Immunohistochemical algorithm for differentiation of lung adenocarcinoma and squamous cell carcinoma based on large series of whole-tissue sections with validation in small specimens

Analysis of major known driver mutations and prognosis in resected adenosquamous lung carcinomas

INTRODUCTION

Genotyping for driver mutations is now routinely used to guide clinical care of patients with lung cancer. Adenosquamous lung carcinoma (AdSqLC) is a subtype of cancer that contains both adenocarcinoma and squamous cell carcinoma. However, the incidence, clinicopathologic characteristics, and prognostic implications of major driver mutations in AdSqLCs are not well established.

METHODS

Seventy-six resected AdSqLCs and 646 lung adenocarcinomas were screened for known genetic alterations involving EGFR, ERBB2, KRAS, BRAF, PIK3CA, AKT1, RET, and ALK. Tumors showing acinar, lepidic, micropapillary, or papillary growth in glandular component were classified as classical AdSqLC.

RESULTS

Of the 76 AdSqLCs, 43 (56.6%) harbored known mutant kinases, including 24 (31.6%) with EGFR mutations, eight (10.5%) with KRAS mutations, two (2.6%) with AKT1 (2.6%) mutations, one (1.3%) with ERBB2 insertion mutation, one (1.3%) with PIK3CA mutation, four (5.3%) with ALK fusions, and three (4%) with KIF5B-RET fusions. No mutation was found in BRAF. The mutational profiles and clinicopathologic characteristics of classical AdSqLC were strikingly similar to that of poorly differentiated adenocarcinoma. However, AdSqLCs with solid growth pattern in glandular component had high frequency of ALK or RET fusions and low EGFR mutation rate.

CONCLUSIONS

To our knowledge, this is the first comprehensive study investigating major oncogenic driver mutations in a large cohort of AdSqLC patients in a Chinese population. The findings suggest that it will be clinically valuable to investigate the growth pattern of glandular component in AdSqLCs.

Large cell carcinoma of the lung: a tumor in search of an author. A clinically oriented critical reappraisal

Large cell carcinoma (LCC) is a merely descriptive term indicating a subtype of lung cancer with no specific features of small-cell lung cancer (SCLC), adenocarcinoma (ADC) or squamous cell carcinoma (SQC). This diagnosis is allowed on surgical specimens only, whereas its counterpart in biopsy/cytology samples is non-small-cell lung carcinoma (NSCLC), not otherwise specified (NOS). Although these two terms do not fulfill the same concept, they can be interchangeable synonyms at the clinical level, reflecting, in different ways, the inability to define a specific subtype. Immunohistochemistry (IHC), next generation sequencing (NGS) analysis and, historically, electron microscopy have been unveiling diverse cell differentiation lineages in LCC, resulting in LCC-favor ADC, LCC-favor SQC and LCC-favor large-cell neuroendocrine carcinoma (LCNEC), the latter hopefully to be included into the neuroendocrine tumor (NET) group in the future. Paradoxically, however, the interpretation issues of LCC/NSCLC-NOS are not diminishing, but even increasing albeight an accurate diagnosis is oncologically required and crucial. Also, rare LCC/NSCLC-NOS cases exhibiting null/unclear phenotype, are difficult to classify, and this terminology could be maintained for the sake of classification (basically these tumors are serendipitous ADC, as also confirmed by the lack of p40). In this review article, seven relevant issues to LCC have been addressed by using a question-answer methodology, with final key points discussing major interpretation issues. In conclusion, most LCC/NSCLC-NOS may be eventually re-classified and addressed by exploiting IHC and/or molecular testing to satisfy the criteria of precision medicine (the right drug, to the right patient, at the right time).

Emerging drugs for squamous cell lung cancer

INTRODUCTION

The management of advanced NSCLC has been shifted by histology-driven treatment and molecularly targeted therapy, especially in lung adenocarcinoma. However, as the second most common histology in NSCLC, the treatment options for squamous cell lung cancer (SQCLC) remain very limited.

AREAS COVERED

The review first discusses the role of histology in management of NSCLC and new cytotoxic agents in SQCLC, and then addresses genomic characterization and potential molecular targets in SQCLC. The article then provides an overview for several major categories of novel molecularly targeted therapies and immune-based strategies with particular attention to ongoing SQCLC trials.

EXPERT OPINION

The key challenges in drug development are to uncover novel actionable targets and to identify predictive biomarkers. Progress in genomic analysis has identified some promising targetable genes and oncogenic pathways in SQCLC with a wave of targeted agents being tested in clinical trials. Immunotherapy has also raised great interest in management of SQCLC, especially agents targeting immune check points, cytotoxic T-lymphocyte antigen-4, programmed death-1 receptor and its ligands. Better understanding of tumor biology and development of novel targeted therapies will help to facilitate more effective personalized therapy for patients with this devastating illness.

Beyond adenocarcinoma: current treatments and future directions for squamous, small cell, and rare lung cancer histologies

Lung cancer encompasses a diverse spectrum of histologic subtypes. Until recently, the majority of therapeutic advances were limited to the minority of patients with adenocarcinoma. With the advent of comprehensive genomic profiling of squamous and small cell lung cancers, new therapeutic targets have emerged. For squamous tumors, the most promising of these include fibroblast growth factor receptor (FGFR), the phosphatidylinositol 3-kinase (PI3K) pathway, discoidin domain receptor 2 (DDR2), and G1/S checkpoint regulators. In 2014, the antiangiogenic agent ramucirumab was approved for all non-small cell lung cancer (NSCLC) histologies, including squamous tumors. Immunotherapeutic approaches also appear to be promising for these cases. Genomic analysis of small cell lung cancer has revealed a high mutation burden, but relatively few druggable driver oncogenic alterations. Current treatment strategies under investigation are focusing on targeting mitotic, cell cycle, and DNA repair regulation, as well as immunotherapy. Pulmonary neuroendocrine tumors represent a diverse spectrum of diseases that may be treated with somatostatin analogs, cytotoxic agents, and molecularly targeted therapies. Radiolabeled somatostatin analogs and combinations with mammalian target of rapamycin (mTOR) inhibitors also show potential. Large cell neuroendocrine tumors share numerous clinical, pathologic, and molecular features with small cell lung cancer; however, whether they should be treated similarly or according to a NSCLC paradigm remains a matter of debate.

