Exhaled volatile organic compounds for diagnosis and monitoring of asthma.

The asthmatic inflammatory process results in the generation of volatile organic compounds (VOCs), which are subsequently secreted by the airways. The study of these elements through gas chromatography-mass spectrometry (GC-MS), which can identify individual molecules with a discriminatory capacity of over 85%, and electronic-Nose (e-NOSE), which is able to perform a quick onboard pattern-recognition analysis of VOCs, has allowed new prospects for non-invasive analysis of the disease in an "omics" approach. In this review, we aim to collect and compare the progress made in VOCs analysis using the two methods and their instrumental characteristics. Studies have described the potential of GC-MS and e-NOSE in a multitude of relevant aspects of the disease in both children and adults, as well as differential diagnosis between asthma and other conditions such as wheezing, cystic fibrosis, COPD, allergic rhinitis and last but not least, the accuracy of these methods compared to other diagnostic tools such as lung function, FeNO and eosinophil count. Due to significant limitations of both methods, it is still necessary to improve and standardize techniques. Currently, e-NOSE appears to be the most promising aid in clinical practice, whereas GC-MS, as the gold standard for the structural analysis of molecules, remains an essential tool in terms of research for further studies on the pathophysiologic pathways of the asthmatic inflammatory process. In conclusion, the study of VOCs through GC-MS and e-NOSE appears to hold promise for the non-invasive diagnosis, assessment, and monitoring of asthma, as well as for further research studies on the disease.

Predictors of undernutrition in COPD patients.

BACKGROUND & AIMS: Chronic obstructive pulmonary disease (COPD) is a chronic disease characterized by persistent respiratory symptoms and airflow limitation. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) report recommends smoking cessation, pharmacological therapy and pulmonary rehabilitation, but this clinical course can be negatively influenced by undernutrition, a condition documented in about 20% of COPD patients. An altered energy balance characterized by an insufficient intake of energy and nutrients is the primary cause of undernutrition, therefore the aim of this study is to investigate whether clinical and instrumental variables collected during a routine respiratory assessment associate with an altered energy balance in order to identify COPD patients at higher risk of undernutrition worth of further assessment. METHODS: A total of forty-nine participants with a diagnosis of stable COPD were included in this mono-center and longitudinal study. Subjects underwent a multidimensional assessment including evaluation of medical history, evaluation of pulmonary function, evaluation of nutritional status, evaluation of energy intake and resting energy expenditure (REE) using EPIC questionnaire and indirect-calorimetry (IC), respectively, evaluation of physical impairment and mood status. RESULTS: The 24% of participants was at risk of undernutrition with a mean energy intake, total protein intake and lipid intake significantly lower than not at risk subjects, while REE was significantly higher. Age, sex, multimorbidity, disability and depression, and pulmonary function tests were not associated with a negative energy balance, with the exception of the Cumulative Illness Rating Scale (CIRS) severity index, which showed a significant association. CONCLUSION: Clinical evaluation and pulmonary function tests are unable to reliably predict undernutrition in COPD patients, so a nutritional screening should always be forecast in this population based on an accurate evaluation of energy intake and expenditure and body composition.

Thoracic Ultrasound Strain Elastosonography as a Noninvasive Biomarker of Chronic Obstructive Pulmonary Disease-Associated Lung Injury: A Feasibility Study.

BACKGROUND: Transthoracic strain elastosonography (TSE) is being increasingly studied for estimating lung-pleura interface stiffness in pulmonary fibrosis. To date, no data exist on its application in chronic obstructive pulmonary disease (COPD). OBJECTIVES: The aim of this article was to describe the TSE pattern in patients with COPD and healthy subjects, either smokers or nonsmokers, and evaluate the feasibility of this technique for early detection of COPD in smokers. METHODS: Nineteen patients with COPD, twenty-one healthy smokers, and twenty healthy nonsmokers underwent spirometry and TSE. Elastosonography was performed by one ultrasound-certified operator on 12 different scans for each participant, on right and left sides, anteriorly and posteriorly, on upper and lower lobes. For each scan, lung-pleura interface stiffness index (SI) was calculated, and the average SI on all 12 scans (SI-12) and on posterior basal scans (SI-PB) was calculated and used for comparisons among groups of participants and correlations with spirometric parameters. RESULTS: Patients with lung injury (i.e., with COPD or healthy smokers) exhibited significantly increased lung-pleura interface stiffness on TSE, measured by SI-12 and SI-PB, than healthy nonsmokers (p < 0.05). Unlike SI-12, SI-PB was able to discriminate between subjects with lung injury and healthy nonsmokers on receiver operating characteristics analysis (area under the curve 0.846, 95% confidence interval 0.730-0.926, p < 0.001) and correlated with forced expiratory volume in the first second (r = -0.31, p = 0.018). CONCLUSION: The measurement of lung-pleura interface stiffness by TSE in posterior basal scans was able to discriminate patients with lung injury from healthy nonsmokers. The role of TSE for detecting early lung damage in COPD should be further investigated.

