No impact of passive smoke on the somatic profile of lung cancers in never-smokers

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

Unveiling the metal mutation nexus: Exploring the genomic impacts of heavy metal exposure in lung adenocarcinoma and colorectal cancer

Mutations that activate oncogenes and deactivate tumor suppressor genes are widely recognized as significant contributors to cancer development. We investigated relationships between heavy metal exposure and the frequencies and types of gene mutations in patients with lung adenocarcinoma (LUAD) and colorectal cancer (CRC). Plasma concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) were measured using inductively coupled plasma mass spectrometry (ICPMS), and next-generation sequencing (NGS) of 1123 cancer-related genes was performed using the tumor tissues. Through Bayesian kernel machine regression (BKMR) analysis, we found associations between the integrated concentrations of the heavy metals and the number of gene mutations, especially insertions/deletions (indels), and Pb, As, and Cd were found to be the most significant contributors to the increased mutation rates. We extracted previously established mutational signatures and observed that they exhibit significant correlations with metal exposure. Moreover, we detected substantial shifts in the mutational landscape when comparing groups with high and low metal exposures. Several frequently mutated genes displayed positive correlations with metal exposure, whereas EGFR indels showed a negative association with Cd exposure. These findings suggest that heavy metal exposure can impact genomic stability in cancer-related genes, underscoring the importance of heavy metal exposure in cancer development.

Lung cancer trends and tumor characteristic changes over 20 years (2000–2020): Results of three French consecutive nationwide prospective cohorts’ studies

Background

Long-term changes in lung cancer (LC) patients are difficult to evaluate. We report results from the French KBP-2020 real-life cohort.

Methods

KBP-2020 was a prospective cohort that included all patients diagnosed with LC in 2020, in nonacademic public hospital in France. Patient and tumour characteristics were described and compared with similarly designed cohorts in 2000 and 2010.

Findings

In 2020, 82 centers included 8,999 patients diagnosed with LC. The proportion of women increased: 34·6% (3114/8999) compared to, 24·3% (1711/7051) and 16·0% (904/5667) in 2010 and 2000 (p<0·0001). The proportion of non-smokers was higher in 2020 (12·6%, 1129/8983) than in previous cohorts (10·9% (762/7008) in 2010; 7·2% (402/5586) in 2000, p<0·0001). In 2020, at diagnosis, 57·6% (4405/7648) of patients had a metastatic/disseminated stage non-small-cell lung cancer (NSCLC) (58·3% (3522/6046) in 2010; 42·6% (1879/4411) in 2000, p<0·0001). Compared with 2000 and 2010 data, early survival improved slightly. In 2020, 3-month mortality of NSCLC varied from 3·0% [2·2 – 3·8] for localized to 9·6% [8·1 – 11·0] for locally advanced to 29·2% [27·8 – 30·6] for metastatic and was 24·8% [22·3 – 27·3] for SCLC.

Interpretation

To our knowledge KBP cohorts have been the largest, prospective, real-world cohort studies involving LC patients conducted in worldwide. The trend found in our study shows an increase in LC in women and still a large proportion of patients diagnosed at metastatic or disseminated stage.

Funding

The study was promoted by the French College of General Hospital Pulmonologists with financial support of industrials laboratories.

Ambient Cumulative PM2.5 Exposure and the Risk of Lung Cancer Incidence and Mortality: A Retrospective Cohort Study

Smoking, sex, air pollution, lifestyle, and diet may act independently or in concert with each other to contribute to the different outcomes of lung cancer (LC). This study aims to explore their associations with the carcinogenesis of LC, which will be useful for formulating further preventive strategies. This retrospective, longitudinal follow-up cohort study was carried out by connecting to the MJ Health Database, Taiwan Cancer Registry database, and Taiwan cause of death database from 2000 to 2015. The studied subjects were persons attending the health check-ups, distributed throughout the main island of Taiwan. Cox proportional hazards regression models were used to investigate the risk factors associated with LC development and mortality after stratifying by smoking status, with a special emphasis on ambient two-year average PM_2.5 exposure, using a satellite-based spatiotemporal model at a resolution of 1 km², and on dietary habit including consumption of fruits and vegetables. After a median follow-up of 12.3 years, 736 people developed LC, and 401 people died of LC-related causes. For never smokers, the risk of developing LC (aHR: 1.32, 95%CI: 1.12–1.56) and dying from LC-related causes (aHR: 1.28, 95%CI: 1.01–1.63) rises significantly with every 10 μg/m³ increment of PM_2.5 exposure, but not for ever smokers. Daily consumption of more than two servings of vegetables and fruits is associated with lowering LC risk in ever smokers (aHR: 0.68, 95%CI: 0.47–0.97), and preventing PM_2.5 exposure is associated with lowering LC risk for never smokers.

