The Underlying Tumor Genomics of Predominant Histologic Subtypes in Lung Adenocarcinoma

Multi-omics analyses reveal distinct molecular characteristics and transformation mechanisms of stage I-III micropapillary lung adenocarcinoma

The micropapillary (MIP) pattern is a high-grade histological subtype of lung adenocarcinoma (LUAD) with poor prognosis. In this study, surgically resected tumor samples from 101 patients with stage I-III MIP-LUAD (MIP ≥30%) were microdissected to separate MIP components from non-MIP components, all of which underwent RNA and DNA whole-exome sequencing (WES). The genomic and transcriptomic landscapes of MIP and non-MIP components within MIP-enriched tumor tissues demonstrated remarkable similarities, notably marked by high epidermal growth factor receptor (EGFR) alteration frequencies. However, when compared to MIP-naïve LUAD tissues, MIP components showed higher chromosomal instability and revealed 18 enriched alterations, encompassing EGFR mutations, EGFR amplifications, and CDKN2A/CDKN2B deletions, which all linked to upregulation of cell proliferation pathways and downregulation of immune pathways. Shared mutations were observed in 97.8% (91/93) of patients with paired DNA WES data for MIP and non-MIP components within the same tissues, suggesting a common origin. The recurrence-free survival analysis identified MACF1, PCLO, ADGRV1, and Fanconi Anemia pathway mutations as negative indicators. In all, we conducted an in-depth analysis of the molecular characteristics and transformation mechanisms of MIP-LUAD, employing microdissection techniques to investigate the genomic and transcriptomic levels within a substantial cohort, providing insights for precision medicine of this aggressive cancer subtype. © 2025 The Pathological Society of Great Britain and Ireland.

Multi‑omics analysis identifies different molecular subtypes with unique outcomes in early-stage poorly differentiated lung adenocarcinoma

INTRODUCTION

Early-stage poorly differentiated lung adenocarcinoma (LUAD) is plagued by a high risk of postoperative recurrence, and its prognostic heterogeneity complicates treatment and surveillance planning. We conducted this integrative multi-omics study to identify those patients with a truly high risk of adverse outcomes.

METHODS

Whole-exome, RNA and whole methylome sequencing were carried out on 101 treatment-naïve early-stage poorly differentiated LUADs. Integrated analyses were conducted to disclose molecular characteristics and explore molecular subtyping. Functional validation of key molecules was carried out through in vitro and in vivo experiments.

RESULTS

Recurrent tumors exhibited significantly higher ploidy (p = 0.024), the fraction of the genome altered (FGA, p = 0.042), and aneuploidy (p < 0.05) compared to non-recurrent tumors, as well as a higher frequency of CNVs. Additionally, recurrent tumors showed hypomethylation at both the global level and in CpG island regions. Integrative transcriptomic and methylation analyses identified three molecular subtypes (C1, C2, and C3), with the C1 subtype presenting the worst prognosis (p = 0.024). Although frequently mutated genes showed similar mutation frequencies across the three subtypes, the C1 subtype exhibited the highest tumor mutation burden (TMB), mutant-allele tumor heterogeneity (MATH), aneuploidy, and HLA loss of heterozygosity (HLA-LOH), along with relatively lower immune cell infiltration. Furthermore, GINS1 and CPT1C were found to promote LUAD progression, and their high expression correlated with a poor prognosis.

CONCLUSIONS

This multi-omics study identified three integrative subtypes with distinct prognostic implications, paving the way for more precise management and postoperative monitoring of early-stage poorly differentiated LUAD.

CellOMaps: A compact representation for robust classification of lung adenocarcinoma growth patterns

Lung adenocarcinoma (LUAD) is a morphologically heterogeneous disease, characterized by five primary histological growth patterns. The classification of such patterns is crucial due to their direct relation to prognosis but the high subjectivity and observer variability pose a major challenge. Related studies in the literature focus on machine learning methods for growth pattern classification, often formulating the problem as a slide-level predominant pattern classification problem. We propose a generalizable machine learning pipeline capable of classifying lung tissue into one of the five patterns or as non-tumor. The proposed pipeline's strength lies in a novel compact Cell Organization Maps (cellOMaps) representation that captures the cellular spatial patterns from Hematoxylin and Eosin (H&E) whole slide images (WSIs). The proposed pipeline provides state-of-the-art performance on LUAD growth pattern classification when evaluated on both internal unseen slides and external datasets, comparing favorably with the current approaches. In addition, our preliminary results show that the model's outputs can be used to predict patients Tumor Mutational Burden (TMB) levels.

Genomic profiling of aggressive pathologic features in lung adenocarcinoma

INTRODUCTION

Pathologic features involving LVI (lympho-vascular invasion), PNI (perineural invasion), STAS (spread through air spaces), and Grade 3 pattern (from the International Association for the Study of Lung Cancer grading system) are related to having an aggressive phenotype and linked to poor prognosis. However, few studies have conducted in-depth analyses of these features simultaneously with genomic profiling.

METHODS

A total of 1559 sequencing of adenocarcinoma samples were included in the common driver mutations analysis, 1306 samples were brought into genomic mapping analysis. OncoSG's East Asian ancestry dataset was implemented for Tumor-Node-Metastasis-Biomarker (TNMB) classification and prognostic assessment.

RESULTS

EGFR was more significantly prevalent in LVI negativity (P = 0.021), STAS negativity (P = 0.002), and moderate grade (P < 0.001). ALK was significantly interrelated with LVI (P = 0.028), STAS (P < 0.001), and poor grade (P < 0.001); ROS1 and STAS positivity (P = 0.031), poor grade (P = 0.016) were significantly related. KRAS (P = 0.003) and BRAF-V600E (P = 0.002) were only significantly intertwined with poor grade. Apart from common driver mutations, TP53, CHEK2, KEAP1, PTEN, RB1, NF1 were significantly enriched in LVI samples (P < 0.05). TP53, PTEN, CTNNB1, HGF, NF1 were more prominent in STAS (P < 0.01). TP53, LRP1B, NF1 were significantly more prevalent in Grade 3 pattern (P < 0.001). The mixture of STK11, PTEN, and TOP2A generated by exclusive mutations may be a potential predictor of TNMB categorization towards survival. The HR of stage II compared I of TNMB was 2.28 (95 % CI 1.36-3.86, P < 0.001), while stage III compared II was 1.95 (95 % CI 1.04-3.21, P = 0.031).

CONCLUSIONS

This analysis demonstrated the correlation of pathologic features with common driver mutations, key mutations and canonical oncogenic signaling pathways. The data highlighted the similarities and differences among these features horizontally, and provide new insights in TNMB classification and prognostic assessment.

Multi-gene panel sequencing reveals the relationship between driver gene mutation and clinical characteristics in lung adenocarcinoma

BACKGROUND

Testing of multiple cancer related genes using next-generation sequencing (NGS) has been widely used for personalized precision medicine of cancer. Integrated analysis of those NGS data and clinical data has offered new opportunities for investigating the relationship between driver genes' mutations and clinical characteristics in large cohorts. This study aims to explore the mutational landscape and its association with clinical features in a lung adenocarcinoma (LUAD) cohort.

METHODS

Tumor tissues from 132 LUAD patients were subjected to customized 30 genes targeted next-generation sequencing. Somatic mutations of the 30 genes were identified and annotated. Statistical analysis was performed to determine the cooccurrence of mutations of different driver genes and the association relationships between gene mutation and clinical features including gender and age.

RESULTS

A total of 96.97% (128/132) of LUAD patients experienced genetic mutations. EGFR had the highest mutation rate (81, 61.36%) among the 30 genes, followed by TP53 (80, 60.61%), BRAF (30, 22.73%), KRAS (21, 15.91%) and ROS1 (21, 15.91%). The L858R substitution and exon19 deletion were the predominant mutations of EGFR, accounting for 82.71% of EGFR-mutated patients. The 27 mutation sites of EGFR were mainly located in the tyrosine kinase catalytic domain (22/27, 81.48%). Mutations of SDHA (p < 0.01), ERBB2 (p < 0.01), and ESR1 (p < 0.05) were negatively correlated with age, and mutations of NF1 (p < 0.01), KRAS (p < 0.01), and TP53 (p < 0.001) were significantly associated with gender.

CONCLUSIONS

This work revealed the mutational landscape and characteristics of 30 core driver genes in a LUAD cohort. Co-mutated genes and genes associated with gender and age indicate their different roles in the corresponding subgroup of the LUAD.

Insights into targeting LKB1 in tumorigenesis

Genetic alterations to serine-threonine kinase 11 (STK11) have been implicated in Peutz-Jeghers syndrome and tumorigenesis. Further exploration of the context-specific roles of liver kinase B1 (LKB1; encoded by STK11) observed that it regulates AMP-activated protein kinase (AMPK) and AMPK-related kinases. Given that both migration and proliferation are enhanced with the loss of LKB1 activity combined with the prevalence of STK11 genetic alterations in cancer biopsies, LKB1 was marked as a tumor suppressor. However, the role of LKB1 in tumorigenesis is paradoxical as LKB1 activates autophagy and reactive oxygen species scavenging while dampening anoikis, which contribute to cancer cell survival. Due to the pro-tumorigenic properties of LKB1, targeting LKB1 pathways is now relevant for cancer treatment. With the recent successes of targeting LKB1 signaling in research and clinical settings, and enhanced cytotoxicity of chemical compounds in LKB1-deficient tumors, there is now a need for LKB1 inhibitors. However, validating LKB1 inhibitors is challenging as LKB1 adaptor proteins, nucleocytoplasmic shuttling, and splice variants all manipulate LKB1 activity. Furthermore, STE-20-related kinase adaptor protein (STRAD) and mouse protein 25 dictate LKB1 cellular localization and kinase activity. For these reasons, prior to assessing the efficacy and potency of pharmacological candidates, the functional status of LKB1 needs to be defined. Therefore, to improve the understanding of LKB1 in physiology and oncology, this review highlights the role of LKB1 in tumorigenesis and addresses the therapeutic relevancy of LKB1 inhibitors.

