A nicotinamide phosphoribosyltransferase-GAPDH interaction sustains the stress-induced NMN/NAD+ salvage pathway in the nucleus.

All cells require sustained intracellular energy flux, which is driven by redox chemistry at the subcellular level. NAD+, its phosphorylated variant NAD(P)+, and its reduced forms NAD(P)/NAD(P)H are all redox cofactors with key roles in energy metabolism and are substrates for several NAD-consuming enzymes (e.g. poly(ADP-ribose) polymerases, sirtuins, and others). The nicotinamide salvage pathway, constituted by nicotinamide mononucleotide adenylyltransferase (NMNAT) and nicotinamide phosphoribosyltransferase (NAMPT), mainly replenishes NAD+ in eukaryotes. However, unlike NMNAT1, NAMPT is not known to be a nuclear protein, prompting the question of how the nuclear NAD+ pool is maintained and how it is replenished upon NAD+ consumption. In the present work, using human and murine cells; immunoprecipitation, pulldown, and surface plasmon resonance assays; and immunofluorescence, small-angle X-ray scattering, and MS-based analyses, we report that GAPDH and NAMPT form a stable complex that is essential for nuclear translocation of NAMPT. This translocation furnishes NMN to replenish NAD+ to compensate for the activation of NAD-consuming enzymes by stressful stimuli induced by exposure to H2O2 or S-nitrosoglutathione and DNA damage inducers. These results indicate that by forming a complex with GAPDH, NAMPT can translocate to the nucleus and thereby sustain the stress-induced NMN/NAD+ salvage pathway.

Mitochondrial impairment activates the Wallerian pathway through depletion of NMNAT2 leading to SARM1-dependent axon degeneration.

Wallerian degeneration of physically injured axons involves a well-defined molecular pathway linking loss of axonal survival factor NMNAT2 to activation of pro-degenerative protein SARM1. Manipulating the pathway through these proteins led to the identification of non-axotomy insults causing axon degeneration by a Wallerian-like mechanism, including several involving mitochondrial impairment. Mitochondrial dysfunction is heavily implicated in Parkinson's disease, Charcot-Marie-Tooth disease, hereditary spastic paraplegia and other axonal disorders. However, whether and how mitochondrial impairment activates Wallerian degeneration has remained unclear. Here, we show that disruption of mitochondrial membrane potential leads to axonal NMNAT2 depletion in mouse sympathetic neurons, increasing the substrate-to-product ratio (NMN/NAD) of this NAD-synthesising enzyme, a metabolic fingerprint of Wallerian degeneration. The mechanism appears to involve both impaired NMNAT2 synthesis and reduced axonal transport. Expression of WLDS and Sarm1 deletion both protect axons after mitochondrial uncoupling. Blocking the pathway also confers neuroprotection and increases the lifespan of flies with Pink1 loss-of-function mutation, which causes severe mitochondrial defects. These data indicate that mitochondrial impairment replicates all the major steps of Wallerian degeneration, placing it upstream of NMNAT2 loss, with the potential to contribute to axon pathology in mitochondrial disorders.

Fluoropyrimidines affect de novo pyrimidine synthesis impairing biofilm formation in Escherichia coli.

