Lung cancer in never smokers: molecular profiles and therapeutic implications

Proteogenomic Characterization Reveals Estrogen Signaling as a Target for Never-Smoker Lung Adenocarcinoma Patients without EGFR or ALK Alterations

Never-smoker lung adenocarcinoma (NSLA) is prevalent in Asian populations, particularly in women. EGFR mutations and anaplastic lymphoma kinase (ALK) fusions are major genetic alterations observed in NSLA, and NSLA with these alterations have been well studied and can be treated with targeted therapies. To provide insights into the molecular profile of NSLA without EGFR and ALK alterations (NENA), we selected 141 NSLA tissues and performed proteogenomic characterization, including whole genome sequencing (WGS), transcriptomic, methylation EPIC array, total proteomic, and phosphoproteomic analyses. Forty patients with NSLA harboring EGFR and ALK alterations and seven patients with NENA with microsatellite instability were excluded. Genome analysis revealed that TP53 (25%), KRAS (22%), and SETD2 (11%) mutations and ROS1 fusions (14%) were the most frequent genetic alterations in NENA patients. Proteogenomic impact analysis revealed that STK11 and ERBB2 somatic mutations had broad effects on cancer-associated genes in NENA. DNA copy number alteration analysis identified 22 prognostic proteins that influenced transcriptomic and proteomic changes. Gene set enrichment analysis revealed estrogen signaling as the key pathway activated in NENA. Increased estrogen signaling was associated with proteogenomic alterations, such as copy number deletions in chromosomes 14 and 21, STK11 mutation, and DNA hypomethylation of LLGL2 and ST14. Finally, saracatinib, an Src inhibitor, was identified as a potential drug for targeting activated estrogen signaling in NENA and was experimentally validated in vitro. Collectively, this study enhanced our understanding of NENA NSLA by elucidating the proteogenomic landscape and proposed saracatinib as a potential treatment for this patient population that lacks effective targeted therapies.

SIGNIFICANCE

The proteogenomic landscape in never-smoker lung cancer without known driver mutations reveals prognostic proteins and enhanced estrogen signaling that can be targeted as a potential therapeutic strategy to improve patient outcomes.

First-line immunotherapy for lung cancer with MET exon 14 skipping and the relevance of TP53 mutations

BACKGROUND

The efficacy of checkpoint inhibitors for non-small cell lung cancer (NSCLC) with MET exon 14 skipping (METΔ14ex) remains controversial.

MATERIALS AND METHODS

110 consecutive METΔ14ex NSCLC patients receiving first-line chemotherapy (CHT) and/or immunotherapy (IO) in 10 German centers between 2016-2022 were analyzed.

RESULTS

Combined CHT-IO was given to 35/110 (32%) patients, IO alone to 43/110 (39%), and CHT to 32/110 (29%) upfront. Compared to CHT, CHT-IO showed longer progression-free survival (median PFS 6 vs. 2.5 months, p = 0.004), more objective responses (ORR 49% vs. 28%, p = 0.086) and numerically longer overall survival (OS 16 vs. 10 months, p = 0.240). For IO monotherapy, OS (14 vs. 16 months) and duration of response (26 vs. 22 months) were comparable to those of CHT-IO. Primary progressive disease (PD) was more frequent with IO compared to CHT-IO (13/43 vs. 3/35, p = 0.018), particularly for never-smokers (p = 0.041). Higher PD-L1 TPS were not associated with better IO outcomes, but TP53 mutated tumors showed numerically improved ORR (56% vs. 32%, p = 0.088) and PFS (6 vs. 3 months, p = 0.160), as well as longer OS in multivariable analysis (HR=0.54, p = 0.034) compared to their wild-type counterparts. Any second-line treatment was administered to 35/75 (47%) patients, with longer survival for capmatinib or tepotinib compared to crizotinib (PFS 10 vs. 3 months, p = 0.013; OS 16 vs. 13 months, p = 0.270).

CONCLUSION

CHT-IO is superior to CHT, and IO alone also effective for METΔ14ex NSCLC, especially in the presence of TP53 mutations and independent of PD-L1 expression, but never-smokers are at higher risk of primary PD.

Characterizing the secretome of EGFR mutant lung adenocarcinoma

Background

Lung cancer is the leading cause of cancer related death worldwide, mainly due to the late stage of disease at the time of diagnosis. Non-invasive biomarkers are needed to supplement existing screening methods to enable earlier detection and increased patient survival. This is critical to EGFR-driven lung adenocarcinoma as it commonly occurs in individuals who have never smoked and do not qualify for current screening protocols.

Methods

In this study, we performed mass spectrometry analysis of the secretome of cultured lung cells representing different stages of mutant EGFR driven transformation, from normal to fully malignant. Identified secreted proteins specific to the malignant state were validated using orthogonal methods and their clinical activity assessed in lung adenocarcinoma patient cohorts.

Results

We quantified 1020 secreted proteins, which were compared for differential expression between stages of transformation. We validated differentially expressed proteins at the transcriptional level in clinical tumor specimens, association with patient survival, and absolute concentration to yield three biomarker candidates: MDK, GDF15, and SPINT2. These candidates were validated using ELISA and increased levels were associated with poor patient survival specifically in EGFR mutant lung adenocarcinoma patients.

Conclusions

Our study provides insight into changes in secreted proteins during EGFR driven lung adenocarcinoma transformation that may play a role in the processes that promote tumor progression. The specific candidates identified can harnessed for biomarker use to identify high risk individuals for early detection screening programs and disease management for this molecular subgroup of lung adenocarcinoma patients.

Isoflavone and soy food intake and risk of lung cancer in never smokers: report from prospective studies in Japan and China

PURPOSE

Evidence from several cohorts has suggested that a higher intake of isoflavone is associated with lower risk of lung cancer in never smokers, but the association has not been investigated by histologic type of lung cancer. Adenocarcinoma is a common histologic type found in never smokers. We hypothesized that a higher intake of isoflavone is associated with a lower risk of lung adenocarcinoma among never smokers. Here, we examined the associations of isoflavone and soy food intake with lung cancer and its histologic types in never smokers.

METHODS

We performed a pooled analysis using data from the Japan Public Health Center-based Prospective Study, Shanghai Women's Health Study and Shanghai Men's Study with 147,296 never smokers aged 40-74 years with no history of cancer. During 1,990,040 person-years of follow-up, 1247 lung cancer cases were documented. Dietary isoflavone and soy food intake were assessed using a food-frequency questionnaire. Multivariable Cox proportional hazards models assessed the associations between isoflavone and soy intake with incidence of lung cancer by histologic type.

RESULTS

A higher intake of dietary isoflavone and soy food were associated with reduced risk of lung adenocarcinoma. The multivariable hazard ratios (HRs) (95% CI) of risk of lung adenocarcinoma for the highest versus lowest intakes of isoflavone and soy food were 0.74 (0.60-0.92) and 0.78 (0.63-0.96), respectively. The multivariable HRs of risk of lung adenocarcinoma associated with each 10 mg/day increase in isoflavone and each 50 g/day increase in soy food intake were 0.81 (0.70-0.94) and 0.84 (0.73-0.96), respectively.

CONCLUSION

Higher intake of isoflavone and soy food was associated with lower risk of lung adenocarcinoma in never smokers.

Chinese never smokers with adenocarcinoma of the lung are younger and have fewer lymph node metastases than smokers

Background

Lung cancers arising in never smokers have been suggested to be substantially different from lung cancers in smokers at an epidemiological, genetic and molecular level. Focusing on non-small cell lung cancer (NSCLC), we characterized lung cancer patients in China looking for demographic and clinical differences between the smoking and never-smoking subgroups.

Methods

In total, 891 patients with NSCLC, including 841 with adenocarcinoma and 50 with squamous cell carcinoma, were recruited in this study. Association of smoking status with demographic and clinical features of NSCLC was determined, and risk factors for lymph node metastasis and TNM stage were evaluated using Multivariate logistic regression analysis.

