A reevaluation of the clinical significance of histological subtyping of non--small-cell lung carcinoma: diagnostic algorithms in the era of personalized treatments

Successful resection of colonic metastasis of lung cancer after colonic stent placement: A case report and review of the literature

BACKGROUND

Lung cancer is the leading cause of cancer deaths worldwide. Although lung cancer can metastasize to various organs such as the liver, lymph nodes, adrenal gland, bone, and brain, metastases to the digestive organs, especially the colon, are rare.

CASE SUMMARY

An 83-year-old man diagnosed with lung cancer received radiation and chemoimmunotherapy, resulting in a complete clinical response. One year after the initial lung cancer diagnosis, the patient presented with obstructive ileus caused by a tumor in the descending colon. An elective left hemicolectomy was successfully performed after the endoscopic placement of a self-expandable metallic stent (SEMS). Pathologically, the tumor of the descending colon was diagnosed as lung cancer metastasis. The postoperative course was uneventful, and the patient is in good condition 13 mo after surgery, with no signs of recurrence. The previous 23 cases of surgical resection of colonic metastasis from lung cancer were reviewed using PubMed to characterize their clinicopathological features and outcomes.

CONCLUSION

SEMS is useful for obstructive colonic metastasis as a bridge to surgery to avoid emergency operations.

Mid-Infrared Imaging Characterization to Differentiate Lung Cancer Subtypes

Introduction: Lung cancer is the most common malignancy worldwide. Squamous cell carcinoma (SQ) and adenocarcinoma (LUAD) are the two most frequent histological subtypes. Small cell carcinoma (SCLC) subtype has the worst prognosis. Differential diagnosis is essential for proper oncological treatment. Life science associated mid- and near-infrared based microscopic techniques have been developed exponentially, especially in the past decade. Vibrational spectroscopy is a potential non-destructive approach to investigate malignancies.

Aims: Our goal was to differentiate lung cancer subtypes by their label-free mid-infrared spectra using supervised multivariate analyses.

Material and Methods: Formalin-fixed paraffin-embedded (FFPE) samples were selected from the archives. Three subtypes were selected for each group: 10-10 cases SQ, LUAD and SCLC. 2 μm thick sections were cut and laid on aluminium coated glass slides. Transflection optical setup was applied on Perkin-Elmer infrared microscope. 250 × 600 μm areas were imaged and the so-called mid-infrared fingerprint region (1800-648cm⁻¹) was further analysed with linear discriminant analysis (LDA) and support vector machine (SVM) methods.

Results: Both “patient-based” and “pixel-based” approaches were examined. Patient-based analysis by using 3 LDA models and 2 SVM models resulted in different separations. The higher the cut-off value the lower is the accuracy. The linear C-support vector classification (C-SVC) SVM resulted in the best (100%) accuracy for the three subtypes using a 50% cut-off value. The pixel-based analysis gave, similarly, the linear C-SVC SVM model to be the most efficient in the statistical indicators (SQ sensitivity 81.65%, LUAD sensitivity 82.89% and SCLC sensitivity 88.89%). The spectra cut-off, the kernel function and the algorithm function influence the accuracy.

Conclusion: Mid-Infrared imaging could be used to differentiate FFPE lung cancer subtypes. Supervised multivariate tools are promising to accurately separate lung tumor subtypes. The long-term perspective is to develop a spectroscopy-based diagnostic tool, revolutionizing medical differential diagnostics, especially cancer identification.

Can cytology reliably subtype non-small cell lung carcinomas?

Cytology specimens play an important role in the diagnosis and predictive testing of lung cancer. While morphological characterisation of small cell and non-small cell lung carcinomas (NSCLC) on cytology is possible, further subtyping of NSCLC into adenocarcinoma and squamous cell carcinoma morphology is also mandatory in the current era of personalised medicine. Notably, cytology specimens in different forms (fine needle aspiration, exfoliative, and cell block) with or without immunocytochemistry are reliable sources for accurate diagnosis of adenocarcinoma and squamous cell carcinoma as evidenced by numerous studies present in the literature. However, there are instances where subtyping of NSCLC based on morphology alone is challenging on cytology samples, especially non-cell block preparations. In this paper, we will discuss current concepts, advances, and challenges of subtyping NSCLC in cytology specimens.

Utility of liquid-based cytology on residual needle rinses collected from core needle biopsy for lung nodule diagnosis

BACKGROUND

Core needle biopsy (CNB) has become the most common tissue sampling modality for pathological diagnosis of peripheral lung nodules. However, approximately 10% of pulmonary CNB specimens cannot be unambiguously diagnosed, even with auxiliary techniques. This retrospective study investigated the diagnostic value of liquid-based cytology on residual pulmonary CNB material collected from needle rinses.

METHODS

Computed tomography-guided pulmonary CNB specimens and relevant cytology of CNB needle rinses (CNR) from July 2017 to June 2020 were reviewed. A total of 406 patients, each of whom underwent a CNB procedure, were included in the study.

RESULTS

Of the 406 cases, a more serious diagnosis was rendered by CNR in 6.4% (n = 26) of cases. Furthermore, among these 26 cases, 13 malignancies were confirmed only from CNR. Of the remaining 13 patients with uncertain lesions identified from CNR, six were diagnosed with definite benign lesions from tissue samples, five were found to harbor malignant neoplasms through repeated CNB or follow-up examination, and two had tuberculosis. The sensitivity (320/332, 96.4%) of combined CNR/CNB (both CNR and CNB) in distinguishing malignancies from benign lesions was higher than that of CNB alone (307/332, 92.5%). A total of 320 malignant neoplasms included 198 cases of primary lung adenocarcinoma and 71 cases of primary lung squamous cell carcinoma.

CONCLUSIONS

CNR with higher nuclear and cytoplasmic resolution than CNB exhibited a high diagnostic efficacy for differentiating malignant from benign lesions in the lung. Moreover, combined CNR/CNB achieved optimal results in reducing the false-negative rate and the subtyping of non-small cell lung cancer.

Diagnostic utility of fine needle aspiration cytology and core biopsy histopathology with or without immunohistochemical staining in the subtyping of the non-small cell lung carcinomas: Experience from an academic centre in Turkey

INTRODUCTION

This retrospective morphological study compared the results of fine needle aspiration (FNA) cytology, haematoxylin-eosin (HE)-stained samples and immunohistochemical (IHC)-stained core needle biopsy (CNB) histology samples for primary non-small cell lung cancer (NSCLC) subtyping. We assessed the diagnostic utility of these methods to investigate the contribution of each method to NSCLC subtyping. We also identified the point at which NSCLC subtyping could be performed using histomorphology alone without IHC.

