antibody assay has been developed for the classification of non-small cell lung cancer (NSCLC). Using this assay the pathologist is able to reliably subtype NSCLC into adenocarcinoma, squamous cell carcinoma, large cell neuroendocrine carcinoma (LCNEC) and NSCLC not otherwise specified (NOS) large cell carcinoma, as required by the new World Health Organization (WHO) classification of 2015, on a single glass slide. In our cohort this classification algorithm showed significant differences in overall survival of the therapeutically important subgroups, which reflects the accuracy of the assay. To investigate the biology of NSCLC subtypes further, several proteins involved in carbohydrate metabolism were analyzed. In a hierarchical cluster analysis it could be shown that adenocarcinoma and squamous cell carcinoma harbor different metabolic shifts and, furthermore, that two distinct groups of squamous cell carcinoma seem to exist, a hypoxia and a transporter type. These results could be verified by analysis of mRNA data obtained from the TCGA database. As a close association between tumor metabolism and anti-tumor immune response has been reported, the lymphocytic infiltrates were characterized with respect to T-cells and their location within the tumor. Besides a negative correlation of lymphocyte density and expression of lactate dehydrogenase, it could be shown that depending on the location and type a high lymphocyte density indicates a significantly better overall survival of NSCLC patients. Investigating the expression of PD-L1 in NSCLC cells, a significant correlation with lymphocyte density was detected. In conclusion, the multi-antibody assay is a new and economically attractive tool for a reliable subclassification of NSCLC. This subtyping results in a better biological stratification of NSCLC and is the basis not only for palliative treatment options but also for further investigations on NSCLC biology. It was discovered that metabolic changes during malignant transformation are different in adenocarcinoma and squamous cell carcinoma. The latter group can be further divided into a hypoxia and a transporter type. Anti-tumor immune responses are influenced by the metabolic shift in NSCLC and lymphocyte density with respect to the location within the tumor is of prognostic significance in NSCLC. Therefore, the results contribute to a better biological understanding of NSCLC and may lead to new treatment options by targeting metabolic enzymes or triggering anti-tumor responses.

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.

Lung adenocarcinoma mimicking pulmonary fibrosis-a case report

Background

Lung cancer is usually presented with cough, dyspnea, pain and weight loss, which is overlapping with symptoms of other lung diseases such as pulmonary fibrosis. Pulmonary fibrosis shows characteristic reticular and nodular pattern, while lung cancers are mostly presented with infiltrative mass, thick-walled cavitations or a solitary nodule with spiculated borders. If the diagnosis is established based on clinical symptoms and CT findings, it would be a misapprehension.

Case presentation

We report a case of lung adenocarcinoma whose symptoms as well as clinical images overlapped strongly with pulmonary fibrosis. The patient’s non-productive cough, progressive dyspnea, restrictive pattern of pulmonary function test and CT scans (showing reticular interstitial opacities) were all indicative of pulmonary fibrosis. The patient underwent a treatment consisting of corticosteroids and antibiotics, to no avail. Histopathology of the lung showed that the patient suffered from mucinous adenocarcinoma. Albeit the immunohistochemical staining was not consistent with lung adenocarcinoma, tumor’s morphological characteristics were consistent, and were used to make the definitive diagnosis.

Conclusion

Given the fact that radiography cannot always make a clear-cut difference between pulmonary fibrosis and lung adenocarcinomas, and that clinical symptoms often overlap, histological examination should be considered as gold standard for diagnosis of lung adenocarcinoma.

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.

[Squamous cell carcinoma, basaloid squamous cell carcinoma and adenosquamous carcinoma in the lung]

The precise distinction between adenocarcinoma and squamous cell carcinoma (SqCC) has become very important for determining the appropriate therapy for patients and more specifically to drive the use of tyrosine kinase inhibitors, pemetrexed, anti-VEGF monoclonal antibody and crizotinib. Squamous pearls and distinct intercellular bridges identify keratinizing SqCC. In non-keratinizing SqCC, immuno-histochemistry is required. Recent studies have shown p40 and TTF1 to be the two best markers of SqCC and adenocarcinoma respectively. Many morphological variants of SqCC have been described. Basaloid SqCC is a poorly differentiated epithelial tumor lacking squamous morphology but showing immuno-histochemical expression of squamous makers. The pronostic of basaloid carcinoma is considered poorer than that of other non-small cell lung cancers. Adenosquamous carcinoma shows components of both SqCC and adenocarcinoma. Both components must be clearly identified either on H&E or by immuno-histochemistry. The adenocarcinoma components justified a screening for gene rearrangements. Finally, the recent WHO classification of lung tumors did not change the criteria applying for the grading of preinvasive bronchial lesion.

Metastatic Adenocarcinoma of Unknown Origin Presenting as Small Bowel Perforation

Metastatic malignant tumors that originate from occult primaries are defined as “cancers of unknown origin.” We herein present the case of a 59-year-old man who presented with small bowel perforation secondary to metastatic adenocarcinoma of an unknown primary site. Imaging exhibited two pulmonary nodules, neither of which was dominant, along with mediastinal and retroperitoneal lymphadenopathy. Immunohistochemical profiling of the small bowel biopsy specimens revealed the tumor was most likely pulmonary in origin.

Alterations of a spectrum of driver genes in female Chinese patients with advanced or metastatic squamous cell carcinoma of the lung

OBJECTIVES

Female patients with squamous cell carcinomas of the lung (SQCLC) in China differ from male patients in that most females are life-long never/light smokers. We hypothesized that the clinical characteristics and mutation profiles of a spectrum of driver genes in Chinese female patients with advanced SQCLC would also differ from those of male patients.