Second-Hand Smoke and Its Synergistic Effect with a Body-Mass Index of >24.9 kg/m2 Increase the Risk of Gout Arthritis in Indonesia

To analyze the association between smoking status (active smoking and exposure to Second-Hand Smoking (SHS)) and the synergistic effect of smoking status and BMI with gout risk, a community-based case-control design was undertaken among 385 participants, including 304 healthy controls and 81 gout patients from seven community health services. Adjusted Odd Ratios (AORs) and 95% Confidence Interval (CIs) of gout for active smoking and SHS were 3.26 (95% CI = 1.07~9.90) and 4.67 (95% CI = 2.18~10.00) compared to non-smokers. Time-dependent manner of active smoking and SHS significantly increased gout risk with AORs and 95% CIs of 5.95 (1.41~25.03) and 10.12 (3.51~29.14). Dose-dependency of active smokers and SHS showed AORs and 95% CIs of 5.15 (1.28~20.63) and 4.37 (1.33~14.28). Smoking 20 cigarettes (one pack) per day for one year is equivalent to one pack-year. Active smoking >20 pack-year and SHS > 26.5 pack-year increased gout risk with AORs and 95% CIs of 7.18 (1.53~33.67) and 9.95 (3.64~27.22). Participants who smoked (active smoking and SHS) and with Body Mass Index (BMI) of > 24.9 kg/m2 synergistically increased gout risk, with an AOR of 9.65 and 95% CI of 3.25~28.65, compared to BMI ≤ 24.9 kg/m2 and non-smoker. Smoking status (active smoking and SHS) and the synergistic effect of smoking status and BMI increased gout risk in Indonesia.

Somatic profile in lung cancers is associated to reproductive factors in never-smokers women: Results from the IFCT-1002 BioCAST study

BACKGROUND

Lung cancer in women is on the rise, with a higher proportion occurring in lifelong never-smokers. Lung cancer in never-smokers (LCINS) exhibits a high frequency of driver oncogene alterations. In this study, we aimed to investigate whether exposure to reproductive factors in women with LCINS may modulate the molecular pattern.

METHODS

All newly diagnosed LCINSs were included in a prospective, observational study (IFCT-1002 BioCAST). Each patient responded to a questionnaire including reproductive factors. Biomarker test results were also collected.

RESULTS

Two hundred and sixty women were included in this analysis, and 166 alterations were characterized. EGFR mutation frequency proved greater among patients with late menarche (74% in age>14 vs. 40% and 41% for 12-14 and ≤12 years, respectively; P=0.020) and tended to decrease with increasingly late age at menopause. In multivariate analysis, EGFR mutation frequency increased by 23% per increment of 1 year of age at menarche (P=0.048), and by 9% for each year at age at first birth (P=0.035). ALK alteration frequency was greater in women with high parity (50% in≥5 vs. 12% and 7% for 1-4 and nulliparity, respectively; P=0.021).

CONCLUSION

In a cohort of women LCINSs, female hormonal factors appear to impact molecular pattern.

Identification of Recurrent Activating HER2 Mutations in Primary Canine Pulmonary Adenocarcinoma

PURPOSE

Naturally occurring primary canine lung cancers share clinicopathologic features with human lung cancers in never-smokers, but the genetic underpinnings of canine lung cancer are unknown. We have charted the genomic landscape of canine lung cancer and performed functional characterization of novel, recurrent HER2 (ERBB2) mutations occurring in canine pulmonary adenocarcinoma (cPAC).

EXPERIMENTAL DESIGN

We performed multiplatform genomic sequencing of 88 primary canine lung tumors or cell lines. Additionally, in cPAC cell lines, we performed functional characterization of HER2 signaling and evaluated mutation-dependent HER2 inhibitor drug dose-response.