METHODOLOGY

Concurrent FNA and CNB specimens obtained via a single computed tomography-guided procedure and diagnosed as NSCLC in the Pathology Department of our university within 3 years were reviewed. The results of FNA samples, HE-stained biopsies and IHC-stained biopsies were compared according to subtype.

RESULTS

A total of 141 subjects were enrolled in the study. For subtyping, FNA provided an accurate diagnosis in 70 (55.1%) of 127 eligible subjects after the exclusion of 14 cases determined as not otherwise specified. CNB histology without IHC achieved a diagnosis in 53 (41.7%) of 127 subjects, which was a significant difference (P < .05). The compatibility rate between HE-stained biopsy samples and IHC-stained biopsy samples was 41.7% (53/127).

CONCLUSION

The diagnosis rates achieved using FNA, HE-stained CNB samples and IHC-stained CNB samples were 54.6% (77/141), 37.6% (53/141) and 90.1% (127/141), respectively. The subtype was identified in 55.1% of the subjects evaluated using FNA and 41.7% of subjects assessed using HE-stained biopsy samples without IHC. FNA provided a better result for squamous cell carcinoma than adenocarcinoma (55.1% vs 47.6%), but the diagnosing of adenocarcinoma and squamous cell carcinoma using HE-stained biopsy samples was similar (42% vs 41.7%).

Mediastinal Nodular Lesions Synchronous to Lung Carcinoma on Frozen Section: Trap and Lesson

Thymoma is the most frequent neoplasm arising in the anterior mediastum. It usually presents as an enlarged central mass. In the literature, multiple thymoma is described as an unusual finding; rare variants have also been described, like the signet ring-like cell variant. Evidence of co-existence of signet ring-like cells and lymphocytes in small biopsies from nodular mediastinal lesions can lead to a diagnosis of metastatic carcinoma, mostly at frozen sections. Thymoma and pulmonary carcinoma are very rarely associated neoplasms. We present a case of two mediastinal lesions discovered during pulmonary carcinoma staging. At frozen section, a diagnosis of 'epithelioid proliferation associated to lymphoid tissue' was advanced on a sample of nodular lesions and of 'carcinoma' on pulmonary biopsy. Double AB Type Thymoma with a signet ring cell-like component, synchronous to pulmonary adenocarcinoma, was the diagnosis made on formalin fixed-paraffin embedded samples. Reporting the coexistence of these two entities can help pathologists and surgeons to establish the best management of similar patients.

The Clinical Impact of Re-biopsies in Lung Adenocarcinoma: a Retrospective Multicenter Study

If a patient's cancer progresses while undergoing targeted therapy, a re-biopsy is not mandatory. But when evaluating the benefits and risks on a case-by-case basis (transformation to small cell, assessing for a clinical trial), physicians should inform patients about the possible need for a re-biopsy (5). This was a retrospective and multicentre study. A total of 644 patients with lung adenocarcinoma were reviewed, 625 of whom were ruled eligible. From them, 399 were found to show disease progression, and 126 re-biopsies were performed. Progression status, re-biopsy sites, success of obtaining adequate tissue, molecular patterns after re-biopsy and subsequent treatments were analysed. Survival differences among patients with disease progression were then examined according to re-biopsy status. Overall, 625 patients with adenocarcinoma and a median age of 61.4 were evaluated. Initial tyrosine kinase inhibitor (TKI) usage numbered 37 patients (5.9%). Progression was diagnosed in 399 (63.8%) patients, out of which 26 (31.6%) underwent re-biopsies. The successful number of re-biopsies was 103 (81.7%). No complications were observed after any of the biopsy procedures. Subsequent treatments were changed in 15 patients (11.9%), who began new TKI treatments. Poor performance status was the most common reason for not performing a biopsy (n = 65; 23.8%), followed by the physician's decision (n = 40; 14.6%). Re-biopsies can demonstrate the new characteristics of a tumour and can detect the activation of pre-existing clones, making possible new treatment opportunities for patients. According to the performance status of the patient and the availability of the progressive lesion, we should increase the rate of re-biopsies before the decision to follow up with the best supportive care.

TTF-1/p63-Positive Poorly Differentiated NSCLC: A Histogenetic Hypothesis from the Basal Reserve Cell of the Terminal Respiratory Unit

TTF-1 is expressed in the alveolar epithelium and in the basal cells of distal terminal bronchioles. It is considered the most sensitive and specific marker to define the adenocarcinoma arising from the terminal respiratory unit (TRU). TTF-1, CK7, CK5/6, p63 and p40 are useful for typifying the majority of non-small-cell lung cancers, with TTF and CK7 being typically expressed in adenocarcinomas and the latter three being expressed in squamous cell carcinoma. As tumors with coexpression of both TTF-1 and p63 in the same cells are rare, we describe different cases that coexpress them, suggesting a histogenetic hypothesis of their origin. We report 10 cases of poorly differentiated non-small-cell lung carcinoma (PD-NSCLC). Immunohistochemistry was performed by using TTF-1, p63, p40 (ΔNp63), CK5/6 and CK7. EGFR and BRAF gene mutational analysis was performed by using real-time PCR. All the cases showed coexpression of p63 and TTF-1. Six of them showing CK7+ and CK5/6− immunostaining were diagnosed as “TTF-1+ p63+ adenocarcinoma”. The other cases of PD-NSCLC, despite the positivity for CK5/6, were diagnosed as “adenocarcinoma, solid variant”, in keeping with the presence of TTF-1 expression and p40 negativity. A “wild type” genotype of EGFR was evidenced in all cases. TTF1 stained positively the alveolar epithelium and the basal reserve cells of TRU, with the latter also being positive for p63. The coexpression of p63 and TTF-1 could suggest the origin from the basal reserve cells of TRU and represent the capability to differentiate towards different histogenetic lines. More aggressive clinical and morphological features could characterize these “basal-type tumors” like those in the better known “basal-like” cancer of the breast.