PATIENTS AND METHODS

We examined the pathological subtype of SQCLC retrospectively by immunohistochemistry (IHC) and screened 38 female and 40 male patients with IIIB/IV-stage SQCLC in China from 2009 to 2012. Mutation analyses of EGFR, PIK3CA, KRAS, and PTEN were performed using PCR-based DNA sequencing. FGFR1 amplification and ALK rearrangements were detected by fluorescent in situ hybridization (FISH). A Cox regression model was used to assess the association between clinical features and genomic mutation status.

RESULTS

There were significantly fewer female patients with a history of smoking than males (5.3% vs. 90%; P<0.001). A younger average age at diagnosis (54.5 vs. 61 years; P=0.032) and a higher percentage of peripheral-type disease (47.4% vs. 25.0%; P=0.040) were observed in females. No difference in ECOG score, tumor size, metastatic status, or overall survival between females and males was seen. PIK3CA mutations were significantly less common in female patients than males (0/38 vs. 6/40; P=0.026). However, no significant difference in the mutational frequencies of EGFR, KRAS, PTEN, ALK, or FGFR1 was observed between females and males.

CONCLUSIONS

Our data demonstrated that female patients with SQCLC are apparently a subtype, with a significantly lower percentage having a smoking history, a younger average age at diagnosis, a higher percentage of peripheral-type disease on radiological presentation, and a lower frequency of PIK3CA mutations. Given the similar survival outcomes between the genders, whether it is a distinct disease entity needs to be studied further in larger populations.

A comprehensive immunohistochemistry algorithm for the histological subtyping of small biopsies obtained from non-small cell lung cancers

AIMS

Need for accurate histologic subtyping of non-small cell lung carcinomas (NSCLCs) is growing. IHC patterns may be ambiguous in some cases, rendering it difficult to determine subtypes.

METHODS AND RESULTS

Tissue microarrays composed of 184 resected NSCLCs were stained for TTF-1, Napsin A, CK7, p40, p63, CK5/6, and mucicarmine. TTF-1 and Napsin A were chosen as the most accurate adenocarcinoma (ADC) marker (ACM), and p40 as squamous cell carcinoma (SCC) marker (SCM). We then prospectively performed IHC using these markers (TTF-1, Napsin A, and p40) in a cohort of small NSCLC biopsies (n = 186) with ambiguous morphology. Of these biopsies, 82.8% (154/186) were classifiable into either ADC or SCC by applying '3-marker IHC panel'. Additional CK7, p63, and CK5/6 were applied in 30 biopsies with equivocal IHC patterns, including 18 ACM-/SCM- (double-negative) and 12 ACM+/SCM+ (double-positive) cases. Decision tree and support vector machine models revealed that TTF-1 was a critical single marker for ADC in double-positive cases (91.7% accuracy), whereas p63 and/or CK5/6 helped to subtype double-negative cases (72.2% accuracy).

CONCLUSIONS

We propose a novel comprehensive algorithm for subtyping NSCLCs using a 3-marker IHC panel and additional p63 and CK5/6 that would be useful for subtyping small NSCLC biopsies.

Judging pathological assessment in cancer specimens

The pathologist plays a critical role in the multidisciplinary team in charge of treating cancer patients, as many of the therapeutic decisions rely on the information conveyed through the pathology reports. The task of the pathologist includes not only an accurate assessment of pathological T and N categories, but also the evaluation of other indicators of prognosis including quality of surgery, margins of resection, as well as additional histopathological and molecular markers that influence prognosis and could predict response to therapy.

Updating the 2011 International Association for the Study of Lung Cancer classification of lung adenocarcinoma: main priorities and implications for clinicians

SUMMARY: 

The classification of adenocarcinoma was revised by the International Association for the Study of Lung Cancer, the American Thoracic Society and the European Respiratory Society in 2011. In the face of advances of medical therapy in advanced stage disease, these groups sought to improve prognostication and to standardize reporting protocols. A discussion of recent alterations in terminology is undertaken. Included with this is clarification of terminology used small biopsy and cytology specimens. In addition, it will be discussed how an architectural-based classification can be used to assess prognosis and how this applies staging and potential patient management. Several studies have confirmed the effectiveness and reproducibility of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification on lung adenocarcinoma. In addition, there is increasing evidence of clinical application in early stage lung adenocarcinoma. While there may be potential revision in the future, the classification provides better and more standardized information for both clinicians and researchers.

Does Immunohistochemistry Affect Response to Therapy and Survival of Inoperable Non–Small Cell Lung Carcinoma Patients? A Survey of 145 Stage III-IV Consecutive Cases

Whether non–small cell lung carcinoma (NSCLC) unveiled by immunohistochemistry (IHC) has the same clinical outcome as those typed by morphology is still matter of debate. A total of 145 stage III-IV, consecutive inoperable NSCLC patients treated by chemotherapy (133 cases) or EGFR tyrosine kinase inhibitor (12 cases) and including 100 biopsies, 11 surgical specimens, and 34 cytological samples had originally accounted for 120 adenocarcinomas (ADs), 19 squamous cell carcinomas (SQCs), and 6 adenosquamous carcinomas (ADSQCs) by integrating morphology and thyroid transcription factor-1 (TTF1)/p40 IHC. Thirty-two NSCLC–not otherwise specified (NSCLC-NOS) cases were identified by morphology revision of the original diagnoses, which showed solid growth pattern ( P < .001), 22 ADs, 5 SQCs, and 5 ADSQCs by IHC profiling ( P < .001), and 10 gene-altered tumors (3 EGFR, 5 KRAS, and 2 ALK). While no significant relationships were observed between response to therapy and original, morphology or IHC diagnoses, driver mutations and tumor differentiation by TTF1 expression, AD run better progression-free survival (PFS) or overall survival (OS) than other tumor types by morphology ( P = .010 and P = .047) and IHC ( P = .033 and P = .046), respectively. Furthermore, patients with NSCLC-NOS confirmed as AD by IHC tended to have poorer OS ( P = .179) and PFS ( P = .193) similar to that of ADSQC and SQC ( P = .702 and P = .540, respectively). A category of less differentiated AD with poorer prognosis on therapy could be identified by IHC, while there were no differences for SQC or ADSQC. The terminology of “NSCLC-NOS, favor by IHC” is appropriate to alert clinicians toward more aggressive tumors.

Efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors for Chinese patients with squamous cell carcinoma of lung harboring EGFR mutation

OBJECTIVE

Epidermal growth factor receptor (EGFR) mutation mostly occurred in lung adenocarcinoma, rarely in squamous cell carcinoma (SQCC). EGFR mutation rate in SQCC varied in previous reports, and the efficacy of EGFR tyrosine kinase inhibitors (TKIs) in SQCC harboring EGFR mutation has not yet been fully evaluated. The aim of this study was to investigate the efficacy EGFR-TKIs for Chinese patients with SQCC of lung harboring EGFR mutation.

PATIENTS AND METHODS

Two cohorts of patients were analyzed. The first cohort included 146 consecutive post-operation SQCC patients from January 2008 to October 2012. The second cohort included 63 patients with advanced SQCC receiving EGFR-TKIs treatment. EGFR mutation analysis was performed with Real-time PCR method. The pathologic diagnosis was validated with immunohistochemistry (IHC) for patients harboring activated EGFR mutation. And the efficacy of EGFR-TKIs in squamous cell carcinoma of lung (SQCC) was evaluated in patients with activated EGFR mutations.

RESULTS

In the first cohort, 146 resected patients, EGFR mutations were detected in 3 patients, with the mutation rate of 2.0%. In cohort two, 63 patients treated with EGFR-TKIs, 15 patients possessed activated EGFR mutations. The response rate and disease control rate in these patients was 26.7% and 66.7% respectively. 5 patients had disease control over 6 months. The progression free survival (PFS) in EGFR-mutated patients was 3.9 months.

CONCLUSIONS

In Chinese SQCC patients, EGFR mutation rate was extremely low. EGFR-TKIs seemed to be less effective in EGFR-mutated SQCC patients, but some patients could still obtain benefit from EGFR-TKIs. To identify this part of patients, further study was warranted in the future.

Histo-cytological diagnostic accuracy in lung cancer

OBJECTIVE

The majority of patients with lung cancer are treated on the basis of a diagnosis made from the analysis of a small tumour biopsy or a cytological sample and histotype is becoming a critical variable in clinical workup as it has led to the introduction of newer biologically targeted therapies. Consequently, simply classifying cancers as small cell lung cancers or non-small cell lung cancers is no longer sufficient.

METHODS

From 2009 to 2011, a review of the histo-cytological database was conducted to identify all small biopsy and cytology specimens collected for diagnostic purposes in patients with a thoracic lesion. In total, 941 patients were studied by examining exfoliative and/or aspirative cytological samples. To establish the accuracy of these methods, cytological and biopsy diagnoses were compared with each other and with subsequent resection specimens when available. Moreover, during the diagnostic workup, we examined a validated panel of immunohistochemical markers.

RESULTS

The diagnostic concordance of pre-operative diagnoses with surgical samples was high in both cytology and biopsy samples [κ = 0.71, confidence interval (CI) = 0.6-0.81; P < 0.0001 and κ = 0.61, CI = 0.41-0.82; P < 0.0001 respectively; good agreement] but concordance between cytology and biopsy was moderate (κ = 0.5, CI = 0.43-0.54; P < 0.0001). Immunohistochemistry-aided diagnoses were definitive for histotype in 92.8% of both cytology (206/222) and biopsy (155/167) specimens.

CONCLUSION

We found that lung cancer diagnosis and subtyping of cytology and biopsy samples are highly feasible and concordant; thus, the diagnostic approach to lung cancer does not require more invasive procedures.

A panel of four immunohistochemical markers (CK7, CK20, TTF-1, and p63) allows accurate diagnosis of primary and metastatic lung carcinoma on biopsy specimens

Accurate classification of lung cancer, as well as the differentiation between primary and metastatic carcinoma to the lung, mostly performed on biopsy or fine needle aspiration specimens, is critical for decisions on therapy and for determining prognosis. The limited amount of biopsy material available for morphological assessment has stimulated attempts to improve diagnostic accuracy through the use of immunohistochemistry (IHC), but an optimal IHC diagnostic algorithm has not been firmly established. We evaluated, on a retrospective series of biopsy specimens, the performance of a four-antibody IHC panel for accurate subclassification of non-small cell lung carcinoma (NSCLC) and for identification of metastatic carcinoma. Tumor morphology was assessed and IHC for CK7, CK20, TTF-1, and p63 was performed according to a two-step algorithm. Matched resection specimens served as gold standard and were compared with the corresponding biopsy. Of 443 biopsy specimens studied, 325 were diagnosed as primary carcinoma of the lung, 198 (44.7 %) as adenocarcinoma, 9 (2 %) as possibly adenosquamous carcinoma, 127 (28.7 %) as squamous cell carcinoma, and 40 (9 %) as NSCLC not further classifiable. Ten cases (2.3 %) were classified as adenocarcinoma of unknown origin and 58 (13 %) as metastasis. Importantly, of the primary lung adenocarcinomas, 35 (17.7 %) had been considered on clinical grounds as a metastasis from a previously diagnosed primary tumor. Of the 55 cases submitted to surgical resection in 47 (85.5 %) the biopsy diagnosis was confirmed, revealing substantial agreement (κ value = 0.757). Our two-step approach allows for accurate subclassification of NSCLC and also to distinguish between primary lung adenocarcinoma and metastasis, notably of colorectal adenocarcinoma, with crucial implications for appropriate patient management.