Results

In patients with adenocarcinoma, never smokers showed a younger age at diagnosis (54.2 ± 12.7vs. 59.3 ± 9.4, p^adjusted<0.001), a lower risk for lymph node metastasis than smokers (7,6% vs. 19.5%, p^adjusted<0.001) and less severe disease as indicated by lower percentages of patients with TNM stage of III or IV (5.5% vs. 14.7%, p^adjusted<0.001 ). By contrast, these associations were not observed in 50 patients with squamous cell carcinoma. Multivariate logistic regression analysis showed that smoking status was a risk factor for lymph node metastasis (OR = 2.70, 95% CI: 1.39–5.31, p = 0.004) but not for TNM stage (OR = 1.18, 95% CI: 0.09–14.43, p = 0.896) in adenocarcinoma.

Conclusion

This study demonstrates that lung adenocarcinoma in never smokers significantly differ from those in smokers regarding both age at diagnosis and risk of lymph node metastasis, supporting the notion that they are distinct entries with different etiology and pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02199-z.

Comprehensive Pan-Cancer Analysis of Senescence With Cancer Prognosis and Immunotherapy

Senescence is a double-edged sword in tumorigenesis and affects the immunotherapy response through the modulation of the host’s immune system. However, there is currently a lack of comprehensive analysis of the senescence-related genes (SRGs) in human cancers, and the predictive role of senescence in cancer immunotherapy response has not been explored. The multi-omics approaches were performed in this article to conduct a systematic pan-cancer genomic analysis of SRGs in cancer. In addition, we calculated the generic senescence score (SS) to quantify the senescence levels in cancers and explored the correlations of SS with cancer prognosis, biological processes, and tumor microenvironment (TME). The gene signatures were deregulated in multiple cancers and indicated a context-dependent correlation with prognosis, tumor-immune evasion, and response to therapy across various tumor types. Further analysis disclosed that SS was positively associated with the infiltration levels of immune suppressive cells, including induced Tregs (iTregs), central memory Ts (Tcms), and natural Tregs (nTregs), and negatively associated with immune killer cells, including natural killers (NKs) and mucosal-associated invariant Ts (MAITs). Moreover, the SS was significantly correlated with tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), immune-related genes, and immune checkpoints and had a predictive value of immunotherapy response. Thus, the expression of SRGs was involved in resistance to several anticancer drugs. Our work illustrates the characterization of senescence across various malignancies and highlights the potential of senescence as a biomarker of the response to immunotherapy.

Radon and Lung Cancer: Current Trends and Future Perspectives

Simple Summary

Radon represents the main risk factor of lung cancer in non-smokers and the second one in smoking patients. In Europe, there are several radon-prone areas, but regulatory policies may vary between countries. Radon causes DNA damage and high genomic tumor instability, but its exact carcinogenesis mechanism in lung cancer remains unknown. Molecular drivers in NSCLC are more often described in non-smoker patients and a potential association between radon exposure and oncogenic-driven NSCLC has been postulated. This is an updated review on indoor radon exposure and its role in lung cancer carcinogenesis, especially focusing on its potential relation with NSCLC with driver genomic alterations. We want to contribute to rising knowledge and awareness on this still silent but preventable lung cancer risk factor.

Abstract

Lung cancer is a public health problem and the first cause of cancer death worldwide. Radon is a radioactive gas that tends to accumulate inside homes, and it is the second lung cancer risk factor after smoking, and the first one in non-smokers. In Europe, there are several radon-prone areas, and although the 2013/59 EURATOM directive is aimed to regulate indoor radon exposition, regulating measures can vary between countries. Radon emits alpha-ionizing radiation that has been linked to a wide variety of cytotoxic and genotoxic effects; however, the link between lung cancer and radon from the genomic point of view remains poorly described. Driver molecular alterations have been recently identified in non-small lung cancer (NSCLC), such as somatic mutations (EGFR, BRAF, HER2, MET) or chromosomal rearrangements (ALK, ROS1, RET, NTRK), mainly in the non-smoking population, where no risk factor has been identified yet. An association between radon exposure and oncogenic NSCLC in non-smokers has been hypothesised. This paper provides a practical, concise and updated review on the implications of indoor radon in lung cancer carcinogenesis, and especially of its potential relation with NSCLC with driver genomic alterations.

Association of Smoking Status with Efficacy of First-line Immune Checkpoint Inhibitors in Advanced Non-small Cell Lung Cancers: A Systematic Review and Meta-analysis

Background: Although smoking status has potential as a biomarker for immune checkpoint blockade in advanced non-small cell lung cancer (NSCLC), its clinical significance remains obscure. This meta-analysis aims to assess the impact of the smoking status on the efficacy of first-line immunotherapy and to find better treatment in never-smoker and ever-smoker patients.

Methods: We searched the MEDLINE, EMBASE, and Cochrane database for trials comparing immunotherapy with conventional chemotherapy as front-line treatment for advanced NSCLC. Random-effects models were used to pool estimates of hazard ratios (HRs) for overall survival with 95% confidence intervals (CIs). Predefined subgroup analysis was performed to investigate the difference in the efficacy between the single checkpoint blockade and checkpoint inhibitor plus chemotherapy combination in the never-smokers and current/former smokers.

Results: Twelve trials involving 6,446 patients were included in the analysis. A statistically significant overall survival benefit over conventional chemotherapy was found for both checkpoint inhibitor monotherapy (HR, 0.71; 95% CI, 0.59-0.85) and checkpoint inhibitor plus chemotherapy (HR, 0.75; 95% CI, 0.63-0.90) in the current/former smoker group. There was no subgroup difference between monotherapy and combination treatment (p=0.67). However, there was an inconsistent survival outcome in the never-smoker group; checkpoint blockade monotherapy did not show significantly better efficacy than chemotherapy alone (HR, 1.05; 95% CI, 0.81-1.37), but combination treatment showed an overall survival benefit (HR, 0.64; 95% CI, 0.43-0.94). A significant subgroup difference existed between monotherapy and combination therapy (p=0.04). Similarly, there was a significant difference in efficacy of monotherapy between the current/former smoker and never-smoker group (p=0.01), but the efficacy of the combination treatment was comparable between the two groups (p=0.45).

Conclusion: Smoking status, which is easily available information, could be used as a guide in clinical practice to choose better treatment in the front-line setting for advanced NSCLC patients.

A review on epidermal growth factor receptor's role in breast and non-small cell lung cancer

Epithelial growth factor receptor (EGFR) is a cell surface transmembrane receptor that mediates the tyrosine signaling pathway to carry the extracellular messages inside the cell and thereby alter the function of nucleus. This leads to the generation of various protein products to up or downregulate the cellular function. It is encoded by cell erythroblastosis virus oncogene B1, so called C-erb B1/ERBB2/HER-2 gene that acts as a proto-oncogene. It belongs to the HER-2 receptor-family in breast cancer and responds best with anti-Herceptin therapy (anti-tyrosine kinase monoclonal antibody). HER-2 positive breast cancer patient exhibits worse prognosis without Herceptin therapy. Similar incidence and prognosis are reported in other epithelial neoplasms like EGFR + lung non-small cell carcinoma and glioblastoma (grade IV brain glial tumor). Present study highlights the role and connectivity of EGF with various cancers via signaling pathways, cell surface receptors mechanism, macromolecules, mitochondrial genes and neoplasm. Present study describes the EGFR associated gene expression profiling (in breast cancer and NSCLC), relation between mitrochondrial genes and carcinoma, and several in vitro and in vivo models to screen the synergistic effect of various combination treatments. According to this study, although clinical studies including targeted treatments, immunotherapies, radiotherapy, TKi-EGFR combined targeted therapy have been carried out to investigate the synergism of combination therapy; however still there is a gap to apply the scenarios of experimental and clinical studies for further developments. This review will give an idea about the transition from experimental to most advanced clinical studies with different combination drug strategies to treat cancer.