Complementary value of electron microscopy and immunohistochemistry in the diagnosis of non-small cell lung cancer: A potential role for electron microscopy in the era of targeted therapy

With the identification of therapeutic targets for lung adenocarcinoma, it has become mandatory to distinguish it from other entities. Some cases remain classified as non-small cell lung carcinoma, not otherwise specified (NSCLC-NOS) with immunohistochemistry. Electron microscopy (EM) can be useful, allowing the identification of glandular differentiation. The aim of this study was to determine the complementary value of immunohistochemistry and EM.Forty-eight NSCLC-NOS cases were selected (PSMAR-Biobank, Barcelona, Spain). Immunohistochemistry (TTF-1, p40) was performed. Tissue was retrieved from paraffin blocks. Results were compared to the final diagnosis, derived from combination of light microscopy, immunohistochemistry, EM, molecular studies and resection specimen.Immunohistochemistry concurred with final diagnosis in 36 cases (75%, Kappa = 0.517). EM agreed with final diagnosis in 35 (72.9%, Kappa = 0.471). Immunohistochemistry had a sensitivity = 73%, specificity = 100%, positive predictive value (PPV) = 100% and negative predictive value (NPV) = 52.4% for adenocarcinoma. All adenocarcinoma cases not solved by immunohistochemistry (n = 10) were classified by EM, and vice versa. Data from EM were identical to those of immunohistochemistry: sensitivity = 73%, specificity = 100%, PPV = 100% and NPV = 52.4%. Combining both techniques, 47 cases were coincident with final diagnosis (97.9%, Kappa = 0.943).EM can provide valuable information in subtyping NSCLC-NOS, being particularly useful when immunohistochemistry is inconclusive. EM could be considered as a complementary tool for decision-making in NSCLC-NOS.

Histopathologic and molecular approach to staging of multiple lung nodules

Distinguishing multiple primary lung cancers from intrapulmonary metastases in patients with synchronous multifocal lung adenocarcinomas can be challenging. The most recent 8th edition American Joint Committee on Cancer staging manual (AJCC staging manual) distinguishes four disease patterns in patients with multiple lung nodules: (I) two or more distinct and histologically different masses (considered unrelated and staged as individual cancers); (II) multiple ground-glass or part-solid nodules, histologically of with lepidic growth pattern (considered separate tumors, T staged based on highest T stage lesion); (III) patchy areas of ground-glass and consolidations, histologically often invasive mucinous adenocarcinomas (considered single tumor with diffuse "pneumonic-type" involvement); and (IV) separate nodules with the same histologic features based on comprehensive histologic subtyping (considered intrapulmonary metastases). Histologic and molecular features, in conjunction with clinical and radiological information, can all be tools to assist with staging of multiple nodules. Histologic features of adenocarcinomas are best characterized using comprehensive histologic subtyping (percentage of lepidic, acinar, solid, papillary and micropapillary pattern). Genomic alterations are commonly assessed using fluorescence in-situ hybridization and next generation sequencing (NGS). The AJCC considers exactly matching breakpoints by comparative genomic hybridization (CGH) as the only evidence for intrapulmonary metastases, and clearly different histologic types or subtypes as the only evidence for separate primary tumors. Similar histologic subtypes or the same biomarker pattern are considered merely relative arguments in favor of a single tumor source. When assessing multifocal lung cancer, pathologists should consider, and carefully weigh the importance of, molecular testing results in addition to the tumor's histologic features. For many cases encountered in routine clinical practice, absolute certainty cannot be reached as to whether they represent multiple primary cancers or intrapulmonary metastases. Classification of difficult cases often benefits from multidisciplinary discussion.

Accuracy of cytology in sub typing non small cell lung carcinomas

BACKGROUND

Sub typing of non small cell lung carcinoma (NSCLC) has an important task in the era of molecular and targeted therapies. Differentiating between squamous cell carcinoma (SQCC) and adenocarcinoma (ADC) is challenging when limited material is available in lung carcinoma. We investigated the accuracy and feasibility of sub typing NSCLCs in cytology and small biopsy material.

METHODS

Concurrent cytology and biopsy material obtained in a single CT- guided procedure in lung carcinoma over a year period retrospectively. Both materials were individually sub typed and analyzed. Immunohistochemistry (IHC) was performed. Accuracy was determined by comparing the results with IHC.

RESULTS

Total 107 of 126 cases of NSCLCs were included for analysis, where both cytology and biopsy material were adequate for interpretation. FNAC allowed tumor typing in 83 (77.6%) cases; 36 (33.6%) were ADC, 47 (43.9%) cases were SQCC and 24 (22.4%) cases diagnosed as Non-small cell carcinoma not otherwise specified (NSCLC-NOS). In biopsy, 86 cases (80.4%) were typed, among which 34 (31.8%) were ADC, 52 (48.6%) were SQCC and 21 (19.6%) were of NSCLC-NOS type. The result of Chi-square index was significant. With the aid of IHC, NSCLC-NOS reduced from 14 (13%) cases to 2 (1.9%) cases.

CONCLUSION

Cytology and small biopsy specimens achieved comparable specificity and accuracy in sub-typing NSCLC and optimal results were obtain when findings from both modalities combine. The advantage of paired specimens is to maximize overall diagnostic yield and the remaining material will be available for ancillary technique like IHC or for molecular testing. Diagn. Cytopathol. 2017;45:598-603. © 2017 Wiley Periodicals, Inc.

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.

Roles of immunohistochemical staining in diagnosing pulmonary squamous cell carcinoma

BACKGROUND

Differentiating morphologic features based on hematoxylin-eosin (HE) staining is the most common method to classify pathological subtypes of non-small-cell lung cancer (NSCLC). However, its accuracy and inter-observer reproducibility in pathological diagnosis of poorly differentiated NSCLC remained to be improved.

MATERIALS AND METHODS

We attempted to explore the role of immunohistochemistry (IHC) staining in diagnosing pulmonary squamous cell carcinoma (SQCC) with poorly differentiated features by HE staining or with elevated serum adenocarcinoma-specific tumor markers (AD-TMs). We also compared the difference of epidermal growth factor receptor (EGFR) mutation rate between patients with confirmed SQCC and those with revised pathological subtype. Logistic regression analyses were used to test the association between different factors and diagnostic accuracy.

RESULTS

A total of 132 patients who met the eligible criteria and had adequate specimens for IHC confirmation were included. Pathological revised cases in poor differentiated subgroup, biopsy samples and high-level AD-TMs cases were more than those with high/moderate differentiation, surgical specimens and normal-level AD-TMs. Moreover, biopsy sample was a significant factor decreasing diagnostic accuracy of pathological subtype (OR, 4.037; 95% CI 1.446-11.267, p=0.008). Additionally, EGFR mutation rate was higher in patients with pathological diagnostic changes than those with confirmed SQCC (16.7% vs 4.4%, p=0.157).

CONCLUSIONS

Diagnosis based on HE staining only might cause pathological misinterpretation in NSCLC patients with poor differentiation or high-level AD-TMs, especially those with biopsy samples. HE staining and IHC should be combined as pathological diagnostic standard. The occurrence of EGFR mutations in pulmonary SQCC might be overestimated.