Excessive MYC Orchestrates Macrophages induced Chromatin Remodeling to Sustain Micropapillary-Patterned Malignancy in Lung Adenocarcinoma

Current understanding of micropapillary (MP)-subtype lung adenocarcinoma (LUAD) remains confined to biological activities and genomic landscapes. Unraveling the major regulatory programs underlying MP patterned malignancy offers opportunities to identify more feasible therapeutic targets for patients with MP LUAD. This study shows that patients with MP subtype LUAD have aberrant activation of the MYC pathway compared to patients with other subtypes. In vitro and xenograft mouse model studies reveal that MP pattern in malignancy cannot be solely due to aberrant MYC expression but requires the involvement of M2-like macrophages. Excessively expressed MYC leads to the accumulation of M2-like macrophages from the bone marrow, which secretes TGFβ, to induce the expression of FOSL2 in tumor cells, thereby remodeling chromatin accessibility at promoter regions of MP-pattern genes to promote the MYC-mediated de novo transcriptional regulation of these genes. Additionally, the MP-pattern in malignancy can be effectively alleviated by disrupting the TGFβ-FOSL2 axis. These findings reveal new functions for the M2-like macrophage-TGFβ-FOSL2 axis in MYC-overexpressing MP-subtype LUAD, identifying targetable vulnerabilities in this pathway.

Impact of histopathological subtypes on invasive lung adenocarcinoma: from epidemiology to tumour microenvironment to therapeutic strategies

Lung adenocarcinoma is the most prevalent type of lung cancer, with invasive lung adenocarcinoma being the most common subtype. Screening and early treatment of high-risk individuals have improved survival; however, significant differences in prognosis still exist among patients at the same stage, especially in the early stages. Invasive lung adenocarcinoma has different histological morphologies and biological characteristics that can distinguish its prognosis. Notably, several studies have found that the pathological subtypes of invasive lung adenocarcinoma are closely associated with clinical treatment. This review summarised the distribution of various pathological subtypes of invasive lung adenocarcinoma in the population and their relationship with sex, smoking, imaging features, and other histological characteristics. We comprehensively analysed the genetic characteristics and biomarkers of the different pathological subtypes of invasive lung adenocarcinoma. Understanding the interaction between the pathological subtypes of invasive lung adenocarcinoma and the tumour microenvironment helps to reveal new therapeutic targets for lung adenocarcinoma. We also extensively reviewed the prognosis of various pathological subtypes and their effects on selecting surgical methods and adjuvant therapy and explored future treatment strategies.

Unraveling immune heterogeneity across pan-cancer and deep insights in lung adenocarcinoma based on alternative splicing

Alternative splicing (AS) participates in tumor development and tumor microenvironment formation. However, the landscape of immune-infiltrating AS events in pan-cancer and mechanisms of AS in lung adenocarcinoma (LUAD) have not been comprehensively characterized. We systematically profiled the immune-infiltrating AS event landscape of pan-cancer using data from The Cancer Genome Atlas, analyzing both commonalities and specific characteristics among different cancer types. We found that AS events tend to occur specifically in one cancer type rather than in multiple cancer types. AS events were used to classify 512 LUAD samples into 2 subtypes by unsupervised clustering: the aberrant splicing subtype and the immune-infiltrating subtype. The 2 subtypes showed significant differences in clinicopathology, prognosis, transcriptomics, genomics, and immune microenvironment. We constructed a classification signature comprising 10 genes involved in 14 AS events using logistic regression. The robustness of the signature was validated in 3 independent datasets using survival analysis. To explore AS mechanisms in LUAD, we constructed subtype-specific coexpression networks using Pearson correlation analysis. AS event of AKT3 regulated by splicing factor ENOX1 was associated with poor prognosis in LUAD. Overall, we outline AS events associated with immune infiltration in pan-cancer, and this study provides insights into AS mechanisms in LUAD patient classification.

High-risk features associated with recurrence in stage I lung adenocarcinoma

OBJECTIVE

There is a lack of knowledge regarding the use of prognostic features in stage I lung adenocarcinoma (LUAD). Thus, we investigated clinicopathologic features associated with recurrence after complete resection for stage I LUAD.

METHODS

We performed a retrospective analysis of patients with pathologic stage I LUAD who underwent R0 resection from 2010 to 2020. Exclusion criteria included history of lung cancer, induction or adjuvant therapy, noninvasive or mucinous LUAD, and death within 90 days of surgery. Fine and Gray competing-risk regression assessed associations between clinicopathologic features and disease recurrence.

RESULTS

In total, 1912 patients met inclusion criteria. Most patients (1565 [82%]) had stage IA LUAD, and 250 developed recurrence: 141 (56%) distant and 109 (44%) locoregional only. The 5-year cumulative incidence of recurrence was 12% (95% CI, 11%-14%). Higher maximum standardized uptake value of the primary tumor (hazard ratio [HR], 1.04), sublobar resection (HR, 2.04), higher International Association for the Study of Lung Cancer grade (HR, 5.32 [grade 2]; HR, 7.93 [grade 3]), lymphovascular invasion (HR, 1.70), visceral pleural invasion (HR, 1.54), and tumor size (HR, 1.30) were independently associated with a hazard of recurrence. Tumors with 3 to 4 high-risk features had a higher cumulative incidence of recurrence at 5 years than tumors without these features (30% vs 4%; P < .001).

CONCLUSIONS

Recurrence after resection for stage I LUAD remains an issue for select patients. Commonly reported clinicopathologic features can be used to define patients at high risk of recurrence and should be considered when assessing the prognosis of patients with stage I disease.

Predicting higher-risk growth patterns in invasive lung adenocarcinoma with multiphase multidetector computed tomography and 18 F-fluorodeoxyglucose PET radiomics

PURPOSE

To develop a predictive model for identifying the higher-risk growth pattern of invasive lung adenocarcinoma using multiphase multidetector computed tomography (MDCT) and 18 F-fluorodeoxyglucose (FDG) PET radiomics.

METHODS

A total of 203 patients with confirmed invasive lung adenocarcinoma between January 2018 and December 2021 were enrolled and randomly divided into training ( n  = 143) and testing sets ( n  = 60). Patients were classified into two groups according to the predominant growth pattern (lower-risk group: lepidic/acinar; higher-risk group: papillary/solid/micropapillary). Preoperative multiphase MDCT and 18 F-FDG PET images were evaluated. The Artificial Intelligence Kit software was used to extract radiomic features. Five predictive models [arterial phase, venous phase, and plain scan (AVP), PET, AVP-PET, clinical, and radiomic-clinical (Rad-Clin) combined model] were developed. The models' performance was assessed using receiver-operating characteristic (ROC) curves and compared using the DeLong test.

RESULTS

Among the radiomics models (AVP, PET, and AVP-PET), the AVP-PET model [area under ROC curve (AUC) = 0.888] outperformed the PET model (AUC = 0.814; P  = 0.015) in predicting the higher-risk growth patterns. The combined Rad-Clin model (AUC = 0.923), which integrates AVP-PET radiomics and five independent clinical predictors (gender, spiculation, long-axis diameter, maximum standardized uptake value, and average standardized uptake value), exhibited superior performance in predicting the higher-risk growth pattern compared with radiomic models ( P  = 0.043, vs. AVP-PET; P  = 0.016, vs. AVP; P  = 0.002, vs. PET) or the clinical model alone (constructing based on five clinical predictors; AUC = 0.793; P < 0.001).

CONCLUSION

The combined Rad-Clin model can predict the higher-risk growth patterns of invasive adenocarcinoma (IAC). This approach could help determine individual therapeutic strategies for IAC patients by distinguishing predominant growth patterns with high risk.

Tobacco smoke carcinogens exacerbate APOBEC mutagenesis and carcinogenesis

Mutations in somatic cells are inflicted by both extrinsic and intrinsic sources and contribute over time to cancer. Tobacco smoke contains chemical carcinogens that have been causatively implicated with cancers of the lung and head & neck1,2. APOBEC family DNA cytosine deaminases have emerged as endogenous sources of mutation in cancer, with hallmark mutational signatures (SBS2/SBS13) that often co-occur in tumors of tobacco smokers with an equally diagnostic mutational signature (SBS4)3,4. Here we challenge the dogma that mutational processes are thought to occur independently and with additive impact by showing that 4-nitroquinoline 1-oxide (NQO), a model carcinogen for tobacco exposure, sensitizes cells to APOBEC3B (A3B) mutagenesis and leads to synergistic increases in both SBS2 mutation loads and oral carcinomas in vivo. NQO-exposed/A3B-expressing animals exhibit twice as many head & neck lesions as carcinogen-exposed wildtype animals. This increase in carcinogenesis is accompanied by a synergistic increase in mutations from APOBEC signature SBS2, but not from NQO signature SBS4. Interestingly, a large proportion of A3B-catalyzed SBS2 mutations occurs as strand-coordinated pairs within 32 nucleotides of each other in transcribed regions, suggesting a mechanism in which removal of NQO-DNA adducts by nucleotide excision repair exposes short single-stranded DNA tracts to enzymatic deamination. These highly enriched pairs of APOBEC signature mutations are termed didyma (Greek for twins) and are mechanistically distinct from other types of clustered mutation (omikli and kataegis). Computational analyses of lung and head & neck tumor genomes show that both APOBEC mutagenesis and didyma are elevated in cancers from smokers compared to non-smokers. APOBEC signature mutations and didyma are also elevated in normal lung tissues in smokers prior to cancer initiation. Collectively, these results indicate that DNA adducting mutagens in tobacco smoke can amplify DNA damage and mutagenesis by endogenous APOBEC enzymes and, more broadly, suggest that mutational mechanisms can interact synergistically in both cancer initiation and promotion.