Transesophageal endoscopic ultrasound in the diagnosis of the lung masses: a multicenter experience with fine-needle aspiration and fine-needle biopsy needles.

BACKGROUND AND AIM: Intraparenchymal lung masses inaccessible through bronchoscopy or endobronchial ultrasound guidance pose a diagnostic challenge. Furthermore, some fragile or hypoxic patients may be poor candidates for transbronchial approaches. Endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/FNB) offers a potential diagnostic approach to lung cancers adjacent to the esophagus. We aimed to evaluate the feasibility, accuracy, and safety of trans-esophageal EUS-FNA/FNB for tissue sampling of pulmonary nodules. METHODS: We retrospectively analyzed data from patients with pulmonary lesions who underwent EUS-FNA/FNB between March 2015 and August 2021 at eight Italian endoscopic referral centers. RESULTS: A total of 47 patients (36 male; mean age 64.47 ± 9.05 years) were included (22 EUS-FNAs and 25 EUS-FNBs). Overall diagnostic accuracy rate was 88.9% (76.3-96.2%). The sensitivity and diagnostic accuracy were superior for EUS FNB sampling versus EUS-FNA (100% vs. 78.73%); P = 0.05, and (100% vs. 78.57%); P = 0.05, respectively. Additionally, sample adequacy was superior for EUS-FNB sampling versus EUS-FNA (100% vs. 78.5%); P = 0.05. Multivariate logistic regression analysis for diagnostic accuracy showed nodule size at the cutoff of 15 mm (OR 2.29, 1.04-5.5, P = 0.05) and use of FNB needle (OR 4.33, 1.05-6.31, P = 0.05) as significant predictors of higher diagnostic accuracy. There were no procedure-related adverse events. CONCLUSION: This study highlights the efficacy and safety of EUS-FNA/FNB as a minimally invasive procedure for diagnosing and staging peri-esophageal parenchymal lung lesions. The diagnostic yield of EUS-FNB was superior to EUS-FNA.

Electrophoretic α1-globulin for screening of α1-antitrypsin deficient variants.

Background Available screening procedures for the detection of α1-antitrypsin-deficient (AATD) mutations have suboptimal cost-effectiveness ratios. The aim in this study was to evaluate and compare the viability of a composite approach, primarily based on the α1-globulin fraction, in identifying AAT genetic analysis eligible patients against standard screening procedures, based on clinically compatible profiling and circulating AAT < 1 g/L. Methods A total of 21,094 subjects were screened for AATD and deemed eligible when meeting one of these criteria: α1-globulin ≤2.6%; α1-globulin 2.6%-2.9% and AST: >37 U/L and ALT: > 78 U/L; α1-globulin %: 2.9-4.6% and AST: >37 U/L and ALT: >78 U/L and erythrocyte sedimentation rate (ESR) >34 mm/h and C-reactive protein (CRP) >3 mg/L. Subjects were genotyped for the AAT gene mutation. Detection rates, including those of the rarest variants, were compared with results from standard clinical screenings. Siblings of mutated subjects were included in the study, and their results compared. Results Eighty-two subjects were identified. Among these, 51.2% were found to carry some Pi*M variant versus 15.9% who were clinically screened. The detection rates of the screening, including relatives, were: 50.5% for the proposed algorithm and 18.9% for the clinically-based screening. Pi*M variant prevalence in the screened population was in line with previous studies. Interestingly, 46% of subjects with Pi*M variants had an AAT plasma level above the 1 g/L threshold. Conclusions A composite algorithm primarily based on the α1-globulin fraction could effectively identify carriers of Pi*M gene mutation. This approach, not requiring clinical evaluation or AAT serum determination, seems suitable for clinical and epidemiological purposes.