Identify specific gene pairs for subarachnoid hemorrhage based on wavelet analysis and genetic algorithm

Subarachnoid hemorrhage (SAH) is a fatal stroke caused by bleeding in the brain. SAH can be caused by a ruptured aneurysm or head injury. One-third of patients will survive and recover. One-third will survive with disability; one-third will die. The focus of treatment is to stop bleeding, restore normal blood flow, and prevent vasospasm. Treatment for SAH varies, depending on the bleeding’s underlying cause and the extent of damage to the brain. Treatment may include lifesaving measures, symptom relief, repair of the bleeding vessel, and complication prevention. However, the useful diagnostic biomarkers of SAH are still limited due to the instability of gene marker expression. To overcome this limitation, we developed a new protocol pairing genes and screened significant gene pairs based on the feature selection algorithm. A classifier was constructed with the selected gene pairs and achieved a high performance.

The Role of UK Oncogene-Focussed Patient Groups in Supporting and Educating Patients with Oncogene-Driven NSCLC: Results from a Patient-Devised Survey

To meet the needs of patients with non-small cell lung cancer (NSCLC) with an oncogene-driver, patients have organised into support groups. These groups are building partnerships to provide support and education and to help patients access treatment through sharing information and promoting advocacy. Here, we report findings from a fully anonymised survey conducted in 2020 across the membership of three Facebook-based patient groups in the UK (EGFR Positive UK, ALK Positive UK and ROS-1 Support Group, n = 465). Of 167 respondents, most were women (73.1%), never-smokers (60.5%) and diagnosed with stage IV disease (86.3%). Benefits included feeling better prepared (79.6%), being inspired by other members’ experiences (71.3%) and being helped with feelings of isolation (49.0%); notably only 27.5% struggled when members died or with feelings of increased anxiety (3%). These findings from a representative population of oncogene-driven NSCLC patients provide new information on the experience of living with lung cancer and highlight the value of specialised support. These patient support groups represent powerful resources to enable enhanced public and patient engagement and meaningful alliances with key stakeholders to help deliver improvement in outcomes for patients.

Genomic Signature of Oral Squamous Cell Carcinomas from Non-Smoking Non-Drinking Patients

Simple Summary

A clinically distinct cohort of non-smoking non-drinking patients who develop oral cavity squamous cell carcinomas has been identified, with previous work suggesting that these patients tend to be older, female, and have poor outcomes. Our study characterised tumour molecular alterations in these patients, identifying differences in genomic profiles as compared to patients who smoke and/or drink. Associations between molecular alterations and other clinical and pathological characteristics were also explored.

Abstract

Molecular alterations in 176 patients with oral squamous cell carcinomas (OSCC) were evaluated to delineate differences in non-smoking non-drinking (NSND) patients. Somatic mutations and DNA copy number variations (CNVs) in a 68-gene panel and human papilloma virus (HPV) status were interrogated using targeted next-generation sequencing. In the entire cohort, TP53 (60%) and CDKN2A (24%) were most frequently mutated, and the most common CNVs were EGFR amplifications (9%) and deletions of BRCA2 (5%) and CDKN2A (4%). Significant associations were found for TP53 mutation and nodal disease, lymphovascular invasion and extracapsular spread, CDKN2A mutation or deletion with advanced tumour stage, and EGFR amplification with perineural invasion and extracapsular spread. PIK3CA mutation, CDKN2A deletion, and EGFR amplification were associated with worse survival in univariate analyses (p < 0.05 for all comparisons). There were 59 NSND patients who tended to be female and older than patients who smoke and/or drink, and showed enrichment of CDKN2A mutations, EGFR amplifications, and BRCA2 deletions (p < 0.05 for all comparisons), with a younger subset showing higher mutation burden. HPV was detected in three OSCC patients and not associated with smoking and drinking habits. NSND OSCC exhibits distinct genomic profiles and further exploration to elucidate the molecular aetiology in these patients is warranted.

Interplay between estrogen and Stat3/NF-κB-driven immunomodulation in lung cancer

K-ras mutant lung adenocarcinoma (LUAD) is the most common type of lung cancer, displays abysmal prognosis and is tightly linked to tumor-promoting inflammation, which is increasingly recognized as a target for therapeutic intervention. We have recently shown a gender-specific role for epithelial Stat3 signaling in the pathogenesis of K-ras mutant LUAD. The absence of epithelial Stat3 in male K-ras mutant mice (LR/Stat3Δ/Δ mice) promoted tumorigenesis and induced a nuclear factor-kappaB (NF-κB)-driven pro-tumor immune response while reducing tumorigenesis and enhancing anti-tumor immunity in female counterparts. In the present study, we manipulated estrogen and NF-κB signaling to study the mechanisms underlying this intriguing gender-disparity. In LR/Stat3Δ/Δ females, estrogen deprivation by bilateral oophorectomy resulted in higher tumor burden, an induction of NF-κB-driven immunosuppressive response, and reduced anti-tumor cytotoxicity, whereas estrogen replacement reversed these changes. On the other hand, exogenous estrogen in males successfully inhibited tumorigenesis, attenuated NF-κB-driven immunosuppression and boosted anti-tumor immunity. Mechanistically, genetic targeting of epithelial NF-κB activity resulted in reduced tumorigenesis and enhanced the anti-tumor immune response in LR/Stat3Δ/Δ males, but not females. Our data suggest that estrogen exerts a context-specific anti-tumor effect through inhibiting NF-κB-driven tumor-promoting inflammation and provide insights into developing novel personalized therapeutic strategies for K-ras mutant LUAD.

From Tumor Mutational Burden to Blood T Cell Receptor: Looking for the Best Predictive Biomarker in Lung Cancer Treated with Immunotherapy

Simple Summary

Immune control inhibitor drugs (anti-PD1/PD-L1/CTLA-4) (ICIs) are showing efficacy in the treatment of lung cancer. Currently the only biomarker with clinical utility for ICIs, such as the expression of PDL1, does not appear to be perfect or effective. Our working group is conducting a pilot study in lung cancer patients receiving ICIs with the aim of analyze the factors that affect the sensitivity of the immunotherapy in lung Cancer. Tumor Mutational Burden (TMB) and the sequencing of the T Cell Receptor (TCR) repertoire in peripheral blood have been postulated as predictive biomarkers of efficacy of immunotherapy. The review focusses on the predictive value of TMB for clinical responses to ICIs and discusses its clinical need after a discussion of the limitations. TCR CDR3 beta analysis and parameters such as clonality and TCR convergence may be good alternatives. For the moment, the combination of biomarkers may be the optimal tool.

Abstract

Despite therapeutic advances, lung cancer (LC) is one of the leading causes of cancer morbidity and mortality worldwide. Recently, the treatment of advanced LC has experienced important changes in survival benefit due to immune checkpoint inhibitors (ICIs). However, overall response rates (ORR) remain low in unselected patients and a large proportion of patients undergo disease progression in the first weeks of treatment. Therefore, there is a need of biomarkers to identify patients who will benefit from ICIs. The programmed cell death ligand 1 (PD-L1) expression has been the first biomarker developed. However, its use as a robust predictive biomarker has been limited due to the variability of techniques used, with different antibodies and thresholds. In this context, tumor mutational burden (TMB) has emerged as an additional powerful biomarker based on the observation of successful response to ICIs in solid tumors with high TMB. TMB can be defined as the total number of nonsynonymous mutations per DNA megabases being a mechanism generating neoantigens conditioning the tumor immunogenicity and response to ICIs. However, the latest data provide conflicting results regarding its role as a biomarker. Moreover, considering the results of the recent data, the use of peripheral blood T cell receptor (TCR) repertoire could be a new predictive biomarker. This review summarises recent findings describing the clinical utility of TMB and TCRβ (TCRB) and concludes that immune, neontigen, and checkpoint targeted variables are required in combination for accurately identifying patients who most likely will benefit of ICIs.

Lung cancer risk and residential radon exposure: A pooling of case-control studies in northwestern Spain

BACKGROUND

Through a pooled case-control study design, we have assessed the relationship between residential radon exposure and lung cancer risk. Other objectives of the study were to evaluate the different risk estimates for the non-small cell lung cancer histological types and to assess the effect modification of the radon exposure on lung cancer risk by tobacco consumption.

