Do all lung adenocarcinomas follow a stepwise progression?

Oncological characteristics of epidermal growth factor receptor-mutated clinical stage IA lung adenocarcinoma with radiologically pure-solid appearance

OBJECTIVES

We evaluated the clinicopathological and oncological characteristics of epidermal growth factor receptor-mutated clinical stage IA radiological pure-solid lung adenocarcinoma and compared them with those of a ground-glass opacity component.

METHODS

Between 2008 and 2020, data from 1014 surgically resected clinical stage 0-IA epidermal growth factor receptor-mutated lung adenocarcinomas were evaluated. Oncological outcomes were assessed using multivariable analysis. Overall survival was estimated using Kaplan-Meier analysis and the log-rank test. The cumulative incidence of recurrence was estimated using the Gray's test.

RESULTS

Of these, 233 (23%) were radiologically pure-solid tumors, which demonstrated a higher proportion of nodal metastasis, micropapillary component, spread through alveolar space, and Ex19 subtype compared with those of tumors with ground-glass opacity (P < .001). Multivariable analysis revealed that the presence of ground-glass opacity was an independently significant factor for overall survival (P = .037) and cumulative incidence of recurrence (P < .001). In cases where the oncological outcomes were stratified by the presence of ground-glass opacity component, the 5-year overall survival was excellent at more than 90% in tumors with ground-glass opacity despite clinical-T categories (P = .2044); however, tumor size significantly affected survival only in pure-solid tumors (T1a, 100%; T1b, 77.7%; T1c, 68.5%; P = .0056). Furthermore, the cumulative incidence of recurrence was low in tumors with ground-glass opacity despite the clinical-T categories, whereas tumor size significantly affected the cumulative incidence of recurrence only in pure-solid tumors (5-year cumulative incidence of recurrence: T1a-b, 18.9%; T1c, 41.3%; P < .001).

CONCLUSIONS

Oncologic behavior and prognosis of radiologically pure-solid tumors were significantly poorer than those of tumors with ground-glass opacity among patients with epidermal growth factor receptor-mutated early-stage lung adenocarcinoma. These findings imply distinct tumorigenesis based on the presence of ground-glass opacity, even in tumors with epidermal growth factor receptor mutations.

Expert consensus on the multidisciplinary diagnosis and treatment of multiple ground glass nodule-like lung cancer (2024 Edition)

ABSTRACT

This expert consensus reviews current literature and provides clinical practice guidelines for the diagnosis and treatment of multiple ground glass nodule-like lung cancer. The main contents of this review include the following: ① follow-up strategies, ② differential diagnosis, ③ diagnosis and staging, ④ treatment methods, and ⑤ post-treatment follow-up.

The Prognostic Impact of Epidermal Growth Factor Receptor Mutation in Clinical Stage I Lung Adenocarcinoma

BACKGROUND

This study investigated the prognostic impact of epidermal growth factor receptor (EGFR) mutation in clinical stage I lung adenocarcinoma patients.

METHODS

Data for 952 patients who received surgical resection and underwent detection of oncogenic driver mutations were retrospectively collected. Recurrence-free survival (RFS) and overall survival (OS) were estimated by the Kaplan-Meier method and compared using the log-rank test. The adjusted hazard ratio (aHR) with 95% CI of the prognosticator was calculated by Cox proportional hazards model, and cumulative incidence function was measured by competing risk regression model.

RESULTS

EGFR mutation was detected in 581 patients (61.0%) and was more frequent in women (63.9%), nonsmokers (85.5%), and those with ground-glass nodules (GGNs; 56.6%). EGFR mutation was not associated with recurrence and death in the entire cohort or GGN cohort. However, for patients with radiologic pure-solid appearance, EGFR mutation was an independent risk factor for RFS (aHR, 1.623; 95% CI, 1.192-2.210) and distant recurrence (aHR, 1.863; 95% CI, 1.311-2.650), but not OS. Subsequently, subgroup analysis based on EGFR mutation subtypes, including exon 19 deletions (19-Del), exon 21 L858R substitution (L858R), and rare mutations in patients with radiologic pure-solid appearance, revealed that all 3 subtypes have poorer RFS (19-Del: aHR, 1.424; 95% CI, 0.991-2.047; L858R: aHR, 1.708; 95% CI, 1.172-2.490; rare mutations: aHR, 2.500; 95% CI, 1.400-4.465) and higher prevalent distant recurrence (19-Del: aHR, 1.595; 95% CI, 1.061-2.400; L858R: aHR, 2.073; 95% CI, 1.371-3.140; rare mutations: aHR, 2.657; 95% CI, 1.397-5.050) compared with wild-type.

CONCLUSIONS

In clinical stage I lung adenocarcinoma, EGFR mutation was associated with worse RFS and higher prevalent distant recurrence in patients with radiologic pure-solid appearance but not in patients with GGN.

Air bronchogram on chest CT in radiological pure-solid appearance lung cancer: Correlation analysis with genetic pathological features and survival outcomes

PURPOSE

To investigate the correlation of air bronchogram sign with clinicopathological characteristics and prognosis in patients with clinical stage (c-stage) I non-small cell lung cancer (NSCLC) with radiological pure-solid appearance.

METHOD

We retrospectively evaluated 276 patients with pure-solid c-stage I NSCLC and assessed the correlation between the air bronchogram and clinicopathological characteristics. A Cox proportional hazards model was performed to identify the effect of air bronchogram and clinicopathological variables on oncological outcomes. Recurrence-free survival (RFS) and overall survival (OS) were calculated by Kaplan-Meier curves and were compared using log-rank tests.

RESULTS

Presence of air bronchogram was associated with a well differentiated degree (P =.026), higher incidence of EGFR mutation (P <.001) and lower recurrence(P =.021). Kaplan-Meier survival curves showed that air bronchogram group was associated with favorable RFS(67.0% vs. 50.2%; P =.015). A multivariable analysis revealed that air bronchogram and EGFR mutation were independent significant prognostic factors associated with RFS (hazard ratio [HR] = 0.495, 95% confidence interval [CI]: 0.322-0.761, P =.001; HR = 1.625, 95% CI: 1.074-2.457, P =.021; respectively), but not with OS. Additionally, we found that pathological lymph node metastasis was identified as an independent prognostic factor associated with poor RFS and OS(HR = 2.808, 95% CI: 1.913-4.123, P <.001 for RFS; HR = 1.983, 95% CI: 1.185-3.318, P =.009 for OS).

CONCLUSIONS

Presence of air bronchogram was associated with well differentiated degree, higher incidence of EGFR mutation and had additional positive prognostic value for RFS in c-stage I NSCLC with a radiological pure-solid appearance.

A problem with clinical T factor in the 8th TNM edition: Prognosis and EGFR mutation status of small sized lung cancers with difficulty to measure the diameter of solid component in part-solid tumor

OBJECTIVE

Clinical T factors in the 8th TNM classification of lung cancer have a practical problem. In some cases, it is difficult to measure the size of the solid components in part-solid tumors, and the classification of these tumors is controversial.

METHODS

We evaluated 590 resected cT1N0M0 stage IA non-small-cell lung cancers based on the 7th edition between 2009 and 2012. Tumor and solid component diameters were measured using thin-section computed tomography (CT). We defined tumors with difficulty in measuring the size of the solid components as lung cancers with scattered or mixed consolidation (LCSMCs). LCSMCs were observed in 79 (13.4%) patients. Other tumors were classified as cTis, cT1mi, cT1a, cT1b, and cT1c, according to the 8th edition. We compared prognosis and epidermal growth factor receptor mutations (EGFRm) status of LCSMCs with those of cT1a, cT1b, and cT1c.

RESULTS

The difference in overall survival (OS) among cT1a, cT1b, and cT1c was significant (5-year-OS: 96.9% vs. 76.8% vs. 65.0%). There was no significant difference in prognosis between LCSCs and cT1a (5-year-OS: 92.4% vs. 96.9%). A significant difference was observed in the frequency of EGFRm between cT1a, cT1b, and cT1c (52.4%, 42.4%, and 29.8%). The incidence of EGFRm in LCSMCs was 54.8% and there was no significant difference between LCSMCs and cT1a.

CONCLUSIONS

The prognosis and frequency of EGFRm in LCSMCs were close to those in cT1a. As we cannot measure the diameter of the solid component in subsolid lung cancers, it may be appropriate to classify these tumors as cT1a tumors.