Validation for histology-driven diagnosis in non-small cell lung cancer using hsa-miR-205 and hsa-miR-21 expression by two different normalization strategies

Targeted therapy of non-small cell lung cancer (NSCLC) demands a more accurate tumor classification that is crucial for patient selection in personalized treatment. MicroRNAs constitute a promising class of biomarkers and a helpful tool for the distinction between lung adenocarcinoma (AC) and squamous cell lung carcinoma (SCC). The aim of this study was to evaluate the impact of two different normalization strategies, using U6 snRNA and hsa-miR-103 as reference genes, on hsa-miR-205 and hsa-miR-21 expression levels, in terms of the classification of subtypes of NSCLC. By means of a quantitative real-time polymerase chain reaction (qRT-PCR) microRNA expression levels were evaluated in a classification set of 98 surgically resected NSCLC fresh-frozen samples, and validated findings in an independent set of 42 NSCLC samples. The microRNA expression levels were exploited to develop a diagnostic test using two data normalization strategies. The performance of microRNA profiling in different normalization methods was compared. We revealed the microRNA-based qRT-PCR tests to be appropriate measures for distinguishing between AC and SCC (the concordance of histologic diagnoses and molecular methods greater than 88%). Performance evaluation of microRNA tests, based on the two normalization strategies, showed that the procedure using hsa-miR-103 as reference target has a slight advantage (sensitivity 83.33 and 100% in classification and validation set, respectively) compared to U6 snRNA. Molecular tests based on microRNA expression allow a reliable classification of subtypes for NSCLC and can constitute a useful diagnostic strategy in patient selection for targeted therapy.

Impact of non-small-cell lung cancer-not otherwise specified immunophenotyping on treatment outcome

INTRODUCTION

The vast majority of non-small-cell lung cancers (NSCLCs) presents as advanced disease, and histological diagnosis is widely based on small samples. The differential activity and toxicity profile of new cytotoxic and molecular-targeted therapies according to histotypes requires a precise subtyping of NSCLC. Immunohistochemistry (IHC) contributes to define the most probable histotype; however, the real impact of IHC characterization of NSCLC-not otherwise specified (NOS) in terms of outcome is not well established.

METHODS

A large series of 224 advanced "nonsquamous" NSCLC diagnosed on small biopsy or cytological samples and homogeneously treated was retrospectively selected, all having adequate follow-up data available. Reviewed diagnoses resulted into two groups: adenocarcinoma (ADC) and NSCLC-NOS. The latter was further characterized by IHC (TTF-1, Napsin-A, p40, and Desmocollin-3) -identify a possible, most probable differentiation lineage.

RESULTS

Sixty-seven percentage of cases were classified as ADC based on morphological examination only ("morphological ADC") and 33% as NSCLC-NOS. IHC profiling of NSCLC-NOS identified 43.2% of cases with an ADC immunophenotype ("NSCLC favor ADC"), 10.8% with a phenotype favoring squamous lineage, and 46% lacking differentiation features. Survival curves confirmed no difference in terms of outcome between the morphological ADC and the NSCLC favor ADC groups, while a significantly poorer outcome was found in the "null" group in terms of best response, progression-free survival or overall survival (OS).

CONCLUSION

Tumors with an IHC profile ADC-like had an OS comparable with that of morphological ADCs. These findings support the use of IHC to optimize lung cancer histological typing and therapy.

Factors affecting the success of next-generation sequencing in cytology specimens

BACKGROUND

The use of cytology specimens for next-generation sequencing (NGS) is particularly challenging because of the unconventional substrate of smears and the often limited sample volume. An analysis of factors affecting NGS testing in cytologic samples may help to increase the frequency of successful testing.

METHODS

This study reviewed variables associated with all in-house cytology cases (n = 207) that were analyzed by NGS with the Ion Torrent platform during a 10-month interval. A statistical analysis was performed to measure the effects of the DNA input threshold, specimen preparation, slide type, tumor fraction, DNA yield, and cytopathologist bias.

RESULTS

One hundred sixty-four of 207 cases (79%) were successfully sequenced by NGS; 43 (21%) failed because of either a low DNA yield or a template/library preparation failure. The median estimated tumor fraction and DNA concentration for the successfully sequenced cases were 70% and 2.5 ng/μL, respectively, whereas they were 60% and 0.2 ng/μL, respectively, for NGS failures. Cell block sections were tested in 91 cases, and smears were used in 116 cases. NGS success positively correlated with the DNA yield but not the tumor fraction. Cell block preparations showed a higher success rate than smears. Frosted-tip slides yielded significantly more DNA than fully frosted slides. Lowering the input DNA concentration below the manufacturer's recommended threshold of 10 ng (>0.85 ng/μL) resulted in a marked increase in the NGS success rate from 58.6% to 89.8%.

CONCLUSIONS

The failure of NGS with cytology samples is usually a result of suboptimal DNA due to multiple pre-analytical factors. Knowledge of these factors will allow better selection of cytology material for mutational analysis.

Squamous non-small cell lung cancer as a distinct clinical entity

Traditionally, the treatment of lung cancer has been based on histologic type [non-small cell lung cancer (NSCLC) or small cell lung cancer], performance status, and stage of disease. However, more recently, treatment decisions are being made based on molecular and histologic characteristics of the tumor. Specifically, the subclassification of NSCLC as squamous or nonsquamous is important in the context of newer treatments because clinical data have demonstrated differences in the tolerability and activity of these agents. Although progress continues to be made in the treatment of nonsquamous NSCLC, a significant unmet need exists for patients with squamous NSCLC. For both targeted and chemotherapeutic agents, the majority of regulatory approvals and updates to clinical practice guidelines for advanced NSCLC have focused on nonsquamous disease. In addition, because of safety concerns, patients with squamous NSCLC have been excluded from a number of clinical trials of investigational agents, particularly those targeting angiogenesis. This review discusses the importance of histology for treatment selection in NSCLC and summarizes recently completed and ongoing trials of investigational agents in squamous NSCLC. In addition, exciting developments in next-generation sequencing of squamous NSCLC have highlighted differences between squamous and nonsquamous disease and revealed potential new therapeutic targets. Advances in the molecular genetics of squamous NSCLC and implications for therapy will also be reviewed. Although progress in squamous NSCLC has faced limitations, momentum is building toward the identification of more effective treatments for this patient population.

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).