METHODS

We collected individual data from various case-control studies performed in northwest Spain that investigated residential radon and lung cancer. Cases had a confirmed anatomopathological diagnosis of primary lung cancer and controls were selected because they were undergoing ambulatory evaluation or surgical procedures that were unrelated to tobacco use. Residential radon was measured using alpha track detectors. Results were analyzed using logistic regression.

RESULTS

3704 participants were enrrolled, 1842 cases and 1862 controls. Data show that lung cancer risk increases with radon exposure, finding a significant association of radon exposure with lung cancer at radon exposures above 50 Bq/m³. The estimated adjusted OR for individuals exposed to concentrations >200 Bq/m³ was 2.06 (95% CI: 1.61-2.64) compared with those exposed to ≤50 Bq/m³. Within a smoking category, lung cancer risk increases markedly as radon concentration increases, reaching an OR of 29.3 (95% CI: 15.4-55.7) for heavy smokers exposed to more than 200 Bq/m.³ CONCLUSIONS: This study confirms that residential radon exposure is a risk factor for lung cancer well below action levels established by international organizations. As expected, there is also an effect modification between radon exposure and tobacco consumption.

A retrospective study of the relationship between the pathologic subtype and lymph node metastasis of lung adenocarcinomas of ≤3 cm diameter

To analyze the relationship between pathologic subtype and lymph node metastasis for lung adenocarcinomas of ≤3 cm diameter.We retrospectively studied 384 patients with operable lung adenocarcinomas of ≤3 cm diameter that had been radically resected by lobectomy or anatomic segmentectomy with systematic nodal dissection, at the Fujian Medical University Union Hospital between March 2014 and March 2016.Lymph node metastasis pN1 + pN2 (pN+) was found in 2 of 104 (1.9%) patients with tumor diameter ≤1.0 cm, 12 of 159 (7.5%) patients with tumor diameter >1.0 cm but ≤2.0 cm, and 35 of 121 (28.9%) patients with tumor size >2.0 cm but ≤3.0 cm (P < .01). Lymph node metastasis pN+ was found in 19 of 53 (35.8%) patients with visceral invasion pleural (VIP) and 30 of 331 (9.0%) patients without VIP (P < .05). It was also found in 16 of 51 (31.3%) patients with high serum CEA concentrations and 28 of 297 (9.4%) patients with normal concentrations (P < .05). In a multivariate analysis, tumor diameter, VIP, high serum CEA concentration, and pathologic subtype were significant risk factors. The prevalences of lymph node metastasis pN+ were: 0.0% (0/2), 0.0% (0/89), 3.2% (1/31), 16.2% (34/209), 7.7% (1/13), 46.7% (7/15), 100% (4/4), and 11.8% (2/17) for adenocarcinoma in situ (AIS); minimally invasive adenocarcinoma (MIA); predominantly lepidic (LEP), acinar (ACI), papillary, solid (SOL), and micropapillary (MIP) tumors; and variants of invasive adenocarcinoma, respectively (P < .05). For predominant SOL and MIP tumors, the prevalences of lymph node involvement were significantly higher than for the other subtypes.We have shown that lymph node metastasis in patients with tumor diameter ≤3 cm differs according to lung adenocarcinoma subtype. AIS and MIA were not associated with lymph node metastasis; therefore, systematic nodal dissection may be unnecessary. The prevalence of lymph node metastasis rate was low for LEP, suggesting that systemic lymph node sampling is sufficient. In contrast, for other pathologic subtypes, including SOL and MIP, systematic lymph node dissection should be performed.

A practical and adaptive approach to lung cancer screening: a review of international evidence and position on CT lung cancer screening in the Singaporean population by the College of Radiologists Singapore

Lung cancer is the leading cause of cancer-related death around the world, being the top cause of cancer-related deaths among men and the second most common cause of cancer-related deaths among women in Singapore. Currently, no screening programme for lung cancer exists in Singapore. Since there is mounting evidence indicating a different epidemiology of lung cancer in Asian countries, including Singapore, compared to the rest of the world, a unique and adaptive approach must be taken for a screening programme to be successful at reducing mortality while maintaining cost-effectiveness and a favourable risk-benefit ratio. This review article promotes the use of low-dose computed tomography of the chest and explores the radiological challenges and future directions.

Indoor PM2.5, tobacco smoking and chronic lung diseases: A narrative review

The lung is one of the most important organs exposed to environmental agents. People spend approximately 90% of their time indoors, and risks to health may thus be greater from exposure to poor air quality indoors than outdoors. Multiple indoor pollutants have been linked to chronic respiratory diseases. Environmental tobacco smoke (ETS) is known as an important source of multiple pollutants, especially in indoor environments. Indoor PM_2.5 (particulate matter with aerodynamic diameter < 2.5 μm) was reported to be the most reliable marker of the presence of tobacco smoke. Recent studies have demonstrated that PM_2.5 is closely correlated with chronic lung diseases. In this paper, we reviewed the relationship of tobacco smoking and indoor PM_2.5 and the mechanism that underpin the link of tobacco smoke, indoor PM_2.5 and chronic lung diseases.

Lung cancer risk and do-it-yourself activities. A neglected risk factor for lung cancer

BACKGROUND

The aim of this study was to assess the relationship between do-it-yourself activities entailing the exposure to carcinogenic substances and the risk of lung cancer.

METHODS

We pooled individual data from different case-control studies conducted in Northwestern Spain which investigated residential radon and lung cancer. Cases had an anatomopathologically confirmed primary lung cancer and controls were selected at the pre-surgery unit with uncomplicated surgeries. Both cases and controls were older than 30 years with no previous cancer history. All participants were interviewed face-to-face using a specific questionnaire. Painting, model building, furniture refinishing and woodworking or home carpentry were the do-it-yourself activities considered risky due to exposure to carcinogenic agents.

RESULTS

We included 1528 cases and 1457 controls. Practicing do-it-yourself risk activities was more frequent among cases: 16.0% were exposed to carcinogenic exposures during leisure time, compared to 11.8% for controls. The overall adjusted OR for lung cancer risk among individuals who practiced do-it-yourself risk activities, was 1.77 (95% CI: 1.36-2.31); this was 2.17 (95% CI: 1.51-3.11) when the analysis was restricted to individuals who performed these activities for at least 10 years. These risks were greater when the analyses were carried out exclusively among never-smokers, with the respective ORs being 2.04 (95% CI: 1.38-3.01) and 3.10 (95% CI: 1.78-5.40).

CONCLUSION

These results support the hypothesis that do-it-yourself activities involving exposure to certain carcinogens are associated with an increased risk of lung cancer, both in ever and never-smokers.

Elemental and mutational analysis of lung tissue in lung adenocarcinoma patients

Background

This study aimed to observe the association between trace element concentrations in lung tissue from lung adenocarcinoma cancer (LADC) patients and mutations in the epidermal growth factor receptor (EGFR) and KRAS genes.

Methods

LADC patients who had undergone lung resection were included in this study. Furthermore, twenty patients without lung cancer were included in this study as the control group. Samples were separately collected from both tumor and peritumor tissues. The mutational status was assessed for EGFR mutations, ALK rearrangements and KRAS mutations. Based on these analyses, patients were grouped into three groups: EGFR mutation, KRAS mutation and wild-type groups. The concentrations of various trace elements in the lung tissues were measured by a particle-induced X-ray emission (PIXE) system, and the results were analyzed for statistical significance.

Results

A total of 110 LADC patients were included in this study. The median age was 70 years, and 60% of the participants were female. Moreover, 18% and 20% of patients were EGFR- and KRAS-positive, respectively. Thirty-two trace elements were measured, and 18 trace elements were detectable. The concentrations of Fe, Co, Ni, Cu, Zn and Br were significantly higher in the KRAS mutation and wild-type groups than in the control group regardless of whether the samples were from tumor or peritumor tissues. For these 6 trace elements, the concentrations were significantly higher in smokers than in non-smokers. Considering the effect of smoking, differences in the trace element concentrations between each mutational group remained.

