Oncogenic mutations are associated with histological subtypes but do not have an independent prognostic value in lung adenocarcinoma

Prognostic implications, genomic and immune characteristics of lung adenocarcinoma with lepidic growth pattern

AIMS

Conflicting data were provided regarding the prognostic impact and genomic features of lung adenocarcinoma (LUAD) with lepidic growth pattern (LP+A). Delineation of the genomic and immune characteristics of LP+A could provide deeper insights into its prognostic implications and treatment determination.

METHODS

We conducted a search of articles in PubMed, EMBASE and the Cochrane Library from inception to January 2024. A domestic cohort consisting of 52 LUAD samples was subjected to whole-exome sequencing as internal validation. Data from The Cancer Genomic Atlas and the Gene Expression Omnibus datasets were obtained to characterise the genomic and immune profiles of LP+A. Pooled HRs and rates were calculated.

RESULTS

The pooled results indicated that lepidic growth pattern was either predominant (0.35, 95% CI 0.22 to 0.56, p<0.01) or minor (HR 0.50, 95% CI 0.36 to 0.70, p<0.01) histological subtype was associated with favourable disease-free survival. Pooled gene mutation rates suggested higher EGFR mutation (0.55, 95% CI 0.46 to 0.64, p<0.01) and lower KRAS mutation (0.14, 95% CI 0.02 to 0.25, p=0.02) in lepidic-predominant LUAD. Lepidic-predominant LUAD had lower tumour mutation burden and pooled positive rate of PD-L1 expression compared with other subtypes. LP+A was characterised by abundance in resting CD4+memory T cells, monocytes and γδ T cells, as well as scarcity of cancer-associated fibroblasts.

CONCLUSIONS

LP+A was a unique histological subtype with a higher EGFR mutation rate, lower tumour mutation burden and immune checkpoint expression levels. Our findings suggested potential benefits from targeted therapy over immunotherapy in LP+A.

[Advances in the Study of Invasive Non-mucinous Adenocarcinoma with Different Pathological Subtypes]

Lung cancer is the leading cause of cancer death in the world today, and adenocarcinoma is the most common histopathological type of lung cancer. In May 2021, World Health Organization (WHO) released the 5th edition of the WHO classification of thoracic tumors, which classifies invasive non-mucinous adenocarcinoma (INMA) into lepidic adenocarcinoma, acinar adenocarcinoma, papillary adenocarcinoma, solid adenocarcinoma, and micropapillary adenocarcinoma based on its histological characteristics. These five pathological subtypes differ in clinical features, treatment and prognosis. A complete understanding of the characteristics of these subtypes is essential for the clinical diagnosis, treatment options, and prognosis predictions of patients with lung adenocarcinoma, including recurrence and progression. This article will review the grading system, morphology, imaging prediction, lymph node metastasis, surgery, chemotherapy, targeted therapy and immunotherapy of different pathological subtypes of INMA.
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Molecular Pathology of Lung Cancer

This overview of the molecular pathology of lung cancer includes a review of the most salient molecular alterations of the genome, transcriptome, and the epigenome. The insights provided by the growing use of next-generation sequencing (NGS) in lung cancer will be discussed, and interrelated concepts such as intertumor heterogeneity, intratumor heterogeneity, tumor mutational burden, and the advent of liquid biopsy will be explored. Moreover, this work describes how the evolving field of molecular pathology refines the understanding of different histologic phenotypes of non-small-cell lung cancer (NSCLC) and the underlying biology of small-cell lung cancer. This review will provide an appreciation for how ongoing scientific findings and technologic advances in molecular pathology are crucial for development of biomarkers, therapeutic agents, clinical trials, and ultimately improved patient care.

Correlation of Epidermal Growth Factor Receptor Mutation With Major Histologic Subtype of Lung Adenocarcinoma According to IASLC/ATS/ERS Classification

OBJECTIVE

Our prospective study aims to define the correlation of EGFR(epidermal growth factor receptor) mutations with major histological subtypes of lung adenocarcinoma from resected and non-resected specimens, according to the WHO 2015 classification, in Moroccan North East Population.

METHODS

Epidermal growth factor receptor mutations of 150 primary lung adenocarcinoma were performed using Real-Time PCR or SANGER sequencing. SPSS 21 was used to assess the relationship between histological subtypes of lung adenocarcinoma and EGFR mutation status.

RESULTS

25 mutations were detected in the series of 150 lung adenocarcinomas, most of which were found in cases with papillary, acinar, patterns than without these patterns and more frequently occurred in the cases without solid pattern than with this pattern. A significant correlation was observed between EGFR mutation and acinar (P = 0,024), papillary pattern (P = 0,003) and, negative association with a solid pattern (P < 0,001). In females, EGFR mutations were significantly correlated with the acinar pattern (P = 0,02), whereas in males with the papillary pattern (P = 0,01). Association between the histologic component and exon 19 deletions and exon 21 mutations were also evaluated and, we found a significant correlation between the papillary major pattern with exon 19 mutations (P = 0,004) and, ex21 with the acinar component (P = 0,03).

CONCLUSION

An analysis of resected and non-resected lung ADC specimens in 150 Moroccan Northeast patients, revealed that acinar and papillary patterns may predict the presence of a mutation in the EGFR gene. While the solid major pattern may indicate a low mutation rate of the EGFR gene.