Metastatic lesions in the gastroduodenum — an unusual manifestation of malignant melanoma and pulmonary adenocarcinoma

The gastrointestinal tract (GIT) is an unusual site for metastasis. The rate of GIT metastases detected clinically is very low because of unspecific symptoms and signs of GIT involvement, which include general weakness, tiredness, weight loss, unspecific abdominal pain, fatigue, and anemia. We report clinical, endoscopic, and pathological patterns of two patients (malignant melanoma and primary lung tumor) with metastatic lesions in the gastroduodenum. The first case is a 59-year-old man with unspecific symptoms as nausea, vomiting and abdominal pain. He underwent resection of skin melanoma on his back one year before. Upper gastrointestinal endoscopy revealed two melanotic polypoid masses with ulcerations at the tip, one in the stomach and one in the duodenal bulb. Endoscopic biopsy of these polypoid masses and immunohistochemical stains confirmed the diagnosis of metastatic malignant melanoma. The second case is a 73-year-old man with a two-day history of melena and unspecific abdominal pain. Three weeks before, the patient was operated on for the adenocarcinoma of the lung. Endoscopy of the upper gastrointestinal tract revealed irregular polypoid mass with ulcerations at the tip: three of the stomach mucosa, two in the duodenal bulb and more than ten hemorrhagic polypoid masses at the desendent duodenum. Biopsies of these lesions confirmed the diagnosis of metastatic lung adenocarcinoma. In patients with a history of malignant melanoma and lung cancer unspecific symptoms, like abdominal pain, anemia, and gastrointestinal bleeding gastroduodenal metastases should be suspected. The diagnosis requires careful endoscopic examinations of the mucosa for metastatic lesions and biopsy with special immunohistochemical stains.

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.

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.

Spatial and temporal distributions of lung cancer histopathology in the state of Maine

Maine has among the highest rates of lung cancer in the United States (US). Maine serves as a geographical representation of US rural communities, and their associated health disparities. As the key risks of tobacco use decrease and radon abatement increases, previously obscured environmental exposures may measurably contribute to the attributable risk fraction of lung cancer. To generate hypotheses of novel environmental exposures associated with lung cancer, we investigated if there was non-random spatial distribution of lung cancer in Maine. Case data (n = 14,038) between 1995 and 2006 were obtained from the Maine Cancer Registry. Population data were obtained from the 2000 US Census. We assessed the spatial distribution of lung cancers among white cases by histopathology subtype [non-small cell lung carcinoma (NSCLC): adenocarcinoma (n = 3680), squamous cell (n = 2801) and large cell (n = 1195); and small cell lung carcinoma (SCLC) (n = 1994)], using spatial scan statistic, assuming a discrete Poisson distribution adjusted for age and population density. Because of time-dependent trends in lung cancer differential diagnostic criteria, we repeated our analyses, limiting it to 2002-2006. While SCLC rates were equivalent across the state, we identified discrete regions with elevated rates of adenocarcinoma among females and squamous cell carcinoma among males. Independent of gender, the most striking geospatial observation was elevated large cell lung cancer specifically in one of the poorest counties in the US. A selective spatial distribution of large cell lung cancer has not been previously reported. More research is needed to identify factors inducing large cell carcinoma pathology, and to determine if in rural communities health disparities are associated with increased risk for this diagnosis.

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.

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.

Semi-nested real-time reverse transcription polymerase chain reaction methods for the successful quantitation of cytokeratin mRNA expression levels for the subtyping of non-small-cell lung carcinoma using paraffin-embedded and microdissected lung biopsy specimens

In patients with inoperable advanced non-small cell lung carcinomas (NSCLCs), histological subtyping using small-mount biopsy specimens was often required to decide the indications for drug treatment. The aim of this study was to assess the utility of highly sensitive mRNA quantitation for the subtyping of advanced NSCLC using small formalin fixing and paraffin embedding (FFPE) biopsy samples. Cytokeratin (CK) 6, CK7, CK14, CK18, and thyroid transcription factor (TTF)-1 mRNA expression levels were measured using semi-nested real-time quantitative (snq) reverse-transcribed polymerase chain reaction (RT-PCR) in microdissected tumor cells collected from 52 lung biopsies. Our results using the present snqRT-PCR method showed an improvement in mRNA quantitation from small FFPE samples, and the mRNA expression level using snqRT-PCR was correlated with the immunohistochemical protein expression level. CK7, CK18, and TTF-1 mRNA were expressed at significantly higher levels (P<0.05) in adenocarcinoma (AD) than in squamous cell carcinoma (SQ), while CK6 and CK14 mRNA expression was significantly higher (P<0.05) in SQ than in AD. Each histology-specific CK, particularly CK18 in AD and CK6 in SQ, were shown to be correlated with a poor prognosis (P=0.02, 0.02, respectively). Our results demonstrated that a quantitative CK subtype mRNA analysis from lung biopsy samples can be useful for predicting the histology subtype and prognosis of advanced NSCLC.

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.

Reliability of EGFR and KRAS mutation analysis on fine-needle aspiration washing in non-small cell lung cancer

INTRODUCTION

Molecular profiling of advanced non-small cell lung cancer (NSCLC) has become essential for predicting customized medical treatment decision. In light of recent advances in non-invasive diagnostic procedures in NSCLC, we aimed to demonstrate the reliability of assessing molecular tests for epidermal growth factor receptor (EGFR) and KRAS genes on cytological samples by comparing the molecular profile obtained on cells from scraped smears with that on paired needle washing in a series of NSCLC cases.

METHODS

Thirty-two cytological specimens obtained by fine-needle aspiration biopsy procedures from primary or metastatic lesions of NSCLCs were Giemsa stained for a rapid on-site evaluation and, in case of an adequate sampling, the cellular material obtained from needle washing was collected into a saline solution. Scraped smears and needle washings were tested for EGFR and KRAS by polymerase chain reaction followed by direct sequencing.

RESULTS

The concordance between EGFR and KRAS mutational status in 29 paired scraped smears and needle washing was 100%, with 7 paired samples showing the same EGFR mutation (4 L858R mutation, 2 E746_A750 deletion and 1 A767_V769 duplication) and 8 paired samples showing the same KRAS mutations (4 G12D, 1 G12A, 1 G12V and 2 G12C). Three scraped smears, uninformative for poor DNA quality, resulted EGFR mutated on paired needle washings.

CONCLUSIONS

Needle washing obtained in the course of NSCLC non-invasive fine needle diagnostic procedures allows reliable mutation testing and can be regarded as an additional important source of biological material for molecular profiling of advanced NSCLC.