Conclusions

Trace elements in the lung may play a role in development of LADC in both smokers and never-smokers. However, prospective studies with larger sample sizes are needed to support this hypothesis.

Correlation Study of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Pathological Subtypes of Invasive Lung Adenocarcinoma and Prognosis

Purpose: To investigate the correlation between ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) metabolic parameters and clinicopathological factors in pathological subtypes of invasive lung adenocarcinoma and prognosis.

Patients and Methods: Metabolic parameters and clinicopathological factors from 176 consecutive patients with invasive lung adenocarcinoma between August 2008 and August 2016 who underwent ¹⁸F-FDG PET/CT examination were retrospectively analyzed. Invasive lung adenocarcinoma was divided into five pathological subtypes:lepidic predominant adenocarcinoma (LPA), acinar predominant adenocarcinoma (APA), papillary predominant adenocarcinoma (PPA), solid predominant adenocarcinoma (SPA), and micropapillary predominant adenocarcinoma (MPA). The differences in metabolic parameters [maximal standard uptake value (SUVmax), mean standard uptake value (SUVmean), total lesion glycolysis (TLG), and metabolic tumor volume (MTV)] and tumor diameter for different pathological subtypes were analyzed. Patients were divided into two groups according to their prognosis: good prognosis group (LPA, APA, PPA) and poor prognosis group (SPA, MPA). Logistic regression was used to filter predictors and construct a predictive model, and areas under the receiver operating curve (AUC) were calculated. Cox regression analysis was performed on prognostic factors.

Results: 82 (46.6%) females and 94 (53.4%) males of patients with invasive lung adenocarcinoma were enrolled in this study. Metabolic parameters and tumor diameter of different pathological subtype had statistically significant (P < 0.05). The predictive model constructed using independent predictors (Distant metastasis, Ki-67, and SUVmax) had good classification performance for both groups. The AUC for SUVmax was 0.694 and combined with clinicopathological factors were 0.745. Cox regression analysis revealed that Stage, TTF-1, MTV, and pathological subtype were independent risk factors for patient prognosis. The hazard ratio (HR) of the poor prognosis group was 1.948 (95% CI 1.042–3.641) times the good prognosis group. The mean survival times of good and poor prognosis group were 50.2621 (95% CI 47.818–52.706) and 35.8214 (95% CI 27.483–44.159) months, respectively, while the median survival time was 47.00 (95% CI 45.000–50.000) and 31.50 (95% CI 23.000–49.000) months, respectively.

Conclusion: PET/CT metabolic parameters combined with clinicopathological factors had good classification performance for the different pathological subtypes, which may provide a reference for treatment strategies and prognosis evaluation of patients.

Radiomic signature: a non-invasive biomarker for discriminating invasive and non-invasive cases of lung adenocarcinoma

Purpose

We aimed to assess the classification performance of a computed tomography (CT)-based radiomic signature for discriminating invasive and non-invasive lung adenocarcinoma.

Patients and Methods

A total of 192 patients (training cohort, n=116; validation cohort, n=76) with pathologically confirmed lung adenocarcinoma were retrospectively enrolled in the present study. Radiomic features were extracted from preoperative unenhanced chest CT images to build a radiomic signature. Predictive performance of the radiomic signature were evaluated using an intra-cross validation cohort. Diagnostic performance of the radiomic signature was assessed via receiver operating characteristic (ROC) analysis.

Results

The radiomic signature consisted of 14 selected features and demonstrated good discrimination performance between invasive and non-invasive adenocarcinoma. The area under the ROC curve (AUC) for the training cohort was 0.83 (sensitivity, 0.84 ; specificity, 0.78; accuracy, 0.82), while that for the validation cohort was 0.77 (sensitivity, 0.94; specificity, 0.52 ; accuracy, 0.82).

Conclusion

The CT-based radiomic signature exhibited good classification performance for discriminating invasive and non-invasive lung adenocarcinoma, and may represent a valuable biomarker for determining therapeutic strategies in this patient population.

Iron accumulation in tumor-associated macrophages marks an improved overall survival in patients with lung adenocarcinoma

Iron-loaded tumor-associated macrophages (iTAMs) show a pro-inflammatory phenotype, hallmarked by anti-tumorigenic activity and an ability to attenuate tumor growth. Here we explored the relevance of these findings in lung cancer patients by investigating the impact of the iTAM content in the tumor microenvironment (TME) on patient survival. We analyzed 102 human non-small cell lung cancer (NSCLC) paraffin-embedded archival tissue samples for iron levels and macrophage numbers. Interestingly, patients with lung adenocarcinoma accumulating iron in the TME show higher numbers of M1-like pro-inflammatory TAMs and a survival advantage compared to iron-negative patients. By contrast, in patients with lung squamous cell carcinoma iron in the TME does not affect survival, suggesting a unique influence of iron on different histological subtypes of non-small cell lung cancer (NSCLC). We conclude that in lung adenocarcinoma iron may serve as a prognostic marker for patient survival and as a potential therapeutic target for anti-cancer therapy.

Unique profiles of targetable genomic alterations and prognosis in young Chinese patients with lung adenocarcinoma

OBJECTIVE

Lung adenocarcinoma in young patients is a rare entity, and the targetable genomic alterations (GAs) are poorly studied. In other cancers, it has been demonstrated that young age defines unique disease biology. Here, the association of young age with GAs and prognosis is studied in a large cohort of Chinese patients.

METHODS

We retrospectively screened 1000 consecutive patients, and identified 181 patients aged 40 years or younger. GAs were identified by next-generation sequencing (NGS) assay. The clinical and genetic characteristics were analyzed.

RESULTS

Among younger group, 167(92.3%) patients were diagnosed with advanced-stage adenocarcinoma, 98(54.1%) were female, 27(14.9%) were smokers, and the median age was 35 years. Targetable GAs which were significantly more common in the younger population (P <  0.001), were associated with young age (P < 0.05). The frequency of ALK translocations, EGFR and KRAS mutations was 37.6%, 34.3% and 6.1%, respectively. Younger patients had a higher prevalence of rare GAs including HER2, ROS1 and MET (P < 0.05). Prognosis for younger patients was similar (median OS of patients with GAs, 23.91 vs 23.67 months, P >  0.05) or better than that for older population (median OS of patients without GAs, 44.28 vs 41.88 months, P <  0.05) according to GAs. Therapy modality was an independent prognostic factor (P <  0.05), and 83% of death rate decreased if given preferred therapy.

CONCLUSION

Younger patients with lung adenocarcinoma had unique prevalence of targetable GAs. Comprehensive genotyping including NGS is recommended for personalized therapy and prognosis evaluation in this population.

Nanotechnology in the diagnosis and treatment of lung cancer

Lung cancer is an umbrella term for a subset of heterogeneous diseases that are collectively responsible for the most cancer-related deaths worldwide. Despite the tremendous progress made in understanding lung tumour biology, advances in early diagnosis, multimodal therapy and deciphering molecular mechanisms of drug resistance, overall curative outcomes remain low, especially in metastatic disease. Nanotechnology, in particular nanoparticles (NPs), continue to progressively impact the way by which tumours are diagnosed and treated. The unique physicochemical properties of materials at the nanoscale grant access to a diverse molecular toolkit that can be manipulated for use in respiratory oncology. This realisation has resulted in several clinically approved NP formulations and many more in clinical trials. However, NPs are not a panacea and have yet to be utilised to maximal effect in lung cancer, and medicine in a wider context. This review serves to: describe the complexity of lung cancer, the current diagnostic and therapeutic environment, and highlight the recent advancements of nanotechnology based approaches in diagnosis and treatment of respiratory malignancies. Finally, a brief outlook on the future directions of nanomedicine is provided; presently the full potential of the field is yet to be realised. By gleaning lessons and integrating advancements from neighbouring disciplines, nanomedicine can be elevated to a position where the current barriers that stymie full clinical impact are lifted.