Clinicopathologic Features and Molecular Biomarkers as Predictors of Epidermal Growth Factor Receptor Gene Mutation in Non-Small Cell Lung Cancer Patients

Lung cancer ranks first in the incidence and mortality of cancer in the world, of which more than 80% are non-small cell lung cancer (NSCLC). The majority of NSCLC patients are in stage IIIB~IV when they are admitted to hospital and have no opportunity for surgery. Compared with traditional chemotherapy, specific targeted therapy has a higher selectivity and fewer adverse reactions, providing a new treatment direction for advanced NSCLC patients. Tyrosine kinase inhibitors of epidermal growth factor receptor (EGFR-TKIs) are the widely used targeted therapy for NSCLC patients. Their efficacy and prognosis are closely related to the mutation status of the EGFR gene. Clinically, detecting EGFR gene mutation is often limited by difficulty obtaining tissue specimens, limited detecting technology, and economic conditions, so it is of great clinical significance to find indicators to predict EGFR gene mutation status. Clinicopathological characteristics, tumor markers, liquid biopsy, and other predictors are less invasive, economical, and easier to obtain. They can be monitored in real-time, which is supposed to predict EGFR mutation status and provide guidance for the accurate, individualized diagnosis and therapy of NSCLC patients. This article reviewed the correlation between the clinical indicators and EGFR gene mutation status in NSCLC patients.

Clinicopathological, Radiological, and Molecular Features of Primary Lung Adenocarcinoma with Morule-Like Components

BACKGROUND

Morule-like component (MLC) was a rare structure in primary lung adenocarcinoma. We aimed to reveal the clinicopathological, radiological, immunohistochemical, and molecular features of lung adenocarcinoma with MLCs.

METHODS

Twenty lung adenocarcinomas with MLCs were collected, and computed tomographic and histological documents were reviewed. Immunohistochemistry, targeted next-generation sequencing, and Sanger sequencing for β-catenin gene were performed.

RESULTS

There were 9 lepidic adenocarcinomas, 8 acinar adenocarcinomas, 2 papillary adenocarcinomas, and 1 minimally invasive adenocarcinoma. Most patients (16/17) were shown a pure solid nodule, and 1 patient was shown a partly solid nodule on chest computed tomography (CT). Nine cases were accompanied with micropapillary components, and 3 were with cribriform components in which 2 suffered a worse prognosis. No significant association was found between the MCLs and the overall survival of lung adenocarcinoma (P = 0.109). The MLCs were often arranged in whorled or streaming patterns. The cells in MLCs showed syncytial and mild appearance. The MLCs were positive for E-cadherin, CK7, TTF-1, napsin-A, vimentin, and β-catenin (membrane), and negative for CK5/6, p40, p63, Synaptophysin, chromogranin A, and Cdx-2. EGFR mutation, ALK-EML4 fusion, HER2 amplification, and PIK3CA mutation were detected in 16 cases, 2 cases, 1 case, and 1 case, respectively. EGFR mutation was more frequent in adenocarcinomas with MLCs than those without MLCs (P = 0.040). β-catenin gene mutation was not detected in any patients.

CONCLUSIONS

MLC is often observed in the background of acinar, lepidic, and papillary adenocarcinomas. Lung adenocarcinomas with MLCs tend to appear as a solid mass on CT and harbor EGFR gene mutations. The micropapillary components and cribriform components may cause poor prognosis of lung adenocarcinomas with MLCs. Vimentin is always positive in MLCs, and it is a useful marker for the identification of MLCs.

Genomic Profiling and Prognostic Value Analysis of Genetic Alterations in Chinese Resected Lung Cancer With Invasive Mucinous Adenocarcinoma

Background

Invasive mucinous adenocarcinoma (IMA) of the lung is a distinct histological subtype with unique clinical and pathological features. Despite previous genomic studies on lung IMA, the genetic characteristics and the prognosis-related biomarkers in Chinese surgically resected lung IMA remain unclear.

Methods

We collected 76 surgically resected primary tumors of invasive lung adenocarcinoma, including 51 IMA and 25 non-mucinous adenocarcinomas (non-IMA). IMA was further divided into pure-IMA (mucinous features≥90%) and mixed-IMA subgroups. Comprehensive genomic profiling based on targeted next-generation sequencing (NGS) of 425 genes was explored and genomic characteristics were evaluated for the correlation with postoperative disease-free survival (DFS).

Results

IMA had a unique genetic profile, with more diverse driver mutations and more tumor drivers/suppressors co-occurrence than that of non-IMA. The frequency of EGFR (72.0% vs. 40.0% vs. 23.1%, p=0.002) and ALK (undetected vs. 20.0% vs. 26.9%, p=0.015) alterations showed a trend of gradual decrease and increase from non-IMA to mixed-IMA to pure-IMA, respectively. The frequency of KRAS mutations in pure-IMA was higher than that in mixed-IMA, albeit statistically insignificant (23.1% vs. 4.0%, p=0.10). TP53 mutation was significantly less in pure-IMA compared to mixed-IMA and non-IMA (23.1% vs. 52.0% vs. 56.0%, p=0.03). Besides, IMA exhibited less arm-level amplifications (p=0.04) and more arm-level deletions (p=0.004) than non-IMA, and the frequency of amplification and deletion also showed a trend of gradual decrease and increase from non-IMA to mixed-IMA to pure-IMA, respectively. Furthermore, prognosis analysis in stage III IMA patients showed that patients harboring alterations in EGFR (mDFS=30.3 vs. 16.0 months, HR=0.19, P=0.027) and PI3K pathway (mDFS=36.0 vs. 16.0 months, HR=0.12, P=0.023) achieved prolonged DFS, while patients with poorly differentiated tumors (mDFS=14.1 vs. 28.0 months, HR=3.75, p=0.037) or with KRAS mutations (mDFS=13.0 vs. 20.0 months, HR=6.95, p=0.027) had shorter DFS. Multivariate analysis showed that KRAS mutations, PI3K pathway alterations, and tumor differentiation status were independent factors that have statistically significant influences on clinical outcomes of IMA patients.

Conclusion

Our study provided genomic insights into Chinese surgically resected lung IMA. We also identified several genomic features that may serve as potential biomarkers on postoperative recurrence in IMA patients with stage III disease.

Gene expression profiling by targeted RNA sequencing in pathological stage I lung adenocarcinoma with a solid component

OBJECTIVES

Solid predominant adenocarcinoma is considered an independent predictor of an unfavorable prognosis in patients with stage I lung adenocarcinoma (LUAD). Furthermore, solid minor components are related to poor prognosis in patients with stage I LUAD. Therefore, it is imperative to elucidate the molecular determinants of the malignant potential of solid components (SC). Several studies reported the gene expression profiling specific for lepidic predominant adenocarcinoma or solid predominant adenocarcinoma, however; there is no report identifying the differentially expressed genes (DEGs) between SC and acinar component (AC) within the same tumor tissue in pathological (p)-stage I LUAD patients.