Exhaled Breath Analysis in Obstructive Sleep Apnea Syndrome: A Review of the Literature.

Background and Objectives: Obstructive sleep apnea syndrome (OSAS) represents an independent risk factor for cardiovascular, metabolic and neurological events. Polysomnography is the gold-standard for the diagnosis, however is expensive and time-consuming and not suitable for widespread use. Breath analysis is an innovative, non-invasive technique, able to provide clinically relevant information about OSAS. This systematic review was aimed to outline available evidence on the role of exhaled breath analysis in OSAS, taking into account the techniques' level of adherence to the recently proposed technical standards. Materials and Methods: Articles reporting original data on exhaled breath analysis in OSAS were identified through a computerized and manual literature search and screened. Duplicate publications, case reports, case series, conference papers, expert opinions, comments, reviews and meta-analysis were excluded. Results: Fractional exhaled Nitric Oxide (FeNO) is higher in OSAS patients than controls, however its absolute value is within reported normal ranges. FeNO association with AHI is controversial, as well as its change after continuous positive airway pressure (C-PAP) therapy. Exhaled breath condensate (EBC) is acid in OSAS, cytokines and oxidative stress markers are elevated, they positively correlate with AHI and normalize after treatment. The analysis of volatile organic compounds (VOCs) by spectrometry or electronic nose is able to discriminate OSAS from healthy controls. The main technical issues regards the dilution of EBC and the lack of external validation in VOCs studies. Conclusions: Exhaled breath analysis has a promising role in the understanding of mechanisms underpinning OSAS and has demonstrated a clinical relevance in identifying individuals affected by the disease, in assessing the response to treatment and, potentially, to monitor patient's adherence to mechanical ventilation. Albeit the majority of the technical standards proposed by the ERS committee have been followed by existing papers, further work is needed to uniform the methodology.

A close relationship between HIF-1α expression and bone metastases in advanced NSCLC, a retrospective analysis.

Background: Hypoxia-inducible factor (HIF-1) is a transcription factor produced in hypoxia condition, it is closely associated with tumor angiogenesis and metastasis. Aim: To investigate the expression of HIF-1α in relation with the presence or absence of bone metastasis. Methods A retrospective analysis was carried out on samples deriving from bronchial biopsy and CT-guided trans-thoracic needle biopsy. Detection of HIF-1 expression was performed on tissue sample by a monoclonal murine antibody, comparing patients with or without bone metastases (BM+). Findings: In the total population the main histotype was adenocarcinoma (71.5%), COPD the prevalent comorbidity (73.6%), the mean pack-year was 36.4. Ninety-five histology samples were considered for analysis and comparison. Subdividing the population according to the presence or not of bone metastases, significant differences were found in pack-years (p = 0.02), time to progression (TTP) (p = 0.001) and COPD comorbidity (p = 0.04). The survival comparison between the two subgroups obtained by Kaplan-Meier method showed a longer TTP in patients with visceral metastases with a HR of 1.3 though the comparison by this method was not significant (p = 0.1). A higher intensity and percentage of expression of HIF-1α was recorded in the group with bone metastases (p = 0.02). The main variable affecting HIF expression in a multivariate analysis was the presence of bone metastases (p = 0.01). Interpretation: Patients affected by NSCLC IV stage with bone metastasis have lower survival. There is a very close link between bone metastasis and HIF-1α expression level. The latter could be considered a predictive factor of bone spread and poor prognosis.

Competence in endosonographic techniques.

Endobronchial ultrasound (EBUS) has revolutionized the field of bronchoscopy because it allows to observe peribronchial structures and distal peripheral lung lesions. The use of EBUS was first described by Hurte and Hanrath in 1992. EBUS technology exists in two forms: radial and convex transducer probes. The radial EBUS probe has a 20-MHZ (12-30 MHz available) rotating transducer that can be inserted together with or without a guide sheath through the working channel (2.0-2.8 mm) of a standard flexible bronchoscope. The transducer rotates and produces a 360-degree circular image around the central position of the probe. There are two types of radial EBUS probes: "peripheral" probes, used to identify parenchymal lung lesions, and "central" probes, with balloon sheaths, used for the assessment of airway walls and peribronchial lymph nodes.

Breath analysis in respiratory diseases: state-of-the-art and future perspectives.