Artificial intelligence system-based histogram analysis of computed tomography features to predict tumor invasiveness of ground-glass nodules

Background

The use of an artificial intelligence (AI)-based diagnostic system can significantly aid in analyzing the histogram of pulmonary nodules. The aim of our study was to evaluate the value of computed tomography (CT) histogram indicators analyzed by AI in predicting the tumor invasiveness of ground-glass nodules (GGNs) and to determine the added value of contrast-enhanced CT (CECT) compared with nonenhanced CT (NECT) in this prediction.

Methods

This study enrolled patients with persistent GGNs who underwent preoperative NECT and CECT scanning. AI-based histogram analysis was performed for pathologically confirmed GGNs, which was followed by screening invasiveness-related factors via univariable analysis. Multivariable logistic models were developed based on candidate CT histogram indicators measured on either NECT or CECT. Receiver operating characteristic (ROC) curve and precision-recall (PR) curve were used to evaluate the models' performance.

Results

A total of 116 patients comprising 121 GGNs were included and divided into the precancerous lesion and adenocarcinoma groups based on invasiveness. In the AI-based histogram analysis, the mean CT value [NECT: odds ratio (OR) =1.009; 95% confidence interval (CI): 1.004-1.013; P<0.001] and solid component volume (NECT: OR =1.005; 95% CI: 1.000-1.010; P=0.032) were associated with the adenocarcinoma and used for multivariable logistic modeling. The area under ROC curve (AUC) and PR curve (AUPR) were not significantly different between the NECT model (AUC =0.765, 95% CI: 0.679-0.837; AUPR =0.907, 95% CI: 0.825-0.953) and the optimal CECT model (delayed phase: AUC =0.772, 95% CI: 0.687-0.843; AUPR =0.895, 95% CI: 0.812-0.944). No significantly different metrics were observed between the NECT and CECT models (precision: 0.707 vs. 0.742; P=0.616).

Conclusions

The AI diagnostic system can help in the diagnosis of GGNs. The system displayed decent performance in GGN detection and alert to malignancy. Mean CT value and solid component volume were independent predictors of tumor invasiveness. CECT provided no additional improvement in diagnostic performance as compared with NECT.

Advances in diagnosis and prediction for aggression of pure solid T1 lung cancer

A growing number of early-stage lung cancers presenting as malignant pulmonary nodules have been diagnosed because of the increased adoption of low-dose spiral computed tomography. But pure solid T1 lung cancer with ≤3 cm in the greatest dimension is not always at an early stage, despite its small size. This type of cancer can be highly aggressive and is associated with pathological involvement, metastasis, postoperative relapse, and even death. However, it is easily misdiagnosed or delay diagnosed in clinics and thus poses a serious threat to human health. The percentage of nodal or extrathoracic metastases has been reported to be >20% in T1 lung cancer. As such, understanding and identifying the aggressive characteristics of pure solid T1 lung cancer is crucial for prevention, diagnosis, and therapeutic strategies, and beneficial to improving the prognosis. With the widespread of lung cancer screening, these highly invasive pure solid T1 lung cancer will become the main advanced lung cancer in future. However, there is limited information regarding precision medicine on how to identify these "early-stage" aggressive lung cancers. To provide clinicians with new insights into early recognition and intervention of the highly invasive pure solid T1 lung cancer, this review summarizes its clinical characteristics, imaging, pathology, gene alterations, immune microenvironment, multi-omics, and current techniques for diagnosis and prediction.

Elevated Mast Cell Abundance Is Associated with Enrichment of CCR2+ Cytotoxic T Cells and Favorable Prognosis in Lung Adenocarcinoma

Mast cells constitute indispensable immunoregulatory sentinel cells in the tumor microenvironment. A better understanding of the regulation and functions of mast cells in lung adenocarcinoma (LUAD) could uncover therapeutic approaches to reprogram the immunosuppressive tumor microenvironment. Here, we performed flow cytometry and single-cell RNA sequencing (scRNA-seq) of patient LUAD samples to comprehensively characterize LUAD-infiltrating mast cells. Mast cells exhibited functional heterogeneity and were enriched in LUAD with ground-glass opacity features (gLUAD). The mast cells in gLUAD exhibited proinflammatory and chemotactic properties while those in radiologically solid LUAD (sLUAD) were associated with tumor angiogenesis. Mast cells were an important source of CCL2 and correlated with the recruitment of CCR2+ CTL, a specific subcluster of preexhausted T cells with tissue-resident memory phenotype and enhanced cytotoxicity. Increased infiltration of mast cells and CCR2+ CTLs and their colocalization showed a strong association with favorable prognosis after surgery but were not associated with improved survival after chemotherapy. Collectively, these findings reveal a key role of mast cells in LUAD and their potential cross-talk with CTLs, suggesting that targeting mast cells may be an immunotherapeutic strategy for LUAD.

SIGNIFICANCE

Comprehensive characterization of mast cells in lung adenocarcinoma elucidates their heterogeneity and identifies interplay between mast cells and CCR2+ T cells that is associated with a favorable prognosis.

Diagnostic performance of RASSF1A and SHOX2 methylation combined with EGFR mutations for differentiation between small pulmonary nodules

BACKGROUND AND AIM

Aberrant methylation of Ras association domain family 1, isoform A (RASSF1A), and short-stature homeobox gene 2 (SHOX2) promoters has been validated as a pair of valuable biomarkers for diagnosing early lung adenocarcinomas (LUADs). Epidermal growth factor receptor (EGFR) is the key driver mutation in lung carcinogenesis. This study aimed to investigate the aberrant promoter methylation of RASSF1A and SHOX2, and the genetic mutation of EGFR in 258 specimens of early LUADs.

METHODS

We retrospectively selected 258 paraffin-embedded samples of pulmonary nodules measuring 2 cm or less in diameter and evaluated the diagnostic performance of individual biomarker assays and multiple panels between noninvasive (group 1) and invasive lesions (groups 2A and 2B). Then, we investigated the interaction between genetic and epigenetic alterations.

RESULTS

The degree of RASSF1A and SHOX2 promoter methylation and EGFR mutation was significantly higher in invasive lesions than in noninvasive lesions. The three biomarkers distinguished between noninvasive and invasive lesions with reliable sensitivity and specificity: 60.9% sensitivity [95% confidence interval (CI) 52.41-68.78] and 80.0% specificity (95% CI 72.14-86.07). The novel panel biomarkers could further discriminate among three invasive pathological subtypes (area under the curve value > 0.6). The distribution of RASSF1A methylation and EGFR mutation was considerably exclusive in early LUAD (P = 0.002).

CONCLUSION

DNA methylation of RASSF1A and SHOX2 is a pair of promising biomarkers, which may be used in combination with other driver alterations, such as EGFR mutation, to support the differential diagnosis of LUADs, especially for stage I.

Transbronchial Techniques for Lung Cancer Treatment: Where Are We Now?

The demand for parenchyma-sparing local therapies for lung cancer is rising owing to an increasing incidence of multifocal lung cancers and patients who are unfit for surgery. With the latest evidence of the efficacy of lung cancer screening, more premalignant or early-stage lung cancers are being discovered and the paradigm has shifted from treatment to prevention. Transbronchial therapy is an important armamentarium in the local treatment of lung cancers, with microwave ablation being the most promising based on early to midterm results. Adjuncts to improve transbronchial ablation efficiency and accuracy include mobile C-arm platforms, software to correct for the CT-to-body divergence, metal-containing nanoparticles, and robotic bronchoscopy. Other forms of energy including steam vapor therapy and pulse electric field are under intensive investigation.

Lepidic growth component as a favorable prognostic factor in non-small cell lung cancer of ≤3 cm

BACKGROUND

Many non-small cell lung cancer (NSCLC) tumors present complex histology with various components. The effects of the lepidic growth component (LGC) on the prognosis of NSCLC have not been investigated. Here, we investigated whether an LGC is a relevant prognostic factor for NSCLC.

METHODS

This study retrospectively investigated the clinicopathologic characteristics of 379 patients with NSCLC ≤3 cm who underwent complete surgical resection between 2004 and 2016 at the University of Yamanashi Hospital. The histologic subtypes were classified into NSCLC with or without an LGC. We evaluated the effect of an LGC on the clinicopathologic features and 5-year overall survival of patients with NSCLC.

RESULTS

On final pathology, 214 (56%) of 379 patients had an LGC, and 165 (44%) did not. Sex, smoking history, ground-glass opacity component, pathologic invasive size, lymph node metastasis, pleural invasion, vessel invasion, pathologic stage, and histologic type were significantly different between the groups. Multivariate analysis of 5-year overall survival, identified age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.035-1.105; p < 0.001), pathologic invasive size (HR, 1.548; 95% CI, 1.088-2.202; p = 0.015) and LGC (HR, 2.11; 95% CI, 1.099-4.051; p = 0.025) as independent prognostic factors. When the pathologic invasive size was matched, the 5-year overall survival of the LGC and non-LGC groups was 93% and 77%, respectively (p = 0.006).