MATERIALS AND METHODS

LUAD tissue samples containing both SC and AC were obtained from 8 patients with p-stage I LUAD and each component was microdissected. Targeted RNA sequencing was performed by a high-throughput chip-based approach.

RESULTS

In total, 1272 DEGs were identified, including 677 upregulated genes and 595 downregulated genes in SC compared with AC. The most highly upregulated gene was TATA binding protein associated factor 7 (TAF7) and the most highly downregulated gene was homeobox B3 (HOXB3), which acts as a metastasis suppressor. A protein-protein interaction (PPI) network analysis of upregulated genes in SC identified ribosomal protein S27a (RPS27a) as a hub gene with the highest degree. First neighbors of RPS27a included PSMA6, which is a highly promising target for lung cancer. The subnetwork of PD-L1 had 10 first neighbors, including CMTM6, which enhances the ability of PD-L1-expressing tumor cells to inhibit T cells. The staining score for PD-L1 in SC was significantly higher than that in AC by immunohistochemistry (p = 0.001).

CONCLUSION

Our results revealed several new DEGs and key PPI network in SC compared to AC, contributing to understanding the biological features of SC and providing therapeutic targets for early-stage LUAD with SC in the future.

The growth of non-solid neoplastic lung nodules is associated with low PD L1 expression, irrespective of sampling technique

Background

Few data are known regarding the molecular features and patterns of growth and presentation which characterize those lung neoplastic lesions presenting as non-solid nodules (NSN).

Methods

We retrospectively reviewed two different cohorts of NSNs detected by CT scan which, after transthoracic fine-needle aspiration (FNA) and core needle biopsy (CNB) received a final diagnosis of malignancy. All the enrolled patients were then addressed to surgical removal of lung cancer nodules or to exclusive radiotherapy. Exhaustive clinical and radiological features were available for each case.

Results

In all 62 analysed cases the diagnosis of adenocarcinoma (ADC) was reached. In cytologic samples, EGFR activating mutations were identified in 2 of the 28 cases (7%); no case showed ALK/EML4 or ROS1 translocations. In the histologic samples EGFR activating mutation were found in 4 out of 25 cases (16%). PD-L1 immunostains could be evaluated in 30 cytologic samples, while the remaining 7 did not reach the cellularity threshold for evaluation. TPS was < 1% in 26 cases,  > 1% < 50% in 3, and > 50% in 1. All surgical samples showed TPS < 1%. Of the 17 cases that could be evaluated on both samples, 15 were concordantly TPS 0, and 2 showed TPS > 1% < 50 on the biopsy samples. TPS was < 1% in 14 cases, > 1%/< 5% in 4 cases, > 5%/< 50% in 2 cases, > 50% in 1 case.

Conclusions

Overall PD-L1 immunostaining documented the predominance of low/negative TPS, with high concordance in FNA and corresponding surgical samples. It can be hypothesized that lung ADC with NSN pattern and predominant in situ (i.e. lepidic) components represent the first steps in tumor progression, which have not yet triggered immune response, and/or have not accumulated a significant rate of mutations and neoantigen production, or that they belong to the infiltrated-excluded category of tumors. The negative prediction of response to immunomodulating therapy underlines the importance of rapid surgical treatment of these lesions. Notably, cell block cytology seems to fail in detecting EGFR mutations, thus suggesting that this kind of sampling technique should be not adequate in case of DNA direct sequencing.

Current status of clinical proteogenomics in lung cancer

Introduction: Lung cancer is the leading cause of cancer death worldwide. Proteogenomics, a way to integrate genomics, transcriptomics, and proteomics, have emerged as a way to understand molecular causes in cancer tumorigenesis. This understanding will help identify therapeutic targets that are urgently needed to improve individual patient outcomes. Areas covered: To explore underlying molecular mechanisms of lung cancer subtypes, several efforts have used proteogenomic approaches that integrate next generation sequencing (NGS) and mass spectrometry (MS)-based technologies. Expert opinion: A large-scale, MS-based, proteomic analysis, together with both NGS-based genomic data and clinicopathological information, will facilitate establishing extensive databases for lung cancer subtypes that can be used for further proteogenomic analyzes. Proteogenomic strategies will further be understanding of how major driver mutations affect downstream molecular networks, resulting in lung cancer progression and malignancy, and how therapy-resistant cancers resistant are molecularly structured. These strategies require advanced bioinformatics based on a dynamic theory of network systems, rather than statistics, to accurately identify mutant proteins and their affected key networks.

Histology and oncogenic driver alterations of lung adenocarcinoma in Chinese

Little is known about association of mucin abundancy with oncogenic-driver alterations, immunohistochemical and clinicopathologic features in lung adenocarcinomas among Chinese. We here retrospectively examined the clinicopathologic and molecular characteristics of pulmonary mucin-producing adenocarcinoma (PMPA) and previously-reported non-mucinous lung adenocarcinomas collected at our institution. Among the 897 non-mucinous adenocarcinomas, 61 PMPA with ≤90% mucin and 39 PMPA with >90% mucin, ALK rearrangements were found in 47 (5.2%) non-mucinous adenocarcinomas, 9 (14.8%) PMPA with ≤90% mucin and 12 (30.8%) PMPA with >90% mucin, respectively, with an ordinal association (coefficient, 95% CI=0.11, 0.06 to 0.17). Similarly, KRAS mutations was found in 53 (5.9%) non-mucinous adenocarcinomas, 7 (11.5%) PMPA with ≤90% mucin and 14 (35.9%) PMPA with >90% mucin (coefficient, 95% CI=0.11, 0.05 to 0.16). However, mucinous abundancy was inversely, ordinally linked to the EGFR mutations (coefficient, 95% CI=-0.28, -0.33 to -0.22). Mucin abundancy seemed not associated with the alterations of HER2, BRAF, ROS1, MET and RET. We divided PMPA with >90% mucin into three histologic types, namely columnar mucinous cell with basal nuclei (type I, n=11), cuboidal cell with goblet cell feature (type II, n=16) and mucinous cribriform pattern (type III, n=12). These histologic subtypes were associated with alterations of ALK, KRAS and MET, and the immunohistochemical reactivity of MUC1, MUC2, MUC5ac, MUC6, TTF-1 and CK20, including high positive rate of MUC6 (90.9%) and CK20 (36.4%) in type I, MUC2 (50%) in type II and MUC1 (100%) in type III. In summary, mucin abundancy is associated with immunohistochemical and oncogenic-driver profiles of lung adenocarcinomas among Chinese.

