Influence of Cigarette Smoking on Histological Subtypes of Stage I Lung Adenocarcinoma

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.

Proteomic Analyses Identify Differentially Expressed Proteins and Pathways Between Low-Risk and High-Risk Subtypes of Early-Stage Lung Adenocarcinoma and Their Prognostic Impacts

The histopathological subtype of lung adenocarcinoma (LUAD) is closely associated with prognosis. Micropapillary or solid predominant LUAD tends to relapse after surgery at an early stage, whereas lepidic pattern shows a favorable outcome. However, the molecular mechanism underlying this phenomenon remains unknown. Here, we recruited 31 lepidic predominant LUADs (LR: low-risk subtype group) and 28 micropapillary or solid predominant LUADs (HR: high-risk subtype group). Tissues of these cases were obtained and label-free quantitative proteomic and bioinformatic analyses were performed. Additionally, prognostic impact of targeted proteins was validated using The Cancer Genome Atlas databases (n = 492) and tissue microarrays composed of early-stage LUADs (n = 228). A total of 192 differentially expressed proteins were identified between tumor tissues of LR and HR and three clusters were identified via hierarchical clustering excluding eight proteins. Cluster 1 (65 proteins) showed a sequential decrease in expression from normal tissues to tumor tissues of LR and then to HR and was predominantly enriched in pathways such as tyrosine metabolism and ECM-receptor interaction, and increased matched mRNA expression of 18 proteins from this cluster predicted favorable prognosis. Cluster 2 (70 proteins) demonstrated a sequential increase in expression from normal tissues to tumor tissues of LR and then to HR and was mainly enriched in pathways such as extracellular organization, DNA replication and cell cycle, and high matched mRNA expression of 25 proteins indicated poor prognosis. Cluster 3 (49 proteins) showed high expression only in LR, with high matched mRNA expression of 20 proteins in this cluster indicating favorable prognosis. Furthermore, high expression of ERO1A and FEN1 at protein level predicted poor prognosis in early-stage LUAD, supporting the mRNA results. In conclusion, we discovered key differentially expressed proteins and pathways between low-risk and high-risk subtypes of early-stage LUAD. Some of these proteins could serve as potential biomarkers in prognostic evaluation.

Prognostic factors including lymphovascular invasion on survival for resected non-small cell lung cancer

OBJECTIVES

The aim of this study was to report on the influence of tumor lymphovascular invasion on overall survival and in patients with resected non-small cell lung cancer and identify prognostic factors for survival.

METHODS

This is a retrospective observational study of a consecutive series of patients who had surgical resection of non-small cell lung cancer in a single institution. The study covers a 3-year period. Overall survival was estimated by Kaplan-Meier method and multivariate Cox regression analysis was used to evaluate the relationship of lymphovascular invasion and other clinicopathologic variables. A multivariate regression was used to assess the relationship between tumor lymphovascular invasion and other clinical and pathologic characteristics.

RESULTS

A total of 524 patients were identified and included in the study. Two hundred twenty-five patients (43%) had tumors with lymphovascular invasion. Patients with tumor lymphovascular invasion had a lower overall survival (P < .0001). Tumor lymphovascular invasion was independently associated with visceral pleural involvement (P < .0001). In a multivariable model, lymphovascular invasion (hazard ratio [HR], 2.58; 95% confidence interval [CI], 1.63-4.09; P < .0001), parietal pleural invasion (HR, 45.4; 95% CI, 2.08-990; P = .015), advanced age (HR, 1.028; 95% CI, 1.009-1.048; P = .004), and N2 lymph node involvement (HR, 1.837; 95% CI, 1.257-2.690; P = .002) were independent prognostic factors for lower overall survival.

CONCLUSIONS

Lymphovascular invasion is associated with a worse overall survival in patients with resected non-small cell lung cancer regardless of tumor stage. Parietal pleural involvement, N2 nodal disease, and advanced age independently predict poor overall survival.