Prevalence, morphology, and natural history of FGFR1-amplified lung cancer, including squamous cell carcinoma, detected by FISH and SISH

The aim of this study was to investigate the prevalence of fibroblast growth factor receptor 1 (FGFR1) amplification by fluorescence in situ hybridization (FISH) in a lung cancer patient cohort and to correlate results with morphology, silver in situ hybridization (SISH), and patient outcome. FGFR1 FISH and SISH were performed in 406 and 385 lung cancer cases, respectively, and the results were compared. High-level FGFR1 amplification was defined as the ratio of FGFR1/centromere 8 ≥2, or tumor cell percentage with ≥15 signals ≥10%, or average number of signals/tumor cell nucleus ≥6. Low-level amplification was defined as tumor cell percentage with ≥5 signals ≥50%. Of 406 tumors tested, there were 191 squamous cell carcinomas, 28 carcinomas with focal squamous morphology, 24 large cell carcinomas with squamous immunoprofile, 115 adenocarcinomas, 17 neuroendocrine tumors, and 31 carcinomas without squamous morphology or immunoprofile. FGFR1 FISH was assessable in 368 tumors, with FGFR1 amplification identified in 50, including 48 tumors with either squamous morphology or immunoprofile (48 of 225, 21.3%), and two 'marker-null' tumors without squamous or glandular morphology or immunoprofile (2 of 143, 1.4%; P<0.0001). FGFR1 SISH was assessable in 347 tumors. All 46 FGFR1 FISH-amplified tumors with tumor available for testing showed amplification with SISH, while all other tumors were negative. There was no relationship between FGFR1 amplification status and disease-free (P=0.88, HR=1.04, 95% confidence interval (CI)=0.67-1.60) or overall survival (P=0.97, HR=1.01, 95% CI=0.65-1.58) in surgically radically treated patients with tumors with any squamous morphology or immunoprofile. FGFR1 amplification is a common abnormality in tumors with any squamous morphology or immunoprofile, but it is also present in 'marker-null' tumors. The results of FGFR1 SISH showed 1:1 correlation with the results of FGFR1 FISH, indicating that SISH may be an alternative method to detect FGFR1 amplification. No relationship was detected between patient outcome and FGFR1 amplification.

Strategic management of transthoracic needle aspirates for histological subtyping and EGFR testing in patients with peripheral lung cancer: An institutional experience

BACKGROUND

Lung cancer therapy is personalized based on the histological subtype and molecular status. Totally, 70% of lung cancer patients present in advanced stages and are diagnosed on small biopsy or cytology specimens, hence an accurate but tissue-sparing approach is necessary. This study aimed to demonstrate efficient utilization of cell block (CB) on transthoracic needle aspiration (TTNA) for lung cancer subtyping, and to investigate the usefulness of needle washing after TTNA for assessing EGFR molecular status.

METHODS

Each TTNA specimen from the 79 peripheral lung masses was divided into three parts; liquid-based cytology (LBC), CB (with or without immunohistochemistry), and needle washing for analysis of EGFR mutation using peptide nucleic acid-mediated real-time PCR clamping.

RESULTS

Totally 79 specimens were diagnosed as malignancy, 75 (94.9%), benign, 3 (3.8%), and inadequate specimen, 1 (1.3%). The combination of LBC and CB (92.0%) showed a higher diagnostic yield for definitive subtyping of lung cancer than LBC alone (72.0%). Of the 75 malignant cases, 17 (22.7%) showed an EGFR mutation in needle washing specimens. EGFR mutational status was compared in all paired needle washing and scraped CBs with a 100% concordance.

CONCLUSIONS

We hereby proposed a strategy to maximize biological information retrieval from a limited TTNA specimen in patients with peripheral lung cancer. This algorithm indicated CB preparation for accurate histological subtyping and waste needle washing for molecular testing.

Histopathologic, immunophenotypic and cytogenetic features of pulmonary mucoepidermoid carcinoma

Pulmonary mucoepidermoid carcinoma is an uncommon but distinctive manifestation of mucoepidermoid carcinoma. Pulmonary mucoepidermoid carcinoma occurs in adults and children and can cause diagnostic problems, especially in small biopsies. Few studies have characterized the histologic and immunophenotypic features of pulmonary mucoepidermoid carcinoma. t(11;19)(q21;p13) is considered disease-defining for mucoepidermoid carcinoma; its significance in pulmonary mucoepidermoid carcinoma warrants further study. Forty three pulmonary mucoepidermoid carcinomas were re-reviewed and graded according to the Brandwein grading system for mucoepidermoid carcinoma. Four cases were excluded because of a split opinion between pathology report and re-review. These cases were negative for MAML2 rearrangement by FISH. TTF-1, napsin A, p40 and p63 immunostains were scored: 0 (negative), 1 (1-25% tumor cells), 2 (26-50%), 3 (51-75%) or 4 (>75%). FISH to detect MAML2 rearrangement used a MAML2-11q21 break-apart probe. Thirty nine pulmonary mucoepidermoid carcinoma (4 low, 30 intermediate, 5 high grade) contained mucous, epidermoid and intermediate cells and lacked keratinization and in situ carcinoma of the overlying epithelium. All cases with available gross description (n=22) had a central/endo- or peribronchial location. All 25 cases tested for immunohistochemistry were positive (scores 1-4) for p63; 23 also expressed p40. In six cases, the p63 score was higher than p40. TTF-1 and napsin were uniformly negative in all 25 cases. MAML2 rearrangement was identified by FISH in each of the 24 cases tested (3 low, 19 intermediate, 2 high grade). Clinical history was available in 29 patients (15 men) (median age, 48 years) with follow-up in 24 (median, 8.4 years). Five patients died of unrelated causes; one developed metastatic pulmonary mucoepidermoid carcinoma. In conclusion, features helpful in distinguishing pulmonary mucoepidermoid carcinoma from other lung cancers include its central/endo- or peribronchial location together with the presence of mucous cells, p63 expression, lack of keratinization and MAML2 rearrangement. TTF-1 and napsin are typically not expressed.

Advances in lung adenocarcinoma classification: a summary of the new international multidisciplinary classification system (IASLC/ATS/ERS)

Due to advances in the understanding of lung adenocarcinoma since the advent of its 2004 World Health System classification, an international multidisciplinary panel [sponsored by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS)] has recently updated the classification system for lung adenocarcinoma, the most common histologic type of lung cancer. Here, we summarize and highlight the new criteria and terminology, certain aspects of its clinical relevance and its potential treatment impact, and future avenues of research related to the new system.

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.

Development in the diagnostic lung cancer pathway: implication for treatment

SUMMARY 

The diagnostic pathway of lung cancer is a multidisciplinary process that has rapidly changed in the last few years. Most advances relate to lung adenocarcinoma, which needs to be differentiated from squamous cell carcinoma and other histological subtypes, since most targetable mutations occur in adenocarcinomas. Tumor heterogeneity can influence sampling and diagnosis, particularly relevant when using small biopsies or cytology samples. Re-biopsy at progression should become part of the diagnostic process, since it can alter the clinical management, explain mechanisms of resistance to targeted therapy and lead to biomarker development. Innovation in plasma-circulating tumor cells, cell-free DNA, and functional imaging are expected to contribute significantly to the noninvasive lung cancer diagnostic pathway.