CONCLUSIONS

LGC is a significantly favorable prognostic factor for NSCLC with a pathologic invasive size of ≤3 cm.

Prognostic Impact of Very Small Ground-Glass Opacity Component in Stage IA Solid Predominant Non-small Cell Lung Cancer

We evaluated the prognostic role of the presence of a very small ground glass opacity (GGO) component in stage IA solid-predominant non-small cell lung cancer (NSCLC). We evaluated surgically resected 1471 patients diagnosed with stage IA solid-predominant NSCLC. They were classified into 3 groups; that is, GGO group (0.5 Collapse

Key Words

• Clinical stage IA
• Ground-glass opacity
• Lung cancer
• Prognosis

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MESH Headings

• Humans
• Carcinoma, Non-Small-Cell Lung/mortality
• Carcinoma, Non-Small-Cell Lung/diagnostic imaging
• Carcinoma, Non-Small-Cell Lung/surgery
• Carcinoma, Non-Small-Cell Lung/pathology
• Lung Neoplasms/mortality
• Lung Neoplasms/pathology
• Lung Neoplasms/diagnostic imaging
• Lung Neoplasms/surgery
• Male
• Female
• Neoplasm Staging
• Middle Aged
• Aged
• Pneumonectomy/mortality
• Time Factors
• Risk Factors
• Retrospective Studies
• Predictive Value of Tests
• Risk Assessment
• Tomography, X-Ray Computed
• Adult
• Treatment Outcome
• Aged, 80 and over

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Grants Collapse

Affiliation(s)

Aritoshi Hattori Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan.
Takeshi Matsunaga Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan
Mariko Fukui Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan
Kazuhiro Suzuki Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan
Kazuya Takamochi Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan
Kenji Suzuki Department of General Thoracic Surgery, Juntendo University School of Medicine, Tokyo, Japan

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Impact of a Ground-glass Opacity Component on c-Stage IA Lung Adenocarcinoma

Studies have shown that tumors with ground-glass opacity (GGO) components are associated with favorable outcomes. However, this view should be confirmed in an international cohort. We aimed to verify the impact of a GGO component on clinical (c)-stage IA lung adenocarcinoma and to describe the biological discrepancies between the part-solid and pure-solid groups. We evaluated 1333 cases of surgically resected c-stage IA lung adenocarcinomas, including 484 part-solid and 849 pure-solid tumors. Furthermore, we matched the solid size between the 2 groups and examined 470 patients. We compared the prognoses between the 2 groups before and after matching. The prognostic and biological differences were described before and after matching. Compared with the pure-solid group, the part-solid group was associated with favorable outcomes [5-year overall survival (OS) 99.4% vs 87.6%, P < 0.001; 5-year recurrence-free survival (RFS) 96.9% vs 82.2%, P < 0.001]. Similar results were obtained after matching (5-year OS 98.9% vs 92.2%, P = 0.012; 5-year RFS 95.0% vs 88.5%, P = 0.007). Multivariable analyses revealed that GGO component appearance was a factor of better OS and RFS. The part-solid tumor, regardless of the size of the solid component, had a similar outcome to the pure-solid tumor of c-stage T1a classification. Also, more epidermal growth factor receptor, human epidermal growth factor receptor-2 mutations, and receptor tyrosine kinase ROS-1-positive were observed in the part-solid group. In comparison, more wild types and Kirsten-Ras were observed in the pure-solid group. Adenocarcinomas with a GGO component were associated with superior outcomes. The GGO component should be considereda new clinical T descriptor. Early-stage lung adenocarcinomas with and without a GGO component may be 2 distinct tumor types.

Ground glass opacity: can we correlate radiological and histological features to plan clinical decision making?

BACKGROUND

The spectrum of ground glass opacity (GGO) is a diagnostic and clinical management quandary. The role of computed tomographic scans in detecting malignant GGO has inter-observer variability. Pure GGO have been traditionally thought to be predominantly benign in nature and has long volume doubling times. This study was undertaken to correlate the findings of radiology and histology of ground glass opacities at our institute.

METHODS

This study is a retrospective observational study of patients who underwent lung resection surgery for radiology proven ground glass opacities between January 2010 and December 2018. A total of 115 patients were included in the study based on inclusion and exclusion criteria and were analysed.

RESULTS

The patients were divided into two groups; pure GGO (n = 50), mixed GGO (n = 65). The pathological tumour size was ≤ 2 cm in 51% of the patients and 27 patients had the size between 2.1 and 3.0 cm. The predominant histopathologic feature was lepidic predominance in 54 patients followed by 24 patients with acinar predominance. Among patients with radiological tumour size of ≤ 2 cm, pure GGO was present in 48% of the patients. Among patients with pure GGO, 96% of the patients had no solid component. 44 patients had only single CT scan before proceeding to surgery. All these patients had mixed GGO.

CONCLUSION

Our study concludes pure GGOs, though lacking solid component have a high propensity to be malignant. The role of repeated CT surveillance in this context without offering curative surgery may be questionable.

Clinical Features and Surgical Treatment of Synchronous Multiple Primary Lung Adenocarcinomas With Different EGFR Mutations

Background

With the popularity of lung cancer screening and advances in imaging technology, more and more synchronous multiple primary lung adenocarcinomas (SMPLA) are being diagnosed clinically, however, the clinical characteristics and prognosis of SMPLA with different EGFR mutations remains unclear. We aimed to explore clinical features and surgical outcomes of these patients to aid in the diagnosis and treatment of SMPLA.

Methods

Medical records of patients with different EGFR mutations who have been diagnosed as SMPLA and underwent surgical resection from March 2015 to December 2019 were retrospectively analyzed. Clinical characteristics, surgical outcomes, recurrence-free survival (RFS) and overall survival (OS) were investigated.

Results

A total of 70 patients (68.6% female and 77.1% non-somkers) were included. Total of 161 lesions in all patients, 84.4% were ground-glass opacity (GGO) lesions. EGFR mutations were detected in 108 lesions, most of which were L858R (35.4%) and 19Del (20.5%). The mutation rate of mixed GGO is significantly higher than that of pure GGO and solid nodules (SN); the mutation rate of invasive adenocarcinoma is significantly higher than that of other histology subtypes; the mutation rate of lesions >20 mm was significantly higher than that of ≤20 mm. However, there is no significant difference in the mutation rate of specific driver gene between different radiological features, pathological characteristics and sizes. After a median follow-up time of 29 months, the 3-year OS and RFS were 94.4% and 86.0%, respectively.

Conclusions

A high discordance of EGFR mutations were identified between tumors in patients with SMPLA. Synchronous multiple lung adenocarcinomas with predominantly multiple GGO should be considered as SMPLA, and surgery may be aggressively performed for these patients due to a good prognosis.

Pan-Driver-Negatives <i>versus</i> Epidermal Growth Factor Receptor Mutants for C-Stage IA Lung Adenocarcinoma with Ground-Glass Opacity

Purpose: We aimed to verify the prognosis of epidermal growth factor receptor (EGFR) mutation of clinical (c)-stage IA lung adenocarcinoma with the ground-glass opacity (GGO) component.

Methods: We evaluated 226 cases of surgically resected c-stage IA lung adenocarcinoma with GGO component. Endpoints were overall survival (OS) and recurrence-free survival (RFS). Kaplan–Meier analysis and the log-rank test were used to estimate the survival differences. Prognostic factors were assessed using the univariable and multivariable Cox proportional hazards model.

Results: Among the 226 cases, 177 cases harbored the EGFR-mutant adenocarcinoma with the GGO component. The mean duration of follow-up time was 54.4 ± 1.2 months. The 5-year OS and RFS did not differ significantly between the EGFR-mutant and wild-type groups (5-year OS 100% vs. 94.3%, hazard ratio [HR] 0.276, P = 0.168; 5-year RFS 94.7% vs. 95.7%, HR 0.873, P = 0.864). Multivariable Cox hazard model revealed that radiologically solid component size (P = 0.010) and pathological node-positive (P = 0.036) were significant predictors of an inferior RFS.

Conclusion: EGFR-mutant was not a prognostic factor of OS and RFS for c-stage IA lung adenocarcinoma with the GGO component. Radiologically solid component size and pathological lymph node status were independent prognostic factors of worse RFS.