Utility of p40 in the Differential Diagnosis of Small Round Blue Cell Tumors of the Sinonasal Tract

The sinonasal tract may give rise to a broad range of neoplasms that share a "small round blue cell" tumor (SBRCT) appearance on routine histology, but treatment strategies depend on precise tumor classification. Immunohistochemistry for p63 is often employed in the sinonasal SRBCT differential diagnosis because it is highly sensitive for squamous cell carcinoma (SCC). However, p63 staining may be observed in other tumor types, a potential diagnostic pitfall. P40 is a more squamous-specific isoform of p63, and it may be more useful in distinguishing poorly differentiated SCC from its mimickers in the sinonasal tract. Immunohistochemistry for p40 and p63 was performed on 171 sinonasal neoplasms with SRBCT morphology: 73 SCCs (67 poorly differentiated, non-keratinizing, or basaloid types and 6 nasopharyngeal carcinomas), 46 esthesioneuroblastomas, 11 sinonasal undifferentiated carcinomas (SNUCs), 11 lymphomas, 9 melanomas, 7 alveolar rhabdomyosarcomas, 4 solid adenoid cystic carcinomas, 4 NUT midline carcinomas, 4 primitive neuroectodermal tumors (PNETs), and 2 small cell carcinomas. P40 was positive in 72 of 73 SCCs, and showed a diffuse distribution in all but one positive case. P40 immunoexpression was also observed in 13 of 46 (28 %) esthesioneuroblastomas, 6 of 11 (55 %) SNUCs, 2 of 4 (50 %) adenoid cystic carcinomas, 3 of 4 (75 %) NUT midline carcinomas, 1 of 2 (50 %) small cell carcinomas, and 1 of 4 (25 %) PNETs; in the non-SCC tumors, p40 staining was focal in most cases. P63 was positive in every p40-positive tumor. In addition, a p63+/p40- phenotype was seen 5 of 11 (45 %) lymphomas, 4 of 7 (57 %) alveolar rhabdomyosarcomas, 1 of 4 (25 %) PNETs, and 3 of 46 (7 %) esthesioneuroblastomas. All sinonasal melanomas were negative for both markers. In the sinonasal SRBCT differential diagnosis, both p40 and p63 are highly sensitive for SCC, but p40 is more specific. Notably, p40 is consistently negative in lymphomas and alveolar rhabdomyosarcomas, two tumors that are frequently p63-positive. It must be remembered, however, that even diffuse p40 immunostaining is not entirely specific for the squamous phenotype, and therefore it should be utilized as part of an immunohistochemical panel.

Lung adenocarcinoma in the era of targeted therapies: histological classification, sample prioritization, and predictive biomarkers

The arrival of targeted therapies has presented both a conceptual and a practical challenge in the treatment of patients with advanced non-small cell lung carcinomas (NSCLCs). The relationship of these treatments with specific histologies and predictive biomarkers has made the handling of biopsies the key factor for success. In this study, we highlight the balance between precise histological diagnosis and the practice of conducting multiple predictive assays simultaneously. This can only be achieved where there is a commitment to multidisciplinary working by the tumor board to ensure that a sensible protocol is applied. This proposal for prioritizing samples includes both recent technological advances and the some of the latest discoveries in the molecular classification of NSCLCs.

Immunohistochemical profiling of ALK fusion gene-positive adenocarcinomas of the lung

Our aim was to determine whether or not non-small-cell lung cancer is squamous cell carcinoma (SQCC); even in small samples, it is essential in view of the side effects attendant on new therapeutics. Lung adenocarcinoma (ADC) with the EML4-ALK fusion gene has been described as demonstrating mucinous cribriform/acinar growth and signet-ring cells, sometimes partially simulating SQCC. We investigated the relation among morphology, anaplastic lymphoma kinase (ALK) rearrangement, and immunophenotype in 321 ADCs by tissue microarray using SQCC markers cytokeratin (CK)5/6, CK14, desmocollin-3, desmoglein-3, p40, p63 versus ADC markers thyroid transcription factor (TTF)-1 and napsin A. Unlike 312 ALK-negative ADCs, 9 ALK-positive cases were negative for 4 SQCC markers. Only 1 ALK-positive ADC showing assertive morphology was positive for CK5/6 and p63 as well as for TTF-1 and napsin A. Coexpression of TTF-1/p40 was not observed, unlike that of TTF-1/p63 reported previously. There was no statistically significant difference between ALK-negative and ALK-positive ADC by immunohistochemical profiling.

How sensitive are epidermal growth factor receptor-tyrosine kinase inhibitors for squamous cell carcinoma of the lung harboring EGFR gene-sensitive mutations?

INTRODUCTION

Epidermal growth factor receptor (EGFR) mutations are found mostly in adenocarcinoma, and rarely in squamous cell carcinoma (SQC). Little is known about SQC harboring EGFR mutations.

METHODS

Between April 2006 and October 2010, we investigated the incidence of EGFR activating mutations in SQC of the lung using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. The efficacy of EGFR-tyrosine kinase inhibitors (TKIs) was retrospectively evaluated in patients with EGFR-mutated SQC. Further pathologic analyses were performed using immunohistochemistry.