New developments in the treatment of squamous cell lung cancer

PURPOSE OF REVIEW

To highlight the recent developments in the molecular characterization of lung squamous cell carcinoma (SQCC) and to summarize the current clinical trials of targeted agents.

RECENT FINDINGS

Lung SQCC is the second-largest histological subtype of nonsmall-cell lung cancer after lung adenocarcinoma and is closely associated with tobacco smoking. Targeted therapies have been successfully used for the treatment of lung adenocarcinoma but have not been implemented in the treatment of lung SQCC to date. Both lung adenocarcinomas and SQCCs are characterized by specific somatic DNA modifications such as exonic mutations, copy-number alterations, and genomic rearrangements which are substantially different between the two subtypes. Progress in genomic characterization using next-generation sequencing (NGS) technologies makes it possible to investigate these somatic DNA modifications at the whole-genome level and to generate comprehensive profiles of genetic alterations. Application of NGS in lung SQCC led to a more detailed understanding of the possible targets and will identify new targeted therapeutic approaches in the near future.

SUMMARY

In this review, we highlight the current knowledge of molecular targets, clinical trials of targeted agents, and druggable aberrations in lung SQCCs.

Hidden treasures in "ancient" microarrays: gene-expression portrays biology and potential resistance pathways of major lung cancer subtypes and normal tissue

Objective: Novel statistical methods and increasingly more accurate gene annotations can transform “old” biological data into a renewed source of knowledge with potential clinical relevance. Here, we provide an in silico proof-of-concept by extracting novel information from a high-quality mRNA expression dataset, originally published in 2001, using state-of-the-art bioinformatics approaches.

Methods: The dataset consists of histologically defined cases of lung adenocarcinoma (AD), squamous (SQ) cell carcinoma, small-cell lung cancer, carcinoid, metastasis (breast and colon AD), and normal lung specimens (203 samples in total). A battery of statistical tests was used for identifying differential gene expressions, diagnostic and prognostic genes, enriched gene ontologies, and signaling pathways.

Results: Our results showed that gene expressions faithfully recapitulate immunohistochemical subtype markers, as chromogranin A in carcinoids, cytokeratin 5, p63 in SQ, and TTF1 in non-squamous types. Moreover, biological information with putative clinical relevance was revealed as potentially novel diagnostic genes for each subtype with specificity 93–100% (AUC = 0.93–1.00). Cancer subtypes were characterized by (a) differential expression of treatment target genes as TYMS, HER2, and HER3 and (b) overrepresentation of treatment-related pathways like cell cycle, DNA repair, and ERBB pathways. The vascular smooth muscle contraction, leukocyte trans-endothelial migration, and actin cytoskeleton pathways were overexpressed in normal tissue.

Conclusion: Reanalysis of this public dataset displayed the known biological features of lung cancer subtypes and revealed novel pathways of potentially clinical importance. The findings also support our hypothesis that even old omics data of high quality can be a source of significant biological information when appropriate bioinformatics methods are used.

Immunotherapy: is a minor god yet in the pantheon of treatments for lung cancer?

Immunotherapy has been studied for many years in lung cancer without significant results, making the majority of oncologists quite skeptical about its possible application for non-small cell lung cancer treatment. However, the recent knowledge about immune escape and subsequent 'cancer immunoediting' has yielded the development of new strategies of cancer immunotherapy, heralding a new era of lung cancer treatment. Cancer vaccines, including both whole-cell and peptide vaccines have been tested both in early and advanced stages of non-small cell lung cancer. New immunomodulatory agents, including anti-CTLA4, anti-PD1/PDL1 monoclonal antibodies, have been investigated as monotherapy in metastatic lung cancer. To date, these treatments have shown impressive results of efficacy and tolerability in early clinical trials, leading to testing in several large, randomized Phase III trials. As these results will be confirmed, these drugs will be available in the near future, offering new exciting therapeutic options for lung cancer treatment.

PD-1 gene promoter polymorphisms correlate with a poor prognosis in non-small cell lung cancer

An imbalance to the regulation of the immune system changes the tumor-specific T-cell immunity in the cancer microenvironment and adjusts the tumor progression and metastasis. Inhibiting the interactions of the immune function mediates the antitumor activity in preclinical models. The programmed death 1 (PD-1) gene -606 G/A polymorphism, which may modify promoter activity and is Asian-specific, was investigated by TaqMan quantitative polymerase chain reaction assay in surgically treated non-small cell lung cancer (NSCLC) cases. In the present study, 583 surgically removed NSCLC cases were included for single-nucleotide polymorphism (SNP) analyses. The PD-1 SNP statuses at the promoter region (rs36084323) were 146 AA (25.0%), 293 GA (50.3%) and 144 GG (24.7%). The ratio was extremely similar to the healthy control in a previous study: 24.9% AA, 47.8% GA and 27.3% GG. The ratio of the GG phenotype was not significantly different for gender (25.1% males and 23.9% female), age (25.2% ≤65 years and 24.4% >65 years), smoking status (26.1% smoker and 21.8% non-smoker) and pathological subtypes [25.4% adenocarcinoma (adeno) and 24.2% squamous cell carcinoma (SCC)]. The GG ratio of PD-1 was not significantly different between pathological stage II-IV (25.5%) and stage I cases (24.1%; P=0.6245). The survival time of the patients with the -606 GG phenotype of PD-1 was significantly lower (n=147, 50 succumbed) compared to the patients with -606 GA or -606 AA (n=435, 109 succumbed) (P=0.0183). The GG phenotype patients had a significantly worse prognosis in the SCC population (P=0.009), however, this was not different to the adeno population (P=0.2594). Thus, PD-1 may promote tumor prognosis and provide a candidate for the blockade of its function as a strategy to antagonize the progression process in NSCLC, particularly lung SCC.