Association between the novel classification of lung adenocarcinoma subtypes and EGFR/KRAS mutation status: A systematic literature review and pooled-data analysis

OBJECTIVES

This study aims to determine the association of EGFR/KRAS mutation status with histological subtypes of lung adenocarcinoma (LAC) based on the IASLC/ATS/ERS classification.

METHODS

Pubmed and Cochrane databases were searched from January 2011 to June 2018 for studies that included patients with LAC who underwent surgical resection were classified according to the new IASLC/ATS/ERS classification. EGFR/KRAS status assessment was requireded. The primary outcome was determined by the odds ratio (OR) of the incidence of mutation status of certain of each histological subtype. The reference group consisted of EGFR/KRAS mutation negative patients.

RESULTS

Twenty-seven eligible studies involving 9022 patients with mutation gene detection were included for analysis. Among them, 6717 (74.5%) patients were from the Asian region and, 2305 (25.5%) patients were from Non-Asian regions. The most prevalent subtype was acinar (34.7%), followed by papillary (22.9%), lepidic (18.9%), solid (13.6%), micropapillary (6.3%), and invasive mucinous adenocarcinoma (3.5%). EGFR mutations were more common in patients with resected lepidic predominant adenocarcinoma (OR,1.76; 95%CI, 1.38-2.24;p < 0.01) and were rarely found in solid predominant adenocarcinoma (OR,0.28; 95%CI, 0.23-0.34;p < 0.01) or IMA (OR,0.10; 95%CI, 0.06-0.14;p < 0.01). Conversely, KRAS mutations were characterized by IMA (OR,7.01; 95%CI, 5.11-9.62;p < 0.01), and were less frequently identified in lepidic (OR,0.58; 95%CI, 0.45-0.75;p < 0.01) and acinar (OR,0.65; 95%CI, 0.55-0.78;p < 0.01) predominant subtypes. Further analyses were performed in Asian and Non-Asian groups and the results were consistent.

CONCLUSIONS

The current study confirms that the IASLC/ATS/ERS classification is associated with driver gene alterations in resected LAC.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.

Cytomorphological features as predictors of epidermal growth factor receptor mutation status in lung adenocarcinoma

Background:

Epidermal growth factor receptor mutation-positive (EGFR-p) lung adenocarcinomas are sensitive to tyrosine kinase inhibitors. Although histopathological subtype is an independent predictor of mutation status, there is a paucity of data on the cytomorphological features correlating with the EGFR mutation status. Therefore, the aim of this study was to determine whether certain cytomorphological features correlate with EGFR mutation in lung adenocarcinoma.

Materials and Methods:

A retrospective analysis of 48 lung adenocarcinoma cases diagnosed on fine needle aspiration cytology with known EGFR mutation status was conducted. All cytology smears with cellblock sections were reviewed. The cytomorphological features including tumor pattern, stromal features, nuclear and cytoplasmic features, and tumor grade were evaluated. Clinicoradiological features such as age, sex, smoking, tumor size, clinical stage, metastases, and presence of mass, nodule, lymphadenopathy, pleural effusion, and clinical outcome were also assessed.

Results:

Of 48 cases, 19 were EGFR-p and 29 were negative. EGFR-p cases showed a positive and significant correlation with flat monolayered sheets and acini, mild nuclear atypia, fine chromatin and smooth nuclear margins and these tumors were well differentiated. EGFR-negative tumors were moderate to poorly differentiated with predominance of solid clusters, moderate to marked nuclear atypia, with irregular nuclear margins and coarse chromatin. Clinically, female sex, nonsmoking status, smaller tumor size, and good clinical outcome correlated with EGFR-p status.

Conclusion:

Certain cytomorphological features correlate with and may suggest EGFR mutation status in advanced lung adenocarcinoma in an appropriate clinical context.

Pathologic subtype-defined prognosis is dependent on both tumor stage and status of oncogenic driver mutations in lung adenocarcinoma

Previous studies have shown that the prognosis of lung adenocarcinoma is associated with pathological characterization. In this study, we investigated whether pathology-based prognosis was further influenced by both tumor stage and oncogenic driver mutations. To this end, we recruited a cohort of 465 lung adenocarcinoma patients in China. These patients were classified into 6 pathology-defined subtypes i.e., lepidic-predominant adenocarcinoma (LPA), acinar-predominant adenocarcinoma (APA), papillary-predominant adenocarcinoma (PPA), micropapillary-predominant adenocarcinoma (MPA), solid-predominant adenocarcinoma (SPA), and invasive mucinous adenocarcinoma (IMA). Oncogenic mutations in EGFR, KRAS, ALK, RET, and BRAF genes were determined using fluorescent real-time RT-PCR. The associations of pathogenic subtype or oncogenic mutation with clinical characteristics were analyzed using Fisher’s exact tests. The interactive effects on overall survival (OS) by pathologic subtype, oncogenic mutations, and tumor stage were also determined. We have found that pathogenic subtype of lung adenocarcinoma correlated with smoking habit and tumor cell differentiation. These pathology-defined subtypes can be regrouped into 3 pathology-based prognostic groups: PPG1 (LPA), PPG2 (IMA+APA+PPA), and PPG3 (MPA+SPA) with a favorable, intermediate, and poor OS, respectively. We further demonstrated that this pathology-determined OS can be affected by both tumor stage and status of oncogenic mutations in EGFR, KRAS, ALK, RET, and BRAF genes. Interestingly, the presence of genetic mutations related to ALK, RET and BRAF had an opposite effect on OS between PPG2 (worsen) and PPG3 (improved) patients, reversing the prognostic favorability for patients within these two groups. In conclusion, prognosis of lung adenocarcinoma was defined interactively by pathologic subtype, tumor stage and oncogenic mutation.