Optimizing the NGS-based discrimination of multiple lung cancers from the perspective of evolution

Next-generation sequencing (NGS) offers a promising approach for differentiating multiple primary lung cancers (MPLC) from intrapulmonary metastasis (IPM), though panel selection and clonal interpretation remain challenging. Whole-exome sequencing (WES) data from 80 lung cancer samples were utilized to simulate MPLC and IPM, with various sequenced panels constructed through gene subsampling. Two clonal interpretation approaches primarily applied in clinical practice, MoleA (based on shared mutation comparison) and MoleB (based on probability calculation), were subsequently evaluated. ROC analysis highlighted MoleB's superior performance, especially with the NCCNplus panel (AUC = 0.950 ± 0.002) and pancancer MoleA (AUC = 0.792 ± 0.004). In two independent cohorts (WES cohort, N = 42 and non-WES cohort, N = 94), NGS-based methodologies effectively stratified disease-free survival, with NCCNplus MoleB further predicting prognosis. Phylogenetic analysis further revealed evolutionary distinctions between MPLC and IPM, establishing an optimized NGS-based framework for differentiating multiple lung cancers.

Pan-cancer landscape analysis of NOP58 and its oncogenic driving role in lung adenocarcinoma

Despite improvements in treatment in recent years, patients with lung adenocarcinoma (LUAD) still face poor prognoses. In this study, we elucidated the potential role of NOP58 ribonucleoprotein in pan-cancer and validated its oncogenic significance in LUAD using bioinformatics and in vitro and in vivo functional assays. NOP58 was found to be overexpressed in various types of tumors. It had great precision for predicting 20 distinct cancer types using receiver operating characteristic curve (ROC) as well as significant connections with the prognoses in particular cancers. In LUAD, NOP58 expression was correlated substantially with the TNM stage, pathologic stage, smoking status, and effectiveness endpoints, when we analyzed its association with clinical characteristics in LUAD. Elevated NOP58 expression was shown as connected with Th2 cell infiltration while also negatively linked with infiltrating other immune cells, such as CD8 T, cytotoxic, and Th1. By inhibiting NOP58 within the LUAD cells, we found a decrease in cells' capability to proliferate, migrate, and invade. Knockdown of NOP58 inhibited tumor growth in mouse xenograft models. Furthermore, the tissue microarray study indicated that there was a greater expression of NOP58 in the tumor tissues compared to adjacent normal tissues in LUAD. Our findings revealed that NOP58 could be an outstanding bio-index for pan-cancer diagnosis and prognosis and an independent prognostic risk factor in LUAD.

Intratumoral heterogeneity of oncogenic drivers in mixed histology lung adenocarcinomas: How tissue selection impacts molecular testing?

Majority of the lung adenocarcinomas show a mixture of different histological patterns. The possibility of histologically heterogeneous areas of the adenocarcinoma showing genetic heterogeneity and harboring different driver mutations, with potentially significant clinical impact, has not been adequately addressed. Currently, there are no guidelines to suggest how to submit tumor tissue in adenocarcinomas with mixed histological features for molecular testing. The objective of this study is to assess intra-tumoral heterogeneity in prominent driver mutations among different morphological patterns of lung adenocarcinoma, its implications on the future of molecular testing as well as its potential impact on patient management. Twenty-three cases of mixed histology lung adenocarcinoma resected between 2018 and 2023 were retrieved from the archives. H&E slides were reviewed to identify the predominant and second most predominant histological patterns. The morphologically different tumor areas were manually macro-dissected for DNA extraction. Next-Generation Sequencing with Ion AmpliSeq™ Cancer Hotspot Panel v2 (Thermo Fisher Scientific, USA). Thirteen cases showed the same pathological variant in both histological components tested. Three cases (13 %) exhibited disparities in the variants detected across the different histological patterns tested (p=0.025). The discrepant findings had a direct therapeutic impact in 4.3 % cases. Seven cases showed no pathogenic variants detected on either of the histological components tested. This study elucidates the presence of infrequent yet significant intra-tumoral heterogeneity in the molecular profiles of mixed histology adenocarcinomas, highlighting the need for guidelines directing tissue selection for molecular testing to avoid missed therapeutic opportunities and mitigate disease relapse.

Modeling lung adenocarcinoma metastases using patient-derived organoids

Approximately 50% of patients with surgically resected early-stage lung cancer develop distant metastasis. At present, there is no in vivo metastasis model to investigate the biology of human lung cancer metastases. Using well-characterized lung adenocarcinoma (LUAD) patient-derived organoids (PDOs), we establish an in vivo metastasis model that preserves the biologic features of human metastases. Results of whole-genome and RNA sequencing establish that our in vivo PDO metastasis model can be used to study clonality and tumor evolution and to identify biomarkers related to organotropism. Investigation of the response of KRASG12C PDOs to sotorasib demonstrates that the model can examine the efficacy of treatments to suppress metastasis and identify mechanisms of drug resistance. Finally, our PDO model cocultured with autologous peripheral blood mononuclear cells can potentially be used to determine the optimal immune-priming strategy for individual patients with LUAD.

Lepidic-Type Lung Adenocarcinomas: Is It Safe to Observe for Growth Before Treating?

BACKGROUND

Lepidic-type adenocarcinomas (LPAs) can be multifocal, and treatment is often deferred until growth is observed. This study investigated the potential downside of that strategy by evaluating the relationship of nodal involvement with tumor size and survival.

METHODS

The impact of tumor size on lymph node involvement and survival was evaluated for National Cancer Database patients who underwent surgery without induction therapy as primary treatment for cT1-3 N0 M0 histologically confirmed LPA from 2006 to 2019 by using logistic regression, Kaplan-Meier, and Cox analyses.

RESULTS

Positive nodes occurred in 442 of 8286 patients (5.3%). The incidence of having positive nodes approximately doubled with each 1-cm increment increase in size. Patients with positive nodes were more likely to have larger tumors (27 mm vs 20 mm, P < .001) and clinical ≥T2 disease (40.7% vs 26.8%, P < .001) compared with node-negative patients. However, tumor size was the only significant independent predictor of having positive nodal disease in logistic regression analysis, and this association grew stronger with each incremental centimeter increase in size. Patients with positive nodes were more likely to undergo adjuvant radiotherapy (23.5% vs 1.1%, P < .001) and chemotherapy (72.9% vs 7.9%, P < .001), and expectedly, had worse survival compared with the node-negative group in univariate (5-year overall survival, 50.9% vs 81.1%, P < .001) and multivariable (hazard ratio, 2.56; 95% CI, 2.14-3.05; P < .001) analyses.

CONCLUSIONS

Nodal involvement is relatively uncommon in early-stage LPAs but steadily increases with tumor size and is associated with dramatically worse survival. These data can be used to inform treatment decisions when evaluating LPA patients.

Comparative analysis of PD-L1 expression and molecular alterations in primary versus metastatic lung adenocarcinoma: a real-world study in China

Objectives

Programmed death-ligand 1 (PD-L1) is the only Food and Drug Administration-approved biomarker for monitoring response to immune checkpoint inhibitor (ICI) therapy in patients with lung adenocarcinoma. Understanding the nuances of molecular phenotypes, clinical attributes, and PD-L1 expression levels in primary and metastatic lung adenocarcinoma may help predict response to therapy and assist in the clinical management of lung adenocarcinoma.

Methods

A total of 235 primary and metastatic lesion specimens from patients with non-small cell lung cancer (NSCLC) an institution in Shandong, China were analyzed. PD-L1 expression was assessed by immunohistochemistry using the 22C3 antibody, and the molecular phenotype was determined by next-generation sequencing of 450 genes. The molecular phenotypes of the primary and metastatic lesions were compared.

Results

Elevated PD-L1 expression was significantly associated with advanced and metastatic disease (P = 0.001). The distribution of PD-L1 expression varied based on the anatomical location, showing a higher frequency of elevated PD-L1 expression in distal metastases than in the primary tumor. Metastatic lesions exhibited a higher proportion of carcinogenic pathway gene alterations and a greater number of DNA damage-repair pathway gene alterations than the primary lesions. Notably, CDKN2A copy number deletions were more prevalent in metastatic lesions than in primary lesions. Clinical data stemming from research conducted at the Memorial Sloan Kettering Cancer Center revealed an association between the absence of CDKN2A expression and a poorer prognosis in stage I lung adenocarcinoma.

Conclusion

Samples of metastatic tumors exhibited a higher proportion of elevated PD-L1 expression, a greater number of pathway alterations, and a higher occurrence of CDKN2A copy number deletions than primary samples. This highlights the importance of reinforcing the clinical management and follow-up of patients with CDKN2A deficiency, particularly within the subset of stage I lung adenocarcinoma.