Non-Small Cell Lung Carcinoma Biomarker Testing: The Pathologist's Perspective

Biomarker testing has become standard of care for patients diagnosed with non-small cell lung carcinoma (NSCLC). Although, it can be successfully performed in circulating tumor cells, at present, the vast majority of investigations are carried out using direct tumor sampling, either through aspiration methods, which render most often isolated cells, or tissue sampling, that could range from minute biopsies to large resections. Consequently, pathologists play a central role in this process. Recent evidence suggests that refining NSCLC diagnosis might be clinically significant, particularly in cases of lung adenocarcinomas (ADC), which in turn, has prompted a new proposal for the histologic classification of such pulmonary neoplasms. These changes, in conjunction with the mandatory incorporation of biomarker testing in routine NSCLC tissue processing, have directly affected the pathologist’s role in lung cancer work-up. This new role pathologists must play is complex and demanding, and requires a close interaction with surgeons, oncologists, radiologists, and molecular pathologists. Pathologists often find themselves as the central figure in the coordination of a process, that involves assuring that the tumor samples are properly fixed, but without disruption of the DNA structure, obtaining the proper diagnosis with a minimum of tissue waste, providing pre-analytical evaluation of tumor samples selected for biomarker testing, which includes assessment of the proportion of tumor to normal tissues, as well as cell viability, and assuring that this entire process happens in a timely fashion. Therefore, it is part of the pathologist’s responsibilities to assure that the samples received in their laboratories, be processed in a manner that allows for optimal biomarker testing. This article goal is to discuss the essential role pathologists must play in NSCLC biomarker testing, as well as to provide a summarized review of the main NSCLC biomarkers of clinical interest.

A genomics-based classification of human lung tumors

We characterized genome alterations in 1255 clinically annotated lung tumors of all histological subgroups to identify genetically defined and clinically relevant subtypes. More than 55% of all cases had at least one oncogenic genome alteration potentially amenable to specific therapeutic intervention, including several personalized treatment approaches that are already in clinical evaluation. Marked differences in the pattern of genomic alterations existed between and within histological subtypes, thus challenging the original histomorphological diagnosis. Immunohistochemical studies confirmed many of these reassigned subtypes. The reassignment eliminated almost all cases of large cell carcinomas, some of which had therapeutically relevant alterations. Prospective testing of our genomics-based diagnostic algorithm in 5145 lung cancer patients enabled a genome-based diagnosis in 3863 (75%) patients, confirmed the feasibility of rational reassignments of large cell lung cancer, and led to improvement in overall survival in patients with EGFR-mutant or ALK-rearranged cancers. Thus, our findings provide support for broad implementation of genome-based diagnosis of lung cancer.

The pivotal role of pathology in the management of lung cancer

The last decade has seen significant advances in our understanding of lung cancer biology and management. Identification of key driver events in lung carcinogenesis has contributed to the development of targeted lung cancer therapies, heralding the era of personalised medicine for lung cancer. As a result, histological subtyping and molecular testing has become of paramount importance, placing increasing demands on often small diagnostic specimens. This has triggered the review and development of the first structured classification of lung cancer in small biopsy/cytology specimens and a new classification of lung adenocarcinoma from the IASLC/ATS/ERS. These have enhanced the clinical relevance of pathological diagnosis, and emphasise the role of the modern surgical pathologist as an integral member of the multidisciplinary team, playing a crucial role in clinical trials and determining appropriate and timely management for patients with lung cancer.

Expression and diagnostic values of calretinin and CK5/6 in cholangiocarcinoma

BACKGROUND

Mesothelin, a mesothelial marker, has been found expressed in and as a potential treatment target of cholangioacarcinoma (CC). It is possible that CC may be derived from the cells sharing mesothelial markers. However, the expression of other mesothelial markers in CC is largely unknown.

METHODS

Thirty CC cases (10 extrahepatic and 20 intrahepatic) were retrieved from our institutional archive. The immunohistochemical study of Calretinin (DC8), WT1 (6F-H2), Lymphatic Endothelial Marker (D2-40), CK5/6 (D5/16 B4) and CK19 (b170) was done on formalin fixed paraffin embedded sections for 2-3 blocks of each case. We compared the expression levels between CC and normal bile duct (NBD) on the same block.

RESULTS

All of the CC and NBD are positive for CK19 (23/23) and negative for WT1 (0/23) and D2-40 (0/23), except one CC positive for D2-40(1/30, 3.3%) and one NBD positive for WT1 (1/23, 4.3%). Calretinin immunoreactivity was detected in 52.2% (12/23) of CC, but none in NBD (0/23). CK5/6 was also detectable in 73.3% (22/30) of CC and all NBD (30/30). Increased expression of calretinin and reduced expression of CK5/6 were more likely associated with CC than NBD (P < 0.001 and P = 0.002, respectively). The sequential staining pattern of positive calretinin and negative CK5/6 in calretinin negative cases has a sensitivity of 69.57% and a specificity of 100% for differentiating CC from NBD. CK5/6 expression was also more likely associated with well-differentiated CC (7/7 versus 12/20 in moderately differentiated, and 9/10 in poorly differentiated, P = 0.019) and extrahepatic CC (10/10 versus 12/20 in intrahepatic, P = 0.029), but there was no association between the calretinin expression and the CC grade or location.

CONCLUSION

Calretinin and CK5/6 immunohistochemical stains may be useful for diagnosing a CC. Their immunohistochemical results should be interpreted with caution in the cases with differential diagnoses of mesothelioma and CC. A full mesothelioma panel, including WT1 and/or D2-40, is recommended to better define a mesothelial lineage. The biology of calretinin and CK5/6 expression in CC is unclear, but might shed light on identifying therapeutic targets for CC.

Unmet needs in squamous cell carcinoma of the lung: potential role for immunotherapy

Squamous cell carcinoma of the lung accounts for 20–30 % of non-small cell lung cancers (NSCLC). Despite the differences in disease characteristics between squamous and non-squamous NSCLC, both have historically been treated similarly in the clinic. Recently approved drugs have revealed differences in activity and safety profiles across histologic subtypes and have applicability in treating non-squamous, but not typically squamous, NSCLC. Exploration of immune checkpoints—co-inhibitory molecules used to regulate immune responses—has resulted in novel immunotherapies designed to interrupt signaling through the cytotoxic T lymphocyte-associated antigen-4 or programmed cell death protein-1 pathways on lymphocytes. Modulation of these pathways can lead to restored antitumor immune responses, and preliminary evidence shows that agents targeting these pathways have activity in lung cancer, including squamous NSCLC.

Intermediate filament: structure, function, and applications in cytology

Intermediate filament (IF) constitutes an important cytoskeletal component in nearly all the vertebrate cells. IFs are present both in the cytoplasm and in the nucleus. They play an important role in providing mechanical strength of the cell and tissue, growth and regeneration, cell survival and apoptosis, and finally cell migration. IFs are also expressed differentially in different body tissues. Therefore, judicious use of IF may provide the diagnosis and confirmation of different malignancies. This is particularly helpful in the diagnosis of metastatic malignant tumor from an unknown primary. Expression of IFs particularly cytokeratin and vimentin is also related to prognosis of tumors. In this review, we have discussed the basic structure, dynamics, distribution of IF in cells, and its role in diagnosis of cytology. Possible prognostic roles of IF are also discussed.