Updates in grading and invasion assessment in lung adenocarcinoma

The pathologic evaluation of lung adenocarcinoma, because of greater understanding of disease progression and prognosis, has become more complex. It is clear that histologic growth patterns reflect indolent and aggressive disease, resulting in clearer morphologic groups that can be the underpinning of a grading system. In addition, the progression of adenocarcinoma from a tumor that preserves alveolar architecture to one that remodels and effaces lung structure has led to criteria that reflect invasive rather than in-situ growth. While some of these are based on tumor cell growth pattern, aspects of this remodeling from desmoplasia to artifacts of lung collapse and sectioning, can lead to difficult to interpret patterns with lower reproducibility between observers. Such scenarios are examined to provide updates on new histologic concepts and to highlight ongoing problem areas.

Gene Expression Profiles of Multiple Synchronous Lesions in Lung Adenocarcinoma

Many studies support a stepwise continuum of morphologic changes between atypical adenomatous hyperplasia (AAH) and lung adenocarcinoma (ADC). Here we characterized gene expression patterns and the association of differentially expressed genes and immune tumor microenvironment behaviors in AAH to ADC during ADC development. Tumor tissues from nine patients with ADC and synchronous multiple ground glass nodules/lesions (GGN/Ls) were analyzed using RNA sequencing. Using clustering, we identified genes differentially and sequentially expressed in AAH and ADC compared to normal tissues. Functional enrichment analysis using gene ontology terms was performed, and the fraction of immune cell types was estimated. We identified up-regulated genes (ACSL5 and SERINC2) with a stepwise change of expression from AAH to ADC and validated those expressions by quantitative PCR and immunohistochemistry. The immune cell profiles revealed increased B cell activities and decreased natural killer cell activities in AAH and ADC. A stepwise change of differential expression during ADC development revealed potential effects on immune function in synchronous precursors and in tumor lesions in patients with lung cancer.

Prognostic model of lung adenocarcinoma constructed by the CENPA complex genes is closely related to immune infiltration

BACKGROUND

Lung adenocarcinoma (LUAD) is still one of the primary malignant diseases leading to higher mortality worldwide. It has been previously reported that multiple genes in the CENPA-nucleosome associated complex (NAC) complex in lung cancer can be used as prognostic markers; however, there is lack of comprehensive research on the CENPA-NAC complex.

METHODS

The hub genes of lung cancer were obtained by analyzing multiple gene expression omnibus (GEO) lung cancer datasets. The key genes of the CENPA-NAC complex in the evolution of LUAD were identified according to lung cancer data obtained from The Cancer Genome Atlas (TCGA) database, and the key genes were constructed as a survival prognostic model. The relationship between the model and immune cell infiltration was studied by the Tumor Immune Estimation Resource (TIMER) and single-sample gene set enrichment analysis (ssGSEA) studies.Droplet Digital polymerase chain reaction (ddPCR) was used to verify the effectiveness of the prognostic model to predict survival using clinical samples.

RESULTS

A comprehensive study showed that CENPA, CENPH, CENPM, CENPN and CENPU were key genes in the development and evolution of LUAD. The constructed survival prognosis model was an independent risk factor for LUAD and can be used to assess the survival of LUAD patients. The risk score was closely related to the infiltration of multiple immune cells. The independent cohorts GSE31210 and GSE50081 further confirmed the validity of the prognostic model, and finally, the model was validated with clinical samples.

CONCLUSIONS

In conclusion, the results of the present study showed that CENPA, CENPH, CENPM, CENPN, and CENPU are a group of potential prognostic markers in LUAD. The constructed model has been confirmed to be applicable in the clinical setting in evaluating the survival of patients with LUAD, and providing more evidence on immunotherapy for LUAD.

High-resolution computed tomography findings independently predict epidermal growth factor receptor mutation status in ground-glass nodular lung adenocarcinoma

BACKGROUND

For lung adenocarcinoma with epidermal growth factor receptor (EGFR) gene mutation, small molecule tyrosine kinase inhibitors are more effective. Some patients could not obtain enough histological specimens for EGFR gene mutation detection. Specific imaging features can predict EGFR mutation status to a certain extent.

AIM

To assess the associations of EGFR mutations with high-resolution computerized tomography (HRCT) features in ground-glass nodular lung adenocarcinoma.

METHODS

This study retrospectively assessed patients with ground-glass nodular lung adenocarcinoma diagnosed between January 2011 and March 2017. EGFR gene mutations in exons 18-21 were detected. The patients were classified into mutant EGFR and wild-type groups, and general data and HRCT image characteristics were assessed.

RESULTS

Among 98 patients, 31 (31.6%) and 67 (68.4%) had mutated and wild-type EGFR in exons 18-21, respectively. Gender, age, smoking history, location of lesions, morphology, edges, borders, pleural indentations, and associations of nodules with bronchus and blood vessels were comparable in both groups (all P > 0.05). Patients with mutant EGFR had larger nodules than those with the wild-type (17.19 ± 6.79 and 14.37 ± 6.30 mm, respectively; P = 0.047). Meanwhile, the vacuole/honeycomb sign was more frequent in the mutant EGFR group (P = 0.011). The logistic regression prediction model included the combination of nodule size and vacuole/honeycomb sign (OR = 1.120, 95%CI: 1.023-1.227, P = 0.014) revealed a sensitivity of 83.9%, a specificity of 52.2% and an AUC of 0.698 (95%CI: 0.589-0.806; P = 0.002).

CONCLUSION

Nodule size and vacuole/honeycomb features could independently predict EGFR mutation status in ground-glass nodular lung adenocarcinoma.

Prognosis of epidermal growth factor receptor-mutated stage I lung adenocarcinoma with radiologically solid features

OBJECTIVES

The prognostic role of the epidermal growth factor receptor (EGFR) mutation remains controversial, especially in early-stage lung adenocarcinoma with a solid appearance. We evaluated the oncological outcomes of clinical stage I (c-stage I) radiologically invasive lung adenocarcinoma by EGFR mutation status.

METHODS

Between 2008 and 2013, the data from 463 surgically resected c-stage I radiologically invasive, i.e. solid-dominant lung adenocarcinomas subjected to EGFR mutant analysis, were evaluated. Oncological outcomes were assessed using multivariable Cox regression analysis. Recurrence-free survival (RFS) was estimated using Kaplan-Meier analysis and the log-rank test.

RESULTS

A total of 229 (49%) samples harboured the EGFR-mutant adenocarcinoma. Overall, the 5-year RFS did not differ significantly between the EGFR-mutant and EGFR wild-type groups (67.3% vs 64.9%; P = 0.639). However, among the clinical T1c/T2a tumour subset (n = 177), a multivariable Cox hazard model revealed that radiologically pure-solid tumour (P = 0.024), EGFR-mutant (P = 0.027) and pathological stage II/III (P < 0.001) were significant predictors of a poor RFS. Furthermore, in the c-T1c/T2a radiologically pure-solid lung adenocarcinoma subset, the EGFR-mutant group showed marginally lower 5-year RFS compared to that with the EGFR wild-type group (n = 134; 34.9% vs 53.0%; P = 0.062). Among them, multivariable Cox regression analysis revealed that EGFR mutant (P = 0.037) and pathological stage II/III (P = 0.011) were independently and significantly prognostic for worse RFS.

CONCLUSIONS

Among the c-stage I radiologically invasive lung adenocarcinomas, the EGFR mutation-positive type was correlated with an increased risk of recurrence in the c-T1c/T2a radiologically pure-solid tumour subset. When considering the prognostic value of EGFR mutations in early-stage lung adenocarcinoma, it is necessary to stratify them based on the presence of a ground-glass opacity component.

Prognostic influence of a ground-glass opacity component in hypermetabolic lung adenocarcinoma

OBJECTIVES

We evaluated the oncological role of a ground-glass opacity (GGO) component in hypermetabolic lung adenocarcinoma with a high maximum standardized uptake value.

METHODS

Between 2008 and 2017, we retrospectively reviewed the data of surgically resected clinically node-negative lung adenocarcinomas with a hypermetabolic activity. Furthermore, they were classified based on the presence of GGO. The prognostic significance of a GGO in hypermetabolic tumours was evaluated using the Cox proportional-hazards model. The overall survival (OS) was estimated by the Kaplan-Meier method using a log-rank test.