Differential Effect of Smoking on Gene Expression in Head and Neck Cancer Patients

Smoking is a well-known behavior that has an important negative impact on human health, and is considered to be a significant factor related to the development and progression of head and neck squamous cell carcinomas (HNSCCs). Use of high-dimensional datasets to discern novel HNSCC driver genes related to smoking represents an important challenge. The Cancer Genome Atlas (TCGA) analysis was performed in three co-existing groups of HNSCC in order to assess whether gene expression landscape is affected by tobacco smoking, having quit, or non-smoking status. We identified a set of differentially expressed genes that discriminate between smokers and non-smokers or based on human papilloma virus (HPV)16 status, or the co-occurrence of these two exposome components in HNSCC. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways classification shows that most of the genes are specific to cellular metabolism, emphasizing metabolic detoxification pathways, metabolism of chemical carcinogenesis, or drug metabolism. In the case of HPV16-positive patients it has been demonstrated that the altered genes are related to cellular adhesion and inflammation. The correlation between smoking and the survival rate was not statistically significant. This emphasizes the importance of the complex environmental exposure and genetic factors in order to establish prevention assays and personalized care system for HNSCC, with the potential for being extended to other cancer types.

Next generation sequencing-based molecular profiling of lung adenocarcinoma using pleural effusion specimens

Background

Molecular profiling of non-small cell lung cancer (NSCLC) is essential for therapeutic decision-making. Pleural effusion obtained by a non-invasive, repeatable procedure may provide an opportunity for molecular profiling and thereby possibly provide information enabling targeted therapy. In this study, we aimed to evaluate the diagnostic performance of pleural effusion as a specimen for molecular analysis.

Methods

Thirty patients with paired malignant pleural effusion and thoracic biopsy specimens were included. Clinically actionable mutations were assessed using a validated targeted next generation sequencing assay. EGFR/KRAS/ALK mutation status in thoracic biopsy specimens was tested using ARMS PCR.

Results

The concordance rate between gene status identified by ARMS and next-generation sequencing (NGS) analysis in the thoracic biopsy and pleural effusion samples was 86.7% (26/30). Compared with the thoracic biopsy specimens, the diagnostic performance of pleural effusion showed a sensitivity of 92.3%, a specificity of 50.0%, and a positive predictive value of 92.3%. Therefore, cases with a low percentage of tumor cells (<5%) can successfully be used to detect actionable mutations in pleural effusion specimens.

Conclusions

These results suggest that pleural effusions are suitable specimens for oncogene mutation analysis and enable targeted therapy for patients with advanced NSCLC.

Lung cancer in never smokers from the Princess Margaret Cancer Centre

Introduction

Lung cancer in never smokers represents a distinct epidemiological, clinical, and molecular entity.

Results

Most 712 never smoking lung cancer patients were female (72%) with a median age at diagnosis of 62.2 years (18–94). Caucasians (46%), East Asians (42%), adenocarcinoma histology (87%) and presentation with metastatic disease at diagnosis (59%) were common. Of 515 patients with available archival tissue, the most common identified single mutations were EGFR (52.2%), followed by ALK (7.5%), KRAS (2.3%), TP53 (1.3%), ERBB2 (1%), BRAF (0.4%), PIK3CA (0.4%), SMAD4 (0.4%), CTNNB1 (0.2%), AKT1 (0.2%), and NRAS (0.2%); 8% tumors had multiple mutations, while 25.8% had none identified. Median overall survival (mOS) was 42.2 months (mo) for the entire cohort. Patients with mutations in their tumors had significantly better mOS (69.5 mo) when compared to those without (31.0 mo) (HR = 0.59; 95% CI: 0.44–0.79; p < 0.001). Earlier stage (p < 0.001), adenocarcinoma histology (p = 0.012), good performance status (p < 0.001) and use of targeted therapy (p < 0.001) were each independently associated with longer survival. Patients with ALK-translocation-positive tumours have significantly longer OS compared to those without any mutations (p = 0.0029) and to those with other and null mutations (p = 0.022).

Conclusions

Lung cancer in never smokers represents a distinct clinical and molecular entity characterized by a high incidence of targetable mutations and long survival.

Methods

We analyzed retrospectively the data from electronic patient records of never smokers diagnosed with lung cancer treated at the Princess Margaret Cancer Centre (Toronto) between 1988–2015 to characterize demographic and clinical features, pathology, molecular profile (using hotspot or targeted sequencing panels), treatment and survival.

Racial and Ethnic Disparities in Early-Stage Lung Cancer Survival

BACKGROUND

Black patients with lung cancer diagnosed at early stages-for which surgical resection offers a potential cure-experience worse overall survival than do their white counterparts. We undertook a population-based study to estimate the racial and ethnic disparity in death from competing causes and assessed its contribution to the gap in overall survival among patients with early-stage lung cancer.

METHODS

We collected survival time data for 105,121 Hispanic, non-Hispanic Asian, non-Hispanic black, and non-Hispanic white patients with early-stage (IA, IB, IIA, and IIB) lung cancer diagnosed between 2004 and 2013 from the Surveillance, Epidemiology, and End-Results registries. We modeled survival time using competing risk regression and included as covariates sex, age at diagnosis, race/ethnicity, stage at diagnosis, histologic type, type of surgical resection, and radiation sequence.

RESULTS

Adjusting for demographic, clinical, and treatment characteristics, non-Hispanic blacks experienced worse overall survival compared with non-Hispanic whites (adjusted hazard ratio [aHR], 1.05; 95% CI, 1.02-1.08), whereas Hispanics and non-Hispanic Asians experienced better overall survival (aHR, 0.93; 95% CI, 0.89-0.98; and aHR, 0.82; 95% CI, 0.79-0.86, respectively). Worse survival from competing causes of death, such as cardiovascular disease and other cancers-rather than from lung cancer itself-led to the disparity in overall survival among non-Hispanic blacks (adjusted relative risk, 1.07; 95% CI, 1.02-1.12).

CONCLUSIONS

Narrowing racial and ethnic disparities in survival among patients with early-stage lung cancer will rely on more than just equalizing access to surgical resection and will need to include better management and treatment of smoking-related comorbidities and diseases.

Peculiar Genes Selection: A new features selection method to improve classification performances in imbalanced data sets

High-Throughput technologies provide genomic and trascriptomic data that are suitable for biomarker detection for classification purposes. However, the high dimension of the output of such technologies and the characteristics of the data sets analysed represent an issue for the classification task. Here we present a new feature selection method based on three steps to detect class-specific biomarkers in case of high-dimensional data sets. The first step detects the differentially expressed genes according to the experimental conditions tested in the experimental design, the second step filters out the features with low discriminative power and the third step detects the class-specific features and defines the final biomarker as the union of the class-specific features. The proposed procedure is tested on two microarray datasets, one characterized by a strong imbalance between the size of classes and the other one where the size of classes is perfectly balanced. We show that, using the proposed feature selection procedure, the classification performances of a Support Vector Machine on the imbalanced data set reach a 82% whereas other methods do not exceed 73%. Furthermore, in case of perfectly balanced dataset, the classification performances are comparable with other methods. Finally, the Gene Ontology enrichments performed on the signatures selected with the proposed pipeline, confirm the biological relevance of our methodology. The download of the package with the implementation of Peculiar Genes Selection, 'PGS', is available for R users at: http://github.com/mbeccuti/PGS.

Risk factors of Lung Cancer in nonsmoker

Generally, the cause of lung cancer is attributed to tobacco smoking. But many of the new lung cancer cases have been reported in nonsmokers. Apart from smoking; air pollution, environmental exposure, mutations, and single-nucleotide polymorphisms are known to be associated with lung cancer. Improper diet, alcohol consumption, marijuana smoking, estrogen, infections with human papillomavirus (HPV), HIV, and Epstein-Barr virus are suggested to be linked with lung cancer but clear evidences to ascertain their relation is not available. This article provides a comprehensive review of various risk factors and the underlying molecular mechanisms responsible for increasing the incidence of lung cancer. The pathologic, histologic, and genetic differences exist with lung cancer among smokers and nonsmokers. A better understanding of the risk factors, differences in pathology and molecular features of lung cancer in smokers and nonsmokers and the mode of action of various carcinogens will facilitate the prevention and management of lung cancer.