KRAS and TP53 co-mutation predicts benefit of immune checkpoint blockade in lung adenocarcinoma

BACKGROUND

Predictive biomarkers in use for immunotherapy in advanced non-small cell lung cancer are of limited sensitivity and specificity. We analysed the potential of activating KRAS and pathogenic TP53 mutations to provide additional predictive information.

METHODS

The study cohort included 713 consecutive immunotherapy patients with advanced lung adenocarcinomas, negative for actionable genetic alterations. Additionally, two previously published immunotherapy and two surgical patient cohorts were analyzed. Therapy benefit was stratified by KRAS and TP53 mutations. Molecular characteristics underlying KRASmut/TP53mut tumours were revealed by the analysis of TCGA data.

RESULTS

An interaction between KRAS and TP53 mutations was observed in univariate and multivariate analyses of overall survival (Hazard ratio [HR] = 0.56, p = 0.0044 and HR = 0.53, p = 0.0021) resulting in a stronger benefit for KRASmut/TP53mut tumours (HR = 0.71, CI 0.55-0.92). This observation was confirmed in immunotherapy cohorts but not observed in surgical cohorts. Tumour mutational burden, proliferation, and PD-L1 mRNA were significantly higher in TP53-mutated tumours, regardless of KRAS status. Genome-wide expression analysis revealed 64 genes, including CX3CL1 (fractalkine), as specific transcriptomic characteristic of KRASmut/TP53mut tumours.

CONCLUSIONS

KRAS/TP53 co-mutation predicts ICI benefit in univariate and multivariate survival analyses and is associated with unique molecular tumour features. Mutation testing of the two genes can be easily implemented using small NGS panels.

Spatial whole exome sequencing reveals the genetic features of highly-aggressive components in lung adenocarcinoma

In invasive lung adenocarcinoma (LUAD), patients with micropapillary (MIP) or solid (SOL) components had a significantly poorer prognosis than those with only lepidic (LEP), acinar (ACI) or papillary (PAP) components. It is interesting to explore the genetic features of different histologic subtypes, especially the highly aggressive components. Based on a cohort of 5,933 patients, this study observed that in different tumor size groups, LUAD with MIP/SOL components showed a different prevalence, and patients with ALK alteration or TP53 mutations had a higher probability of developing MIP/SOL components. To control individual differences, this research used spatial whole-exome sequencing (WES) via laser-capture microdissection of five patients harboring these five coexistent components and identified genetic features among different histologic components of the same tumor. In tracing the evolution of components, we found that titin (TTN) mutation might serve as a crucial intratumor potential driver for MIP/SOL components, which was validated by a cohort of 146 LUAD patients undergoing bulk WES. Functional analysis revealed that TTN mutations enriched the complement and coagulation cascades, which correlated with the pathway of cell adhesion, migration, and proliferation. Collectively, the histologic subtypes of invasive LUAD were genetically different, and certain trunk genotypes might synergize with branching TTN mutation to develop highly aggressive components.

The genomic landscape of lung cancer in never-smokers from the Women's Health Initiative

Over 200,000 individuals are diagnosed with lung cancer in the United States every year, with a growing proportion of cases, especially lung adenocarcinoma, occurring in individuals who have never smoked. Women over the age of 50 comprise the largest affected demographic. To understand the genomic drivers of lung adenocarcinoma and therapeutic response in this population, we performed whole genome and/or whole exome sequencing on 73 matched lung tumor/normal pairs from postmenopausal women who participated in the Women's Health Initiative. Somatic copy number alterations showed little variation by smoking status, suggesting that aneuploidy may be a general characteristic of lung cancer regardless of smoke exposure. Similarly, clock-like and APOBEC mutation signatures were prevalent but did not differ in tumors from smokers and never-smokers. However, mutations in both EGFR and KRAS showed unique allelic differences determined by smoking status that are known to alter tumor response to targeted therapy. Mutations in the MYC-network member MGA were more prevalent in tumors from smokers. Fusion events in ALK, RET, and ROS1 were absent, likely due to age-related differences in fusion prevalence. Our work underscores the profound effect of smoking status, age, and sex on the tumor mutational landscape and identifies areas of unmet medical need.

Clinicopathological and molecular characterization of resected lung adenocarcinoma: Correlations with histopathological grading systems in Chinese patients

PURPOSE

Driver mutations inform lung adenocarcinoma (LUAD) targeted therapy. Association of histopathological attributes and molecular profiles facilitates clinically viable testing platforms. We assessed correlations between LUAD clinicopathological features, mutational landscapes, and two grading systems among Chinese cases.

METHODS

79 Chinese LUAD patients undergoing resection were subjected to targeted sequencing. 68 were invasive nonmucinous adenocarcinoma (INMA), graded via: predominant histologic pattern-based grading system (P-GS) or novel IASLC grading system (I-GS). Driver mutation distributions were appraised and correlated with clinical and pathological data.

RESULTS

Compared to INMA, non-INMA exhibited smaller, well-differentiated tumors with higher mucin content. INMA grade correlated with size, lymph invasion (P-GS), and driver/EGFR mutations. Mutational spectra varied markedly between grades, with EGFR p.L858R and exon 19 deletion mutations predominating in lower grades; while high-grade P-GS tumors often harbored EGFR copy number variants and complex alterations alongside wild-type cases. I-GS upgrade of P-GS grade 2 to grade 3 was underpinned by ≥20 % high-grade regions bearing p.L858R or ALK fusions. Both systems defined tumors of distinctive phenotypic attributes and molecular genotypes.

CONCLUSIONS

INMA represent larger, mucin-poor, molecularly heterogeneous LUAD with divergent grade-specific mutation profiles. Stronger predictor of clinicopathological attributes and driver mutations, P-GS stratification offers greater accuracy for molecular testing. A small panel encompassing EGFR and ALK captures the majority of P-GS grade 1/2 mutations whereas expanded panels are optimal for grade 3.

Real-world outcomes of lobectomy, segmentectomy and wedge resection for the treatment of stage c-IA lung carcinoma

OBJECTIVES

To determine safety and survival outcomes associated with lobectomy, segmentectomy and wedge resection for early-stage lung cancer by quiring the French population-based registry EPIdemiology in THORacic surgery (EPITHOR).

METHODS

Retrospective analysis of 19 452 patients with stage c IA lung carcinoma who underwent lobectomy, segmentectomy or wedge resection between 2016 and 2022 with curative-intent. Main outcome measures were 90-day mortality and 5-year overall survival estimates. Proportional hazards regression and propensity score matching were used to adjust outcomes for key patient, tumour and practice environment factors.

RESULTS

The treatment distribution was 72.2% for lobectomy, 21.5% for segmentectomy and 6.3% for wedge. Unadjusted 90-day mortality rates were 1.6%, 1.2% and 1.1%, respectively (P = 0.10). Unadjusted 5-year overall survival estimates were 80%, 78% and 70%, with significant inter-group survival curves differences (P < 0.0001). Multivariable proportional hazards regression showed that wedge was associated with worse overall survival [adjusted hazard ratio (AHR), 1.23 (95% confidence interval 1.03-1.47); P = 0.021] compared with lobectomy, while no significant difference was disclosed when comparing segmentectomy to lobectomy (1.08 [0.97-1.20]; P = 0.162). The three-way propensity score analyses confirmed similar 90-day mortality rate for wedge resection and segmentectomy compared with lobectomy (hazard ratio: 0.43; 95% confidence interval 0.16-1.11; P = 0.081 and 0.99; 0.48-2.10; P = 0.998, respectively), but poorer overall survival (1.45; 1.13-1.86; P = 0.003 and 1.31; 1-1.71; P = 0.048, respectively).

CONCLUSIONS

Wedge resection was associated with comparable 90-day mortality but lower overall survival when compared to lobectomy. Overall, all types of sublobar resections may not offer equivalent oncologic effectiveness in real-world settings.

Integrated multi-omics analysis and machine learning to refine molecular subtypes, prognosis, and immunotherapy in lung adenocarcinoma

Lung adenocarcinoma (LUAD) has a malignant characteristic that is highly aggressive and prone to metastasis. There is still a lack of suitable biomarkers to facilitate the refinement of precision-based therapeutic regimens. We used a combination of 10 known clustering algorithms and the omics data from 4 dimensions to identify high-resolution molecular subtypes of LUAD. Subsequently, consensus machine learning-related prognostic signature (CMRS) was developed based on subtypes related genes and an integrated program framework containing 10 machine learning algorithms. The efficiency of CMRS was analyzed from the perspectives of tumor microenvironment, genomic landscape, immunotherapy, drug sensitivity, and single-cell analysis. In terms of results, through multi-omics clustering, we identified 2 comprehensive omics subtypes (CSs) in which CS1 patients had worse survival outcomes, higher aggressiveness, mRNAsi and mutation frequency. Subsequently, we developed CMRS based on 13 key genes up-regulated in CS1. The prognostic predictive efficiency of CMRS was superior to most established LUAD prognostic signatures. CMRS demonstrated a strong correlation with tumor microenvironmental feature variants and genomic instability generation. Regarding clinical performance, patients in the high CMRS group were more likely to benefit from immunotherapy, whereas low CMRS were more likely to benefit from chemotherapy and targeted drug therapy. In addition, we evaluated that drugs such as neratinib, oligomycin A, and others may be candidates for patients in the high CMRS group. Single-cell analysis revealed that CMRS-related genes were mainly expressed in epithelial cells. The novel molecular subtypes identified in this study based on multi-omics data could provide new insights into the stratified treatment of LUAD, while the development of CMRS could serve as a candidate indicator of the degree of benefit of precision therapy and immunotherapy for LUAD.