RESULTS

Of the 1134 surgically resected clinically node-negative lung adenocarcinoma, 603 cases with hypermetabolic activity (maximum standardized uptake value ≥3.0 mg/dl) were evaluated. Among them, there were 120 (20%) cases in the With GGO group and 483 (80%) in the Solid group. The 5-year OS of patients with hypermetabolic lung adenocarcinoma was significantly different between the With GGO and Solid groups (83.1% vs 59.4%, P < 0.001). After stratifying by the presence of GGO, maximum standardized uptake value and maximum tumour size were independently significant prognosticators in the Solid group by multivariable analysis; however, no clinical factors were associated with survival among the With GGO group. The 5-year OS was favourable despite the solid component size among the With GGO group (T1a + T1b: 85.5%, T1c: 80.0%, T2a or more: 84.2%, P = 0.904). For the Solid group, survival diminished drastically with increasing tumour size (T1a + T1b: 68.7%, T1c: 62.8%, T2a or more: 48.0%, P < 0.001).

CONCLUSIONS

The prognosis of lung adenocarcinoma with GGO was favourable even in hypermetabolic tumours. Accordingly, the presence of GGO should be considered as an important parameter in the next clinical T classification.

Significance of stratifin in early progression of lung adenocarcinoma and its potential therapeutic relevance

Lung cancer is the most common cause of global cancer-related mortality, and the main histological type is adenocarcinoma, accounting for 50% of non-small cell lung cancer. In 2015, the World Health Organization (WHO) histological classification defined the concepts of "adenocarcinoma in situ" (AIS) and "minimally invasive adenocarcinoma" (MIA), which are considered to be adenocarcinomas at a very early stage. Although AIS and MIA have a very favorable outcome, once they progress to early but invasive adenocarcinoma (eIA), they can sometimes have a fatal outcome. We previously compared the expression profiles of eIA and AIS, and identified stratifin (SFN; 14-3-3 sigma) as a protein showing significantly higher expression in eIA than in AIS. Expression of SFN is controlled epigenetically by DNA demethylation, and its overexpression is significantly correlated with poorer outcome. In vitro and in vivo analyses have shown that SFN facilitates early progression of adenocarcinoma by enhancing cell proliferation. This review summarizes genetic and epigenetic abnormalities that can occur in early-stage lung adenocarcinoma and introduces recent findings regarding the biological significance of SFN overexpression during the course of lung adenocarcinoma progression. Therapeutic strategies for targeting SFN are also discussed.

Loss of IL-34 Expression Indicates Poor Prognosis in Patients With Lung Adenocarcinoma

Interleukin 34 (IL-34), an additional ligand of the colony-stimulating factor-1 receptor (CSF-1R), promotes the secretion of pro-inflammatory cytokines and stimulates NF-κB and JNK-related signaling pathways. However, the potential mechanism and prognostic value of IL-34 in lung adenocarcinoma (LUAD) remain obscure. In this study, IL-34 was found to be downregulated in LUAD tissues compared with para-carcinoma tissues, and loss of IL-34 expression was correlated with shorter overall survival (OS), which was validated by bioinformatics\ analysis in TCGA (The Cancer Genome Atlas) cohort and immunohistochemical analysis in the NTU (Nantong University) cohort, respectively. Subsequently, loss of IL-34 promotes negative regulation of the immune system and inhibits the infiltration of immune cells. Moreover, IL-34 deficiency was shown to be an independent adverse prognostic factor for patients with LUAD, and subgroup analysis indicated that IL-34 might contribute to the stratified management of patients with LUAD. IL-34-based nomogram model significantly improved the accuracy of prognostic predictions for OS of patients with LUAD, both in the TCGA cohort and the NTU cohort. Taken together, our data suggested that loss of IL-34 expression is associated with poor prognosis and negative regulation of the immune system of patients with LUAD, contributing to the stratified management of patients with LUAD.

Adenocarcinoma spectrum lesions of the lung: Detection, pathology and treatment strategies

Adenocarcinoma has become the most prevalent lung cancer sub-type and its frequency is increasing. The earliest stages in the development of lung adenocarcinomas are visible using modern computed tomography (CT) as ground glass nodules. These pre-invasive nodules can progress over time to become invasive lung adenocarcinomas. Lesions in this developmental pathway are termed 'adenocarcinoma spectrum' lesions. With the introduction of lung cancer screening programs there has been an increase in the detection of these lesions raising questions about natural history, surveillance and treatment. Here we review how the radiological appearance of an adenocarcinoma spectrum lesion relates to its underlying pathology and explore the natural history and factors driving lesion progression. We examine the molecular changes that occur at each stage of adenocarcinoma spectrum lesion development, including the effects of the driver mutations, EGFR and KRAS, that are key to invasive adenocarcinoma pathology. A better understanding of the development of pre-invasive disease will create treatment targets. Our understanding of how tumours interact with the immune system has led to the development of new therapeutic strategies. We review the role of the immune system in the development of adenocarcinoma spectrum lesions. With a clear preinvasive phase there is an opportunity to treat early adenocarcinoma spectrum lesions before an invasive lung cancer develops. We review current management including surveillance, surgical resection and oncological therapy as well as exploring potential future treatment avenues.

[Expert Consensus for Thermal Ablation of Pulmonary Subsolid Nodules (2021 Edition)]

局部热消融技术在肺部结节治疗领域正处在起步与发展阶段，为了肺结节热消融治疗的临床实践和规范发展，由“中国医师协会肿瘤消融治疗技术专家组”“中国医师协会介入医师分会肿瘤消融专业委员会”“中国抗癌协会肿瘤消融治疗专业委员会”“中国临床肿瘤学会消融专家委员会”组织多学科国内有关专家，讨论制定了“热消融治疗肺部亚实性结节专家共识（2021年版）”。主要内容包括：①肺部亚实性结节的临床评估；②热消融治疗肺部亚实性结节技术操作规程、适应证、禁忌证、疗效评价和相关并发症；③存在的问题和未来发展方向。

Clinical T1aN0M0 lung cancer: differences in clinicopathological patterns and oncological outcomes based on the findings on high-resolution computed tomography

OBJECTIVES

To elucidate the clinicopathological characteristics and oncological outcomes of clinical T1aN0M0 (c-T1N0M0) lung cancer based on the newest 8th TNM classification.

METHODS

A total of 257 patients with c-T1aN0M0 lung cancer were retrospectively included in this study. According to the solid component size manifesting on the high-resolution computed tomography (HRCT), all lesions were classified as the pure ground-glass nodule (pure-GGN) with a diameter > 3 cm (n = 19), part-solid (n = 174), and pure-solid (n = 64) groups. We evaluated the prognostic impact of clinicopathologic variables including radiological presentations by establishing Cox proportional hazards model.

RESULTS

When we evaluated the prognostic impact based on the radiological subtypes, the 5-year recurrence-free survival (RFS) and overall survival (OS) were significantly different among pure-GGN, part-solid, and pure-solid groups (RFS: 100% versus 95.4% versus 76.6%, p < 0.0001; OS: 100% versus 98.9% versus 87.5%, p < 0.0001). Cox regression analysis revealed the preoperative carcinoembryonic antigen (CEA) level and consolidation tumor ratio (CTR) were independently significant prognosticators related to RFS and OS. Furthermore, a receiver operating characteristic (ROC) verified the CTR (area under ROC [AUC] 0.784, 95%CI 0.697-0.869) was equipped with good performance to predict the postoperative recurrence with a cutoff point at 0.5. Lung cancer with higher CTR tended to be associated with lower survival in the c-T1aN0M0 stage.

CONCLUSIONS

For the c-T1aN0M0 lung cancer, pulmonary nodules manifested as the pure-GGN and part-solid subtypes had an excellent prognosis and may be considered as the "early-stage" cancer, whereas those with pure-solid appearance were associated with the high risk of recurrence despite the sub-centimeter size.

KEY POINTS

• Radiological subtypes could further stratify the risk of lung cancer in cT1a. • Sub-solid nodule has a favorable survival in c-T1a lung cancer, whereas pure-solid nodule is not always "early-stage" lung cancer and is relatively prone to postoperative recurrence despite the sub-centimeter size. • The preoperative CEA level and CTR are valuable prognosticators to predict the recurrence in c-T1a lung cancer.

Subsolid lesions exceeding 3 centimeters: the ground-glass opacity component still matters

BACKGROUND

Recent studies on the favorable prognosis of ground-glass opacities (GGO) featured lung adenocarcinoma compared with solid nodules were limited to small tumors measuring ≤3.0 cm. This study aimed to investigate whether GGO component could predict better prognosis in patients with large subsolid lesions exceeding 3cm compared with small solid nodules within the same clinical T category.

