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Histopathological diagnosis of pulmonary tumors is essential for treatment decisions. The distinction between primary lung adenocarcinoma and pulmonary metastasis from the gastrointestinal (GI) tract may be difficult. Therefore, we compared the diagnostic value of several immunohistochemical markers in pulmonary tumors. Tissue microarrays from 629 resected primary lung cancers and 422 resected pulmonary epithelial metastases from various sites (whereof 275 colorectal cancer) were investigated for the immunohistochemical expression of CDH17, GPA33, MUC2, MUC6, SATB2, and SMAD4, for comparison with CDX2, CK20, CK7, and TTF-1. The most sensitive markers for GI origin were GPA33 (positive in 98%, 60%, and 100% of pulmonary metastases from colorectal cancer, pancreatic cancer, and other GI adenocarcinomas, respectively), CDX2 (99/40/100%), and CDH17 (99/0/100%). In comparison, SATB2 and CK20 showed higher specificity, with expression in 5% and 10% of mucinous primary lung adenocarcinomas and both in 0% of TTF-1-negative non-mucinous primary lung adenocarcinomas (25-50% and 5-16%, respectively, for GPA33/CDX2/CDH17). MUC2 was negative in all primary lung cancers, but positive only in less than half of pulmonary metastases from mucinous adenocarcinomas from other organs. Combining six GI markers did not perfectly separate primary lung cancers from pulmonary metastases including subgroups such as mucinous adenocarcinomas or CK7-positive GI tract metastases. This comprehensive comparison suggests that CDH17, GPA33, and SATB2 may be used as equivalent alternatives to CDX2 and CK20. However, no single or combination of markers can categorically distinguish primary lung cancers from metastatic GI tract cancer., (© 2023. The Author(s).)

Immune checkpoint inhibitors (ICI) targeting programmed cell death-1 or its ligand (PD-L1) have improved outcomes in non-small cell lung cancer (NSCLC). High tumor PD-L1 expression, detected by immunohistochemistry (IHC) typically on formalin-fixed paraffin-embedded (FFPE) histological specimens, is linked to better response. Following our previous investigation on PD-L1 in cytological samples, the aim of this study was to further explore the potential impacts of various clinicopathological and molecular factors on PD-L1 expression. Two retrospective NSCLC cohorts of 1131 and 651 specimens, respectively, were investigated for PD-L1 expression (<1%/1−49%/≥50%), sample type, sample site, histological type, and oncogenic driver status. In both cohorts, PD-L1 was positive (≥1%) in 55% of the cases. Adenocarcinomas exhibited lower PD-L1 expression than squamous cell carcinomas (p < 0.0001), while there was no difference between sample types, tumor locations, or between the two cohorts in multivariate analysis (all p ≥ 0.28). Mutational status correlated significantly with PD-L1 expression (p < 0.0001), with the highest expression for KRAS-mutated cases, the lowest for EGFR-mutated, and the KRAS/EGFR wild-type cases in between. There was no difference in PD-L1 levels between different prevalent KRAS mutations (all p ≥ 0.44), while mucinous KRAS-mutated adenocarcinomas exhibited much lower PD-L1 expression than non-mucinous (p < 0.0001). Our data indicate that cytological and histological specimens are comparable for PD-L1 evaluation. Given the impact of KRAS mutations and the mucinous growth pattern on PD-L1 expression, these factors should be further investigated in studies on ICI response.

Objectives: Among patients who underwent primary surgery for non-small cell lung cancer (NSCLC), recurrent disease is frequent and cannot be accurately predicted solely from TNM stage and histopathological features. The aim of this study was to examine the association of tumor markers in pre-operative serum with recurrent disease., Material and Methods: Blood samples were collected prior to lung cancer surgery from 107 patients with stage I-III lung adenocarcinoma surgically treated at Lund University hospital, Lund, Sweden, between 2005 and 2011. The serum tumor markers Carcinoembryonic antigen (CEA), Neuron-specific enolase (NSE), Cancer antigen 125 (CA 125), Human epididymis protein 4 (HE4) and Carbohydrate antigen (CA 19-9) were analyzed retrospectively and clinical follow-up data were collected from patient charts. Forty (37%) patients were diagnosed with recurrent disease., Results: Sixty-eight (64%) patients had at least one elevated tumor marker prior to surgery. In analysis of disease-free survival (DFS), CA 125 and/or CA 19-9 were significantly associated with recurrent disease adjusted to stage and adjuvant treatment (hazard ratio 2.8, 95% confidence interval 1.4-5.7, p = 0.006)., Conclusion: High pre-operative serum CA 19-9 and/or CA 125 might indicate an increased incidence of recurrent disease in resectable lung adenocarcinomas.