Guideline Recommendations for Testing of ALK Gene Rearrangement in Lung Cancer: A Proposal of the Korean Cardiopulmonary Pathology Study Group

Rearrangement of anaplastic lymphoma kinase (ALK) gene is the best predictor of response to crizotinib, an ALK tyrosine kinase inhibitor. However, the prevalence of the ALK fusion is low, so accurate patient identification is crucial for successful treatment using ALK inhibitors. Furthermore, most patients with lung cancer present with advanced-stage disease at the time of diagnosis, so it is important for pathologists to detect ALK-rearranged patients while effectively maximizing small biopsy or cytology specimens. In this review, we propose a guideline recommendation for ALK testing approved by the Cardiopulmonary Pathology Study Group of the Korean Society of Pathologists.

Primary pulmonary non-small cell carcinomas: the College of American Pathologists Interlaboratory Comparison Program confirms a significant trend toward subcategorization based upon fine-needle aspiration cytomorphology alone

Context.-Subtyping of non-small cell lung carcinomas (NSCLCs) is necessary for optimal patient management with specific diagnoses triggering specific molecular tests and affecting therapy. Objective.-To assess the accuracy of the participants of the College of American Pathologists Interlaboratory Comparison Program in diagnosing and subtyping NSCLC fine-needle aspiration (FNA) slides, based on morphology alone, considering preparation and participant type and trends over time. Design.-The performance of program participants was reviewed for the 5-year period spanning 2007-2011. Lung FNA challenges with reference diagnoses of adenocarcinoma and squamous cell carcinoma (SCC) were evaluated for diagnostic concordance by using a nonlinear mixed model analysis. Results.-There were 10 493 pathologist and 6378 cytotechnologist responses with concordance rates of 97.4% and 97.9% for malignancy, respectively. Overall concordance rates for subcategorization were 54.6% for adenocarcinoma and 74.9% for SCC. For the exact reference diagnoses, pathologists performed better for adenocarcinoma and cytotechnologists performed better for SCC. Accurate subcategorization of adenocarcinomas significantly increased over time with 31.5% of adenocarcinomas classified as NSCLC in 2007 and 25.5% of adenocarcinomas classified as NSCLC in 2011 (P < .001). In comparing preparation types, modified Giemsa-stained smears showed the lowest overall concordance (46.8%). Modified Giemsa-stained smears with SCCs were the least likely to be accurately subcategorized (36.4%). Conclusions.-Participants are proficient at interpreting NSCLCs as malignant by FNA but are less successful at subcategorization with cytomorphology alone. During the study period, a statistically significant trend was confirmed toward greater accuracy of subcategorization of adenocarcinomas, suggesting that participants are cognizant of the impact that more specific cytomorphologic interpretations have in directing molecular triage and therapy.

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

In lung cancer, targeted therapies depend on accurate histological subclassification of the tumor. The majority of lung cancers can be subclassified based on hematoxylin and eosin staining; however, classification may be difficult in small biopsies. In this study, we investigated the utility of a newly developed triple marker (combination of TTF1/Napsin A/p40) and compared the sensitivity and specificity of this novel marker with individual markers in the subclassification of non-small cell lung carcinomas. Lung cancer tissue microarrays were constructed using surgical resection material from the Johns Hopkins Hospital. They included 77 adenocarcinomas (ADCs), 77 squamous cell carcinomas (SqCCs), and 46 cases of metastatic lung ADCs. Immunostaining patterns of all markers were scored semi-quantitatively and compared. In ADCs, the sensitivity and specificity of the triple marker were 93.5% and 77.5%, respectively. The sensitivity and specificity of TTF1 and Napsin A were 85.7% and 75.0%, and 89.6% and 90.0%. In SqCCs, the sensitivity and specificity of the triple marker were 88.3% and 92.5%, while the p40, p63 and CK5/6 showed 80.5% and 90.0%; 93.5% and 80.0%; and 89.6% and 80.0%. In addition, the sensitivity and specificity of the triple marker in metastatic ADCs showed 71.7% and 73.5%, respectively. Our triple marker (combination of TTF1/Napsin A/p40) showed a similar sensitivity and specificity for the subclassification of NSCLC when compared to individual markers. Our study not only demonstrates a useful combination of immunomarkers but also optimally conserves tissue for molecular marker testing.

Toward an evidence-based proposal for the best minimal immunohistochemical panel to infer lung carcinoma in metastatic supraclavicular lymph node

Carcinomas from either pulmonary or extrapulmonary sites can metastatise to supraclavicular lymph nodes. Immunohistochemistry (IHC) is invaluable to comment on the possible primary site. However, the optimal number of antibodies to be tested is debatable. Seven antibodies were tested on 135 metastatic supraclavicular lymph node biopsies to propose a "best minimal" IHC panel to infer lung carcinoma, incorporating the principles of "evidence-based medicine." The 135 cases were divided into the following: category I (110 cases), wherein the primary was in the lung based on histologic analysis (Ia, n = 14 [12.7%]), cytologic analysis (Ib, n = 43 [39.1%]), or strong clinicoradiologic evidence (Ic, n = 53 [48.2%]), and category II (25 cases) with a histologically proven extrapulmonary primary site. Categories Ia and Ib were together designated as the "control group," and category Ic was designated as the "test group." The antibodies tested were cytokeratin (CK 7, CK20), epithelial membrane antigen, carcinoembryonic antigen, thyroid transcription factor-1 (TTF-1), surfactant protein B (SPB), and vimentin. Results of both individual and panels of antibodies were statistically evaluated. The sensitivity and specificity of single antibodies for inferring a lung primary was as follows: CK7 (90%/56%), CK20 (98%/40%), epithelial membrane antigen (90.9%/4%), carcinoembryonic antigen (80.9%/36%), TTF-1 (62.7%/100%), SPB (65.6%/100%), and vimentin (60.9%/60%). The highest sensitivity (85%) and specificity (100%) were seen with a 4-antibody panel: CK7, CK20, TTF-1, and SPB. This panel revealed the highest binomial probability (.8), for diagnosing lung cancer. The results were validated using a "split sample method," and a high concordance was noted between the control and test groups. To conclude, such evidence-based validated studies analyzing IHC results would be invaluable to guide the practice of surgical pathology in the future.