RESULTS

Thirty-three of 249 patients with SQC (13.3%) had EGFR mutations, including exon 19 deletion (19 of 33 patients, 58%), L858R point mutation in exon 21 (12 of 33, 36%), and G719S point mutation in exon 18 (2 of 33, 6%). Twenty of these 33 patients received EGFR-TKI therapy, and five of these 20 responded to EGFR-TKIs with a response rate of 25.0% (95% confidence interval [CI], 8.7%-49.1%). The patients' median progression-free survival and median overall survival were 1.4 months (95% CI, 0.7-5.8 months) and 14.6 months (95% CI, 2.9-undeterminable months), respectively. Approximately one third of the EGFR-mutated SQC patients achieved progression-free survival for longer than 6 months. Some of these patients had high carcinoembryonic antigen levels or a history of never smoking, or were positive for thyroid transcription factor-1.

CONCLUSIONS

Although EGFR-TKIs seem to be generally less effective in EGFR-mutated SQC than in EGFR-mutated adenocarcinoma, some EGFR-mutated SQC patients can obtain clinical benefit from EGFR-TKIs. To better identify these patients, not only EGFR mutation status, but also clinical factors and pathologic findings should be taken into consideration.

Subtyping non-small cell lung cancer: relevant issues and operative recommendations for the best pathology practice

Morphology still remains the cornerstone in lung cancer classification and cytology and small biopsy samples should be interpreted by morphology, whenever feasible, according to shared and widely agreed-upon diagnostic schemes. However, as novel therapy strategies are being offered on the basis of the diverse tumor characteristics, pathologists are now challenged by the need to offer clinicians more detailed typing of non-small cell lung cancer, not otherwise specified (NSCLC-NOS), especially when dealing with limited diagnostic material or poorly differentiated tumors. Close integration of morphology, immunohistochemistry, and clinical data is highly warranted according to a multidisciplinary approach to limit the category of NSCLC-NOS as much as possible or exclude unsuspected metastases, so rendering more definite and clinically useful diagnoses. Among the many proposed immunohistochemical markers, which as a whole are more practical and diagnostically useful than cumbersome and expensive molecular assays, a 2-hit model including thyroid transcription factor-1 (TTF-1) and p40 (the latter more specific for squamous differentiation than p63) seems to be the most effective to basically highlight adenocarcinoma (positivity for TTF-1 regardless of p63) and squamous (always strongly and diffusely positive for p40 or p63 and negative for TTF-1) differentiation. This minimalist 2-hit diagnostic approach paves the way to novel perspectives in clinical trials on lung cancer, and it is also in keeping with the need of strategically preserving diagnostic material for molecular assays that are essential for personalizing therapies.

Pulmonary large cell carcinoma lacking squamous differentiation is clinicopathologically indistinguishable from solid-subtype adenocarcinoma

CONTEXT

Pulmonary large cell carcinoma (LCC) includes tumors not readily diagnosed as adenocarcinoma (ADC) or squamous cell carcinoma on morphologic grounds, without regard to immunophenotype, according to the World Health Organization (WHO). This ambiguous designation may cause confusion over selection of mutation testing and directed therapies. Several groups have proposed the use of immunohistochemistry (IHC) to recategorize LCC as ADC or squamous cell carcinoma; however, it remains unclear if strictly defined LCCs are a clinicopathologically distinct lung tumor subset.

OBJECTIVE

To compare the pathologic, molecular, and clinical features of 2 morphologically similar tumors: solid-subtype ADC and LCC.

DESIGN

Tumors were included on the basis of solid growth pattern; tumors with squamous or neuroendocrine differentiation were excluded. Solid ADC (n = 42) and LCC (n = 57) were diagnosed by using WHO criteria (5 intracellular mucin droplets in ≥2 high-power fields for solid ADC) and tested for KRAS, EGFR, and ALK alterations.

RESULTS

Both solid ADC and LCC groups were dominated by tumors with "undifferentiated"-type morphology and both had a high frequency of thyroid transcription factor 1 expression. KRAS was mutated in 38% of solid ADCs versus 43% of LCCs (P = .62). One ALK-rearranged and 1 EGFR-mutated tumor were detected in the solid ADC and LCC groups, respectively. There were no significant differences in clinical features or outcomes; the prevalence of smoking in both groups was greater than 95%.

CONCLUSIONS

Other than a paucity of intracellular mucin, LCC lacking squamous or neuroendocrine differentiation is indistinguishable from solid-subtype ADC. We propose the reclassification of these tumors as mucin-poor solid adenocarcinomas.

Volumetric optical frequency domain imaging of pulmonary pathology with precise correlation to histopathology

BACKGROUND

Lung cancer is the leading cause of cancer-related mortality. Radiology and bronchoscopy techniques do not have the necessary resolution to evaluate lung lesions on the microscopic scale, which is critical for diagnosis. Bronchial biopsy specimens can be limited by sampling error and small size. Optical frequency domain imaging (OFDI) provides volumetric views of tissue microstructure at near-histologic resolution and may be useful for evaluating pulmonary lesions to increase diagnostic accuracy. Bronchoscopic OFDI has been evaluated in vivo, but a lack of correlated histopathology has limited the ability to develop accurate image interpretation criteria.

METHODS

We performed OFDI through two approaches (airway-centered and parenchymal imaging) in 22 ex vivo lung specimens, using tissue dye to precisely correlate imaging and histology.

RESULTS

OFDI of normal airway allowed visualization of epithelium, lamina propria, cartilage, and alveolar attachments. Carcinomas exhibited architectural disarray, loss of normal airway and alveolar structure, and rapid light attenuation. Squamous cell carcinomas showed nested architecture. Atypical glandular formation was appreciated in adenocarcinomas, and uniform trabecular gland formation was seen in salivary gland carcinomas. Mucinous adenocarcinomas showed alveolar wall thickening with intraalveolar mucin. Interstitial fibrosis was visualized as signal-dense tissue, with an interstitial distribution in mild interstitial fibrotic disease and a diffuse subpleural pattern with cystic space formation in usual interstitial pneumonitis.