Lung cancer in never-smokers - what are the differences?

INTRODUCTION

Characteristics of never-smokers with lung cancer are still not fully clarified. The aim of this study was to compare never-smokers and ever-smokers with non-small cell lung cancer (NSCLC) regarding patient and tumor characteristics.

METHODS

All consecutive newly NSCLC patients with known smoking status diagnosed between 2011 and 2015 were included in this retrospective cohort study. Clinical, histological, and molecular characteristics were compared between ever-smokers and never-smokers.

RESULTS

Of the 558 included patients, 125 (22.4%) were never-smokers. These patients were more likely to be female (74% vs. 7%, p < .001), older (67 vs. 66 years-old, p = .019), and have adenocarcinoma (93% vs. 65%, p < .001). Never-smokers took longer to seek medical care after the symptoms onset (3 vs. 2 months, p < .001), regardless of the symptoms, histological type, or gender (OR: 1.2 [1.4-2.0]). The metastatic pattern was different in never-smokers: pleural metastases were more frequent (OR: 2.1 [1.1-4.0]), regardless of the histological type and gender. Never-smokers had a higher prevalence of ALK translocations (26% vs. 4%, p < .001) and EGFR mutations (36% vs. 8%, p < .001). The type of EGFR mutation was also significantly different between groups.

CONCLUSIONS

Never-smokers with NSCLC present distinct demographic and clinical characteristics. The characteristics of tumor also differ between never-smokers and ever-smokers, which may suggest different carcinogenic pathways.

Residential radon, EGFR mutations and ALK alterations in never-smoking lung cancer cases

The aim of this study was to assess if residential radon exposure might cause EGFR mutations or ALK rearrangements in never-smokers.We designed a multicentre case-control study in a radon-prone area (Galicia, Spain); only lung cancer cases were included in the study. We obtained residential radon measurements and clinical information for all the participants. We compared the median values of residential radon between patients with EGFR mutations or ALK rearrangements versus those without them.323 patients were included. Median age was 70 years and 19.5% were males. 42 and 15% of patients were EGFR- and ALK-positive, respectively. The most frequent EGFR alterations were exon 19 deletions and exon 21 (L858R) single-point substitution mutations. ALK-positive patients were 10 years younger than ALK-negative patients. Residential radon levels were two-fold higher in patients with exon 19 deletions compared with patients with exon 21 (L858R) single-point substitution mutations (216 versus 118 Bq·m^-3; p=0.057). There were no differences in residential radon levels by EGFR mutation status. ALK-positive patients (n=12) essentially had two-fold residential radon levels compared with ALK-negative patients (290 versus 164 Bq·m^-3, respectively).Residential radon may have a role in the molecular signature of lung cancer in never-smokers, although more studies with larger sample sizes are needed to support this hypothesis.

Early Events in the Molecular Pathogenesis of Lung Cancer

The majority of cancer-related deaths in the United States and worldwide are attributed to lung cancer. There are more than 90 million smokers in the United States who represent a significant population at elevated risk for lung malignancy. In other epithelial tumors, it has been shown that if neoplastic lesions can be detected and treated at their intraepithelial stage, patient prognosis is significantly improved. Thus, new strategies to detect and treat lung preinvasive lesions are urgently needed in order to decrease the overwhelming public health burden of lung cancer. Limiting these advances is a poor knowledge of the earliest events that underlie lung cancer development and that would constitute markers and targets for early detection and prevention. This review summarizes the state of knowledge of human lung cancer pathogenesis and the molecular pathology of premalignant lung lesions, with a focus on the molecular premalignant field that associates with lung cancer development. Lastly, we highlight new approaches and models to study genome-wide alterations in human lung premalignancy in order to facilitate the discovery of new markers for early detection and prevention of this fatal disease. Cancer Prev Res; 9(7); 518-27. ©2016 AACR.

Advances in EGFR as a Predictive Marker in Lung Adenocarcinoma

BACKGROUND

Worldwide, lung cancer is the most common cause of mortality. Toxins from tobacco smoke are known to increase the risk of lung cancer; however, up to 15% of lung cancer-related deaths in men and up to 50% of lung cancer-related deaths in women occur in people who do not smoke. Despite the fact that chemotherapy generally provides a survival benefit for non-small-cell lung cancer, not every patient will respond to therapy and many experience therapy-related adverse events. Thus, predictive markers are used to determine which patients are more likely to respond to a given regimen.

METHODS

We reviewed the current medical literature in English relating to predictive markers that may be positive, such as the presence of an activating EGFR mutation.

RESULTS

The advances in using EGFR as a molecular predictive marker were summarized. This biomarker influences therapeutic response in patients with lung adenocarcinoma. Clinical evidence supporting its value is also reviewed.

CONCLUSIONS

The use of EGFR as a predictive factor in lung adenocarcinoma may help target therapy to individual tumors to achieve the best likelihood for long-term survival and to avoid adverse events from medications unlikely to be effective.

The performance of NLST screening criteria in Asian lung cancer patients

BACKGROUND

Screening high-risk individuals with low dose CT decreased lung cancer mortality in the National Lung Screening Trial (NLST), but the validity of directly extrapolating these results to an Asian population is unclear. Using statistical models on Surveillance, Epidemiology and End Result (SEER) data, 27% of lung cancer patients in the United States were estimated to meet the screening criteria. This study aims to evaluate the performance of the NLST criteria in Asian lung cancer patients and to examine the characteristics of those who did not meet the criteria.

METHODS

We conducted a retrospective study of Asian lung cancer patients treated at Maimonides Cancer Center between 1/2008 and 6/2013. Data on demographics, smoking history, cancer stage, histology, and EGFR/ALK mutation status were collected and analyzed.

RESULTS

Of 116 eligible patients, 75 patients (65%) were smokers which included 26 light smokers (22%). Thirty-two patients (27.8%) met the NLST criteria. Extending the age limit to 79 would cover 8% more patients while removing the lower age limit would only cover 2% more. None of the female patients met the criteria as they were all never or light smokers. Two-thirds of male patients younger than age 55 were never or light smokers. The EGFR mutation rate was 67% in female and 28% in male patients.

CONCLUSION

The percentage of Asian patients meeting the NLST criteria is similar to that estimated for the United States population, suggesting that extension of the criteria to an Asian population is valid. One-third of the patients were non-smokers and an additional one-fourth were light smokers, comprised mostly of female and young male patients. Further strategies for screening these individuals based on non-tobacco factors are urgently needed.

Association between the COMT 158 G/A polymorphism and lung cancer risk: a meta-analysis

Catechol-O-methyltransferase (COMT) 158 G/A gene polymorphism seem to associate with lung cancer, but the results are inconclusive. This meta-analysis aims to investigate the association between COMT 158 G/A gene polymorphism and lung cancer susceptibility. We searched PubMed, Embase, China National Knowledge Infrastructure (CNKI), VIP Chinese science and technology periodical database (VIP) and Wanfang databases up to March 25, 2015 for articles on the connection between the COMT 158 G/A polymorphism and the risk of lung cancer. Pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were used to estimate the connection. STATA (Version 12.0) was adopted for data analysis. Overall, 6 articles of 7 studies including 2,293 cases and 2,768 controls were included in our meta-analysis. In general analysis, no significant association was found between COMT 158 G/A polymorphism and the risk of lung cancer (AA + AG vs. GG: OR 1.14, 95% CI 0.90-1.44, P=0.28). However, in subgroup analysis of different method of genotyping, we found significant increase of lung cancer risk (OR 1.30, 95% CI 1.04-1.62, I(2)=61.5%, P=0.02), also there was significant association between COMT 158 G/A polymorphism and the risk of lung cancer in Chinese non-smoker women of unsorted cancer type (OR 1.48, 95% CI 1.24-1.77, I(2)=0%, P=0.00). The study indicates that COMT 158 G/A G->A gene transition might contribute to lung cancer, especially in Chinese non-smoker women.