[Advances of molecular targeted therapy in squamous cell lung cancer]

肺鳞癌（squamous-cell lung cancer, SQCLC）是一种常见的肺癌病理类型，全世界每年约40余万人死于肺鳞癌，发病与吸烟密切相关。然而，研究表明，在肺腺癌中有明显疗效的靶向药物却无法让肺鳞癌患者获益，如人表皮生长因子受体（epidermal growth factor receptor, EGFR）抑制剂、间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）抑制剂等。通过大量基因组学研究表明，纤维母细胞生长因子受体1（fibroblast growth factor receptor 1, FGFR1）基因扩增和盘状结构域受体2（the discoidin domain receptor 2, DDR2）基因突变等都可能成为新的用于治疗肺鳞癌的潜在药物分子靶点。此外，肺鳞癌患者基因组中也存在特异性的基因变异位点，这些改变在肺鳞癌细胞周期调控、氧化应激反应、细胞凋亡和鳞状上皮分化过程中发挥了重要作用，也可能为寻找候选分子靶点提供依据。本综述通过回顾近年来肺鳞癌分子靶向治疗的相关研究，分析靶向治疗在肺鳞癌中的研究进展，使肺鳞癌的个体化靶向治疗成为可能。

Mesothelin overexpression is a marker of tumor aggressiveness and is associated with reduced recurrence-free and overall survival in early-stage lung adenocarcinoma

PURPOSE

In an effort to identify molecular markers of tumor aggressiveness and therapeutic targets in lung adenocarcinoma (ADC), we investigated the expression of mesothelin (MSLN) in lung ADC, as well as its biologic and clinical relevance.

EXPERIMENTAL DESIGN

In a training and validation set of patients with early-stage (I-III) lung ADC (n = 1,209), a tissue microarray consisting of tumors and normal lung tissue was used to examine the association between MSLN expression and recurrence-free survival (RFS) and overall survival (OS). The influence of MSLN overexpression on lung ADC was investigated in vitro and in vivo by use of clinically relevant orthotopic and metastatic xenogeneic and syngeneic mouse models.

RESULTS

MSLN was expressed in 69% of lung ADC tumors, with one in five patients strongly expressing MSLN and no expression in normal lung tissue. Increased MSLN expression was associated with reduced OS [HR = 1.78; 95% confidence interval (CI), 1.26-2.50; P < 0.01] and RFS (HR = 1.67; 95% CI, 1.21-2.27; P < 0.01) in multivariate analyses, even after adjustment for currently known markers of tumor aggressiveness in lung ADC: male sex, smoking history, increasing stage, morphologic pattern, visceral pleural invasion, lymphatic or vascular invasion, and mutation status. In vitro, lung ADC cells overexpressing MSLN demonstrated increased cell proliferation, migration, and invasion; in vivo, mice with MSLN(+) tumors demonstrated decreased survival (P = 0.001).

CONCLUSIONS

MSLN expression in patients with early-stage lung ADC is associated with increased risk of recurrence and reduced OS, indicating that MSLN expression is a molecular marker of tumor aggressiveness and a potential target for therapy.

Ancillary Studies, Including Immunohistochemistry and Molecular Studies, in Lung Cytology

The importance of cytologic techniques for investigation of respiratory conditions has been recognized since the earliest days of clinical cytology. Cytology is able to detect most of mycoses and parasitic and viral infections based on the morphologic recognition of these agents. The most relevant application of lung cytology today is in the diagnosis and management of lung cancer; approximately 70% of those cancers are diagnosed at a late stage and are unresectable. This article addresses the most common ancillary techniques, such as special stains, immunocytochemistry, and molecular testing, used to refine the cytologic diagnosis of lung cancer and to guide personalized therapy.

EGFR-mediated Beclin 1 phosphorylation in autophagy suppression, tumor progression, and tumor chemoresistance

Cell surface growth factor receptors couple environmental cues to the regulation of cytoplasmic homeostatic processes, including autophagy, and aberrant activation of such receptors is a common feature of human malignancies. Here, we defined the molecular basis by which the epidermal growth factor receptor (EGFR) tyrosine kinase regulates autophagy. Active EGFR binds the autophagy protein Beclin 1, leading to its multisite tyrosine phosphorylation, enhanced binding to inhibitors, and decreased Beclin 1-associated VPS34 kinase activity. EGFR tyrosine kinase inhibitor (TKI) therapy disrupts Beclin 1 tyrosine phosphorylation and binding to its inhibitors and restores autophagy in non-small-cell lung carcinoma (NSCLC) cells with a TKI-sensitive EGFR mutation. In NSCLC tumor xenografts, the expression of a tyrosine phosphomimetic Beclin 1 mutant leads to reduced autophagy, enhanced tumor growth, tumor dedifferentiation, and resistance to TKI therapy. Thus, oncogenic receptor tyrosine kinases directly regulate the core autophagy machinery, which may contribute to tumor progression and chemoresistance.

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.

Tumor cell expression of vascular endothelial growth factor receptor 2 is an adverse prognostic factor in patients with squamous cell carcinoma of the lung

A robust immunohistochemical (IHC) assay for VEGFR2 was developed to investigate its utility for patient tailoring in clinical trials. The sensitivity, specificity, and selectivity of the IHC assay were established by siRNA knockdown, immunoblotting, mass spectrometry, and pre-absorption experiments. Characterization of the assay included screening a panel of multiple human cancer tissues and an independent cohort of non-small cell lung carcinoma (NSCLC, n = 118) characterized by TTF-1, p63, CK5/6, and CK7 IHC. VEGFR2 immunoreactivity was interpreted qualitatively (VEGFR2 positive/negative) in blood vessels and by semi-quantitative evaluation using H-scores in tumor cells (0-300). Associations were determined among combinations of VEGFR2 expression in blood vessels and tumor cells, and clinico-pathologic characteristics (age, sex, race, histologic subtype, disease stage) and overall survival using Kaplan-Meier analyses and appropriate statistical models. VEGFR2 expression both in blood vessels and in tumor cells in carcinomas of the lung, cervix, larynx, breast, and others was demonstrated. In the validation cohort, 99/118 (83.9%) NSCLC tissues expressed VEGFR2 in the blood vessels and 46/118 (39.0%) showed high tumor cell positivity (H-score ≥10). Vascular and tumor cell expression were inversely correlated (p = 0.0175). High tumor cell expression of VEGFR2 was associated with a 3.7-fold reduction in median overall survival in lung squamous-cell carcinoma (SCC, n = 25, p = 0.0134). The inverse correlation between vascular and tumor cell expression of VEGFR2 and the adverse prognosis associated with high VEGFR2 expression in immunohistochemically characterized pulmonary SCC are new findings with potential therapeutic implications. The robustness of this novel IHC assay will support further evaluation of its utility for patient tailoring in clinical trials of antiangiogenic agents.