METHODS

From 2010 to 2015, a total of 1010 patients with completely resected clinical N0 lung adenocarcinoma were enrolled, including 860 solid lesions and 150 subsolid lesions exceeding 3cm. To analyze the prognostic significance of GGO component, propensity score matching adjusting solid component size was performed.

RESULTS

After propensity score matching, 144 pairs of patients were finally analyzed. The mean size of the solid component was 23.7mm in the GGO group and 24.4mm in the solid group(p=0.450). The GGO group had significantly better overall survival and recurrence-free survival (p=0.011 and p=0.003, respectively), which were also validated in patients with solid-predominant lesions. Subgroup analysis showed the GGO group was associated with better prognosis in each clinical T category.

CONCLUSIONS

The prognosis of patients with GGO lesions exceeding 3cm was better than that of patients with small solid lesions even within the same clinical T category. Clinical T classification incorporating GGO component may provide better prognostic prediction for patients with lung cancer exceeding 3cm.

Bioinformatics analysis combined with experiments predicts CENPK as a potential prognostic factor for lung adenocarcinoma

BACKGROUND

Lung cancer is the most common malignant tumor. Identification of novel diagnostic and prognostic biomarkers for lung cancer is a key research imperative. The role of centromere protein K (CENPK) in cancer is an emerging research hotspot. However, the role of CENPK in the progression of lung adenocarcinoma (LAC) is not well characterized.

METHODS

In this study, we identified CENPK as a potential new gene for lung cancer based on bioinformatics analysis. In addition, in vitro experiments were performed to verify the function of this gene. We investigated the expression of CENPK in LAC by analyses of datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Differential expression analyses, gene ontology (GO) enrichment, Kyoto encyclopedia of genes and genomes (KEGG) analysis, and gene set enrichment analysis (GSEA) were conducted to evaluate the diagnostic and prognostic relevance of CENPK. Then, for evaluating the biological behavior and role of CENPK in lung cancer cells, we did a series of vitro experiments, such as immunohistochemistry analysis, Western blot analysis, CCK8 assay, transwell assay, flow cytometry, and wound healing assay.

RESULTS

We demonstrated overexpression of CENPK in LAC; in addition, increased expression of CENPK was associated with clinical progression. Moreover, CENPK was found to be an independent risk factor in patients with LAC. Furthermore, we observed activation of CENPK-related signaling pathways in patients with LAC.

CONCLUSIONS

Our findings indicate a potential role of CENPK in promoting tumor proliferation, invasion, and metastasis. It may serve as a novel diagnostic and prognostic biomarker in patients with LAC.

Clinical impact of a small component of ground-glass opacity in solid-dominant clinical stage IA non-small cell lung cancer

OBJECTIVE

Non-small cell lung cancers with a ground-glass opacity component have better prognosis than those with solid nodules of equivalent consolidation size. However, the impact of small ground-glass opacity components on prognosis is unknown. Therefore, we aimed to evaluate the significance of a small ground-glass opacity component in solid-dominant clinical stage IA non-small cell lung cancers.

METHODS

We reviewed the cases of 543 surgically resected solid-dominant c-stage IA non-small cell lung cancers, which was defined as a tumor with consolidation tumor ratio of 0.75 or more on computed tomography. The patients were classified into 2 groups: 0.75 or less consolidation tumor ratio less than 1 (n = 126) and consolidation tumor ratio of 1 (n = 417). The prognoses were compared between the 2 groups.

RESULTS

Among the 543 cases, multivariable analyses revealed that pure-solid appearance was a predictor of worse overall survival (hazard ratio, 2.051; 95% confidence interval, 1.044-4.028). Compared with the part-solid group, the pure-solid group was associated with poor survival in c-stages IA2 (5-year overall survival: 91.5% vs 76.8%, hazard ratio, 2.942; 95% confidence interval, 1.402-6.173; recurrence-free survival: 89.0% vs 68.8%, hazard ratio, 3.439; 95% confidence interval, 1.776-6.669) and IA3 (5-year overall survival: 93.5% vs 63.0%, hazard ratio, 5.110; 95% confidence interval, 1.607-16.241; recurrence-free survival: 80.5% vs 54.1%, hazard ratio, 2.789; 95% confidence interval, 1.290-6.027). The T categories significantly affected 5-year overall survival only in the pure-solid group (cT1a, 89.3%; cT1b, 76.8%; cT1c, 63.0%).

CONCLUSIONS

A small ground-glass opacity component has an impact on the prognosis of patients with solid-dominant c-stage IA non-small cell lung cancer. Therefore, c-stage IA non-small cell lung cancers should be evaluated separately for tumors with ground-glass opacity and pure-solid tumors.

The expression of trefoil factor 3 is related to histologic subtypes and invasiveness in lung adenocarcinoma

Adenocarcinoma is the most common histological type of lung cancer and has various histologic subtypes, including lepidic, papillary, acinar and invasive mucinous adenocarcinoma. Histologic subtypes are associated with tumor invasiveness. For example, the lepidic subtype is less invasive than the papillary/acinar subtype. Trefoil factor 3 (TFF3) is a small secreting protein that is a member of the trefoil factor family, which is involved in mucosal stabilization and repair through its mitogenic and antiapoptotic activities. TFF3 overexpression is associated with various types of cancer. In lung cancer, TFF3 is expressed significantly in adenocarcinoma. However, the relationship between TFF3 expression and histologic subtypes in lung adenocarcinoma is unclear. The current study immunohistochemically revealed that, beside invasive mucinous carcinoma, the expression of TFF3 in papillary and acinar adenocarcinoma was significantly higher than that in lepidic adenocarcinoma. To further confirm these results, the expression of TFF3 in cases with both lepidic and papillary/acinar areas were examined. The expression of TFF3 in papillary/acinar areas was significantly higher when compared with lepidic areas in a single sample. Furthermore, using the lung adenocarcinoma cell line A549, TFF3-knockdown cells were generated. The results revealed that knockdown of TFF3 attenuated invasion. In vitro and immunohistochemical assays using clinical samples demonstrated that TFF3 expression was associated with lung adenocarcinoma invasiveness. To the best of our knowledge, the current study is the first to report that TFF3 expression was associated with the histologic subtypes of lung adenocarcinoma.

Approach to the Subsolid Nodule

Most focal persistent ground glass nodules (GGNs) do not progress over 10 years. Research suggests that GGNs that do not progress, those that do, and solid lung cancers are fundamentally different diseases, although histologically they seem similar. Surveillance of GGNs to identify those that gradually progress is safe and does not risk losing a window. GGNs with 5 mm solid component or less than 10 mm consolidation (mediastinal and lung windows, respectively, on thin slice CT) are highly curable with resection. The optimal type of resection is unclear; sublobar resection is reasonable but an adequate margin is critically important.

DUS4L Silencing Suppresses Cell Proliferation and Promotes Apoptosis in Human Lung Adenocarcinoma Cell Line A549

Purpose

This study aims to investigate the potential role of DUS4L (dihydrouridine synthase 4 like) in lung adenocarcinoma (LUAD) and explore its associated pathways in human LUAD.

Methods

Firstly, we evaluated the relationships between clinicopathological characteristics and DUS4L expression via analysis of TCGA RNA sequencing data and other publicly available databases. Then, DUS4L was effectively silenced in LUAD cell line A549 using the lentiviral shRNA (short-hairpin RNA) transfection to assess its effects on cell proliferation, cycle and apoptosis in LUAD cells. RNA-seq technology was applied to shDUS4L and shCtrl-transfected cells to generate the corresponding gene expression profiles. Differentially expressed genes (DEGs) were identified using the DESeq2 program package. Also, DEGs were subjected to Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis to explore the associated molecular signaling pathways and relevant biological functions.

Results

Analysis of TCGA data revealed that DUS4L was highly upregulated in LUAD tissues which was related to clinical T and TNM stages of LUAD. The knockdown of DUS4L effectively inhibited cell proliferation and promoted apoptosis in A549 cells. Furthermore, the DEGs between the shDUS4L and shCtrl A549 cells were mainly enriched in biological processes associated with spliceosome, ribosome, RNA catabolic process, ncRNA (non-coding RNA) processing, and p53 signaling pathway.

Conclusion

Altogether, our results suggest that DUS4L is significantly associated with tumorigenesis and could be utilized as a novel biomarker and therapeutic target for LUAD.