Associations between epidermal growth factor receptor mutations and histological subtypes of lung adenocarcinoma according to the IASLC/ATS/ERS classification in Chinese patients

Background

This retrospective study was conducted to investigate the relationship between epidermal growth factor receptor (EGFR) mutation and histological subtypes of lung adenocarcinoma according to the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS) classification in Chinese patients.

Methods

Three hundred and seventy six surgically resected lung adenocarcinomas from Chinese PLA General Hospital were included in the study. Patients’ clinical and pathological characteristics including age, gender, smoking history, tumor size, tumor node metastasis stage, and tumor differentiation were analyzed. Histologic subtypes of adenocarcinoma were categorized according to the IASLC/ATS/ERS classification of lung adenocarcinoma. An amplification‐refractory mutation system was performed to detect EGFR mutations.

Results

One hundred and fifty three lung adenocarcinomas had EGFR mutations. In univariate analysis, EGFR mutations were associated with gender (P < 0.001), smoking history (P < 0.001), tumor differentiation (P < 0.001), and acinar predominant (P < 0.001), papillary predominant (P = 0.034), solid predominant (P = 0.022), invasive mucinous (P = 0.012) and mucinous (P = 0.001) subtypes.

Conclusions

In Chinese patients with lung adenocarcinoma, smoking history, tumor differentiation, and acinar predominant and mucinous subtypes were independent predictors of EGFR mutation.

Molecular characteristics of multifocal invasive mucinous adenocarcinoma of the lung: Report of a rare case

Invasive mucinous adenocarcinoma (IMA) is an uncommon entity in the lung, with a poor prognosis. Multifocal IMA of the lung is even more unusual, and there is little experience with effective treatments. Herein, we present a case of multifocal IMA diagnosed in a 36 year‐old man by video‐assisted thoracoscopic surgery. A right middle lobe and a nodule in the right upper lobe were resected, as were mediastinal lymph nodes, leaving behind an autonomous right lower lobe nodule. To explore the feasibility of molecular treatment, next‐generation sequencing of genetic mutations was performed after four cycles of chemotherapy (pemetrexed + cisplatin). Ultimately, a KIAA1468‐RET fusion gene was detected at a disproportionate level (~67.3%), indicating that targeted therapy may be efficacious in treating this disease.

Pulmonary invasive mucinous adenocarcinoma and mixed invasive mucinous/nonmucinous adenocarcinoma-a clinicopathological and molecular genetic study with survival analysis

Invasive mucinous adenocarcinoma is a variant of lung adenocarcinoma, which may be mixed with nonmucinous adenocarcinoma. KRAS mutations are common, but other clinical and genetic features are not clearly established. Lung adenocarcinomas (n=760) with ≥5 years of follow-up comprised 3 nonoverlapping cohorts for survival analysis. Mucinous tumors were evaluated with Ion AmpliSeq Cancer Hotspot Panel v2. Cases without detected mutations were tested for ALK and ROS1 and by OncoScan array. Fifty-seven invasive mucinous adenocarcinomas and 54 mixed mucinous/nonmucinous adenocarcinomas were identified. Mucinous tumors constituted 27 of 218 nonselected patients (12.4%), 23 of 268 never-smokers (8.6%), and 61 of 274 in a smokers cohort enriched for lepidic growth (22.3%). In the lepidic-enriched smokers, patients with mucinous tumors experienced worse overall survival (P=.006) and progression-free survival (P=.024), which persisted on multivariable analysis. No survival differences were observed in the other cohorts. KRAS mutations were common (76% of invasive mucinous adenocarcinomas, 68% of mixed mucinous/nonmucinous), and 38% of KRAS mutations occurred with other mutations, especially STK11. Six cases had potentially targetable mutations (3 ALK, 2 EGFR, 1 BRAF V600E). All ALK-rearranged tumors were mixed mucinous/nonmucinous. Four of 6 cases without hotspot mutations showed complex copy number/structural abnormalities. Pulmonary invasive mucinous adenocarcinomas and mixed nonmucinous/mucinous adenocarcinomas are clinically and genetically similar, except for a higher rate of ALK rearrangement in mixed tumors. Survival for mucinous tumors is similar to that for nonmucinous tumors in a nonselected cohort, although worse survival was seen in a cohort of smokers enriched for lepidic growth.

ALK rearrangement in specific subtypes of lung adenocarcinoma: immunophenotypic and morphological features

Lung adenocarcinomas are characterized by a variety of genetic and epigenetic changes that lead to activation of specific signaling pathways. This allowed the classification of lung adenocarcinomas according to genetic alterations and the clinical development of novel anticancer agents that affect the activity of specific oncoproteins. In such a context, chromosomal rearrangements that cause constitutive activation of ALK gene define a category of lung adenocarcinomas that is amenable to targeted therapy with ALK inhibitors. Thus, a major issue of current research is to define the morphological and immunophenotypic features of lung ALK-rearranged adenocarcinomas to improve the selection of tumors suitable for molecular genotyping. ALK status was determined, by immunohistochemistry and fluorescence in situ hybridization, in 94 surgically resected lung adenocarcinomas and correlated with histomorphological parameters. Indeed, ALK rearrangement was observed in 10/94 (11%) lung adenocarcinomas and enriched in tumors with a predominant mucinous (46%; p < 0.05) and solid (29%; p < 0.05) pattern. By contrast, it was lacking or sporadically observed in lung adenocarcinomas with predominant acinar, papillary or lepidic pattern. Moreover, the presence of signet-ring cells was predominantly observed in ALK-rearranged tumors (47%; p < 0.05). These data suggest that ALK rearrangement is associated with specific and distinct clinical-pathological characters compared to other genotypes. Thus, the knowledge of these characteristics can improve the diagnostic accuracy and lead to a better understanding of the behavior of ALK-rearranged NSCLC.