Clinicopathologic and Molecular Characteristics of HER2 (ERBB2)-Altered Non-Small Cell Lung Cancer: Implications for Precision Medicine

The heterogeneous relationship between protein expression, amplification, and mutations in human epidermal growth factor receptor 2 (HER2) in non-small cell lung cancer (NSCLC) and the optimal methods for detecting these alterations remain unclear. We aimed to elucidate the clinicopathological and molecular characteristics of HER2-altered NSCLC and investigate practical approaches for identifying patients who might benefit from HER2-targeted therapies. Using next-generation sequencing data from 1680 individuals, we searched for patients with HER2-altered NSCLCs, including amplifications and mutations. Clinicopathological data and tissue slides were reviewed. Immunohistochemistry (IHC) and silver in situ hybridization were performed according to the American Society of Clinical Oncology/College of American Pathologists guidelines. Our analysis identified 89 (5.3%) patients with HER2-altered NSCLCs, comprising 30 (1.8%) with amplification and 59 (3.6%) mutations, and they were compared with 165 control patients. Of the 59 HER2-mutated cases, 52 harbored tyrosine kinase domain (TKD) mutations, primarily HER2 exon 20 insertions. HER2 TKD alterations were associated with younger age, female sex, nonsmoking status, adenocarcinoma with a micropapillary pattern, lung-to-lung metastasis, and poor overall survival. The 33 patients with TKD mutations and 3 with non-TKD point mutations showed incomplete or complete membranous HER2 immunoreactivity (1+ and 2+, 61.07%). Six patients exhibiting amplifications had an IHC score of ≤2+ despite their high copy numbers and concomitantly displayed other actionable EGFR, KRAS, SMARCA4, and other HER2 mutations. These HER2-altered NSCLCs with molecular coalterations showed heterogeneous patterns through HER2 IHC and silver in situ hybridization. Therefore, next-generation sequencing should be used to identify HER2 mutations in patients with NSCLC who present with concomitant alterations. In addition, the above clinicopathological characteristics and HER2 IHC results can be valuable determinants for identifying patients with HER2-altered NSCLC. These insights hold promise for the development of more effective diagnostic and therapeutic strategies for this complex subset of NSCLC patients.

Development of a predictive model to predict postoperative bone metastasis in pathological I-II non-small cell lung cancer

Background

Bone is a common metastatic site in postoperative metastasis, but related risk factors for early-stage non-small cell lung cancer (NSCLC) remain insufficiently investigated. Thus, the study aimed to identify risk factors for postoperative bone metastasis in early-stage NSCLC and construct a nomogram to identify high-risk individuals.

Methods

Between January 2015 and January 2021, we included patients with resected stage I-II NSCLC at the Department of Thoracic Surgery, West China Hospital. Univariable and multivariable Cox regression analyses were used to identify related risk factors. Additionally, we developed a visual nomogram to forecast the likelihood of bone metastasis. Evaluation of the model involved metrics such as the area under the curve (AUC), C-index, and calibration curves. To ensure reliability, internal validation was performed through bootstrap resampling.

Results

Our analyses included 2,106 eligible patients, with 54 (2.56%) developing bone metastasis. Multivariable Cox analyses showed that tumor nodules with solid component, higher pT stage, higher pN stage, and histologic subtypes especially solid/micropapillary predominant types were considered as independent risk factors of bone metastasis. In the training set, the developed model demonstrated AUCs of 0.807, 0.769, and 0.761 for 1-, 3-, and 5-year follow-ups, respectively. The C-index, derived from 1,000 bootstrap resampling, showed values of 0.820, 0.793, and 0.777 for 1-, 3-, and 5-year follow-ups. The calibration curve showed that the model was well calibrated.

Conclusions

The predictive model is proven to be valuable in estimating the probability of bone metastasis in early-stage NSCLC following surgery. Leveraging four easy-to-acquire clinical parameters, this model effectively identifies high-risk patients and enables individualized surveillance strategies for better patient care.

Genomic landscape and tumor mutational features of resected preinvasive to invasive lung adenocarcinoma

Introduction

Adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) are considered pre-invasive forms of lung adenocarcinoma (LUAD) with a 5-year recurrence-free survival of 100%. We investigated genomic profiles in early tumorigenesis and distinguished mutational features of preinvasive to invasive adenocarcinoma (IAC) for early diagnosis.

Methods

Molecular information was obtained from a 689-gene panel in the 90 early-stage LUAD Chinese patients using next-generation sequencing. Gene signatures were identified between pathology subtypes, including AIS/MIA (n=31) and IAC (n=59) in this cohort. Mutational and clinicopathological information was also obtained from the Cancer Genome Atlas (TCGA) as a comparison cohort.

Results

A higher mutation frequency of TP53, RBM10, MUC1, CSMD, MED1, LRP1B, GLI1, MAP3K, and RYR2 was observed in the IAC than in the AIS/MIA group. The AIS/MIA group showed higher mutation frequencies of ERBB2, BRAF, GRIN2A, and RB1. Comparable mutation rates for mutually exclusive genes (EGFR and KRAS) across cohorts highlight the critical transition to invasive LUAD. Compared with the TCGA cohort, EGFR, KRAS, TP53, and RBM10 were frequently mutated in both cohorts. Despite limited gene mutation overlap between cohorts, we observed variant mutation types in invasive LUAD. Additionally, the tumor mutation burden (TMB) values were significantly lower in the AIS/MIA group than in the IAC group in both the Chinese cohort (P=0.0053) and TCGA cohort (P<0.01).

Conclusion

These findings highlight the importance of distinguishing preinvasive from invasive LUAD in the early stages of LUAD and both pathology and molecular features in clinical practice, revealing genomic tumor heterogeneity and population differences.

PIK3CA mutation as an acquired resistance driver to EGFR-TKIs in non-small cell lung cancer: Clinical challenges and opportunities

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have significantly enhanced the treatment outcomes in non-small cell lung cancer (NSCLC) patients harboring EGFR mutations. However, the occurrence of acquired resistance to EGFR-TKIs is an unavoidable outcome observed in these patients. Disruption of the PI3K/AKT/mTOR signaling pathway can contribute to the emergence of resistance to EGFR TKIs in lung cancer. The emergence of PIK3CA mutations following treatment with EGFR-TKIs can lead to resistance against EGFR-TKIs. This review provides an overview of the current perspectives regarding the involvement of PI3K/AKT/mTOR signaling in the development of lung cancer. Furthermore, we outline the state-of-the-art therapeutic strategies targeting the PI3K/AKT/mTOR signaling pathway in lung cancer. We highlight the role of PIK3CA mutation as an acquired resistance mechanism against EGFR-TKIs in EGFR-mutant NSCLC. Crucially, we explore therapeutic strategies targeting PIK3CA-mediated resistance to EGFR TKIs in lung cancer, aiming to optimize the effectiveness of treatment.

Exploring the molecular and immune-landscape of lung cancer associated with cystic airspaces

To explore the molecular biological characteristics of lung cancer associated with cystic airspaces (LCCA) and its potential roles on prognosis. A total of 165 LCCAs and 201 non-LCCAs were enrolled in this study. Bulk RNA sequencing was implemented in eight LCCAs and nine non-LCCAs to explore the differentially expressed genes. TCGA data were used to analyze LCCA-specific genes that associated with overall survival (OS). The median age was 60 (IQR 53 to 65) years in LCCA cohort. We found LCCA were predominant in men and had less visceral pleura invasion (VPI) or lympho-vascular invasion (LVI). Moreover, LCCA presented with higher histological heterogeneity. Kaplan-Meier analysis showed that patients of age more than 60 and positive VPI had significantly less PFS in LCCA. Cox regression suggested that LCCA, micropapillary subtype proportion and VPI were the independent risk factors for PFS. LCCA had up-regulated pathways associated with EMT, angiogenesis and cell migration. In addition, LCCA displayed higher levels of immunosuppressor infiltration (M2 macrophages, CAFs and MDSCs) and distinct cell death and metabolic patterns. BCR/TCR repertoire analysis revealed less BCR richness, clonality and high-abundance shared clonotypes in LCCA. Finally, Cox regression analysis identified that four cystic-specific genes, KCNK3, NRN1, PARVB and TRHDE-AS1, were associated with OS of lung adenocarcinoma (LUAD). And cystic-specific risk scores (CSRSs) were calculated to construct a nomogram, which performance well. Our study for the first time indicated significantly distinct molecular biological and immune characteristics between LCCA and non-LCCA, which provide complementary prognostic values in early-stage non-small cell lung cancer (NSCLC).

Lung adenocarcinoma: selection of surgical approaches in solid adenocarcinoma from the viewpoint of clinicopathologic features and tumor microenvironmental heterogeneity

Introduction

Solid adenocarcinoma represents a notably aggressive subtype of lung adenocarcinoma. Amidst the prevailing inclination towards conservative surgical interventions for diminutive lung cancer lesions, the critical evaluation of this subtype's malignancy and heterogeneity stands as imperative for the formulation of surgical approaches and the prognostication of long-term patient survival.

Methods

A retrospective dataset, encompassing 2406 instances of non-solid adenocarcinoma (comprising lepidic, acinar, and papillary adenocarcinoma) and 326 instances of solid adenocarcinoma, was analyzed to ascertain the risk factors concomitant with diverse histological variants of lung adenocarcinoma. Concurrently, RNA-sequencing data delineating explicit pathological subtypes were extracted from 261 cases in the TCGA database and 188 cases in the OncoSG database. This data served to illuminate the heterogeneity across lung adenocarcinoma (LUAD) specimens characterized by differential histological features.