Chemiluminescence of Cigarette Smoke: Salient Features of the Phenomenon

The study disclosed herein provides for the first time a detailed experimental support for the general mechanism of the cigarette-smoke-derived chemiluminescence, as an example par excellence of the excited-state generation in a chemically complex aerosol medium. The mechanism involves chemiexcitation in a unimolecular transformation of the smoke-borne free radical species. However, the concentration of these radicals, [r∙], obeys a bimolecular (second-order) kinetics and depends on a particulate-phase content (total particulate matter, TPM) of the cigarette smoke. The decrease in [r∙] with increasing the TPM amount manifests radical-scavenging propensity of the smoke particulate phase. Astonishingly, no energy transfer takes place from the primary excited light-emitting species to luminophoric molecules abundant in the smoke. The reported results build up fundamentals of a facile chemiluminescence assay for free radical properties of the smoke. The experimental approaches developed for this study are of general scope and may be used for mechanistic elucidation of the excited-state generation in chemical systems and environments of an arbitrary complexity.

Prognostic value of tumor-infiltrating lymphocytes differs depending on histological type and smoking habit in completely resected non-small-cell lung cancer

BACKGROUND

T-cell infiltration in tumors has been used as a prognostic tool in non-small-cell lung cancer (NSCLC). However, the influence of smoking habit and histological type on tumor-infiltrating lymphocytes (TILs) in NSCLC remains unclear.

PATIENTS AND METHODS

We evaluated the prognostic significance of TILs (CD4⁺, CD8⁺, CD20⁺, and FOXP3⁺) according to histological type and smoking habit using automatic immunohistochemical staining and cell counting in 218 patients with NSCLC.

RESULTS

In multivariate survival analyses of clinical, pathological, and immunological factors, a high ratio of FOXP3⁺ to CD4⁺ T cells (FOXP3/CD4) [hazard ratio (HR): 4.46, P < 0.01 for overall survival (OS); HR: 1.96, P < 0.05 for recurrence-free survival (RFS)] and a low accumulation of CD20⁺ B cells (HR: 2.45, P = 0.09 for OS; HR: 2.86, P < 0.01 for RFS) were identified as worse prognostic factors in patients with adenocarcinoma (AD). In non-AD, a low number of CD8⁺ T cells were correlated with an unfavorable outcome (HR: 7.69, P < 0.01 for OS; HR: 3.57, P < 0.02 for RFS). Regarding smoking habit in AD, a high FOXP3/CD4 ratio was poorly prognostic with a smoking history (HR: 5.21, P < 0.01 for OS; HR: 2.38, P < 0.03 for RFS), whereas a low accumulation of CD20⁺ B cells (HR: 4.54, P = 0.03 for OS; HR: 2.94, P < 0.01 for RFS) was confirmed as an unfavorable factor in non-smokers with AD.

CONCLUSIONS

A low number of CD8⁺ T cells in non-AD, a high FOXP3/CD4 ratio in smokers with AD, and a low number of CD20⁺ B cells in non-smokers with AD were identified as independent unfavorable prognostic factors in resected NSCLC. Evaluating the influence of histological type and smoking habit on the immunological environment may lead to the establishment of immunological diagnosis and appropriate individualized immunotherapy for NSCLC.

Nonpredominant lepidic pattern correlates with better outcome in invasive lung adenocarcinoma

OBJECTIVES

Histologic heterogeneity is a typical feature of pulmonary adenocarcinoma. This study aimed to deconstruct the intratumoral growth pattern composition and to examine the prognostic relevance of the current lung adenocarcinoma classification in a series of Finnish lung cancer patients.

MATERIALS AND METHODS

A cohort of 112 patients with surgically operated stage I-IV lung adenocarcinoma was retrospectively reviewed. Histologic subtyping was performed according to the classification system established by the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society (IASLC/ATS/ERS). Systematically collected clinical information including survival data was correlated with the subtype status. In addition, emphasis was placed on the nonpredominant histologic patterns, gender and smoking history.

RESULTS

The most common subtype was acinar predominant adenocarcinoma with 56 cases (50%). Most tumors were composed of a mixture of two or more growth patterns, and single pattern tumors were rare (9.8%). Micropapillary predominant adenocarcinoma and solid predominant adenocarcinoma were the subtypes with the lowest disease-specific survival rates (5-year DSS 21.4% and 30.4%; shared mean DSS 46.3 months, p=0.040). A nonpredominant lepidic component was observed in 24 (21.4%) tumors, and its presence predicted a better outcome (mean DSS 127.4 months vs. 55.7 months, p=0.001). This association was confirmed by multivariate analysis (p=0.004). Solid pattern and solid, papillary, micropapillary and cribriform predominant histology associated with smoking (p<0.001), while mucinous pattern was more common in nonsmokers (p<0.001) and in women (p=0.050).