Clinicopathological and prognostic features of surgically resected pathological stage I lung adenocarcinoma harboring epidermal growth factor receptor and K-ras mutation

BACKGROUND

This study aimed to evaluate mutations of the epidermal growth factor receptor (EGFR) and K-ras genes and their clinicopathological and prognostic features in patients with resected pathological stage I adenocarcinoma.

METHODS

We examined 224 patients with surgically resected lung adenocarcinoma and analyzed the prognostic and predictive value of these mutations in 162 patients with pathological stage I adenocarcinoma.

RESULTS

Mutations of the EGFR and K-ras genes were detected in 100 (44.6%) and 19 (8.5%) of all tumors, and in 81 (50.0%) and 17 (10.5%) of the pathological stage I tumors, respectively. EGFR mutations were significantly associated with female gender, smoking habit (never smoker), and low grade. By contrast, K-ras mutations were significantly associated with male gender, smoking habit (ever smoker), and the presence of mucinous components. No significant differences were observed in recurrence-free or overall survival between the EGFR-mutant, K-ras-mutant, and wild-type groups (five-year recurrence-free survival 77.8% vs. 87.8% vs. 79.5%; five-year overall survival 82.8% vs. 82.4% vs. 79.2%, respectively). Multivariate analysis showed that neither EGFR nor K-ras mutation was an independent prognostic factor.

CONCLUSIONS

The present study demonstrated that pathological stage I adenocarcinoma harboring EGFR and K-ras gene mutations have distinct clinicopathological features. The presence of these mutations alone were not prognostic factors in patients with resected pathological stage I adenocarcinoma.

Clinicopathological features and relation between anaplastic lymphoma kinase (ALK) mutation and histological subtype of lung adenocarcinoma in Eastern European Caucasian population

Introduction: The incidence of echinoderm microtubule-associated protein-like4-anaplastic lymphoma kinase (EML4-ALK) mutation among surgically treated patients with adenocarcinoma of the lung of the Eastern European ethnicity is underreported. The aim of this trial was the determination of EML4-ALK mutation frequency in investigated population, and the evaluation of correlations between lung adenocarcinoma subtype and clinical characteristics with mutation status.

Patients and methods: This was a prospective trial which included 195 patients with adenocarcinoma of the lung who underwent surgical treatment. ALK mutation screening was performed by immunohistochemistry (IHC). IHC scores of 2+ and 3+ were regarded as positive. Confirmatory FISH was performed in all IHC positive and in 2:1 ratio in negative patients.

Results: Overall ALK mutation rate established by IHC was 6.2%, while FISH confirmed rate of 5.1%. The FISH confirmed ALK positivity in 7.6% Hungarians, 5.5% Serbians, and 6.6% Slovakians. Acinar subtype of adenocarcinoma of the lung was significantly (p=0.02) related to EML4-ALK positive mutation status. Most of the patients were males (56.9%), smokers (50.8%), or former smokers (28.7%) with acinar (55.4%) or solid (35.9%) adenocarcinoma of the lung. Sensitivity and specificity of IHC were 100% and 98.9% respectively.

Conclusions: ALK mutation rate in surgically treated patients with adenocarcinoma of the lung was found to be 6.2% by IHC and 5.1% by FISH. Acinar subtype of the adenocarcinoma of the lung was significantly related to ALK positive mutation.

NRG1 fusion in a French cohort of invasive mucinous lung adenocarcinoma

Invasive mucinous lung adenocarcinoma (IMA) is a rare subtype of lung adenocarcinoma with no effective treatment option in advanced disease. KRAS mutations occur in 28–87% of the cases. NRG1 fusions were recently discovered in KRAS‐negative IMA cases and otherwise negative for known driver oncogenes and could represent an attractive therapeutic target. Published data suggest that NRG1 fusions occur essentially in nonsmoking Asian women. From an IMA cohort of 25 French patients of known ethnicity, driver oncogenes EGFR, KRAS, BRAF, ERBB2 mutations, and ALK and ROS1 rearrangements presence were analyzed. In the IMA samples remaining negative for these driver oncogenes, an NRG1 rearrangement detection was performed by FISH. A driver oncogene was identified in 14/25 IMA, namely 12 KRAS mutations (48%), one ROS1 rearrangement (4%), and one ALK rearrangement (4%). The detection of NRG1 rearrangement by FISH was conducted in the 11 pan‐negative IMA. One sample was NRG1FISH‐positive and 100% of the tumor nuclei analyzed were positive. This NRG1‐positive patient was a 61‐year‐old nonsmoking woman of Vietnamese ethnicity and was the sole patient of Asian ethnicity of the cohort. She died 6 months after the diagnosis with a pulmonary multifocal disease. NRG1FISH detection should be considered in patients with IMA pan‐negative for known driver oncogenes. These results might suggest that NRG1 fusion is more frequent in IMA from Asian patient. Larger studies are needed.