CONCLUSIONS

To our knowledge, this study is the first demonstration of volumetric OFDI with precise correlation to histopathology in lung pathology. We anticipate that OFDI may play a role in assessing airway and parenchymal pathology, providing fresh insights into the volumetric features of pulmonary disease.

Distinct profile of driver mutations and clinical features in immunomarker-defined subsets of pulmonary large-cell carcinoma

Pulmonary large-cell carcinoma-a diagnostically and clinically controversial entity-is defined as a non-small-cell carcinoma lacking morphologic differentiation of either adenocarcinoma or squamous cell carcinoma, but suspected to represent an end stage of poor differentiation of these tumor types. Given the recent advances in immunohistochemistry to distinguish adenocarcinoma and squamous cell carcinoma, and the recent insights that several therapeutically relevant genetic alterations are distributed differentially in these tumors, we hypothesized that immunophenotyping may stratify large-cell carcinomas into subsets with distinct profiles of targetable driver mutations. We therefore analyzed 102 large-cell carcinomas by immunohistochemistry for TTF-1 and ΔNp63/p40 as classifiers for adenocarcinoma and squamous cell carcinoma, respectively, and correlated the resulting subtypes with nine therapeutically relevant genetic alterations characteristic of adenocarcinoma (EGFR, KRAS, BRAF, MAP2K1/MEK1, NRAS, ERBB2/HER2 mutations and ALK rearrangements) or more common in squamous cell carcinoma (PIK3CA and AKT1 mutations). The immunomarkers classified large-cell carcinomas as variants of adenocarcinoma (n=62; 60%), squamous cell carcinoma (n=20; 20%) or marker-null (n=20; 20%). Genetic alterations were found in 38 cases (37%), including EGFR (n=1), KRAS (n=30), BRAF (n=2), MAP2K1 (n=1), ALK (n=3) and PIK3CA (n=1). All molecular alterations characteristic of adenocarcinoma occurred in tumors with immunoprofiles of adenocarcinoma or marker-null, but not in tumors with squamous immunoprofiles (combined mutation rate 50% vs 30% vs 0%, respectively; P<0.001), whereas the sole PIK3CA mutation occurred in a tumor with squamous profile (5%). Furthermore, marker-null large-cell carcinomas were associated with significantly inferior disease-free (P<0.001) and overall (P=0.001) survival. In conclusion, the majority (80%) of large-cell carcinomas can be classified by immunomarkers as variants of adenocarcinoma or squamous cell carcinoma, which stratifies these tumors into subsets with a distinct distribution of driver mutations and distinct prognoses. These findings have practical implications for diagnosis, predictive molecular testing and therapy selection.

ΔNp63 (p40) distribution inside lung cancer: a driver biomarker approach to tumor characterization

ΔNp63 (henceforth simply p40) is a squamous/basal-type biomarker corresponding to nontransactivating (non-TA) isoforms of p63 gene. Its prospective relevance as driver biomarker in lung cancer has not yet been thoroughly investigated. In all, 72 adenocarcinomas (ADs), 27 squamous cell carcinomas (SQCs), 13 pleomorphic carcinomas (PLCs), 10 small-cell lung carcinomas (SCLCs), 5 large-cell neuroendocrine carcinomas (LCNECs), 5 adenosquamous carcinomas (ADSQCs), 3 large-cell carcinomas with basaloid features (B-LCC), 2 carcinoids, 2 carcinosarcomas (CS), 2 salivary-gland type tumors (SGTTs) of the lung, and 5 pleural malignant epithelioid mesotheliomas (MEMs) were prospectively diagnosed by morphology and verified by immunohistochemistry for p40, p63, and thyroid transcription factor 1 (TTF1). Histological scores (HS) were devised by multiplying the percentage of immunoreactive cells (0 to 100%) by immunostaining intensity (low = 1 vs strong = 2, according to internal controls). There was a nonrandom distribution of p40 across the diverse tumor groups and cell differentiation lineages, with p40-HS > 100 closely paralleling squamous or myoepithelial carcinomas (SQC, B-LCC, SQC-containing PLC, ADSQC with predominant SQC, SGTT), and p40-HS ≤ 10 pinpointing AD, AD-containing PLC, or CS and neuroendocrine (NE) tumors. At variance, p63-HS was significantly higher than p40 in AD (P < .0001) and NE tumors (P = .0156), with positive predictive value being 83% and 95% and overall accuracy being 95% and 99%, respectively. Also, TTF1 was shared by gland-differentiated and NE tumors. MEM cases were always negative for all biomarkers. The HS-guided assessment of p40 allowed an effective orientation among thoracic malignancies at the level of individual tumor patients thereby contributing to prospectively realize a driver, holistic approach to cancer characterization.