Introduction: Lobectomy is the standard curative treatment for non-small cell carcinoma (NSCLC) of the lung. Most studies on lobectomy have focused on short-term outcome and 30-day mortality. The aim of this study was to determine both short-term and long-term surgical outcome in all patients who underwent lobectomy for NSCLC in Iceland over a 24-year period., Material and Methods: The study involved 489 consecutive patients with NSCLC who underwent lobectomy with curative intent in Iceland, 1991-2014. Patient demographics, pTNM stage, rate of perioperative complications, and 30-day mortality were registered. Overall survival was analyzed with the Kaplan?Meier method. The Cox proportional hazards model was used to evaluate factors that were prognostic of overall mortality. To study trends in survival, the study period was divided into six 4-year periods. The median follow-up time was 42 months and no patients were lost to follow-up., Results: The average age of the patients was 67 years and 53.8% were female. The pTNM disease stage was IA in 148 patients (30.0%), IB in 125 patients (25.4%), IIA in 96 patients (19.5%), and IIB in 50 patients (10.1%), but 74 (15.0%) were found to be stage IIIA, most often diagnosed perioperatively. The total rate of major complications was 4.7%. Thirty-day mortality was 0.6% (three patients). One- and 5-year overall survival was 85.0% and 49.2%, respectively, with 3-year survival improving from 48.3% to 72.8% between the periods 1991-1994 and 2011-2014 (p = .0004). Advanced TNM stage and age were independent negative prognostic factors for all-cause mortality, and later calendar year and free surgical margins were independent predictors of improved survival., Conclusions: The short-term outcome of lobectomy for NSCLC in this population-based study was excellent, as reflected in the low 30-day mortality and low rate of major complications. The long-term survival was acceptable and the overall 3-year survival had improved significantly during the study period.

Introduction: Histopathological classification of lung cancer is of central importance in the diagnostic routine, and it guides therapy in most patients. The fourth edition of the World Health Organization (WHO) Classification of Lung Tumours was recently published and includes changes to the diagnostic procedure for non-small cell carcinomas (NSCCs), with more emphasis on immunohistochemical (IHC) staining., Methods: A total of 656 unselective cases of resected pulmonary NSCC were diagnosed according to the 2004 WHO classification. After IHC staining with cytokeratin 5, p40, p63, thyroid transcription factor 1 (clones 8G7G3/1 and SPT24), and napsin A, the diagnoses were revised in accordance with the new fourth edition of the WHO classification., Results: Reclassification led to a new histological annotation in 36 of the 656 cases (5%). Most notable was the decrease in cases previously classified as large cell carcinomas (56 versus 12 cases). This was partially due to the exclusion of 21 neuroendocrine tumors from this group, with 20 cases ascribed to the adenocarcinoma group on the basis of IHC markers. Only seven cases of adenocarcinoma or squamous cell carcinoma were reclassified after the addition of IHC staining. There was a substantial overlap in staining properties between different markers of squamous and adenocarcinomatous differentiation, respectively, but in 17 to 31 cases (3%-5%), the diagnosis depended on the choice of markers., Conclusions: The fourth edition of the WHO Classification of Lung Tumours leads to changes in histological type in 5% of resected NSCCs. The incorporation of IHC staining into NSCC diagnostics demands awareness that the choice of ancillary stains has an effect on diagnosis., (Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Purpose: Lung cancer is the worldwide leading cause of death from cancer. DNA methylation in gene promoter regions is a major mechanism of gene expression regulation that may promote tumorigenesis. However, whether clinically relevant subgroups based on DNA methylation patterns exist in lung cancer remains unclear., Experimental Design: Whole-genome DNA methylation analysis using 450K Illumina BeadArrays was performed on 12 normal lung tissues and 124 tumors, including 83 adenocarcinomas, 23 squamous cell carcinomas (SqCC), 1 adenosquamous cancer, 5 large cell carcinomas, 9 large cell neuroendocrine carcinomas (LCNEC), and 3 small-cell carcinomas (SCLC). Unsupervised bootstrap clustering was performed to identify DNA methylation subgroups, which were validated in 695 adenocarcinomas and 122 SqCCs. Subgroups were characterized by clinicopathologic factors, whole-exome sequencing data, and gene expression profiles., Results: Unsupervised analysis identified five DNA methylation subgroups (epitypes). One epitype was distinctly associated with neuroendocrine tumors (LCNEC and SCLC). For adenocarcinoma, remaining four epitypes were associated with unsupervised and supervised gene expression phenotypes, and differences in molecular features, including global hypomethylation, promoter hypermethylation, genomic instability, expression of proliferation-associated genes, and mutations in KRAS, TP53, KEAP1, SMARCA4, and STK11. Furthermore, these epitypes were associated with clinicopathologic features such as smoking history and patient outcome., Conclusions: Our findings highlight one neuroendocrine and four adenocarcinoma epitypes associated with molecular and clinicopathologic characteristics, including patient outcome. This study demonstrates the possibility to further subgroup lung cancer, and more specifically adenocarcinomas, based on epigenetic/molecular classification that could lead to more accurate tumor classification, prognostication, and tailored patient therapy., (©2014 American Association for Cancer Research.)