The evolving role of the pathologist in the management of lung cancer

Major advances in pathology, molecular biology, patient diagnosis and care, as well as the advent of personalized therapy, have resulted in a greatly increased role for the pathologist, who has emerged as a key member of the lung cancer management team. A new multidisciplinary, clinically relevant classification of pulmonary adenocarcinoma has resulted in a paradigm shift in how we view and practice lung cancer pathology. In the future, the role of the pathologist will continue to grow and become fully integrated with clinical care.

EGFR mutation-specific antibodies in pulmonary adenocarcinoma: a comparison with DNA direct sequencing

INTRODUCTION

Epidermal growth factor receptor (EGFR) gene mutations are usually detected by direct sequencing to identify patients with advanced pulmonary adenocarcinomas as candidates for tyrosine kinase inhibitor therapy. The aim of the study was to evaluate the efficacy of EGFR mutation-specific antibodies in identifying EGFR-mutated adenocarcinomas.

MATERIALS AND METHODS

Thirty-three consecutive cases of pulmonary adenocarcinomas sequenced for EGFR mutations were retrieved from our files. Immunohistochemistry was performed with the rabbit monoclonal antibodies E746-A750del (6B6) and L858R (43B2). The results obtained using the 2 procedures were statistically compared by Coehn κ and by calculation of sensitivity and specificity.

RESULTS

There were 21 women and 12 men, ranging in age from 48 to 78 years. All cases were lung adenocarcinomas, 23 primaries and 10 metastatic. The mutational spectrum was as follows: 12 cases mutated in exon 19 (9 with E746-A750del, 1 with homozygote L747-T751del, 1 with L747-P753del, 1 with E747-S752del), 6 in exon 21 (5 with L858R, 1 with L861Q+L862L), and 15 EGFR wild type. Immunohistochemistry detected 6/9 cases with an E746-A750del mutation (κ=0.744, sensitivity: 66.7%, specificity: 100%) and 5/5 cases with an L858R mutation (κ=1, sensitivity: 100%, specificity: 100%). Four cases showed faint and focal immunostaining and were interpreted as negative. All other cases were negative. Overall, the 2 antibodies had 61.1% sensitivity and 100% specificity for EGFR mutations.

CONCLUSIONS

EGFR mutation-specific antibodies may represent a first-line screening tool to identify patients as candidates for tyrosine kinase inhibitor therapy.

Diagnosis of lung cancer in small biopsies and cytology: implications of the 2011 International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification

The new International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society lung adenocarcinoma classification provides, for the first time, standardized terminology for lung cancer diagnosis in small biopsies and cytology; this was not primarily addressed by previous World Health Organization classifications. Until recently there have been no therapeutic implications to further classification of NSCLC, so little attention has been given to the distinction of adenocarcinoma and squamous cell carcinoma in small tissue samples. This situation has changed dramatically in recent years with the discovery of several therapeutic options that are available only to patients with adenocarcinoma or NSCLC, not otherwise specified, rather than squamous cell carcinoma. This includes recommendation for use of special stains as an aid to diagnosis, particularly in the setting of poorly differentiated tumors that do not show clear differentiation by routine light microscopy. A limited diagnostic workup is recommended to preserve as much tissue for molecular testing as possible. Most tumors can be classified using a single adenocarcinoma marker (eg, thyroid transcription factor 1 or mucin) and a single squamous marker (eg, p40 or p63). Carcinomas lacking clear differentiation by morphology and special stains are classified as NSCLC, not otherwise specified. Not otherwise specified carcinomas that stain with adenocarcinoma markers are classified as NSCLC, favor adenocarcinoma, and tumors that stain only with squamous markers are classified as NSCLC, favor squamous cell carcinoma. The need for every institution to develop a multidisciplinary tissue management strategy to obtain these small specimens and process them, not only for diagnosis but also for molecular testing and evaluation of markers of resistance to therapy, is emphasized.

Tissue-sparing application of the newly proposed IASLC/ATS/ERS classification of adenocarcinoma of the lung shows practical diagnostic and prognostic impact

The histologic subtype of non-small cell lung cancer (NSCLC) determines treatment strategies and the need for genetic analyses. Since most NSCLC are diagnosed on small biopsy or cytologic specimens, an accurate but tissue-sparing approach is necessary. To date, consensus for a general diagnostic algorithm is lacking. To test the diagnostic and clinical relevance of the recently published multidisciplinary guidelines by the International Association for the Study of Lung Cancer, American Thoracic Society, and European Respiratory Society, we examined 371 surgically resected NSCLCs brought into tissue microarray format. The antibody panel thyroid transcription factor-1 (TTF-1), p63, cytokeratin (CK)5/6, and CK7 is diagnostic for most cases (>94%). Faint/focal staining for CK7 is negligible for classificatory purposes. Grading adenocarcinomas according to histologic architecture is prognostically significant (median overall survival for well/moderate differentiation, 72.5 months; for poor differentiation, 38.5 months; P = .019). Double stains combining the aforementioned nuclear and membranous markers are highly diagnostic for NSCLC, conserving tumor tissue for subsequent analyses.

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.

Individualized therapy for patients with non-small cell lung cancer: emerging trends and challenges

Non-small cell lung cancer is the leading cause of cancer death in the United States. Efforts to improve outcomes have led to a greater understanding of the predictive and prognostic value of histologic and molecular characteristics of individual tumors. In standard practice, biopsy specimens are examined first on a histologic level, then on a molecular level with the recognition that both histologic subtype and gene expression profile can guide treatment decisions and have a profound effect on clinical outcomes. Epidermal growth factor activation mutations were among the first biomarkers shown to have therapeutic implications, and levels of gene expression for an array of other biomarkers are being evaluated in clinical trials. Ongoing studies underscore the need to implement molecular and histologic screening as part of routine clinical practice. To achieve an integration of clinical, histologic, and molecular parameters when making treatment decisions, collaboration between oncologists and pathologists is essential.

Impact of histopathological diagnosis with ancillary immunohistochemical studies on lung cancer subtypes incidence and survival: a population-based study

PURPOSE

The aim of this study was to assess the impact of immunohistochemical- (IHC-) studies on incidence and survival of lung cancer histotypes.

PATIENTS AND METHODS

Lung cancers occurred in southern Switzerland between 1996 and 2010 were selected by the Ticino Cancer Registry and categorised into adenocarcinoma (AC), squamous-cell-carcinoma (SqCC), small-cell-carcinoma (SmCC), and large-cell carcinoma/non-small-cell lung cancer (LCC/NSCLC). Incidence rates, annual-percentage-change (APC), and two-year overall survival (OS) (follow-up: 31.12.2010) were performed.