Simultaneous multi-antibody staining in non-small cell lung cancer strengthens diagnostic accuracy especially in small tissue samples

Histological subclassification of non-small cell lung cancer (NSCLC) has growing therapeutic impact. In advanced cancer stages tissue specimens are usually bioptically collected. These small samples are of extraordinary value since molecular analyses are gaining importance for targeted therapies. We therefore studied the feasibility, diagnostic accuracy, economic and prognostic effects of a tissue sparing simultaneous multi-antibody assay for subclassification of NSCLC. Of 265 NSCLC patients tissue multi arrays (TMA) were constructed to simulate biopsy samples. TMAs were stained by a simultaneous bi-color multi-antibody assay consisting of TTF1, Vimentin, p63 and neuroendocrine markers (CD56, chromogranin A, synaptophysin). Classification was based mainly on the current proposal of the IASLC with a hierarchical decision tree for subclassification into adenocarcinoma (LAC), squamous cell carcinoma (SCC), large cell neuroendocrine carcinoma (LCNEC) and NSCLC not otherwise specified. Investigation of tumor heterogeneity showed an explicit lower variation for immunohistochemical analyses compared to conventional classification. Furthermore, survival analysis of our combined immunohistochemical classification revealed distinct separation of each entity's survival curve. This was statistically significant for therapeutically important subgroups (p = 0.045). As morphological and molecular cancer testing is emerging, our multi-antibody assay in combination with standardized classification delivers accurate and reliable separation of histomorphological diagnoses. Additionally, it permits clinically relevant subtyping of NSCLC including LCNEC. Our multi-antibody assay may therefore be of special value, especially in diagnosing small biopsies. It futher delivers substantial prognostic information with therapeutic consequences. Integration of immunohistochemical subtyping including investigation of neuroendocrine differentiation into standard histopathological classification of NSCLC must, therefore, be considered.

In vivo optical coherence tomography: the role of the pathologist

Optical coherence tomography (OCT) is a nondestructive, high-resolution imaging modality, providing cross-sectional, architectural images at near histologic resolutions, with penetration depths up to a few millimeters. Optical frequency domain imaging is a second-generation OCT technology that has equally high resolution with significantly increased image acquisition speeds and allows for large area, high-resolution tissue assessments. These features make OCT and optical frequency domain imaging ideal imaging techniques for surface and endoscopic imaging, specifically when tissue is unsafe to obtain and/or suffers from biopsy sampling error. This review focuses on the clinical impact of OCT in coronary, esophageal, and pulmonary imaging and the role of the pathologist in interpreting high-resolution OCT images as a complement to standard tissue pathology.

Targeting the PI3K/AKT/mTOR pathway: biomarkers of success and tribulation

PI3K/AKT/mTOR pathway is an established oncogenic driver in humans. Targeted biologic agents against components of this pathway have shown promising activity leading to the approval of the allosteric inhibitors of mTOR, everolimus, and temsirolimus for the treatment of advanced cancers of the kidney, breast, and pancreas. Despite the established and promising activity of this therapeutic strategy, the duration and quality of benefit remains suboptimal in unselected patients. Improved understanding of the biologic consequence of altered PI3K/AKT/mTOR signaling is informing the development of protein (phosphorylated forms of S6, AKT, eIF4e) and genetic (PIK3CA mutation, PTEN loss of function, TSC1 and TSC2 mutation, PIK3CA-GS genetic profile) biomarkers to identify patients most likely to benefit from this therapeutic strategy. This review provides an overview of the biologic rational and promising results of protein and genetic biomarkers for selecting patients appropriate for therapy with inhibitors of this pathway.

Applying biomarker testing to clinical practice in lung cancer

SUMMARY Until recently, therapeutic options for lung cancer were limited, and the division into non-small-cell lung cancer and small-cell lung cancer and staging of the disease was adequate for treatment decisions in most lung cancer patients. With the discovery of new treatment options, new challenges emerged. This review focuses on recent diagnostic and predictive biomarkers in lung cancer. In addition, new techniques will enable us to perform more molecular analyses in a shorter timespan. These developments require a modern interaction between treating physicians and pathologists for optimal tissue management, allowing more molecular markers to be tested.

The surgeon's role in molecular biology

The biomolecular era is rapidly becoming shaped around the supreme interest in targeted therapy for patients with non-small cell lung cancer. Tissue analysis has become crucial in the definition of biomarkers and genomic signatures able to predict the response to treatment or even survival. Lung screening programs and minimally invasive thoracic surgery are jointly aimed at increasing the quantity and quality of specimens of non-small cell lung cancer caught at the earliest stages with the attendant, significant, effect on patient survival. In addition, biomolecular researchers are disclosing an ever-increasing cohort of patients with specific genetic mutations that make their cancer susceptible to individualized treatment. When needed for immunohistochemical characterization, investigators are ready to request "research biopsies" to consolidate tissue availability for clinical trials, translational research, and in biobanks. With unique and diverse tools in the surgical armamentarium, the thoracic surgeon plays a central role in this new multidisciplinary professional environment, actively participating in creating the foundations of the biomolecular era.

ΔNp63 (p40) and thyroid transcription factor-1 immunoreactivity on small biopsies or cellblocks for typing non-small cell lung cancer: a novel two-hit, sparing-material approach

INTRODUCTION

Diagnosing non-small cell lung cancer on biopsy/cellblock samples by morphology may be demanding. As sparing material for molecular testing is mandatory, a minimalist immunohistochemistry (IHC)-based diagnostic approach is warranted by means of novel, reliable, and easy-to-assess biomarkers.

METHODS

Forty-six consecutive biopsy/cellblock samples and the corresponding resection specimens (as the gold standard for morphology and IHC) from 30 adenocarcinomas (AD), 10 squamous carcinomas (SQC), 5 adenosquamous carcinomas (ADSQC), and 1 sarcomatoid carcinoma (SC) were IHC-evaluated for p40 [corresponding to nontransactivating ΔNp63 isoforms] and thyroid transcription factor-1 (TTF1) by semiquantitative assessment. For p40, also immunodecoration intensity was taken into account and dichotomized as strong or low.