CONCLUSIONS

Micropapillary and solid predominant adenocarcinomas showed significantly lower survival rate than other major subtypes, yet the prognostic value of the current lung adenocarcinoma classification is not limited only to the predominant growth patterns. The more favorable outcome associated with the nonpredominant lepidic pattern further emphasizes the importance of histologic subtyping and assessment of tumor heterogeneity in the diagnostics of lung adenocarcinoma.

Visceral pleural invasion remains a size-independent prognostic factor in stage I non-small cell lung cancer

BACKGROUND

The prognostic effect of visceral pleural invasion remains controversial when a tumor is less than 3 cm in stage I non-small cell lung cancer patients. We conducted this meta-analysis to evaluate the prognostic impact of visceral pleural invasion in these early patients.

METHODS

We searched PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure and included published studies on the prognostic significance of visceral pleural invasion in stage I non-small cell lung cancer. Meta-analysis was performed and heterogeneity and publication bias were also evaluated.

RESULTS

Twenty-two studies were included in the meta-analysis. In all stage I patients, visceral pleural invasion was associated with death (hazard ratio1.427; p = 0.000) and recurrence (hazard ratio1.600; p = 0.000). In subgroup analyses, visceral pleural invasions were consistently associated with death in each tumor size subgroup and recurrence in tumor less than 3 cm subgroup. Publication bias was not found.

CONCLUSIONS

Visceral pleural invasion is a size-independent poor prognostic factor in stage I non-small cell lung cancer patients. We suggest adjuvant treatment should be considered in stage I patients with visceral pleural invasion.

Human papillomavirus and non-small cell lung cancer

Lung cancer is the most common cause of cancer-related deaths in the world, causing more than one million deaths worldwide each year. Human papillomavirus (HPV) are small non-enveloped DNA viruses that infect squamous epithelial cells. Relevant studies have reported lung cancer-related HPV infection rates that fluctuate between 10% and 80%, depending on the various research methods and geographical factors. Various scholars gathered statistics from global research reports and found that 22.4% of the patients with lung cancer presented with an HPV infection, which suggested that HPV infection may relate to the tumorigenesis of non-small cell lung cancer. This article will review the history and discovery of HPV, the correlation between HPV and lung cancer development, and carcinogenesis caused by HPV regulatory genes, such as p53, p21, p16INK4a, and genes related to hypermethylation and genome instability in lung cancer patients with HPV infection. In addition, because studies have highlighted the difference in clinical prognosis for HPV-positive and HPV-negative patients, articles demonstrating the correlation between HPV infection and prognosis for lung cancer patients will be reviewed.

Clinical significance and role of lymphatic vessel invasion as a major prognostic implication in non-small cell lung cancer: a meta-analysis

Background

Lymphatic vessel invasion (LVI) exerts an important process in the progression and local spread of cancer cells. However, LVI as a prognostic factor for survival in non-small cell lung cancer (NSCLC) remains controversial.

Methodology/Principal Findings

A meta-analysis of published studies from PubMed and EMBASE electronic databases was performed to quantity the effects of LVI on both relapse-free survival and overall survival for patients with NSCLC. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were used to assess the strength of these effects. This meta-analysis included 18,442 NSCLC patients from 53 eligible studies. LVI appeared in 32.1% (median; range, 2.8% to 70.9%) of tumor samples. In all, patients with LVI were 2.48 times more likely to relapse by univariate analysis (95% CI: 1.92–3.22) and 1.73 times by multivariate analysis (95% CI: 1.24–2.41) compared with those without LVI. For the analyses of LVI and overall survival, the pooled HR estimate was 1.97 (95% CI: 1.75–2.21) by univariate analysis and 1.59 (95% CI: 1.41–1.79) by multivariate analysis. Multivariate analysis showed a risk was 91% higher for recurrence (HR  = 1.91, 95% CI: 1.14–2.91) and 70% higher for mortality (HR = 1.70, 95% CI: 1.38–2.10) in LVI-positive I stage patients compared with LVI-negative I stage patients. Subgroup analyses showed similar significant adjusted risks for recurrence and death in adenocarcinomas, and a significant adjusted risk for death in studies that utilized elastic staining with or without immunohistochemistry in defining LVI.

Conclusions/Significance

The present study indicates that LVI appears to be an independent poor prognosticator in surgically managed NSCLC. NSCLC patients with LVI would require a more aggressive treatment strategy after surgery. However, large, well-designed prospective studies with clinically relevant modeling and standard methodology to assess LVI are required to address some of these important issues.