RESULTS

We discovered somatic, coding HER2 point mutations in 38% of cPACs (28/74), but none in adenosquamous (cPASC, 0/11) or squamous cell (cPSCC, 0/3) carcinomas. The majority (93%) of HER2 mutations were hotspot V659E transmembrane domain (TMD) mutations comparable to activating mutations at this same site in human cancer. Other HER2 mutations were located in the extracellular domain and TMD. HER2 ^V659E was detected in the plasma of 33% (2/6) of dogs with localized HER2 ^V659E tumors. HER2 ^V659E cPAC cell lines displayed constitutive phosphorylation of AKT and significantly higher sensitivity to the HER2 inhibitors lapatinib and neratinib relative to HER2-wild-type cell lines (IC₅₀ < 200 nmol/L in HER2 ^V659E vs. IC₅₀ > 2,500 nmol/L in HER2 ^WT).

CONCLUSIONS

This study creates a foundation for molecular understanding of and drug development for canine lung cancer. These data also establish molecular contexts for comparative studies in dogs and humans of low mutation burden, never-smoker lung cancer, and mutant HER2 function and inhibition.

The Relationship Between Air Pollution and Lung Cancer in Nonsmokers in Taiwan

INTRODUCTION

For never-smokers (smoked <100 lifetime cigarettes), lung cancer (LC) has emerged as an important issue. We aimed to investigate the effects of prevalence changes in tobacco smoking and particulate matter (PM) 2.5 (PM_2.5) levels on LC in Taiwan, in relation to contrasting PM_2.5 levels, between Northern Taiwan (NT) and Southern Taiwan (ST).

METHODS

We reviewed 371,084 patients with LC to assess smoking prevalence and correlations between the incidence of adenocarcinoma lung cancer (AdLC) and non-AdLC. Two subsets were selected to assess different AdLC stage trends and the effect of PM_2.5 on survival of patients with AdLC.

RESULTS

From 1995 to 2015, the proportion of male adult ever-smokers decreased from 59.4% to 29.9% whereas the female smoking rate remained low (3.2% to 5.3%). AdLC incidence in males and females increased from 9.06 to 23.25 and 7.05 to 24.22 per 100,000 population, respectively. Since 1993, atmospheric visibility in NT improved (from 7.6 to 11.5 km), but deteriorated in ST (from 16.3 to 4.2 km). The annual percent change in AdLC stages IB to IV was 0.3% since 2009 (95% confidence interval [CI]: -1.9%-2.6%) in NT, and 4.6% since 2007 (95% CI: 3.3%-5.8%) in ST; 53% patients with LC had never smoked. Five-year survival rates for never-smokers, those with EGFR wild-type genes, and female patients with AdLC were 12.6% in NT and 4.5% in ST (hazard ratio: 0.79, 95% CI: 0.70-0.90).

CONCLUSIONS

In Taiwan, greater than 50% of patients with LC had never smoked. PM_2.5 level changes can affect AdLC incidence and patient survival.

A quantitative method for assessing smoke associated molecular damage in lung cancers

BACKGROUND

While tobacco exposure is the cause of the vast majority of lung cancers, an important percentage arise in lifetime never smokers. Documenting the precise extent of tobacco induced molecular changes may be of importance. Also, the contribution of environmental tobacco smoke (ETS) is difficult to assess.

METHODS

We developed and validated a quantitative method to assess the extent of tobacco related molecular damage by combing the most characteristic changes associated with tobacco smoke, the tumor mutation burden (TMB) and type of molecular changes present in lung cancers. Using maximum entropy (MaxEnt) as a classifier, we developed a F score. F score values >0 were considered to show evidence of tobacco related molecular damage, while values ≤0 were considered to lack evidence of tobacco related molecular damage. Compared to the stated patient tobacco exposure histories, the F scores had sensitivity, specificity and accuracy values of 85-87%. Using this method, we analyzed public data sets of lung adenocarcinoma (LUAD), lung squamous cell (LUSC) and small cell lung cancer (SCLC).