INTRODUCTION: The vast majority of respiratory diseases are associated with the production of volatile organic compounds (VOCs), the analysis of which might improve our knowledge about these disorders and their clinical management. The aim of this narrative review is to provide a comprehensive summary of current evidence supporting the application of breath analysis in the field of respiratory diseases, as well as suggesting potential applications available in the near future. Areas covered: A computerized literature search was performed to identify relevant articles reporting original data on the clinical use of breath analysis in respiratory diseases. Papers focusing on diseases other than respiratory, technical issues of VOC sampling and analysis, in vitro experiments or exogenous compounds were excluded. Expert commentary: Currently available evidence on the application of breath analysis in respiratory diseases is encouraging; however, it is mostly based on single-center studies without external validation. The standardization of the technique, together with multicenter clinical trials with external validation, will ensure it is ready for clinical use. Current and new applications in respiratory diseases may represent a major breakthrough in the field, so much so as to deserve further efforts in outlining the most effective way to apply VOC analysis for clinical purposes.

Biopsy needles for mediastinal lymph node sampling by endosonography: current knowledge and future perspectives.

Due to the increasing role of endosonography [endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and esophageal ultrasound-guided fine needle aspiration (EUS-FNA)] in the diagnosis of several lung diseases, the knowledge of technical aspects is mandatory to optimize the success of the procedure. Among those technicalities related to the procedure, the choice of a needle over another one-either in terms of dimension and type-may have a role in the diagnostic process, especially in some diseases such as lymphoproliferative disorders. In this review, we analyze the current knowledge about the biopsy needle for endosonography, providing also some hints for the future.

Screening of Obstructive Sleep Apnea Syndrome by Electronic-Nose Analysis of Volatile Organic Compounds.

Obstructive Sleep Apnea Syndrome (OSAS) carries important social and economic implications. Once the suspicion of OSAS has arisen, Polysomnography (PSG) represents the diagnostic gold standard. However, about 45% of people who have undergone PSG are free from OSAS. Thus, efforts should be made to improve the selection of subjects. We verified whether the pattern of Volatile Organic Compounds (VOCs) helps to select patients amenable to PSG. We studied 136 subjects (20 obese non-OSAS, 20 hypoxic OSAS, 20 non-hypoxic OSAS, and 20 non-hypoxic Chronic Obstructive Pulmonary Disease (COPD) vs 56 healthy controls) without any criteria of exclusion for comorbidity to deal with a real-life population. VOCs patterns were analyzed using electronic-nose (e-nose) technology. A Discriminant Analysis (Partial Least Square-Discriminant Analysis) was performed to predict respiratory functions and PSG parameters. E-nose distinguished controls (100% correct classification) from others and identified 60% of hypoxic, and 35% of non-hypoxic OSAS patients. Similarly, it identified 60% of COPD patients. One-by-one group comparison yielded optimal discrimination of OSAS vs controls and of COPD vs controls (100% correct classification). In conclusion, e-nose technology applied to breath-analysis can discriminate non-respiratory from respiratory diseased populations in real-life multimorbid populations and exclude OSAS. If confirmed, this evidence may become pivotal for screening purposes.

The technique of endoscopic airway tumor treatment.

More than half of primary lung cancers are not resectable at diagnosis and 40% of deaths may be secondary to loco-regional disease. Many of these patients suffer from symptoms related to airways obstruction. Indications for therapeutic endoscopic treatment are palliation of dyspnea and other obstructive symptoms in advanced cancerous lesions and cure of early lung cancer. Bronchoscopic management is also indicated for all those patients suffering from benign or minimally invasive neoplasm who are not suitable for surgery due to their clinical conditions. Clinicians should select cases, evaluating tumor features (size, location) and patient characteristics (age, lung function impairment) to choose the most appropriate endoscopic technique. Laser therapy, electrocautery, cryotherapy and stenting are well-described techniques for the palliation of symptoms due to airway involvement and local treatment of endobronchial lesions. Newer technologies, with an established role in clinical practice, are endobronchial ultrasound (EBUS), autofluorescence bronchoscopy (AFB), and narrow band imaging (NBI). Other techniques, such as endobronchial intra-tumoral chemotherapy (EITC), EBUS-guided-transbronchial needle injection or bronchoscopy-guided radiofrequency ablation (RFA), are in development for the use within the airways. These endobronchial interventions are important adjuncts in the multimodality management of lung cancer and should become standard considerations in the management of patients with advanced lung cancer, benign or otherwise not approachable central airway lesions. We aimed at revising several endobronchial treatment modalities that can augment standard antitumor therapies for advanced lung cancer, including rigid and flexible bronchoscopy, laser therapy, endobronchial prosthesis, and photodynamic therapy (PDT).