Results

Solid adenocarcinoma is associated with an elevated incidence of pleural invasion, microscopic vessel invasion, and lymph node metastasis, relative to other subtypes of lung adenocarcinoma. Furthermore, the tumor microenvironment (TME) in solid pattern adenocarcinoma displayed suboptimal oxygenation and acidic conditions, concomitant with augmented tumor cell proliferation and invasion capacities. Energy and metabolic activities were significantly upregulated in tumor cells of the solid pattern subtype. This subtype manifested robust immune tolerance and capabilities for immune evasion.

Conclusion

This present investigation identifies multiple potential metrics for evaluating the invasive propensity, metastatic likelihood, and immune resistance of solid pattern adenocarcinoma. These insights may prove instrumental in devising surgical interventions that are tailored to patients diagnosed with disparate histological subtypes of LUAD, thereby offering valuable directional guidance.

Is there a prognostic difference among stage I lung adenocarcinoma patients with different BRAF-mutation status?

BACKGROUND

The data of the prognostic role of V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations in early-stage lung adenocarcinoma (LUAD) patients is scarce. This study aimed to investigate the proportion, clinicopathological features, and prognostic significance of patients with stage I LUAD carrying BRAF mutations.

METHODS

We collected 431 patients with pathological stage I LUAD from cBioPortal for Cancer Genomics and 1604 LUAD patients tested for BRAF V600E and epidermal growth factor receptor (EGFR) mutations from Shanghai Pulmonary Hospital. Survival curves were drawn by the Kaplan-Meier method and compared by log-rank test. Cox proportional hazard models, propensity-score matching (PSM), and overlap weighting (OW) were performed in this study. The primary endpoint was recurrence-free survival (RFS).

RESULTS

The proportion of BRAF mutations was estimated at 5.6% in a Caucasian cohort. BRAF V600E mutations were detected in six (1.4%) patients in Caucasian populations and 16 (1.0%) patients in Chinese populations. Two BRAF V600E-mutant patients were detected to have concurrent EGFR mutations, one for 19-del and one for L858R. For pathological stage I LUAD patients, BRAF mutations were not significantly associated with worse RFS than wild-type BRAF patients (HR = 1.111; p = 0.885). After PSM and OW, similar results were presented (HR = 1.352; p = 0.742 and HR = 1.246; p = 0.764, respectively). BRAF V600E mutation status also lacked predictive significance for RFS (HR, 1.844; p = 0.226; HR = 1.144; p = 0.831 and HR = 1.466; p = 0.450, respectively).

CONCLUSIONS

In this study, we demonstrated that BRAF status may not be capable of predicting prognosis in stage I LUAD patients. There is a need for more data to validate our findings.

Cancer cell immunity-related protein co-expression networks are associated with early-stage solid-predominant lung adenocarcinoma

Background

Solid-predominant lung adenocarcinoma (SPA), which is one of the high-risk subtypes with poor prognosis and unsatisfactory response to chemotherapy and targeted therapy in lung adenocarcinoma, remains molecular profile unclarified. Weighted correlation network analysis (WGCNA) was used for data mining, especially for studying biological networks based on pairwise correlations between variables. This study aimed to identify disease-related protein co-expression networks associated with early-stage SPA.

Methods

We assessed cancerous cells laser-microdissected from formalin-fixed paraffin-embedded (FFPE) tissues of a SPA group (n = 5), referencing a low-risk subtype, a lepidic predominant subtype group (LPA) (n = 4), and another high-risk subtype, micropapillary predominant subtype (MPA) group (n = 3) and performed mass spectrometry-based proteomic analysis. Disease-related co-expression networks associated with the SPA subtype were identified by WGCNA and their upstream regulators and causal networks were predicted by Ingenuity Pathway Analysis.

Results

Among the forty WGCNA network modules identified, two network modules were found to be associated significantly with the SPA subtype. Canonical enriched pathways were highly associated with cellular growth, proliferation, and immune response. Upregulated HLA class I molecules HLA-G and HLA-B implicated high mutation burden and T cell activation in the SPA subtype. Upstream analysis implicated the involvement of highly activated oncogenic regulators, MYC, MLXIPL, MYCN, the redox master regulator NFE2L2, and the highly inhibited LARP1, leading to oncogenic IRES-dependent translation, and also regulators of the adaptive immune response, including highly activated IFNG, TCRD, CD3-TCR, CD8A, CD8B, CD3, CD80/CD86, and highly inhibited LILRB2. Interestingly, the immune checkpoint molecule HLA-G, which is the counterpart of LILRB2, was highly expressed characteristically in the SPA subtype and might be associated with antitumor immunity.

Conclusion

Our findings provide a disease molecular profile based on protein co-expression networks identified for the high-risk solid predominant adenocarcinoma, which will help develop future therapeutic strategies.

Spatial transcriptomics reveals heterogeneity of histological subtypes between lepidic and acinar lung adenocarcinoma

BACKGROUND

Patients who possess various histological subtypes of early-stage lung adenocarcinoma (LUAD) have considerably diverse prognoses. The simultaneous existence of several histological subtypes reduces the clinical accuracy of the diagnosis and prognosis of early-stage LUAD due to intratumour intricacy.

METHODS

We included 11 postoperative LUAD patients pathologically confirmed to be stage IA. Single-cell RNA sequencing (scRNA-seq) was carried out on matched tumour and normal tissue. Three formalin-fixed and paraffin-embedded cases were randomly selected for 10× Genomics Visium analysis, one of which was analysed by digital spatial profiler (DSP).

RESULTS

Using DSP and 10× Genomics Visium analysis, signature gene profiles for lepidic and acinar histological subtypes were acquired. The percentage of histological subtypes predicted for the patients from samples of 11 LUAD fresh tissues by scRNA-seq showed a degree of concordance with the clinicopathologic findings assessed by visual examination. DSP proteomics and 10× Genomics Visium transcriptomics analyses revealed that a negative correlation (Spearman correlation analysis: r = -.886; p = .033) between the expression levels of CD8 and the expression trend of programmed cell death 1(PD-L1) on tumour endothelial cells. The percentage of CD8+ T cells in the acinar region was lower than in the lepidic region.

CONCLUSIONS

These findings illustrate that assessing patient histological subtypes at the single-cell level is feasible. Additionally, tumour endothelial cells that express PD-L1 in stage IA LUAD suppress immune-responsive CD8+ T cells.

Development of an invasion score based on metastasis-related pathway activity profiles for identifying invasive molecular subtypes of lung adenocarcinoma

The invasive capacity of lung adenocarcinoma (LUAD) is an important factor influencing patients' metastatic status and survival outcomes. However, there is still a lack of suitable biomarkers to evaluate tumor invasiveness. LUAD molecular subtypes were identified by unsupervised consistent clustering of LUAD. The differences in prognosis, tumor microenvironment (TME), and mutation were assessed among different subtypes. After that, the invasion-related gene score (IRGS) was constructed by genetic differential analysis, WGCNA analysis, and LASSO analysis, then we evaluated the relationship between IRGS and invasive characteristics, TME, and prognosis. The predictive ability of the IRGS was verified by in vitro experiments. Next, the "oncoPredict" R package and CMap were used to assess the potential value of IRGS in drug therapy. The results showed that LUAD was clustered into two molecular subtypes. And the C1 subtype exhibited a worse prognosis, higher stemness enrichment activity, less immune infiltration, and higher mutation frequency. Subsequently, IRGS developed based on molecular subtypes demonstrated a strong association with malignant characteristics such as invasive features, higher stemness scores, less immune infiltration, and worse survival. In vitro experiments showed that the higher IRGS LUAD cell had a stronger invasive capacity than the lower IRGS LUAD cell. Predictive analysis based on the "oncoPredict" R package showed that the high IRGS group was more sensitive to docetaxel, erlotinib, paclitaxel, and gefitinib. Among them, in vitro experiments verified the greater killing effect of paclitaxel on high IRGS cell lines. In addition, CMap showed that purvalanol-a, angiogenesis-inhibitor, and masitinib have potential therapeutic effects in the high IRGS group. In summary we identified and analyzed the molecular subtypes associated with the invasiveness of LUAD and developed IRGS that can efficiently predict the prognosis and invasive ability of the tumor. IRGS may be able to facilitate the precision treatment of LUAD to some extent.

Evolutionary proteogenomic landscape from pre-invasive to invasive lung adenocarcinoma

Lung adenocarcinoma follows a stepwise progression from pre-invasive to invasive. However, there remains a knowledge gap regarding molecular events from pre-invasive to invasive. Here, we conduct a comprehensive proteogenomic analysis comprising whole-exon sequencing, RNA sequencing, and proteomic and phosphoproteomic profiling on 98 pre-invasive and 99 invasive lung adenocarcinomas. The deletion of chr4q12 contributes to the progression from pre-invasive to invasive adenocarcinoma by downregulating SPATA18, thus suppressing mitophagy and promoting cell invasion. Proteomics reveals diverse enriched pathways in normal lung tissues and pre-invasive and invasive adenocarcinoma. Proteomic analyses identify three proteomic subtypes, which represent different stages of tumor progression. We also illustrate the molecular characterization of four immune clusters, including endothelial cells, B cells, DCs, and immune depression subtype. In conclusion, this comprehensive proteogenomic study characterizes the molecular architecture and hallmarks from pre-invasive to invasive lung adenocarcinoma, guiding the way to a deeper understanding of the tumorigenesis and progression of this disease.