RESULTS

Less than 10% of LUSCs and SCLCs had negative F scores, while 27% to 35% of LUADs had positive scores. The F score showed a highly significant downward trend when LUADs were subdivided into the following categories: ever, reformed ≤15 years, reformed >15 years and never smokers. Most of the examined bronchial carcinoids (a lung cancer type not associated with smoke exposure) had negative F scores. In addition, most LUADs with EGFR mutations had negative F scores, while almost all with KRAS mutations had positive scores.

CONCLUSIONS

We have established and validated a quantitative assay that will be of use in assessing the presence and degree of smoke associated molecular damage in lung cancers arising in ever and never smokers.

Meta-Analysis and Systematic Review in Environmental Tobacco Smoke Risk of Female Lung Cancer by Research Type

More than 50% of women worldwide are exposed to Environmental Tobacco Smoke (ETS). The impact of ETS on lung cancer remains unclear. Cohort studies since the late 1990s have provided new evidence of female lung cancer risk due to ETS. The objective of this meta-analysis and systematic review was to analyze the association of ETS with female lung cancer risk from 1997 to 2017, organised based on research design. According to our applied inclusion and exclusion criteria, 41 published studies were included. The relative risk (RR) from the cohort studies or odds ratio (OR) from case-control studies were extracted to calculate the pooled risks based on the type of study. The summary risks of ETS were further explored with the modulators of ETS exposure sources and doses. The pooled risks of lung cancer in non-smoking women exposed to ETS were 1.35 (95% CI: 1.17⁻1.56), 1.17 (95% CI: 0.94⁻1.44), and 1.33 (95% CI: 1.17⁻1.51) for case-control studies, cohort studies, and both types of studies, respectively. The summary RR estimate of the cohort studies was not statistically significant, but the RR increased with increasing doses of ETS exposure (p trend < 0.05). Based on the results of this study, ETS might be an important risk factor of female lung cancer in non-smokers.

Association between lung cancer somatic mutations and occupational exposure in never-smokers

Occupational exposure constitutes a common risk factor for lung cancer. We observed molecular alterations in 73% of never-smokers, 35% of men and 8% of women were exposed to at least one occupational carcinogen. We report herein associations between molecular patterns and occupational exposure.BioCAST was a cohort study of lung cancer in never-smokers that reported risk factor exposure and molecular patterns. Occupational exposure was assessed via a validated 71-item questionnaire. Patients were categorised into groups that were unexposed and exposed to polycyclic aromatic hydrocarbons (PAH), asbestos, silica, diesel exhaust fumes (DEF), chrome and paints. Test results were recorded for EGFR, KRAS, HER2, BRAF and PIK3 mutations, and ALK alterations.Overall, 313 out of 384 patients included in BioCAST were analysed. Asbestos-exposed patients displayed a significantly lower rate of EGFR mutations (20% versus 44%, p=0.033), and a higher rate of HER2 mutations (18% versus 4%, p=0.084). ALK alterations were not associated with any occupational carcinogens. The DEF-exposed patients were diagnosed with a BRAF mutation in 25% of all cases. Chrome-exposed patients exhibited enhanced HER2 and PIK3 mutation frequency.Given its minimal effects in the subgroups, we conclude that occupational exposure slightly affects the molecular pattern of lung cancers in never-smokers. In particular, asbestos-exposed patients have a lower chance of EGFR mutations.

Environmental tobacco smoke exposure and EGFR and ALK alterations in never smokers' lung cancer. Results from the LCRINS study

Environmental tobacco smoke (ETS) exposure is a main risk factor of lung cancer in never smokers. Epidermal Growth Factor Receptor (EGFR) mutations and ALK translocations are more frequent in never smokers' lung cancer than in ever-smokers. We performed a multicenter case-control study to assess if ETS exposure is associated with the presence of EGFR mutations and its types and if ALK translocations were related with ETS exposure. All patients were never smokers and had confirmed lung cancer diagnosis. ETS exposure during childhood showed a negative association on the probability of EGRF mutation though not significant. Exposure during adulthood, at home or at workplace, did not show any association with EGFR mutation. The mutation type L858R seemed the most associated with a lower probability of EGFR alterations for ETS exposure at home in adult life. There is no apparent association between ETS exposure and ALK translocation. These results might suggest that ETS exposure during childhood or at home in adult life could influence the EGFR mutations profile in lung cancer in never smokers, reducing the probability of presenting EFGR mutation.

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.