Purpose: Cigarette smoking is the major pathogenic factor for lung cancer. The precise mechanisms of tobacco-related carcinogenesis and its effect on the genomic and transcriptional landscape in lung cancer are not fully understood., Experimental Design: A total of 1,398 (277 never-smokers and 1,121 smokers) genomic and 1,449 (370 never-smokers and 1,079 smokers) transcriptional profiles were assembled from public lung adenocarcinoma cohorts, including matched next-generation DNA-sequencing data (n = 423). Unsupervised and supervised methods were used to identify smoking-related copy-number alterations (CNAs), predictors of smoking status, and molecular subgroups., Results: Genomic meta-analyses showed that never-smokers and smokers harbored a similar frequency of total CNAs, although specific regions (5q, 8q, 16p, 19p, and 22q) displayed a 20% to 30% frequency difference between the two groups. Importantly, supervised classification analyses based on CNAs or gene expression could not accurately predict smoking status (balanced accuracies ∼60% to 80%). However, unsupervised multicohort transcriptional profiling stratified adenocarcinomas into distinct molecular subgroups with specific patterns of CNAs, oncogenic mutations, and mutation transversion frequencies that were independent of the smoking status. One subgroup included approximately 55% to 90% of never-smokers and approximately 20% to 40% of smokers (both current and former) with molecular and clinical features of a less aggressive and smoking-unrelated disease. Given the considerable intragroup heterogeneity in smoking-defined subgroups, especially among former smokers, our results emphasize the clinical importance of accurate molecular characterization of lung adenocarcinoma., Conclusions: The landscape of smoking-related CNAs and transcriptional alterations in adenocarcinomas is complex, heterogeneous, and with moderate differences. Our results support a molecularly distinct less aggressive adenocarcinoma entity, arising in never-smokers and a subset of smokers., (©2014 American Association for Cancer Research.)