The hypoxic tumor microenvironment: driving the tumorigenesis of non-small-cell lung cancer

Since the application of molecular biology in cancer biology, lung cancer research has classically focused on molecular drivers of disease. One such pathway, the hypoxic response pathway, is activated by reduced local oxygen concentrations at the tumor site. Hypoxia-driven gene and protein changes enhance epithelial-to-mesenchymal transition, remodel the extracellular matrix, drive drug resistance, support cancer stem cells and aid evasion from immune cells. However, it is not the tumor cells alone which drive this response to hypoxia, but rather their interaction with a complex milieu of supporting cells. This review will focus on recent advances in our understanding of how these cells contribute to the tumor response to hypoxia in non-small-cell lung cancer.

Pathogenic mechanisms of lung adenocarcinoma in smokers and non-smokers determined by gene expression interrogation

Cigarette smoking is the leading risk factor for lung cancer, which accounts for the highest number of cancer-related mortalities worldwide in men and women. Individuals with a history of smoking are 15-30 times more likely to develop lung cancer compared with those who do not smoke. However, our understanding of the underlying molecular mechanisms that contribute to lung tumorigenesis in smokers versus non-smokers remains incomplete. In order to investigate such mechanisms, the present study aimed to systemically interrogate microarray datasets from tumor biopsies and matching normal tissues from stage I and II lung adenocarcinoma patients who had never smoked or were current smokers. The gene expression analysis identified 422 (99 upregulated and 323 downregulated) and 534 (174 upregulated and 360 downregulated) differentially-expressed genes from the never-smokers and current smokers, respectively, and the two groups shared 277 genes that exhibited similar trends of alteration. These genes encode regulators that are involved in a variety of cellular functions, including collagen metabolism and homeostasis of caveolae plasma membranes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes characterization indicated that biological pathways, including extracellular matrix-receptor interaction and cell migration and proliferation, were all affected in the lung cancer patients regardless of the smoking status. However, smoking induced a unique gene expression pattern characterized by upregulation of cell cycle regulators (CDK1, CCNB1 and CDC20), as well as significantly affected biological networks, including p53 signaling pathways. Taken together, these findings suggest novel mechanistic insights, and provide an improved understanding of the smoking-induced molecular alterations that contribute to the pathogenesis of lung adenocarcinoma.

Timeliness of Diagnosing Lung Cancer: Number of Procedures and Time Needed to Establish Diagnosis: Being Right the First Time

To study number of procedures and time to diagnose lung cancer and factors affecting the timeliness of clinching this diagnosis. Retrospective cohort study of lung cancer patients who consecutively underwent diagnostic bronchoscopy in 1 year (October 2013 to September 2014). Out of 101 patients diagnosed with lung cancer from bronchoscopy, average time interval between first abnormal computed tomogram (CT) scan-to-1st procedure, 1st procedure-to-diagnosis, and 1st abnormal CT scan-to-diagnosis was 16 ± 26, 11 ± 19, and 27 ± 33 days, respectively. These intervals were significantly longer in those requiring repeat procedures. Multivariate analysis revealed inconclusive 1st procedure to be the predictor of prolonged (>30 days) CT scan to diagnosis time (P = 0.04). Twenty-nine patients (28.7%) required repeat procedures (n = 63). Reasons behind repeating the procedures were inadequate procedure (n = 14), inaccessibility of lesion (n = 9), inappropriate procedure (n = 5), mutation analysis (n = 2), and others (n = 2). Fifty had visible endo-bronchial lesion, 20 had positive bronchus sign, and 83 had enlarged mediastinal/hilar lymph-nodes or central masses adjacent to the airways. Fewer procedures, and shorter procedure to diagnosis time, were observed in those undergoing convex probe endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) (P = 0.04). Most patients exhibit enlarged mediastinal lymph node or mass adjacent to the central airway accessible by convex probe EBUS-TBNA. Hence, combining it with conventional bronchoscopic techniques such as bronchoalveolar lavage, brush, and forceps biopsy increases detection rate, and reduces number of procedures and time to establish diagnosis. This may translate into cost and resource savings, timeliness of diagnosis, greater patient satisfaction, and conceivably better outcomes.

Identification of Genetic Mutations in Human Lung Cancer by Targeted Sequencing

Lung cancer remains the most prevalent malignancy and the primary cause of cancer-related deaths worldwide. Unique mutations patterns can be found in lung cancer subtypes, in individual cancers, or within a single tumor, and drugs that target these genetic mutations and signal transduction pathways are often beneficial to patients. In this study, we used the Ion Torrent AmpliSeq Cancer Panel to sequence 737 loci from 45 cancer-related genes and oncogenes to identify genetic mutations in 48 formalin-fixed, paraffin-embedded (FFPE) human lung cancer samples from Chinese patients. We found frequent mutations in EGFR, KRAS, PIK3CA, and TP53 genes. Moreover, we observed that a portion of the lung cancer samples harbored two or more mutations in these key genes. This study demonstrates the feasibility of using the Ion Torrent sequencing to efficiently identify genetic mutations in individual tumors for targeted lung cancer therapy.

Association of TERT Polymorphisms with Clinical Outcome of Non-Small Cell Lung Cancer Patients

TERT is of great importance in cancer initiation and progression. Many studies have demonstrated the TERT polymorphisms as risk factors for many cancer types, including lung cancer. However, the impacts of TERT variants on cancer progression and treatment efficacy have remained controversial. This study aimed to investigate the association of TERT polymorphisms with clinical outcome of advanced non-small cell lung cancer (NSCLC) patients receiving first-line platinum-based chemotherapy, including response rate, clinical benefit, progression-free survival (PFS), overall survival (OS), and grade 3 or 4 toxicity. Seven polymorphisms of TERT were assessed, and a total of 1004 inoperable advanced NSCLC patients treated with platinum-based chemotherapy were enrolled. It is exhibited that the variant heterozygote of rs4975605 showed significant association with a low rate of clinical benefit, and displayed a much stronger effect in never-smoking female subset, leading to the clinical benefit rate decreased from 82.9% (C/C genotype) to 56.4% (C/A genotype; adjusted OR, 3.58; P=1.40×10(-4)). It is also observed that the polymorphism rs2736109 showed significant correlation with PFS (log-rank P=0.023). In age > 58 subgroup, patients carrying the heterozygous genotype had a longer median PFS than those carrying the wild-type genotypes (P=0.002). The results from the current study, for the first time to our knowledge, provide suggestive evidence of an effect of TERT polymorphisms on disease progression variability among Chinese patients with platinum-treated advanced NSCLC.

A family history of cancer and lung cancer risk in never-smokers: A clinic-based case-control study

OBJECTIVE

Some population-based studies involving lung cancer patients have reported that inherited susceptibility is responsible for the familial aggregation observed in non-smoking lung cancer patients; however, it has been found that the false-negative rates in clinic-ascertained probands are significantly lower than population-ascertained probands. In this clinic-based study, we sought to determine the relationship between a family history of cancer and lung cancer risk in Chinese never-smokers.

METHODS

In this clinic-based case-control study, all 318 probands and 509 controls were Chinese. The data on demographic characteristics, age, gender, race, lung disease history, living environment, occupational exposure, and smoking history were collected from a structured questionnaire. Multiple conditional logistic regression was used to estimate adjusted odds ratios (aOR) and 95% CIs after adjusting for possible confounders.

RESULTS

The risk of lung cancer was increased in individuals with a family history of lung (aOR, 3.21; p<0.001) or any other cancer (aOR, 1.79; p<0.001). Analyses were carried out using stratified relative gender; first-degree female relatives tended to have a higher risk than first-degree male relatives. Similarly, the aOR for a female developing a malignant tumor was two times greater than controls.

CONCLUSIONS

Our analysis provides further evidence of the importance of genetic factors underlying lung cancer in patients who are never-smokers, especially in patients with a maternal history of cancer.