Proteomic analysis reveals LRPAP1 as a key player in the micropapillary pattern metastasis of lung adenocarcinoma

Objectives

Lung adenocarcinomas have different prognoses depending on their histological growth patterns. Micropapillary growth within lung adenocarcinoma, particularly metastasis, is related to dismal prognostic outcome. Metastasis accounts for a major factor leading to mortality among lung cancer patients. Understanding the mechanisms underlying early stage metastasis can help develop novel treatments for improving patient survival.

Methods

Here, quantitative mass spectrometry was conducted for comparing protein expression profiles among various histological subtypes, including adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive adenocarcinoma (including acinar and micropapillary [MIP] types). To determine the mechanism of MIP-associated metastasis, we identified a protein that was highly expressed in MIP. The expression of the selected highly expressed MIP protein was verified via immunohistochemical (IHC) analysis and its function was validated by an in vitro migration assay.

Results

Proteomic data revealed that low-density lipoprotein receptor-related protein-associated protein 1 (LRPAP1) was highly expressed in MIP group, which was confirmed by IHC. The co-expressed proteins in this study, PSMD1 and HSP90AB1, have been reported to be highly expressed in different cancers and play an essential role in metastasis. We observed that LRPAP1 promoted lung cancer progression, including metastasis, invasion and proliferation in vitro and in vivo.

Conclusion

LRPAP1 is necessary for MIP-associated metastasis and is the candidate novel anti-metastasis therapeutic target.

Prognostic biomarker discovery based on proteome landscape of Chinese lung adenocarcinoma

Despite recent innovations in imaging and genomic screening promotes advance in diagnosis and treatment of lung adenocarcinoma (LUAD), there remains high mortality of LUAD and insufficient understanding of LUAD biology. Our previous study performed an integrative multi-omic analysis of LUAD, filling the gap between genomic alterations and their biological proteome effects. However, more detailed molecular characterization and biomarker resources at proteome level still need to be uncovered. In this study, a quantitative proteomic experiment of patient-derived benign lung disease samples was carried out. After that, we integrated the proteomic data with previous dataset of 103 paired LUAD samples. We depicted the proteomic differences between non-cancerous and tumor samples and among diverse pathological subtypes. We also found that up-regulated mitophagy was a significant characteristic of early-stage LUAD. Additionally, our integrative analysis filtered out 75 potential prognostic biomarkers and validated two of them in an independent LUAD serum cohort. This study provided insights for improved understanding proteome abnormalities of LUAD and the novel prognostic biomarker discovery offered an opportunity for LUAD precise management.

Updates on lung adenocarcinoma: invasive size, grading and STAS

Advancements in the classification of lung adenocarcinoma have resulted in significant changes in pathological reporting. The eighth edition of the tumour-node-metastasis (TNM) staging guidelines calls for the use of invasive size in staging in place of total tumour size. This shift improves prognostic stratification and requires a more nuanced approach to tumour measurements in challenging situations. Similarly, the adoption of new grading criteria based on the predominant and highest-grade pattern proposed by the International Association for the Study of Lung Cancer (IASLC) shows improved prognostication, and therefore clinical utility, relative to previous grading systems. Spread through airspaces (STAS) is a form of tumour invasion involving tumour cells spreading through the airspaces, which has been highly researched in recent years. This review discusses updates in pathological T staging, adenocarcinoma grading and STAS and illustrates the utility and limitations of current concepts in lung adenocarcinoma.

EGFR co-mutation is associated with the risk of recurrence in invasive lung adenocarcinoma with the micropapillary component

BACKGROUND

Invasive lung adenocarcinoma (LUAD) patients with the micropapillary (MPP) component tend to have extremely poor prognosis. To optimize clinical outcomes, a better understanding of specific concurrent gene alterations and their impact on the prognosis of patients with the MPP component is necessary.

METHOD

A total of 621 Chinese patients with surgically resected invasive LUAD who underwent genetic testing for lung cancer were enrolled in this retrospective study. The genomic profiling of major lung cancer-related genes based on next-generation sequencing (NGS) was carried out on formalin-fixed paraffin-embedded tumor samples.

RESULT

Among 621 patients with invasive LUAD, 154 (24.8%, 154/621) had the MPP component. We found that PIK3CA (4.5% vs 1.3%), KRAS (9.1% vs 4.7%), and ROS1 (2.6% vs 0.4%) were more frequent in patients with the MPP component than those without the MPP component (P < 0.05). The co-mutation occurred in 66 patients (10.6%, 66/621), of which 19 patients with the MPP component. Most of them were EGFR co-mutations (89.5%, 17/19), including EGFR and PIK3CA, EGFR and ERBB2, and other types. Patients with the MPP component who harbored EGFR co-mutations showed significantly worse recurrence-free survival (RFS) than single EGFR mutation (median RFS 20.1 vs 30.5 months; hazard ratio [HR]: 8.008; 95% confidence interval [CI]: 1.322-48.508).

CONCLUSIONS

Patients with the MPP component harbored the co-mutation of driver genes had a higher risk of recurrence after surgery, especially in patients with EGFR co-mutation. EGFR co-mutation was a significant prognostic factor for RFS in patients with the MPP component.

The landscape of actionable genomic alterations in lung adenocarcinomas in India

Lung adenocarcinoma (LUAD), the most prevalent form of non-small cell lung cancer (NSCLC), remains a leading cause of cancer-related death globally, including in India, with a 5-year survival rate below 10%. Despite these grim statistics, recent advances in the use of next-generation sequencing (NGS) for identifying genetic alterations and the emergence of targeted therapies have opened new possibilities for personalized treatment based on distinct molecular signatures. To understand the molecular pattern of NSCLC, a retrospective study was conducted with 53 Indian LUAD patient samples, using a targeted NGS panel of 46 cancer-relevant oncogenes to identify clinically relevant variants. Pathogenic or likely pathogenic variants were detected in 94% of the 53 cases. Non-synonymous mutations, rearrangements, copy number alterations, insertions, and deletions of functional relevance were observed in 31 out of 46 genes. The most frequently mutated genes included TP53 (52.8%) and EGFR (50.9%), followed by RET, PIK3CA and ERBB2; some patients had multiple alterations in the same gene. Gender-based enrichment analysis indicated that ALK and IDH2 alterations were more prevalent in females, while TP53 and PTEN were more common in males. No significant correlation was found between mutations and other clinicopathological attributes, such as age, stage, and subtype. A higher prevalence of EGFR, RET, PIK3CA, ERBB2 and ALK mutations were observed compared to previous LUAD genetic studies coupled with a lower frequency of KRAS mutations. Clinically actionable variants were annotated using OncoKB and categorized into the four therapeutic levels based on their clinical evidence. Seventy-nine percent of cases had at least one clinically actionable alteration. Most patients (39.6%) had the highest level of actionability (Level 1) wherein an FDA-approved drug is available specifically for the observed mutation in lung cancer patients. EGFR Exon19 in-frame deletions and EGFR L858R were the most frequent among targetable variants (20.7%). These findings emphasize the importance of a selective NGS panel in enabling personalized medicine approaches by identifying actionable molecular alterations and informing the choice of targeted therapy for more effective treatment options in Indian NSCLC patients.

Comparison of gene mutation profile in different lung adenocarcinoma subtypes by targeted next-generation sequencing

BACKGROUND

Disease prognosis after resection of lung cancer could be affected by pathological subtypes. In this study, we investigated the difference of gene variation and significantly altered pathways between adenocarcinoma in situ (AIS)/microinvasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) subtypes to reveal the molecular mechanism of prognosis differences.

METHODS

Sixty one tumor tissues were subjected to DNA extraction and customized 136 gene targeted next-generation sequencing. Comparisons between groups were performed with two-sided Fisher's exact test for categorical variables and two-tailed unpaired t test for numerical variables.

RESULTS

A total of 402 somatic mutations involved in 70 genes were detected in all these samples, and 74.29% of these genes were mutated in at least two samples. PMS2, ARID1A, EGFR, and POLE were the most frequently mutated genes. ALK_EML4 fusion was observed in one IAC patient and RET_ KIF5B fusion in one AIS patient. A significant higher proportion of patients with TP53 gene mutation was observed in the IAC group (P = 0.0057). The average onset age in IAC group is 62.48 years, which is greater than other subtypes (P = 0.0166). It revealed that mutations in genes involved in the mTOR signaling pathway (56.52% vs 26.32%, P = 0.0288) and Hippo signaling pathway (34.78% vs 10.53%, P = 0.0427) were significantly enriched in IAC subtypes, suggesting the key involvement of mTOR and Hippo signaling pathways in lung tumor development and malignant progression.

CONCLUSIONS

This study revealed the heterogeneity of gene mutations and significantly altered pathways between different lung cancer subtypes, suggesting the potential mechanism of different prognosis.

High-risk histological subtype-related FAM83A hijacked FOXM1 transcriptional regulation to promote malignant progression in lung adenocarcinoma

Background

According to the histopathology, lung adenocarcinoma (LUAD) could be divided into five distinct pathological subtypes, categorized as high-risk (micropapillary and solid) group, intermediate-risk (acinar and papillary) group, and low-risk (lepidic) group. Despite this classification, there is limited knowledge regarding the role of transcription factors (TFs) in the molecular regulation of LUAD histology patterns.