Introduction: In lung adenocarcinoma, the mutational spectrum is dominated by EGFR and KRAS mutations. Improved knowledge about genomic and transcriptional alterations in and between mutation-defined subgroups may identify genes involved in disease development or progression., Methods: Genomic profiles from 457 adenocarcinomas, including 113 EGFR-mutated, 134 KRAS-mutated and 210 EGFR and KRAS-wild type tumors (EGFRwt/KRASwt), and gene expression profiles from 914 adenocarcinomas, including 309 EGFR-mutated, 192 KRAS-mutated, and 413 EGFRwt/KRASwt tumors, were assembled from different repositories. Genomic and transcriptional differences between the three mutational groups were analyzed by both supervised and unsupervised methods., Results: EGFR-mutated adenocarcinomas displayed a larger number of copy number alterations and recurrent amplifications, a higher fraction of total loss-of-heterozygosity, higher genomic complexity, and a more distinct expression pattern than EGFR-wild type adenocarcinomas. Several of these differences were also consistent when the three mutational groups were stratified by stage, gender and smoking status. Specific copy number alterations were associated with mutation status, predominantly including regions of gain with the highest frequency in EGFR-mutated tumors. Differential regions included both large and small regions of gain on 1p, 5q34-q35.3, 7p, 7q11.21, 12p12.1, 16p, and 21q, and losses on 6q16.3-q21, 8p, and 9p, with 20-40% frequency differences between the mutational groups. Supervised gene expression analyses identified 96 consistently differentially expressed genes between the mutational groups, and together with unsupervised analyses these analyses highlighted the difficulty in broadly resolving the three mutational groups into distinct transcriptional entities., Conclusions: We provide a comprehensive overview of the genomic and transcriptional landscape in lung adenocarcinoma stratified by EGFR and KRAS mutations. Our analyses suggest that the overall genomic and transcriptional landscape of lung adenocarcinoma is affected, but only to a minor extent, by EGFR and KRAS mutation status.

Purpose: In lung adenocarcinoma, EGFR and KRAS mutations dominate the mutational spectrum and have clear therapeutic implications. We sought to determine whether transcriptional subgroups of clinical relevance exist within EGFR-mutated, KRAS-mutated, or EGFR and KRAS wild-type (EGFRwt/KRASwt) adenocarcinomas., Experimental Design: Gene expression profiles from 1,186 adenocarcinomas, including 215 EGFR-mutated, 84 KRAS-mutated, and 219 EGFRwt/KRASwt tumors, were assembled and divided into four discovery (n = 522) and four validation cohorts (n = 664). Subgroups within the mutation groups were identified by unsupervised consensus clustering, significance analysis of microarrays (SAM) analysis, and centroid classification across discovery cohorts. Genomic alterations in identified mutation subgroups were assessed by integration of genomic profiles for 158 cases with concurrent data. Multicohort expression subgroup predictors were built for each mutation group using the discovery cohorts, and validated in the four validation cohorts., Results: Consensus clustering within the mutation groups identified reproducible transcriptional subgroups in EGFR-mutated and EGFRwt/KRASwt tumors, but not in KRAS-mutated tumors. Subgroups displayed differences in genomic alterations, clinicopathologic characteristics, and overall survival. Multicohort gene signatures derived from the mutation subgroups added independent prognostic information in their respective mutation group, for adenocarcinoma in general and stage I tumors specifically, irrespective of mutation status, when applied to the validation cohorts. Consistent with their worse clinical outcome, high-risk subgroups showed higher expression of proliferation-related genes, higher frequency of copy number alterations/amplifications, and association with a poorly differentiated tumor phenotype., Conclusions: We identified transcriptional subgroups in EGFR-mutated and EGFRwt/KRASwt adenocarcinomas with significant differences in clinicopathologic characteristics and patient outcome, not limited to a mutation-specific setting., (©2013 AACR.)

Objectives: To assess immunohistochemical (IHC) stains differentially expressed between different types of lung cancer., Methods: We evaluated 16 different IHC stains in 209 prospectively included, surgically treated primary lung cancers, including 121 adenocarcinomas, 65 squamous cell carcinomas, 15 large-cell carcinomas, 5 adenosquamous carcinomas, 2 sarcomatoid carcinomas, and 1 small-cell carcinoma, using the tissue microarray technique., Results: Cytokeratin 5 (CK5) and P63 were both positive in 10% or more of the cells in 97% of the squamous cell carcinomas, with the former being positive (<10% of the cells) in only 2 non-squamous cell carcinomas. Thyroid transcription factor 1 (TTF1) and napsin A were positive in 10% or more of the cells in 88% and 87% of the adenocarcinomas, respectively, with 94% of the adenocarcinomas being positive in at least 1 marker. Fifteen percent of the adenocarcinomas were positive for estrogen receptor., Conclusions: CK5, TTF1, and napsin A are sensitive markers for squamous cell carcinoma and adenocarcinoma of the lung.