MicroRNA Expression Profile on Solid Subtype of Invasive Lung Adenocarcinoma Reveals a Panel of Four miRNAs to Be Associated with Poor Prognosis in Chinese Patients

According to the reclassification of lung adenocarcinoma (LAC) proposed in 2011, solid predominant lung adenocarcinoma (SPA) has been associated with poor outcomes for LAC patients. However, the prognostic value of the presence of solid subtype remains unclear. Besides, there is little data about the roles of microRNA (miRNA) in solid subtype of LAC. In this study, 243 LAC patients were classified into solid subtype positive and negative groups (S+ LAC, n=134 and S- LAC, n=109) according to whether the solid subtype was more than 5% of the tumor component or not. We analyzed the relationship between solid subtype and patients' outcome by univariate and multivariate analyses. Solid subtype was proved to be significantly associated with the 5-year overall survival and played as an independent prognostic factor for stage I-III invasive LAC patients. Then miRNA microarray was used to identify differentially expressed miRNAs in solid subtype, resulting in 31 differential miRNAs. Quantitative reverse transcription-PCR (QRT-PCR) was used to validate 4 key miRNAs (miR-133b, miR-155-5p, miR-124-3p, miR-145-5p). Further, CCK-8 and transwell assays were performed to validate the impact of one dysregulated miRNA (miR-133b) on LAC cell function. Interestingly, while miR-133b could significantly inhibit the proliferation of A549 and SPC-A1, it showed no effect on the migration or invasion of LAC cell lines. These results suggest that solid subtype can exert independent prognostic impact on LAC patients, and 4 important dysregulated miRNAs in solid subtype of LAC may be involved in the malignancy of S+LAC, thus may further have clinical perspective for S+ LAC in the future.

Relationship of epidermal growth factor receptor activating mutations with histologic subtyping according to International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society 2011 adenocarcinoma classification and their impact on overall survival

Background:

There is limited Indian data on epidermal growth factor receptor (EGFR) gene activating mutations (AMs) prevalence and their clinicopathologic associations. The current study aimed to assess the relationship between EGFR AM and histologic subtypes and their impact on overall survival (OS) in a North Indian cohort.

Patients and Methods:

Retrospective analysis of nonsmall cell lung cancer patients who underwent EGFR mutation testing (n = 186) over 3 years period (2012–2014). EGFR mutations were tested using polymerase chain reaction amplification and direct sequencing. Patients were classified as EGFR AM, EGFR wild type (WT) or EGFR unknown (UKN). Histologically adenocarcinomas (ADC) were further categorized as per the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society-2011 classification.

Results:

Overall EGFR AM prevalence was 16.6%. The ratio of exon 19 deletions to exon 21 L858R mutations was 3.17:1. Female sex (P = 0.002), never smoking status (P = 0.002), metastatic disease (P = 0.032), and nonsolid subtype of ADC (P = 0.001) were associated with EGFR AM on univariate logistic regression analysis (LRA). On multivariate LRA, solid ADC was negatively associated with EGFR AM. Median OS was higher in patients with EGFR AM (750 days) as compared to EGFR-WT (459 days) or EGFR-UKN (291 days) for the overall population and in patients with Stage IV disease (750 days vs. 278 days for EGFR-WT, P = 0.024). On univariate Cox proportional hazard (CPH) analysis, smoking, poor performance status (Eastern Cooperative Oncology Group ≥ 2), EGFR-UKN status, and solid ADC were associated with worse OS while female sex and lepidic ADC had better OS. On multivariate CPH analysis, lepidic ADC (hazard ratio [HR] =0.12) and EGFR-WT/EGFR-UKN (HR = 2.39 and HR = 3.30 respectively) were independently associated with OS in separate analyses.

Conclusions:

Histologic subtyping of ADC performed on small biopsies is independently associated with EGFR AM and with better OS. EGFR AM presence is a positive prognostic factor for OS.

Prognostic implications of immunohistochemistry markers for EGFR-TKI therapy in Chinese patients with advanced lung adenocarcinoma harboring EGFR mutations

Background

Epidermal growth factor receptor (EGFR) mutations in non-small-cell lung cancer predict dramatic clinical responses to tyrosine kinase inhibitor (TKI) treatment. The conclusion on EGFR mutation-specific antibodies by immunohistochemistry (IHC) is not consistent. We evaluated the clinical availability of EGFR mutation-specific antibodies, investigating the prediction role of mutant EGFRs and other IHC markers in TKI therapy in patients with advanced lung adenocarcinoma.

Materials and methods

We analyzed 637 primary lung adenocarcinomas from an unselected Chinese population. For IHC, antibodies against EGFR exon 19 E746_A750 deletions, exon 21 L858R mutations, thyroid transcription factor-1 (TTF-1), and Napsin-A were applied. Positivity was defined as staining score >0.

Results

Specificities of E746_A750 and L858R antibodies were 99.6% and 99.3%, while sensitivities were 86.0% and 82.7%, respectively. Tumors with Napsin-A positivity, TTF-1 positivity, EGFR mutations, and lepidic pattern showed a lower marker of proliferation index (Ki67). Higher expression scores of mutant EGFR protein, TTF-1 positivity, lower Ki67 proliferation index, and lepidic pattern were associated with longer progression-free survival.

Conclusion

High scores of mutant EGFR, Napsin-A positivity, TTF-1 positivity, lower Ki67 index, and lepidic pattern were favorable predictors for TKI therapy in patients with advanced lung adenocarcinoma.

Laricitrin suppresses increased benzo(a)pyrene-induced lung tumor-associated monocyte-derived dendritic cell cancer progression

Benzo(a)pyrene (BaP) stimulates lung cancer cells, promoting monocyte-derived dendritic cells to secrete soluble factors, including heparin binding-epidermal growth factor and C-X-C motif chemokine 5. The secretions from monocyte-derived dendritic cells stimulate the progression of lung cancer cells, including the migration and invasion of cells. To the best of our knowledge, these secretions remain unknown, and require additional study. The present study identified that treatment with BaP-H1395-tumor-associated dendritic cell-conditioned medium had the most marked effect on cell migration and invasion. This result may be associated with the female gender, stage 2 adenocarcinoma or mutation of the proto-oncogene B-Raf (BRAF), according to the cell line background. Laricitrin, a dietary flavonoid derivative present in grapes and red wine, suppresses certain factors and decreases the progression of lung cancer cells that are promoted by BaP in the lung cancer tumor microenvironment. The results of the present study suggest that prolonged exposure to BaP exacerbates lung cancer, particularly in female lung cancer patients with the BRAF mutation, but that laricitrin may ameliorate this effect.