Methods

Publish data was mined to explore the candidate TFs associated with high-risk histopathology in LUAD, which was validated in tissue samples. Colony formation, CCK8, EdU, transwell, and matrigel assays were performed to determine the biological function of FAM83A in vitro. Subcutaneous tumor-bearing in BALB/c nude mice and xenograft perivitelline injection in zebrafish were utilized to unreal the function of FAM83A in vivo. We also performed chromatin immunoprecipitation (ChIP), dual-luciferase reporter, and rescue assays to uncover the underline mechanism of FAM83A. Immunohistochemistry (IHC) was performed to confirm the oncogenic role of FAM83A in clinical LUAD tissues.

Results

Screening the transcriptional expression data from TCGA-LUAD, we focus on the differentially expressed TFs across the divergent pathological subtypes, and identified that the expression of FAM83A is higher in patients with high-risk groups compared with those with intermediate or low-risk groups. The FAM83A expression is positively correlated with worse overall survival, progression-free survival, and advanced stages. Gain- and loss-of-function assays revealed that FAM83A promoted cell proliferation, invasion, and migration of tumor cell lines both in vivo and in vitro. Pathway enrichment analysis shows that FAM83A expression is significantly enriched in cell cycle-related pathways. The ChIP and luciferase reporter assays revealed that FAM83A hijacks the promoter of FOXM1 to progress the malignant LUAD, and the rescue assay uncovered that the function of FAM83A is partly dependent on FOXM1 regulation. Additionally, patients with high FAM83A expression positively correlated with higher IHC scores of Ki-67 and FOXM1, and patients with active FAM83A/FOXM1 axis had poor prognoses in LUAD.

Conclusions

Taken together, our study revealed that the high-risk histological subtype-related FAM83A hijacks FOXM1 transcriptional regulation to promote malignant progression in lung adenocarcinoma, which implies targeting FAM83A/FOXM1 is the therapeutic vulnerability.

Mutational signatures and their association with survival and gene expression in urological carcinomas

Different sources of mutagenesis cause consistently identifiable patterns of mutations and mutational signatures that mirror the various carcinogenetic processes. We used publicly available data from the Cancer Genome Atlas to evaluate the associations between the activity of the mutational signatures and various survival endpoints in six types of urological cancers after adjusting for established prognostic factors. The predictive power of the signatures was evaluated with dynamic area under curve models. In addition, links between mutational signature activities and differences in gene expression patterns were analysed. APOBEC-related signature SBS2 was associated with improved overall survival (OS) and disease-specific survival (DSS) in bladder carcinomas in the multivariate analysis, while clock-like signature SBS1 predicted shortened DSS and progression-free interval (PFI) in clear cell renal cell carcinomas (ccRCC). In papillary renal cell carcinomas (pRCC), SBS45 was a predictor of improved outcomes, and APOBEC-related SBS13 was a predictor of worse outcomes. Gene expression analyses revealed various enriched pathways between the low- and high-signature groups. Interestingly, in both the ccRCC and pRCC cohorts, the genes of several members of the melanoma antigen (MAGE) family were highly upregulated in the signatures, which predicted poor outcomes, and downregulated in signatures, which were associated with improved survival. To summarize, SBS signatures provide substantial prognostic value compared with just the traditional prognostic factors in certain cancer types. APOBEC-related SBS2 and SBS13 seem to provide robust prognostic information for particular urological cancers, maybe driven by the expression of specific groups of genes, including the MAGE gene family.

MET exon 14 skipping is overexpressed in an allele-specific manner in lung adenocarcinoma primary samples

MET exon 14 skipping ( METΔ14 ) is a well-characterized oncogene in the Ras-MAPK pathway driving lung adenocarcinoma (LUAD). Previous studies on METΔ14 revealed this aberrantly spliced oncogene is expressed in LUAD primary samples and is associated with heterozygous somatic mutations and deletions near exon 14 splice sites. Upon further examination of DNA and RNA sequencing data from primary samples, we highlight that METΔ14 is overexpressed in an allele-specific manner. These data suggest that dose-dependence of METΔ14 may be critical to oncogenesis.

Efficacy of Preoperative Biopsy in Predicting the Newly Proposed Histologic Grade of Resected Lung Adenocarcinoma

A novel histologic grading system for invasive lung adenocarcinomas (LUAD) has been newly proposed and adopted by the World Health Organization (WHO) classification. We aimed to evaluate the concordance of newly established grades between preoperative biopsy and surgically resected LUAD samples. Additionally, factors affecting the concordance rate and its prognostic impact were also analyzed. In this study, surgically resected specimens of 222 patients with invasive LUAD and their preoperative biopsies collected between January 2013 and December 2020 were used. We determined the histologic subtypes of preoperative biopsy and surgically resected specimens and classified them separately according to the novel WHO grading system. The overall concordance rate of the novel WHO grades between preoperative biopsy and surgically resected samples was 81.5%, which was higher than that of the predominant subtype. When stratified by grades, the concordance rate of grades 1 (well-differentiated, 84.2%) and 3 (poorly differentiated, 89.1%) was found to be superior compared to grade 2 (moderately differentiated, 66.2%). Overall, the concordance rate was not significantly different from biopsy characteristics, including the number of biopsy samples, biopsy sample size, and tumor area size. On the other hand, the concordance rate of grades 1 and 2 was significantly higher in tumors with smaller invasive diameters, and that of grade 3 was significantly higher in tumors with larger invasive diameters. Preoperative biopsy specimens can predict the novel WHO grades, especially grades 1 and 3 of surgically resected specimens, more accurately than the former grading system, regardless of preoperative biopsy or clinicopathologic characteristics.

ARID1A mutations in lung cancer: biology, prognostic role, and therapeutic implications

Mutations in the AT-interacting domain-rich protein 1A (ARID1A) gene, a critical component of the switch/sucrose nonfermentable (SWI/SNF) complex, are frequently found in most human cancers. Approximately 5-10% of lung cancers carry ARID1A mutations. ARID1A loss in lung cancer correlates with clinicopathological features and poor prognosis. Co-mutation of ARID1A and epidermal growth factor receptor (EGFR) results in the limited efficacy of EGFR tyrosine kinase inhibitors (EGFR-TKIs) but increases the clinical benefit of immune checkpoint inhibitors (ICIs). ARID1A gene mutation plays a role in cell cycle regulation, metabolic reprogramming, and epithelial-mesenchymal transition. We present the first comprehensive review of the relationship between ARID1A gene mutations and lung cancer and discuss the potential of ARID1A as a new molecular target.

Feasibility of shape-sensing robotic-assisted bronchoscopy for biomarker identification in patients with thoracic malignancies

OBJECTIVE

Molecular diagnostic assays require samples with high nucleic acid content to generate reliable data. Similarly, programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) requires samples with adequate tumor content. We investigated whether shape-sensing robotic-assisted bronchoscopy (ssRAB) provides adequate samples for molecular and predictive testing.

METHODS

We retrospectively identified diagnostic samples from a prospectively collected database. Pathologic reports were reviewed to assess adequacy of samples for molecular testing and feasibility of PD-L1 IHC. Tumor cellularity was quantified by an independent pathologist using paraffin-embedded sections. Univariable and multivariable linear regression models were constructed to assess associations between lesion- and procedure-related variables and tumor cellularity.

RESULTS

In total, 128 samples were analyzed: 104 primary lung cancers and 24 metastatic lesions. On initial pathologic assessment, ssRAB samples were deemed to be adequate for molecular testing in 84% of cases; on independent review of cellular blocks, median tumor cellularity was 60% (interquartile range, 25%-80%). Hybrid capture-based next-generation sequencing was successful for 25 of 26 samples (96%), polymerase chain reaction-based molecular testing (Idylla; Biocartis) was successful for 49 of 52 samples (94%), and PD-L1 IHC was successful for 61 of 67 samples (91%). Carcinoid and small cell carcinoma histologic subtype and adequacy on rapid on-site evaluation were associated with higher tumor cellularity.

CONCLUSIONS

The ssRAB platform provided adequate tissue for next-generation sequencing, polymerase chain reaction-based molecular testing, and PD-L1 IHC in >80% of cases. Tumor histology and adequacy on intraoperative cytologic assessment might be associated with sample quality and suitability for downstream assays.

KRAS(G12D) drives lepidic adenocarcinoma through stem-cell reprogramming

Many cancers originate from stem or progenitor cells hijacked by somatic mutations that drive replication, exemplified by adenomatous transformation of pulmonary alveolar epithelial type II (AT2) cells1. Here we demonstrate a different scenario: expression of KRAS(G12D) in differentiated AT1 cells reprograms them slowly and asynchronously back into AT2 stem cells that go on to generate indolent tumours. Like human lepidic adenocarcinoma, the tumour cells slowly spread along alveolar walls in a non-destructive manner and have low ERK activity. We find that AT1 and AT2 cells act as distinct cells of origin and manifest divergent responses to concomitant WNT activation and KRAS(G12D) induction, which accelerates AT2-derived but inhibits AT1-derived adenoma proliferation. Augmentation of ERK activity in KRAS(G12D)-induced AT1 cells increases transformation efficiency, proliferation and progression from lepidic to mixed tumour histology. Overall, we have identified a new cell of origin for lung adenocarcinoma, the AT1 cell, which recapitulates features of human lepidic cancer. In so doing, we also uncover a capacity for oncogenic KRAS to reprogram a differentiated and quiescent cell back into its parent stem cell en route to adenomatous transformation. Our work further reveals that irrespective of a given cancer's current molecular profile and driver oncogene, the cell of origin exerts a pervasive and perduring influence on its subsequent behaviour.