The role of molecular analyses in the diagnosis and treatment of non-small-cell lung carcinomas

Non-small-cell lung cancer (NSCLC) subtyping has recently been a key factor in determining patient management with novel drugs. In addition, the identification of distinct oncogenic driver mutations frequently associated with NSCLC histotype and coupled to the clinical responses to targeted therapies have revolutionized the impact of histologic type and molecular biomarkers in lung cancer. Several molecular alterations involving different genes (EGFR, KRAS, ALK, BRAF, and HER2) seem to have a remarkable predilection for adenocarcinoma and specific inhibitors of EGFR and ALK are now available for patients with adenocarcinoma harboring the relevant gene alterations. The efficacy of histology-based and molecular-targeted therapies had a deep impact in (1) re-defining classification of lung cancer (particularly adenocarcinomas) and (2) routine clinical practice of pathologists involved in optimization of handling of tissue samples in order to guarantee NSCLC subtyping with the help of immunohistochemistry and adequately preserve tumor cells for molecular analysis. In agreement with the modern multidisciplinary approach to lung cancer, we reviewed here the diagnostic and predictive value of molecular biomarkers according to the clinical, pathologic, and molecular biologist viewpoints.

Large cell carcinoma of the lung: clinically oriented classification integrating immunohistochemistry and molecular biology

This study aimed at challenging pulmonary large cell carcinoma (LLC) as tumor entity and defining different subgroups according to immunohistochemical and molecular features. Expression of markers specific for glandular (TTF-1, napsin A, cytokeratin 7), squamous cell (p40, p63, cytokeratins 5/6, desmocollin-3), and neuroendocrine (chromogranin, synaptophysin, CD56) differentiation was studied in 121 LCC across their entire histological spectrum also using direct sequencing for epidermal growth factor receptor (EGFR) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations and FISH analysis for ALK gene translocation. Survival was not investigated. All 47 large cell neuroendocrine carcinomas demonstrated a true neuroendocrine cell lineage, whereas all 24 basaloid and both 2 lymphoepithelioma-like carcinomas showed squamous cell markers. Eighteen out of 22 clear cell carcinomas had glandular differentiation, with KRAS mutations being present in 39 % of cases, whereas squamous cell differentiation was present in four cases. Eighteen out of 20 large cell carcinomas, not otherwise specified, had glandular differentiation upon immunohistochemistry, with an exon 21 L858R EGFR mutation in one (5 %) tumor, an exon 2 KRAS mutation in eight (40 %) tumors, and an ALK translocation in one (5 %) tumor, whereas two tumors positive for CK7 and CK5/6 and negative for all other markers were considered adenocarcinoma. All six LCC of rhabdoid type expressed TTF-1 and/or CK7, three of which also harbored KRAS mutations. When positive and negative immunohistochemical staining for these markers was combined, three subsets of LCC emerged exhibiting glandular, squamous, and neuroendocrine differentiation. Molecular alterations were restricted to tumors classified as adenocarcinoma. Stratifying LCC into specific categories using immunohistochemistry and molecular analysis may significantly impact on the choice of therapy.

A comprehensive comparative analysis of the histomorphological features of ALK-rearranged lung adenocarcinoma based on driver oncogene mutations: frequent expression of epithelial-mesenchymal transition markers than other genotype

Molecular classification of lung cancer correlates well with histomorphological features. However, specific histomorphological features that differentiate anaplastic lymphoma kinase (ALK)-rearranged tumors from ALK-negative tumors have not been fully evaluated. Eighty ALK-rearranged and 213 ALK-negative (91 epidermal growth factor receptor-mutated; 29 K-ras-mutated; 93 triple-negative) resected lung adenocarcinomas were analyzed for several histomorphological parameters and histological subtype. ALK-rearranged tumors were associated with younger age at presentation, frequent nodal metastasis, and higher stage of disease at diagnosis. ALK-rearranged tumors were more likely to show a solid predominant pattern than ALK-negative tumors (43.8%; 35/80; p<0.001). Unlike ALK-negative tumors, a lepidic predominant pattern was not observed in ALK-rearranged tumors (p<0.001). In multivariate analysis, the most significant morphological features that distinguished ALK-rearranged tumors from ALK-negative tumors were cribriform formation (odds ratio [OR], 3.253; p = 0.028), presence of mucin-containing cells (OR, 4.899; p = 0.008), close relationship to adjacent bronchioles (OR, 5.361; p = 0.001), presence of psammoma bodies (OR, 4.026; p = 0.002), and a solid predominant pattern (OR, 13.685; p = 0.023). ALK-rearranged tumors exhibited invasive histomorphological features, aggressive behavior and frequent expression of epithelial-mesenchymal transition markers (loss of E-cadherin and expression of vimentin) compared with other genotype (p = 0.015). Spatial proximity between bronchus and ALK-rearranged tumors and frequent solid histologic subtype with p63 expression may cause diagnostic difficulties to differentiate squamous cell carcinoma in the small biopsy, whereas p40 was rarely expressed in ALK-rearranged adenocarcinoma. Knowledge of these features may improve the diagnostic accuracy and lead to a better understanding of the characteristic behavior of ALK-rearranged tumors.

KRAS mutations are associated with solid growth pattern and tumor-infiltrating leukocytes in lung adenocarcinoma

KRAS mutations define a clinically distinct subgroup of lung adenocarcinoma patients, characterized by smoking history, resistance to EGFR-targeted therapies, and adverse prognosis. Whether KRAS-mutated lung adenocarcinomas also have distinct histopathological features is not well established. We tested 180 resected lung adenocarcinomas for KRAS and EGFR mutations by high-sensitivity mass spectrometry-based genotyping (Sequenom) and PCR-based sizing assays. All tumors were assessed for the proportion of standard histological patterns (lepidic, acinar, papillary, micropapillary, solid, and mucinous), several other histological and clinical parameters, and TTF-1 expression by immunohistochemistry. Among 180 carcinomas, 63 (35%) had KRAS mutations (KRAS+), 35 (19%) had EGFR mutations (EGFR+), and 82 (46%) had neither mutation (KRAS-/EGFR-). Solid growth pattern was significantly over-represented in KRAS+ carcinomas: the mean±s.d. for the amount of solid pattern in KRAS+ carcinomas was 27±34% compared with 3±10% in EGFR+ (P<0.001) and 15±27% in KRAS-/EGFR- (P=0.033) tumors. Furthermore, at least focal (≥20%) solid component was more common in KRAS+ (28/63; 44%) compared with EGFR+ (2/35; 6%; P<0.001) and KRAS-/EGFR- (21/82; 26%; P=0.022) carcinomas. KRAS mutations were also over-represented in mucinous carcinomas and were significantly associated with the presence of tumor-infiltrating leukocytes and heavier smoking history. EGFR mutations were associated with non-mucinous non-solid patterns, particularly lepidic and papillary, lack of necrosis, lack of cytological atypia, hobnail cytology, TTF-1 expression, and never/light smoking history. In conclusion, extended molecular and clinicopathological analysis of lung adenocarcinomas reveals a novel association of KRAS mutations with solid histology and tumor-infiltrating inflammatory cells and expands on several previously recognized morphological and clinical associations of KRAS and EGFR mutations. Solid growth pattern was recently shown to be a strong predictor of aggressive behavior in lung adenocarcinomas, which may underlie the unfavorable prognosis associated with KRAS mutations in these tumors.