Chest ultrasonography in health surveillance of asbestos related pleural disease.

High resolution computed tomography, (HRCT), is currently considered the diagnostic gold standard to diagnose early stage malignant pleural mesothelioma and other non-malignant pleural conditions, but it is expensive and exposes the patient to radiation dose. In a screening and population medicine perspective, Thoracic Ultrasounds may become a valuable alternative because it can detect minimal changes in pleural surface, is widely available and safe. On these bases, we therefore validated thoracic US in subjects with history of exposure to asbestos, having HRCT as the reference standard. One hundred-fifty subjects were screened and 117 were recruited. Pleural abnormalities at US and/or HRCT were detected in 66 out of 117 subjects (prevalence=57%), and their prevalence was unrelated to both mansion and smoking habit, while mean age and mean length of exposure were higher in those having pleural abnormalities (age=47±5 vs 44±6years, p<0.05;years of exposure=20±7 vs 17±5, p<0.05). Thirteen out of 19 subjects with pleural abnormalities at HRCT were also identified by thoracic US, whereas 47 participants had lesions seen at US, but not at the HRCT scan. Positive and negative percent agreement were 66.6% and 51.8%, respectively; the McNemar's test for equality showed a p-value <0.001. In conclusion, chest US might complement HRCT in the health surveillance of asbestos exposed population to detect earlier lesions or to follow up US approachable lesions. Further research is needed to clarify whether this approach may enhance early recognition of pleural mesothelioma and ameliorate prognosis.

EBUS-STAT Subscore Analysis to Predict the Efficacy and Assess the Validity of Virtual Reality Simulation for EBUS-TBNA Training Among Experienced Bronchoscopists.

BACKGROUND: Linear endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) represents a pivotal innovation in interventional pulmonology; determining the best approach to guarantee systematic and efficient training is expected to become a main issue in the forthcoming years. Virtual reality simulators have been proposed as potential EBUS-TBNA training instruments, to avoid unskilled beginners practicing directly in real-life settings. A validated and perfected simulation program could be used before allowing beginners to practice on patients. Our goal was to test the reliability of the EBUS-Skills and Task Assessment Tool (STAT) and its subscores for measuring the competence of experienced bronchoscopists approaching EBUS-guided TBNA, using only the virtual reality simulator as both a training and an assessment tool. METHODS: Fifteen experienced bronchoscopists, with poor or no experience in EBUS-TBNA, participated in this study. They were all administered the Italian version of the EBUS-STAT evaluation tool, during a high-fidelity virtual reality simulation. This was followed by a single 7-hour theoretical and practical (on simulators) session on EBUS-TBNA, at the end of which their skills were reassessed by EBUS-STAT. RESULTS: An overall, significant improvement in EBUS-TBNA skills was observed, thereby confirming that (a) virtual reality simulation can facilitate practical learning among practitioners, and (b) EBUS-STAT is capable of detecting these improvements. The test's overall ability to detect differences was negatively influenced by the minimal variation of the scores relating to items 1 and 2, was not influenced by the training, and improved significantly when the 2 items were not considered. Apart from these 2 items, all the remaining subscores were equally capable of revealing improvements in the learner. Lastly, we found that trainees with presimulation EBUS-STAT scores above 79 did not show any significant improvement after virtual reality training, suggesting that this score represents a cutoff value capable of predicting the likelihood that simulation can be beneficial. CONCLUSIONS: Virtual reality simulation is capable of providing a practical learning tool for practitioners with previous experience in flexible bronchoscopy, and the EBUS-STAT questionnaire is capable of detecting these changes. A pretraining EBUS-STAT score below 79 is a good indicator of those candidates who will benefit from the simulation training. Further studies are needed to verify whether a modified version of the questionnaire would be capable of improving its performance among experienced bronchoscopists.

Alpha-1 Antitrypsin Deficiency: Current Perspective from Genetics to Diagnosis and Therapeutic Approaches.