Systemic analyses of expression patterns and clinical features for GIMAPs family members in lung adenocarcinoma

GTPase of immunity-associated proteins (GIMAPs) are frequently prescribed as important components of immune regulation complexes, which were known to play key roles in lung adenocarcinoma. However, little is known about the function of distinct GIMAPs in lung adenocarcinoma. To address this issue, this study investigated the biological function and pathway of GIMAPs in lung adenocarcinoma using multiple public databases. Absent expression of GIMAPs was found in lung adenocarcinoma at mRNA and protein levels. While a purity-corrected value uncovered that all GIMAPs were positively associated with the immune infiltration of lung adenocarcinoma. Furthermore, the expressions of GIMAPs were considered to be negatively associated with clinical cancer stages, patient’s gender and pathological tumor grades in patients with lung adenocarcinoma. Besides, higher mRNA expression of GIMAPs was significantly associated with longer overall survival of patients with lung adenocarcinoma. Taken together, these results may enable GIMAPs family members as diagnostic and survival biomarker candidates or even potential therapeutic targets for patients with lung adenocarcinoma.

A case of a rare non-invasive lung adenocarcinoma

BACKGROUND

According to the WHO classification, adenocarcinoma in situ (AIS) is a localised small (≤3 cm) adenocarcinoma whose growth is restricted to neoplastic cells along pre-existing alveolar structures, lacking stromal, lymphovascular, or pleural invasion. There is no evidence to define AIS as having a tumour size of ≤3 cm. It is extremely rare for adenocarcinomas with pure lepidic growth lacking invasion to be >3.0 cm. The biological characteristics of these large AISs should be revealed.

PRESENTATION OF CASE

The patient was an 82-year-old asymptomatic woman. Chest computed tomography showed a 6-cm-diameter pure ground-glass opacity in the left lower lung. The patient underwent lobectomy. On histologic examination, the tumour was restricted to neoplastic cells along pre-existing alveolar structures, lacking stromal, vascular, alveolar space, and pleural invasion. Papillary patterns were absent. Initially, the histopathological diagnosis was AIS, but the total tumour diameter exceeded 3 cm. The final pathological diagnosis was lepidic adenocarcinoma lacking an invasive component and harbouring an EGFR exon 20 insertion V774_C775insHV mutation using next-generation sequencing (NGS).

CONCLUSION

We report a rare case of lepidic adenocarcinoma with a total tumour diameter of 6 cm and without an invasive component. Although EGFR mutations are oncogenic driver mutations, AISs have fewer EGFR mutations than invasive adenocarcinomas do. An adenocarcinoma that progresses to AIS, not stepwise progression, might have uncommon mutations and might be another type of adenocarcinoma. NGS could be useful for detecting uncommon genes that reveal the biological characteristics of AIS, and may contribute to the validation of next TNM classification.

Prognostic Significance of Ground-Glass Opacity Components in 5-Year Survivors With Resected Lung Adenocarcinoma

BACKGROUND

Reports on the prognosis for 5-year survivors with lung adenocarcinoma after resection are sparse. This study aimed to identify factors associated with overall survival (OS) and cancer-specific survival (CSS) for 5-year survivors with completely resected lung adenocarcinoma, and to determine whether preoperative imaging factors, including the presence of ground-glass opacity (GGO) components, affect late recurrence in long-term survivors.

METHODS

Complete resection of lung adenocarcinoma was performed for 1681 patients between January 2000 and December 2013. Of these patients, 936 who survived 5 years or longer after surgery were identified, and factors associated with OS and CSS were determined using the Cox proportional hazard model.

RESULTS

Multivariable analysis demonstrated that lymph node metastasis (p < 0.01) and absence of GGO components (p < 0.01) were independently associated with OS and CSS for the 5-year survivors. The absence of GGO components was significantly associated with OS (p < 0.01) and CSS (p < 0.01) also for the 5-year survivors with stage 1 disease (n = 782) and for the 5-year survivors without recurrence (n = 809). The incidence of recurrence anytime during the 10-year postoperative follow-up period differed significantly between the 5-year survivors with and without GGO components.

CONCLUSIONS

The absence of GGO components was significantly associated with an unfavorable prognosis for the 5-year survivors with completely resected lung adenocarcinoma regardless whether they had recurrences not.

A Simple Method to Train the AI Diagnosis Model of Pulmonary Nodules

Background

The differential diagnosis of subcentimetre lung nodules with a diameter of less than 1 cm has always been one of the problems of imaging doctors and thoracic surgeons. We plan to create a deep learning model for the diagnosis of pulmonary nodules in a simple method.

Methods

Image data and pathological diagnosis of patients come from the First Affiliated Hospital of Zhejiang University School of Medicine from October 1, 2016, to October 1, 2019. After data preprocessing and data augmentation, the training set is used to train the model. The test set is used to evaluate the trained model. At the same time, the clinician will also diagnose the test set.

Results

A total of 2,295 images of 496 lung nodules and their corresponding pathological diagnosis were selected as a training set and test set. After data augmentation, the number of training set images reached 12,510 images, including 6,648 malignant nodular images and 5,862 benign nodular images. The area under the P-R curve of the trained model is 0.836 in the classification of malignant and benign nodules. The area under the ROC curve of the trained model is 0.896 (95% CI: 78.96%~100.18%), which is higher than that of three doctors. However, the P value is not less than 0.05.

Conclusion

With the help of an automatic machine learning system, clinicians can create a deep learning pulmonary nodule pathology classification model without the help of deep learning experts. The diagnostic efficiency of this model is not inferior to that of the clinician.

PNO1, which is negatively regulated by miR-340-5p, promotes lung adenocarcinoma progression through Notch signaling pathway

Many studies have shown that the hyperactivation of ribosome biogenesis plays essential roles in the initiation and progression of cancers. As a ribosome assembly factor, PNO1 plays an important role in ribosome biogenesis. However, little is known about the expression and function of PNO1 in human tumors. In our present study, we aimed to explore the functional roles and the underlying molecular mechanisms of PNO1 in human lung adenocarcinoma (LUAD). Both bioinformatics databases and tumor tissues demonstrated that the expression of PNO1 in LUAD tissues was higher than that in adjacent tissues and predicted poor survival in LUAD patients. In vitro and in vivo assays suggested that downregulation of PNO1 expression suppressed LUAD cell proliferation and invasion. Further studies found that miR-340-5p depressed PNO1 expression via direct binding to the 3′ untranslated region (UTR) of PNO1. PNO1 expression was negatively correlated with miR-340-5p expression in LUAD cells and tissue samples. Moreover, upregulation or downregulation of miR-340-5p expression reversed the effects of PNO1 inhibition and overexpression, respectively. Meanwhile, downregulation of PNO1 inhibited Notch signaling pathway which modulated epithelial mesenchymal transition (EMT). These results indicate that PNO1, negatively regulated by miR-340-5p, played an important role in LUAD progression via Notch signaling pathway. The miR-340-5p/PNO1/Notch axis might be a potential target for individualized and precise treatment of LUAD patients in the future.

Risk of lung adenocarcinoma from smoking and radiation arises in distinct molecular pathways

KRAS mutations of lung adenocarcinoma (LADC) are associated with smoking but little is known on other exposure-oncogene associations. Hypothesizing that different inciting agents may cause different driver mutations, we aimed to identify distinct molecular pathways to LADC, applying two entirely different approaches. First, we examined clinicopathologic features and genomic signatures of environmental exposures in the large LADC Campbell data set. Second, we designed a molecular mechanistic risk model of LADC (M3LADC) that links environmental exposure to incidence risk by mathematically emulating the disease process. This model was applied to incidence data of Japanese atom-bomb survivors which contains information on radiation and smoking exposure. Grouping the clinical data by driver mutations revealed two main distinct molecular pathways to LADC: one unique to transmembrane receptor-mutant patients that displayed robust signatures of radiation exposure and one shared between submembrane transducer-mutant patients and patients with no evident driver mutation that carried the signature of smoking. Consistently, best fit of the incidence data was achieved with a M3LADC with two pathways: in one LADC risk increased with radiation exposure and in the other with cigarette consumption. We conclude there are two main molecular pathways to LADC associated with different environmental exposures. Future molecular measurements in lung cancer tissue of atom-bomb survivors may allow to further test quantitatively the M3LADC-predicted link of radiation to transmembrane receptor mutations. Moreover, the developed molecular mechanistic model showed that for low doses, as relevant e.g. for medical imaging, smokers have the same radiation risk compared with never smokers.

Prognostic impact of a ground-glass opacity component in clinical stage IA non-small cell lung cancer

OBJECTIVE

We performed a validation study to confirm the prognostic importance of the presence of a ground-glass opacity component based on data of the Japan Clinical Oncology Group study, JCOG0201, which was a prospective observational study to predict the pathological noninvasiveness of clinical stage IA lung cancer in Japan.