RESULTS

Nonrandom and overlapping distributions of the relevant markers were found in biopsy/cellblock and surgical specimens, which closely correlated with each other and the diverse tumor categories, with no differences in area under curve-receiver-operating-characteristic curves for each marker between any two samples, including p40 and p63. Diagnostic combinations were p40-/TTF1+ or TTF1- for AD (where p40 was negative, apart from 5/30 AD showing at the best 1-2% tumor cells with low intensity); p40+/TTF1- (p40 strong and by far higher than 50%) for SQC; and p40+/TTF1+ or p40+/TTF1- (p40 strong and less than 50%) for ADSQC. The single SC case was p40-/TTF1-, suggesting glandular lineage. Practically, 41/46 (89%) tumors were correctly classified by IHC on small samples, including 30 AD, 10 SQC, 1/5 ADSQC, and no SC. Underdiagnosis of ADSQC was actually because of sampling error of biopsies/cellblocks rather than insufficient biomarker robustness, whereas underdiagnosis of SC was really because of the failure of either marker to highlight epithelial-mesenchymal transition.

CONCLUSIONS

This minimalist IHC-based model of p40 and TTF1 on biopsy/cellblock samples was effective to correctly subtype most cases of lung cancer.

Subtyping of non-small cell lung carcinoma: a comparison of small biopsy and cytology specimens

BACKGROUND

There is growing evidence that lung adenocarcinoma and squamous cell carcinoma (SQCC) have distinct oncogenic mutations and divergent therapeutic responses, which is driving the heightened emphasis on accurate pathologic subtyping of non-small cell lung carcinoma (NSCLC). The relative feasibility and accuracy of NSCLC subtyping by small biopsy versus cytology is not well established, particularly in current practice where immunohistochemistry (IHC) is becoming routinely used to aid in this distinction.

METHODS

Concurrent biopsy and cytology specimens obtained during a single procedure and diagnosed as NSCLC during a 2-year period (n = 101) were reviewed. Concordance of diagnoses in the two methods was assessed. Accuracy was determined based on subsequent resection or autopsy diagnosis (n = 21) or IHC for thyroid transcription factor 1 and p63 on a subset of cases (n = 43).

RESULTS

The distribution of definitive versus favored versus unclassified categories (reflecting the degree of diagnostic certainty) was similar for biopsy (71% versus 23% versus 6%, respectively) and cytology (69% versus 19% versus 12%, respectively), p = 0.29. When results from paired specimens were combined, the rate of definitive diagnoses by at least one method was increased to 84% and the unclassified rate was decreased to 4%. NSCLC subtype concordance between biopsy and cytology was 93%. Kappa coefficient (95% confidence interval) for agreement between methods was 0.88 (0.60-0.89) for adenocarcinoma and 0.76 (0.63-0.89) for SQCC. In pairs with discordant diagnoses (n = 7) the correct tumor type was identified with a similar frequency by biopsy (n = 4) and cytology (n = 3). Factors contributing to mistyping were poor differentiation, necrosis, low cellularity, and lack of supporting IHC. All concordant diagnoses for which verification was available (n = 57) were correct. IHC was used more frequently to subtype NSCLC in biopsy than cytology (32% versus 6%; p = 0.0001).

CONCLUSIONS

Small biopsy and cytology achieve comparable rates of definitive and accurate NSCLC subtyping, and the optimal results are attained when the two modalities are considered jointly. The lower requirement for IHC in cytology highlights the strength of cytomorphology in NSCLC subtyping. Whenever clinically feasible, obtaining parallel biopsy and cytology specimens is encouraged.

Clarifying the spectrum of driver oncogene mutations in biomarker-verified squamous carcinoma of lung: lack of EGFR/KRAS and presence of PIK3CA/AKT1 mutations

PURPOSE

There is persistent controversy as to whether EGFR and KRAS mutations occur in pulmonary squamous cell carcinoma (SQCC). We hypothesized that the reported variability may reflect difficulties in the pathologic distinction of true SQCC from adenosquamous carcinoma (AD-SQC) and poorly differentiated adenocarcinoma due to incomplete sampling or morphologic overlap. The recent development of a robust immunohistochemical approach for distinguishing squamous versus glandular differentiation provides an opportunity to reassess EGFR/KRAS and other targetable kinase mutation frequencies in a pathologically homogeneous series of SQCC.

EXPERIMENTAL DESIGN

Ninety-five resected SQCCs, verified by immunohistochemistry as ΔNp63(+)/TTF-1(-), were tested for activating mutations in EGFR, KRAS, BRAF, PIK3CA, NRAS, AKT1, ERBB2/HER2, and MAP2K1/MEK1. In addition, all tissue samples from rare patients with the diagnosis of EGFR/KRAS-mutant "SQCC" encountered during 5 years of routine clinical genotyping were reassessed pathologically.

RESULTS

The screen of 95 biomarker-verified SQCCs revealed no EGFR/KRAS [0%; 95% confidence interval (CI), 0%-3.8%], four PIK3CA (4%; 95% CI, 1%-10%), and one AKT1 (1%; 95% CI, 0%-5.7%) mutations. Detailed morphologic and immunohistochemical reevaluation of EGFR/KRAS-mutant "SQCC" identified during clinical genotyping (n = 16) resulted in reclassification of 10 (63%) cases as AD-SQC and five (31%) cases as poorly differentiated adenocarcinoma morphologically mimicking SQCC (i.e., adenocarcinoma with "squamoid" morphology). One (6%) case had no follow-up.

CONCLUSIONS

Our findings suggest that EGFR/KRAS mutations do not occur in pure pulmonary SQCC, and occasional detection of these mutations in samples diagnosed as "SQCC" is due to challenges with the diagnosis of AD-SQC and adenocarcinoma, which can be largely resolved by comprehensive pathologic assessment incorporating immunohistochemical biomarkers.