Alpha-1 antitrypsin (A1AT) is a 52-kDa, acute phase glycoprotein encoded by the protease inhibitor (PI) locus, located on the long arm of chromosome 14 (14q31-32.3). Its structure is composed of a total of 7 exons, 4 coding (II, III, IV, and V) and 3 non-coding (IA, IB, and IC). A1AT is produced primarily by hepatocytes and acts as a serine protease inhibitor with antiprotease and immunoregulatory activities. The main target of A1AT is neutrophil elastase (NE), an enzyme released during a neutrophil-mediated inflammatory process. When the enzyme is not adequately balanced by A1AT activity, it can cause tissue injury and destruction. A1AT deficiency (A1ATD) is a genetic autosomal recessive disease, characterized by low serum levels of A1AT. The condition may lead to liver disease, early-onset pulmonary emphysema and, rare multi-organ vasculitis, necrotizing panniculitis and fibromyalgia. At least 100 allelic variants of the polymorphic PI locus have been described with groups including associations with different A1AT plasma levels and functions. Treatments with purified A1AT preparations, obtained through pooled human plasma (augmentation therapy), have been proven to improve survival and disease-related quality of life, as well as, slow down the progression of organ damage. Furthermore, ongoing research is now focusing on the development of specifically targeted, new medications. The aim of this review is to summarize our knowledge of the genetic A1AT variants, focusing on their variable clinical manifestation, report routine and recently updated laboratory diagnostic techniques, and to highlight the relevance of early diagnosis of A1ATD. Moreover, we will review the role of augmentation therapy recommendations and future perspectives focusing on a personalized treatment of A1ATD.

"Impact of Smoking Cessation Treatment" on Lung Function and Response Rate in EGFR Mutated Patients: A Short-Term Cohort Study.

BACKGROUND: Erlotinib is a validated drug "for the treatment of patients affected by advanced unresectable non small cell lung cancer (NSCLC) with EGFR mutations". We want to focus on potential functional benefits deriving from a combined therapy containing TKI (erlotinib) and a nicotinic partial agonist (varenicicline) in smokers. METHODS: we analyzed the records of patients affected by NSCLC treated undergoing "first line therapy with Erlotinib" and smoking cessation (with varenicicline). Response to therapy was evaluated by CT scan. Data concerning clinical history, smoking habit, nicotine dependence were collected after three months from the beginning of the recruitment. Pulmonary function tests including spirometry with pletismographic technique and exhaled carbon monoxide (CO) were performed with recording of resistances, flows, volumes. A group of ten current smokers affected by NSCLC with EGFR activating mutation and concurrent mild COPD undergoing anti-EGFR treatment without smoking cessation was used to compare clinical and functional data. A control group of NSCLC wild type with mild COPD undergoing smoking cessation was assessed for functional data. RESULTS: Twenty-five patients were enrolled. All of them reported partial response at CT re-evaluation. All functional indexes and parameters were improved after combined treatment a significant increase of FEV1 level and a decrease of exhaled CO. In particular, a mean increase of FEV1 from 1.93 (SD 0.48) to 2.03(SD 0.46) liters was recorded. A notable reduction of sRAW (specific resistances) was also observed. The improvement of some parameters such as CO, heart rate (HR), sRAW and FEV1 resulted statistically significant. A better response to therapy was found "in the study group compared to the second group of mutated NSCLC patients". In this second group, we also observed an improvement of functional obstructive parameters although it was less remarkable than study group. Only sRAW and FEF 25/75 were significantly increased. The group of NSCLC wild type undergoing only smoking cessation showed a lower increase of FEV1 by about 50 ml compared to the first group. CONCLUSION: The combination of anti-EGFR treatment and concurrent therapy for smoking cessation seems to be more effective than erlotinib alone in improving lung function and clinical response in advanced NSCLC patients with EGFR-mutations. It is conceivable that erlotinib may potentiate the action of varenicline. We have also outlined some relevant patents concerning varenicline and EGFR-TKI.

Exhaled breath analysis by electronic nose in respiratory diseases.

Breath analysis via electronic nose is a technique oriented around volatile organic compound (VOC) profiling in exhaled breath for diagnostic and prognostic purposes. This approach, when supported by methodologies for VOC identification, has been often referred to as metabolomics or breathomics. Although breath analysis may have a substantial impact on clinical practice, as it may allow early diagnosis and large-scale screening strategies while being noninvasive and inexpensive, some technical and methodological limitations must be solved, together with crucial interpretative issues. By integrating a review of the currently available literature with more speculative arguments about the potential interpretation and application of VOC analysis, the authors aim to provide an overview of the main relevant aspects of this promising field of research.