RESULTS

2467 cases were selected: 997 (40.4%) AC; 522 (21.2%) LCC/NSCLC, 378 (15.3%) SmCC, and 570 (23.1%) SqCC. Trend-analysis showed significant increase in AC (APC: 4.6; 95% CI: 3.1; 6.0) and decrease of LCC/NSCLC, with significant joinpoint in 2003 (APC: -14.7; 95% CI: -21.6; -7.1). Improved OS and decreased OS were detected in SqCC and LCC/NSCLC, respectively.

CONCLUSIONS

This study highlights that diagnosis with ancillary immunohistochemical studies will change incidence and survival of precisely defined lung cancer subtypes. It calls attention to the need for cautious interpretation of studies and clinical trials, where the diagnosis was based on histology unaccompanied by IHC studies, and to the need of standardised diagnostic procedures.

The role of molecular analyses in the era of personalized therapy for advanced NSCLC

Platinum-based doublet chemotherapy is the traditional treatment of choice for advanced non-small cell lung cancer (NSCLC); however, the efficacy of these regimens has reached a plateau. Increasing evidence demonstrates that patients with sensitizing mutations in the epidermal growth factor receptor (EGFR) experience improved progression-free survival and response rates with first-line gefitinib or erlotinib therapy relative to traditional platinum-based chemotherapy, while patients with EGFR-mutation negative tumors gain greater benefit from platinum-based chemotherapy. These results highlight the importance of molecular testing prior to the initiation of first-line therapy for advanced NSCLC. Routine molecular testing of tumor samples represents an important paradigm shift in NSCLC therapy and would allow for individualized therapy in specific subsets of patients. As these and other advances in personalized treatment are integrated into everyday clinical practice, pulmonologists will play a vital role in ensuring that tumor samples of adequate quality and quantity are collected in order to perform appropriate molecular analyses to guide treatment decisions. This article provides an overview of clinical trial data supporting molecular analysis of NSCLC, describes specimen acquisition and testing methods currently in use, and discusses future directions of personalized therapy for patients with NSCLC.

Utility of 10 immunohistochemical markers including novel markers (desmocollin-3, glypican 3, S100A2, S100A7, and Sox-2) for differential diagnosis of squamous cell carcinoma from adenocarcinoma of the Lung

INTRODUCTION

Recent clinical trials revealed that accurate histologic typing of non-small cell lung cancer, especially squamous cell carcinoma (SCC), is essential.

PATIENTS AND METHODS

We analyzed 10 antibodies expression in 150 SCC cases (53 well-, 51 moderately, and 46 poorly differentiated cases) and 159 adenocarcinoma (AC) cases (49 well-, 52 moderately, and 58 poorly differentiated cases).

RESULTS

In all SCC and AC cases, p63 was the most sensitive marker for SCC (98.7%), followed by high-molecular-weight (HM) cytokeratin (CK) (97.3%), CK5/6 (93.3%), Sox2 (80%), thrombomodulin (79.3%), desmocollin-3 (72.7%), S100A7 (70.7%), S100A2 (63.3%), and glypican-3 (46.7%). Desmocollin-3 was the most specific marker for SCC (100%), followed by CK5/6 (98%), Sox2 (95.5%), glypican-3 (92.4%), S100A7 (86.8%), thrombomodulin (79.9%), S100A2 (64.6%), p63 (51.6%), and HMCK (33.3%). Thyroid transcription factor-1 (TTF-1) expression was observed in 87.4% of AC cases and 2.0% of SCC cases. When analyzing only poorly differentiated tumors, HMCK was the most sensitive marker for SCC (100%), followed by p63 (97.8%), CK5/6 (87.0%), Sox2 (71.7%), thrombomodulin (58.7%), desmocollin-3 (52.2%), S100A2 (50%), glypican-3 (45.7%), and S100A7 (45.7%). Desmocollin-3 was the most specific marker for poorly differentiated SCC (100%), followed by CK5/6 (98.3%), glypican-3 (94.8%), Sox2 (94.8%), S100A2 (81%), S100A7 (75.9%), thrombomodulin (72.4%), p63 (48.3%), and HMCK (36.8%). The 10-fold crossvalidated classification and regression tree analysis revealed that the combination of CK5/6 and TTF-1 was the best immunohistochemical marker panel for the differentiation between SCC and AC.

CONCLUSION

CK5/6 is the best marker for differentiating SCC and AC, irrespective of the histological grade of the tumor. Thus, the combination of CK5/6 and TTF-1 is the most recommended combination of immunohistochemical markers.

The challenge of NSCLC diagnosis and predictive analysis on small samples. Practical approach of a working group

Until recently, the division of pulmonary carcinomas into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) was adequate for therapy selection. Due to the emergence of new treatment options subtyping of NSCLC and predictive testing have become mandatory. A practical approach to the new requirements involving interaction between pulmonologist, oncologist and molecular pathology to optimize patient care is described. The diagnosis of lung cancer involves (i) the identification and complete classification of malignancy, (ii) immunohistochemistry is used to predict the likely NSCLC subtype (squamous cell vs. adenocarcinoma), as in small diagnostic samples specific subtyping is frequently on morphological grounds alone not feasible (NSCLC-NOS), (iii) molecular testing. To allow the extended diagnostic and predictive examination (i) tissue sampling should be maximized whenever feasible and deemed clinically safe, reducing the need for re-biopsy for additional studies and (ii) tissue handling, processing and sectioning should be optimized. Complex diagnostic algorithms are emerging, which will require close dialogue and understanding between pulmonologists and others who are closely involved in tissue acquisition, pathologists and oncologists who will ultimately, with the patient, make treatment decisions. Personalized medicine not only means the choice of treatment tailored to the individual patient, but also reflects the need to consider how investigative and diagnostic strategies must also be planned according to individual tumour characteristics.

Heterogeneity of large cell carcinoma of the lung: an immunophenotypic and miRNA-based analysis

Large cell carcinomas (LCCs) of the lung are heterogeneous and may be of different cell lineages. We analyzed 56 surgically resected lung tumors classified as LCC on the basis of pure morphologic grounds, using a panel of immunophenotypic markers (adenocarcinoma [ADC]-specific, thyroid transcription factor-1, cytokeratin 7, and napsin A; squamous cell carcinoma [SQCC]-specific, p63, cytokeratin 5, desmocollin 3, and Δnp63) and the quantitative analysis of microRNA-205 (microRNA sample score [mRSS]). Based on immunoprofiles 19 (34%) of the cases were reclassified as ADC and 14 (25%) as SQCC; 23 (41%) of the cases were unclassifiable. Of these 23 cases, 18 were classified as ADC and 5 as SQCC according to the mRSS. Our data show that an extended panel of immunohistochemical markers can reclassify around 60% of LCCs as ADC or SQCC. However, a relevant percentage of LCCs may escape convincing immunohistochemical classification, and mRSS could be used for further typing, but its clinical relevance needs further confirmation.