Background: Lung cancer is the worldwide leading cause of death from cancer. Tobacco usage is the major pathogenic factor, but all lung cancers are not attributable to smoking. Specifically, lung cancer in never-smokers has been suggested to represent a distinct disease entity compared to lung cancer arising in smokers due to differences in etiology, natural history and response to specific treatment regimes. However, the genetic aberrations that differ between smokers and never-smokers' lung carcinomas remain to a large extent unclear., Methods: Unsupervised gene expression analysis of 39 primary lung adenocarcinomas was performed using Illumina HT-12 microarrays. Results from unsupervised analysis were validated in six external adenocarcinoma data sets (n=687), and six data sets comprising normal airway epithelial or normal lung tissue specimens (n=467). Supervised gene expression analysis between smokers and never-smokers were performed in seven adenocarcinoma data sets, and results validated in the six normal data sets., Results: Initial unsupervised analysis of 39 adenocarcinomas identified two subgroups of which one harbored all never-smokers. A generated gene expression signature could subsequently identify never-smokers with 79-100% sensitivity in external adenocarcinoma data sets and with 76-88% sensitivity in the normal materials. A notable fraction of current/former smokers were grouped with never-smokers. Intriguingly, supervised analysis of never-smokers versus smokers in seven adenocarcinoma data sets generated similar results. Overlap in classification between the two approaches was high, indicating that both approaches identify a common set of samples from current/former smokers as potential never-smokers. The gene signature from unsupervised analysis included several genes implicated in lung tumorigenesis, immune-response associated pathways, genes previously associated with smoking, as well as marker genes for alveolar type II pneumocytes, while the best classifier from supervised analysis comprised genes strongly associated with proliferation, but also genes previously associated with smoking., Conclusions: Based on gene expression profiling, we demonstrate that never-smokers can be identified with high sensitivity in both tumor material and normal airway epithelial specimens. Our results indicate that tumors arising in never-smokers, together with a subset of tumors from smokers, represent a distinct entity of lung adenocarcinomas. Taken together, these analyses provide further insight into the transcriptional patterns occurring in lung adenocarcinoma stratified by smoking history.

Background: Carcinomas of the small intestine are rare, but the risk is greatly increased in patients with hereditary nonpolyposis colorectal cancer (HNPCC) due to an inherited mismatch repair (MMR) gene mutation, most commonly affecting the genes MLH1 or MSH2. Defective MMR is characterized by microsatellite instability (MSI) and loss of MMR protein expression in the tumor tissue. However, a subset of several sporadic tumor types, including about 15% of colon cancers, also evolve through defective MMR., Methods: The authors have assessed the frequency of MSI and analyzed the immunohistochemical expression of MLH1 and MSH2 in a population-based series of 89 adenocarcinomas of the small intestine. To study the contribution of MSI and defective MMR protein expression in young patients, 43 cancers of the small intestine from patients below age 60 years (including 24 tumors from the population-based series and an additional 19 tumors from young individuals) were also analyzed., Results: MSI was detected in 16/89 tumors (18%) in the population-based series, and immunohistochemistry revealed loss of expression for MLH1 in 7/16 MSI tumors and in 2/73 MSS tumors, whereas all tumors showed normal expression for MSH2. Among the young patients, the authors identified MSI in 10/43 tumors (23%), and 6 of these 10 MSI tumors showed immunohistochemical loss of MMR protein expression, which affected MLH1 in 3 cases and MSH2 in 3 cases., Conclusions: The frequency of MSI (18%) in adenocarcinomas of the small intestine equals that of colon cancer. However, silencing of MLH1 seems to explain the MSI status in only about half of the MSI tumors. Among patients with cancer of the small intestine before age 60 years, MSI is found in 23% of the cases, with MLH1 and MSH2 being affected at equal frequencies, indicating that HNPCC may underly a subset of such cases., (Copyright 2003 American Cancer Society.DOI 10.1002/cncr.11197)