Utilization of p40 (ΔNp63) with p63 and cytokeratin 5/6 immunohistochemistry in non-small cell lung carcinoma fine-needle aspiration biopsy

OBJECTIVE

Specific subclassification of pulmonary non-small cell carcinoma (NSCCA) is clinically necessary, and the aim of this study is to examine the utilization of p40 (ΔNp63) in fine-needle aspiration (FNA) biopsy for lung NSCCA.

STUDY DESIGN

Database files of the Washington University Medical Center were searched. Patients who underwent endobronchial ultrasound and CT FNA of a primary lung neoplasia were selected and immunohistochemistry (IHC) was performed. A panel of markers was utilized, including p40, p63, cytokeratin (CK) 5/6, thyroid transcription factor, and napsin.

RESULTS

One hundred patients were identified and comprised 38 squamous cell carcinomas (SCCA), 46 adenocarcinomas (AdCA), and 16 NSCCA. For SCCA, p40 was positive in 34/38 cases (89%) and negative in 4/38 cases (11%); p63 was positive in 33/38 cases (87%) and negative in 5/38 cases (13%); CK5/6 was positive in 38/38 cases. For AdCA cases, p40 was negative, p63 was positive in 2 cases (5%) and CK5/6 was negative in 43/46 cases (92%).

CONCLUSION

For NSCCA, p40 had 89% sensitivity and 100% specificity compared to p63 with 86% sensitivity and 96% specificity and CK5/6 with 100% sensitivity and 96% specificity. In the evaluation of FNA biopsy for pulmonary NSCCA, p40 is a useful IHC marker for neoplastic subclassification, with better specificity in comparison to p63.

Stage IV lung cancer: Is cure possible?

Reporting a case, 53 years old male with stage IV Nonsamall cell lung cancer in view of cytologically proven malignant pleural effusion. Usually the management of stage IV lung cancer is with palliative intent where the patient receives palliative chemotherapy along with palliative radiotherapy and surgery if required. Most of the data on curative management of oligometastatic non-small cell lung cancer includes patient with adrenal metastasis and some reports with brain metastasis. There is scarce literature on the surgical management of stage IV lung cancer with pleural effusion.

Characterization of specific p63 and p63-N-terminal isoform antibodies and their application for immunohistochemistry

The TP63 gene gives rise to protein isoforms with different properties and functions due to the presence (TAp63) or absence (ΔNp63) of an N-terminal p53-like transactivation domain. Immunohistochemistry for p63 has clinical value for certain tumour types, but investigations have been hampered by a lack of well characterized antibodies and the inability to discriminate between these N-terminal isoforms with opposite functional properties. We have extensively characterized a series of monoclonal antibodies to recombinant human TAp63 and two commercial p63 monoclonals by Western blot, immunostaining and phage display epitope mapping. Twenty-eight of 29 (96.6 %) novel monoclonals that recognized all p63 isoforms showed substantial cross-reactivity with p73, as did the commercial antibody, 4A4. One novel clone, PANp63-6.1, showed slight cross-reaction with p73 by Western blotting but not immunohistochemistry and the SFI-6 monoclonal did not cross-react with p73 or p53. Phage display revealed that the PANp63-6.1 epitope has one amino acid difference between p63 and p73, the 4A4 epitope is identical in both, whereas the SFI-6 epitope is unique to p63, accounting for these findings. We also produced and characterized a TAp63-specific clone that does not recognize p53 or p73, and we prepared polyclonal sera specific for ΔNp63 isoforms. Immunohistochemistry demonstrated that TAp63 is expressed in a variety of epithelial and other cell types during development, often in a converse pattern to ΔNp63, but has a very limited expression in normal adult tissues and is independent of ΔNp63. TAp63 was expressed in 17.6 % of squamous cancers of cervix that expressed p63, unlike normal cervix where TAp63 was not expressed. TAp63 did not associate with proliferative index, but cervical carcinomas with TAp63 expression showed improved survival. These data highlight the need for rigorous antibody characterization and indicate that p63-isoform identification may improve the clinical value of p63 expression analyses.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture published articles from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. EVIDENCE was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.

Molecular testing guideline for selection of lung cancer patients for EGFR and ALK tyrosine kinase inhibitors: guideline from the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology

OBJECTIVE

To establish evidence-based recommendations for the molecular analysis of lung cancers that are that are required to guide EGFR- and ALK-directed therapies, addressing which patients and samples should be tested, and when and how testing should be performed.

PARTICIPANTS

Three cochairs without conflicts of interest were selected, one from each of the 3 sponsoring professional societies: College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology. Writing and advisory panels were constituted from additional experts from these societies.

EVIDENCE

Three unbiased literature searches of electronic databases were performed to capture articles published published from January 2004 through February 2012, yielding 1533 articles whose abstracts were screened to identify 521 pertinent articles that were then reviewed in detail for their relevance to the recommendations. Evidence was formally graded for each recommendation.

CONSENSUS PROCESS

Initial recommendations were formulated by the cochairs and panel members at a public meeting. Each guideline section was assigned to at least 2 panelists. Drafts were circulated to the writing panel (version 1), advisory panel (version 2), and the public (version 3) before submission (version 4).

CONCLUSIONS

The 37 guideline items address 14 subjects, including 15 recommendations (evidence grade A/B). The major recommendations are to use testing for EGFR mutations and ALK fusions to guide patient selection for therapy with an epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase (ALK) inhibitor, respectively, in all patients with advanced-stage adenocarcinoma, regardless of sex, race, smoking history, or other clinical risk factors, and to prioritize EGFR and ALK testing over other molecular predictive tests. As scientific discoveries and clinical practice outpace the completion of randomized clinical trials, evidence-based guidelines developed by expert practitioners are vital for communicating emerging clinical standards. Already, new treatments targeting genetic alterations in other, less common driver oncogenes are being evaluated in lung cancer, and testing for these may be addressed in future versions of these guidelines.