Role of surgical intervention in managing gastrointestinal metastases from lung cancer

AIM: To investigate the clinicopathological characteristics of late-stage lung cancer patients with gastrointestinal (GI)-tract metastases, focusing on therapeutic options and outcomes.

METHODS: Our institution (the National Taiwan University Hospital) diagnosed 8159 patients with lung cancer between 1987 and 2008, of which 21 developed symptomatic GI metastases. This study reviewed all of the patients’ information, including survival data, pathological reports, and surgical notes.

RESULTS: The most common histological type of lung cancer was adenocarcinoma, and 0.26% of patients with lung cancer developed GI metastases. The median duration from lung cancer diagnosis to GI metastases was three months (range, 0-108 mo), and the average time from diagnosis of GI metastasis to death was 2.8 mo. Most patients with symptomatic gastric and/or duodenal metastases exhibited GI bleeding and were diagnosed by panendoscopy. In contrast, small bowel metastases typically presented as an acute abdomen and were not diagnosed until laparotomy. All patients with small bowel or colonic metastases underwent surgical intervention, and their perioperative mortality was 22%. Our data revealed a therapeutic effect in patients with solitary GI metastasis and a favorable palliative effect on survival when metastases were diagnosed preoperatively. In patients with multiple GI metastases, the presentation varied according to the locations of the metastases.

CONCLUSION: Surgical treatment is worthwhile in a select group of patients with bowel perforation or obstruction. Physicians should be more alert to symptoms or signs indicating GI metastases.

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

Immunohistochemistry is increasingly utilized to differentiate lung adenocarcinoma and squamous cell carcinoma. However, detailed analysis of coexpression profiles of commonly used markers in large series of whole-tissue sections is lacking. Furthermore, the optimal diagnostic algorithm, particularly the minimal-marker combination, is not firmly established. We therefore studied whole-tissue sections of resected adenocarcinoma and squamous cell carcinoma (n=315) with markers commonly used to identify adenocarcinoma (TTF-1) and squamous cell carcinoma (p63, CK5/6, 34βE12), and prospectively validated the devised algorithm in morphologically unclassifiable small biopsy/cytology specimens (n=38). Analysis of whole-tissue sections showed that squamous cell carcinoma had a highly consistent immunoprofile (TTF-1-negative and p63/CK5/6/34βE12-diffuse) with only rare variation. In contrast, adenocarcinoma showed significant immunoheterogenetity for all 'squamous markers' (p63 (32%), CK5/6 (18%), 34βE12 (82%)) and TTF-1 (89%). As a single marker, only diffuse TTF-1 was specific for adenocarcinoma whereas none of the 'squamous markers,' even if diffuse, were entirely specific for squamous cell carcinoma. In contrast, coexpression profiles of TTF-1/p63 had only minimal overlap between adenocarcinoma and squamous cell carcinoma, and there was no overlap if CK5/6 was added as a third marker. An algorithm was devised in which TTF-1/p63 were used as the first-line panel, and CK5/6 was added for rare indeterminate cases. Prospective validation of this algorithm in small specimens showed 100% accuracy of adenocarcinoma vs squamous cell carcinoma prediction as determined by subsequent resection. In conclusion, although reactivity for 'squamous markers' is common in lung adenocarcinoma, a two-marker panel of TTF-1/p63 is sufficient for subtyping of the majority of tumors as adenocarcinomas vs squamous cell carcinoma, and addition of CK5/6 is needed in only a small subset of cases. This simple algorithm achieves excellent accuracy in small specimens while conserving the tissue for potential predictive marker testing, which is now an essential consideration in advanced lung cancer specimens.

Immunochemistry and lung cancer: application in diagnosis, prognosis and targeted therapy

Immunochemistry is now an established ancillary technique in lung cancer diagnosis. Not only does it help in supporting the morphological diagnosis of malignancy, but its role now extends to the determination of cell lineage, ascertaining the primary site of tumour origin and contributing to decisions on prognosis and treatment. Early detection and confirmation of lung cancer facilitate early treatment decisions. Lung cancer management now has a multidisciplinary approach which includes cytopathologists and clinicians. Some clinicians may not understand what immunochemistry is and what its role is in lung cancer diagnosis, prognosis and therapy. The purpose of this paper is to define immunochemistry, on the background of basic respiratory airway epithelial structure and cancer biology, and discuss its application in the diagnosis, treatment and determination of prognosis of lung cancer.

Usefulness of immunohistochemical and histochemical studies in the classification of lung adenocarcinoma and squamous cell carcinoma in cytologic specimens

Histologic subtyping of non-small cell lung carcinoma (NSCLC) is important because the efficacy of new treatments depends on tumor histologic features. We assessed the diagnostic accuracy of classification of lung adenocarcinoma and squamous cell carcinoma (SCC) on cytologic and biopsy specimens based on cytomorphologic studies alone or in combination with ancillary studies compared with resection specimens. Compared with adenocarcinoma, the diagnosis of SCC was based more often on cytomorphologic studies alone (139/185 [75.1%] vs 107/263 [40.7%]). Significantly increased use of immunohistochemical studies in cytology was noted after introduction of targeted lung carcinoma therapies (22/156 [14.1%] for adenocarcinoma and 5/46 [11%] for SCC from 2000-2004 vs 134/156 [85.9%] for adenocarcinoma and 41/46 [89%] for SCC from 2005-2010). Use of immunohistochemical studies resulted in increased diagnostic accuracy for adenocarcinoma (56% [44/78] from 2000-2004 vs 83.2% [154/185] after 2005) but not for SCC (77% [57/74] before 2004 vs 73.9% [82/111] from 2005-2010). Adenocarcinoma showed high expression of cytokeratin (CK)7 (146/146 [100%]), thyroid transcription factor-1 (131/152 [86.2%]), surfactant A (29/36 [81%]), and periodic acid-Schiff with diastase (69/86 [80%]). All SCCs were positive for CK5/6 and p63. Use of immunohistochemical studies on cytologic cell blocks may improve classification of NSCLC.