Associations between the IASLC/ATS/ERS lung adenocarcinoma classification and EGFR and KRAS mutations

We sought to investigate the frequency of mutations in epidermal growth factor receptor (EGFR) and Kirsten-RAS (KRAS) by each pathological subtype for patients with resected pulmonary adenocarcinoma as defined by the IASLC/ATS/ERS classification. Histological examination determined the predominant subtype according to the IASLC/ATS/ERS classification. EGFR and KRAS mutations were determined by high-resolution melting and Sanger sequencing. Clinical data were collected from medical records and clinicians. The 178 consecutive patients consisted of 48% males, median age 68 years (range 20-87) and smoking history 78%. The tumour stage was I in 62%, II in 18% and III in 20%. The mutation rates were: EGFR 30%; KRAS 28%. The rate of EGFR mutations in the acinar predominant reference group (n=76), was 37%. The solid predominant subtype showed significantly fewer EGFR mutations [3/33 (9%), odds ratio 0.17 (0.05-0.61), p=0.007]. No differences in mutation rate were observed in other subtypes. No association was found between KRAS mutations and predominant histological subtype. Advanced stage and solid predominant subtype were negative prognostic factors. EGFR mutations can be present in adenocarcinoma of any predominant subtype, however rarely in solid predominant tumours. No association was found between KRAS mutation and the predominant histological subtype.

Differences in driver genes between smoking-related and non-smoking-related lung cancer in the Chinese population

Recently, non-smoking-related lung cancer was classified as an independent disease entity because it is different from tobacco-associated lung cancer. Non-smoking-related lung cancer occurs more often in women than men, and the predominant histological type is adenocarcinoma (ADC) rather than squamous cell carcinoma. Most of the driver gene alterations that have been identified in ADC in never-smokers include epidermal growth factor receptor mutations, KRAS mutations, echinoderm microtubule-associated protein like 4/anaplastic lymphoma kinase fusion, and ROS1 fusion, among others. Meanwhile, significant progress has been made in the treatment of ADC. However, in comparison with ADC, no such available molecular targets exist for smoking-associated lung cancer, for which treatment strategies are limited. Next-generation sequencing has been widely applied to the discovery of more genetic profiles of lung cancers. This review summarizes the differences between smoking-related and non-smoking-related lung cancer as follows: different somatic mutation burdens, C:G→A:T transversions, common and novel driver genes, and treatment strategies. Overall, smoking-related lung cancer is more complicated than non-smoking-related lung cancer. Furthermore, we review the prevalence of driver genes in smoking-associated and non-smoking-associated lung cancers in the Chinese population.

Classification of different patterns of pulmonary adenocarcinomas

The epidemic increase of adenocarcinoma histology accounting for more than 50% of primary lung malignancies and the advent of effective molecular targeted-therapies against specific gene alterations characterizing this tumor type have led to the reconsideration of the pathologic classification of lung cancer. The new 2015 WHO classification provided the basis for a multidisciplinary approach emphasizing the close correlation among clinical, radiologic and molecular characteristics and histopathologic pattern of lung adenocarcinoma. The terms 'bronchioloalveolar carcinoma' and 'mixed adenocarcinoma' have been eliminated, introducing the concepts of 'adenocarcinoma in situ', 'minimally invasive adenocarcinoma' and the use of descriptive predominant patterns in invasive adenocarcinomas (lepidic, acinar, papillary, solid and micropapillary patterns). 'Invasive mucinous adenocarcinoma' is the new definition for mucinous bronchioloalveolar carcinoma, and some variants of invasive adenocarcinoma have been included, namely colloid, enteric and fetal-type adenocarcinomas. A concise update of the immunomorphologic, radiological and molecular characteristics of the different histologic patterns of lung adenocarcinoma is reported here.

Prevalence and Clinicopathological Characteristics of HER2 and BRAF Mutation in Chinese Patients with Lung Adenocarcinoma

Aims

To determine the prevalence and clinicopathological characteristics of BRAF V600E mutation and HER2 exon 20 insertions in Chinese lung adenocarcinoma (ADC) patients.

Methods

Given the fact that the driver mutations are mutually exclusive in lung ADCs, 204 EGFR/KRAS wild-type cases were enrolled in this study. Direct Sanger sequencing was performed to examine BRAF V600E and HER2 exon 20 mutations. The association of BRAF and HER2 mutations with clinicopathological characteristics was statistically analyzed.

Results

Among the 204 lung ADCs tested, 11 cases (5.4%) carried HER2 exon 20 insertions and 4 cases (2.0%) had BRAF V600E mutation. HER2 mutation status was identified to be associated with a non-smoking history (p<0.05). HER2 mutation occurs in 9.4% of never smokers (10/106), 8.7% of female (8/92) and 2.7% of male (3/112) in this selected cohort. All four BRAF mutated patients were women and three of them were never-smokers. No HER2 mutant patients harbor BRAF mutation.

Conclusions

HER2 and BRAF mutations identify a distinct subset of lung ADCs. Given the high prevalence of lung cancer and the availability of targeted therapy, Chinese lung ADC patients without EGFR and KRAS mutations are recommended for HER2 and BRAF mutations detection, especially for those never smokers.

Overview of clinicopathologic features of ALK-rearranged lung adenocarcinoma and current diagnostic testing for ALK rearrangement

Patients with non-small cell lung cancer (NSCLC) who harbor anaplastic lymphoma kinase (ALK) gene rearrangements can derive significant clinical benefit from ALK tyrosine kinase inhibitor. Accurate patient identification is absolutely crucial for successful using ALK inhibitor treatment. However, lung cancer patients with ALK gene rearrangement after ALK inhibitor therapy eventually develop acquired resistance to treatment. In this review, the authors summarize the clinicopathologic features of ALK-rearranged NSCLC and the pros and cons of current diagnostic testing. In addition, we discuss the current diagnostic flow of ALK testing and consideration of rebiopsy sample during disease progression in patients treated by ALK inhibitors.