METHODS

Among the 811 patients registered in JCOG0201, 671 were confirmed eligible by study monitoring and a central review of computed tomography. Registered c-stage IA lung cancer was less than 30 mm in maximum tumor size, which was classified into a with ground-glass opacity group (pure ground-glass opacity and part-solid tumor) or solid group based on the status of a ground-glass opacity component. T staging was reassigned in accordance with the 8th edition of the TNM staging system. To validate the prognostic impact, overall survival was estimated.

RESULTS

Of the cases, 432 (64%) were in the with ground-glass opacity group and 239 (36%) were in the solid group with a median follow-up time of 10.1 years. The 5-year overall survival was significantly different between the with ground-glass opacity group and solid group (95.1% vs 81.1%). The 5-year overall survival was excellent regardless of the solid component size in the with ground-glass opacity group (c-T1a or less: 97.2%, c-T1b: 93.4%, c-T1c: 91.7%). In contrast, prognostic impact of the tumor size was definitive in the solid group (c-T1a: 87.5%, c-T1b: 85.9%, c-T1c: 73.7%).

CONCLUSIONS

Favorable prognostic impact of the presence of a ground-glass opacity component was demonstrated in JCOG0201. The presence or absence of a ground-glass opacity should be considered as an important parameter in the next clinical T classification.

Lung Cancer Staging and Associated Genetic and Epigenetic Events

The first step in treating lung cancer is to establish the stage of the disease, which in turn determines the treatment options and prognosis of the patient. Many factors are involved in lung cancer staging, but all involve anatomical information. However, new approaches, mainly those based on the molecular biology of cancer, have recently changed the paradigm for lung cancer treatment and have not yet been incorporated into staging. In a group of patients of the same stage who receive the same treatment, some may experience unexpected recurrence or metastasis, largely because current staging methods do not reflect the findings of molecular biological studies. In this review, we provide a brief summary of the latest research on lung cancer staging and the molecular events associated with carcinogenesis. We hope that this paper will serve as a bridge between clinicians and basic researchers and aid in our understanding of lung cancer.

Epidemiology of lung cancer and lung cancer screening programs in China and the United States

Lung cancer is a heterogeneous disease that is impacted by environmental exposures and by constitutional genetic or epigenetic susceptibilities to disease development and progression. The United States and China have distinct and diverse populations and geographic environmental exposures that contribute to unique patterns of lung cancer incidence and mortality. In this paper, the authors compare trends of incidence and mortality of lung cancer in the US and China, and the impact on lung cancer screening programs in the two countries. It is worth noting that the mortality of lung cancer in the US has decreased gradually while in China it is still increasing over recent years. While decreasing smoking prevalence and the impact of clean air legislation have helped to mitigate the trend in the US relative to China, the increasingly widespread implementation of lung cancer chest CT screening is expected to impact lung cancer incidence and mortality in both countries. Currently there are few studies to compare the environmental and genetic risk factors for US and Chinese populations with regards to lung cancer incidence and mortality. The authors discuss the impact of gender and exposure risks, mainly smoking and environmental pollutants. Of high importance is the incidence of lung cancer in never smokers that is significantly higher in China than in the United States; this is particularly notable in women. These data suggest inclusion of ambient air pollution exposure and gender into lung cancer risk prognostic models to better capture high-risk individuals, especially for non-smoking women.

[Computed tomography findings, clinicopathological features, genetic characteristics and prognosis of in situ and minimally invasive lung adenocarcinomas]

OBJECTIVE

To investigate the computed tomography findings, clinicopathological features, genetic characteristics and prognosis of in situ adenocarcinoma (AIS) and minimally invasive adenocarcinoma (MIA) of the lung.

METHODS

We retrospectively analyzed the data including computed tomography (CT) images, histopathological findings, Ki-67 immunostaining, and genetic mutations in patients with lung adenocarcinoma undergoing surgery at our hospital between 2014 and 2019.

RESULTS

Of the total of 480 patients with lung adenocarcinoma we reviewed, 73 (15.2%) had AIS (n=28) or MIA (n=45) tumors. The age of the patients with MIA was significantly younger than that of patients with AIS (P &lt; 0.02). CT scans identified pure ground-glass nodules in 46.4% of AIS cases and in 44.4% of MIA cases. Multiple GGOs were more common in MIA than in AIS cases (P &lt; 0.05), and bluured tumor margins was less frequent in AIS cases (P &lt; 0.05). No significant difference was found in EGFR mutations between MIA and AIS cases. A Ki-67 labeling index (LI) value ≥2.8% did not differentiate MIA from AIS. The follow-up time in MIA group was significantly shorter than that in AIS group, but no recurrence or death occurred.

CONCLUSIONS

Despite similar surgical outcomes and favorable survival outcomes, the patients with AIS and MIA show differences in terms of age, CT findings, EGFR mutations and Ki-67 LI.

Driver Mutations in Normal Airway Epithelium Elucidate Spatiotemporal Resolution of Lung Cancer

Rationale: Uninvolved normal-appearing airway epithelium has been shown to exhibit specific mutations characteristic of nearby non-small cell lung cancers (NSCLCs). Yet, its somatic mutational landscape in patients with early-stage NSCLC is unknown.Objectives: To comprehensively survey the somatic mutational architecture of the normal airway epithelium in patients with early-stage NSCLC.Methods: Multiregion normal airways, comprising tumor-adjacent small airways, tumor-distant large airways, nasal epithelium and uninvolved normal lung (collectively airway field), matched NSCLCs, and blood cells (n = 498) from 48 patients were interrogated for somatic single-nucleotide variants by deep-targeted DNA sequencing and for chromosomal allelic imbalance events by genome-wide genotype array profiling. Spatiotemporal relationships between the airway field and NSCLCs were assessed by phylogenetic analysis.Measurements and Main Results: Genomic airway field carcinogenesis was observed in 25 cases (52%). The airway field epithelium exhibited a total of 269 somatic mutations in most patients (n = 36) including key drivers that were shared with the NSCLCs. Allele frequencies of these acquired variants were overall higher in NSCLCs. Integrative analysis of single-nucleotide variants and allelic imbalance events revealed driver genes with shared "two-hit" alterations in the airway field (e.g., TP53, KRAS, KEAP1, STK11, and CDKN2A) and those with single hits progressing to two in the NSCLCs (e.g., PIK3CA and NOTCH1).Conclusions: Tumor-adjacent and tumor-distant normal-appearing airway epithelia exhibit somatic driver alterations that undergo selection-driven clonal expansion in NSCLC. These events offer spatiotemporal insights into the development of NSCLC and, thus, potential targets for early treatment.

The incidence of lymph node metastasis in patients with different oncogenic driver mutations among T1 non-small-cell lung cancer

OBJECTIVE

To investigate the incidence and distribution of lymph node metastasis in patients with different gene mutations among pathological T1 non-small-cell lung cancers (NSCLC).

METHODS

NSCLC cases resected in our institution between 2016 and 2018 were included. Driver mutation testing was performed in all resected tumor tissues. These patients were grouped by the type of gene mutations. On the basis of protein that mutant-genes encoded involved in the molecular pathway, the genotypes were further classified into four distinct groups: upstream receptor mutant protein (EGFR, HER2 and MET); downstream regulator mutant protein (KRAS and BRAF); fusion mutant protein (ROS1, ALK and RET) and the wild type group. The incidence of lymph node metastasis was compared among different groups.

RESULTS

Of the 1052 patients enrolled, the frequency of positive mutations was 68.0%. The incidence of lymph node metastasis were as follows: wild type (19.3%), ROS1 (72.8%), BRAF (55.5%), ALK (44.7%), HER2 (40%), RET (23.1%), KRAS (15.3%), EGFR (15.3%) and MET mutation (0%) (P < 0.001). The incidence of lymph node metastasis was significantly higher in fusion mutant protein group (45.1%) compared with others (wild type 19.3%, downstream regulator mutant protein 19.1%, upstream receptor mutant protein 15.3%, all P < 0.001). Patients with fusion genes also showed higher proportion of vascular invasion and positive lymph node ratio of greater than 0.33 compared to others.

CONCLUSION

Different genotypes of NSCLC have different propensity to develop lymph node metastasis. Cases of fusion gene mutations had a higher risk and burden of lymph node metastasis than other genotypes, which may indicate that more intensive treatment or surveillance strategies should be applied for these patients.