Antivirulence agents are considered a promising strategy to treat bacterial infections. Fluoropyrimidines possess antivirulence and antibiofilm activity against Gram-negative bacteria; however, their mechanism of action is yet unknown. Consistent with their known antibiofilm activity, fluoropyrimidines, particularly 5-fluorocytosine (5-FC), impair curli-dependent surface adhesion by Escherichia coli MG1655 via downregulation of curli fimbriae gene transcription. Curli inhibition requires fluoropyrimidine conversion into fluoronucleotides and is not mediated by c-di-GMP or the ymg-rcs envelope stress response axis, previously suggested as the target of fluorouracil antibiofilm activity in E. coli. In contrast, 5-FC hampered the transcription of curli activators RpoS and stimulated the expression of Fis, a curli repressor affected by nucleotide availability. This last observation suggested a possible perturbation of the de novo pyrimidine biosynthesis by 5-FC: indeed, exposure to 5-FC resulted in a ca. 2-fold reduction of UMP intracellular levels while not affecting ATP. Consistently, expression of the de novo pyrimidine biosynthesis genes carB and pyrB was upregulated in the presence of 5-FC. Our results suggest that the antibiofilm activity of fluoropyrimidines is mediated, at least in part, by perturbation of the pyrimidine nucleotide pool. We screened a genome library in search of additional determinants able to counteract the effects of 5-FC. We found that a DNA fragment encoding the unknown protein D8B36_18,480 and the N-terminal domain of the penicillin-binding protein 1b (PBP1b), involved in peptidoglycan synthesis, could restore curli production in the presence of 5-FC. Deletion of the PBP1b-encoding gene mrcB, induced csgBAC transcription, while overexpression of the gene encoding the D8B36_18,480 protein obliterated its expression, possibly as part of a coordinated response in curli regulation with PBP1b. While the two proteins do not appear to be direct targets of 5-FC, their involvement in curli regulation suggests a connection between peptidoglycan biosynthesis and curli production, which might become even more relevant upon pyrimidine starvation and reduced availability of UDP-sugars needed in cell wall biosynthesis. Overall, our findings link the antibiofilm activity of fluoropyrimidines to the redirection of at least two global regulators (RpoS, Fis) by induction of pyrimidine starvation. This highlights the importance of the de novo pyrimidines biosynthesis pathway in controlling virulence mechanisms in different bacteria and makes the pathway a potential target for antivirulence strategies.

The Noble Suicide: The Case of a Self-Contained Dagger in the Heart and a Literal Raw.

According to WHO estimates, more than 700,000 people die each year due to suicide and suicides performed with a bladed weapon account for approximately 1.6%-3% of all suicides. It is statistically more common to find injuries to the heart, lungs, and thoracic vessels in homicides, whereas in suicides there is a higher frequency of vascular injuries to the extremities of the limbs. Also in suicides, the presence of "hesitation marks," related to the attempts the victim makes before having the courage to kill himself, can often be found. In the case presented by the authors, these parameters are subverted: There was only one injury and it was the fatal one, it was located on the chest and reached the heart. But it was suicide. The circumstantial data, the psychological explanation, and the previous similar suicide attempt left no doubt about it. The man decided to commit suicide because he could no longer find meaning in his life after losing hope for a career as a pianist, having been diagnosed with a degenerative disease in his hands. The man hated himself and his existence: The future appeared extremely negative and the only escape was self-suppression. This case report makes an essential contribution to the already existing Literature as it shows a suicide that occurred in an unusual manner.

The Job that Kills the Worker: Analysis of Two Case Reports on Work-Related Stress Deaths in the COVID-19 Era.

The COVID-19 pandemic caused an increasing number of corporate layoffs and downsizing, as well as causing many employees to be absent due to illness, with inevitable consequences on the health of active workers both from a physical point of view, due to the need to make up for staff and organizational shortages, and from a mental point of view, due to the inevitable consequences related to the uncertainty of the social context. This context has certainly caused an increase in work-related stress, which is the pathological outcome of a process that affects workers who are subjected to excessive (emotional-relational or high or low or inadequate activity) or improper work loads. The purpose of this paper is to evaluate the main aspects of this issue, through the analysis proposed by two case reports, both of which occurred during the COVID-19 pandemic, in which occupational stress emerged as an etiological agent in the determinism of death.

Healthcare Liability and Thyroidectomy: When Is the Surgeon Wrong?

Thyroid surgeries can often lead to operative complications, sometimes with consequences on the patient's health. This often leads to claims for compensation but the assessments of consultants and judges are not always objective. Based on these considerations, the authors analyzed forty-seven sentences issued between 2013 and 2022 regarding claims of alleged medical malpractice. This analysis aims to examine the cases presented in the sentences and the evaluations proposed by the judges to offer ideas for objective evaluation by the legislation in force in Italy.

Requests for Compensation in Cases Involving Patients' Falls in Healthcare Settings: A Retrospective Analysis.

Falls are the most frequent adverse events recorded in healthcare facilities. By employing a multifaceted strategy to ensure prevention interventions that are specific to the patient type and environmental risk management, risk factor evaluation may help to reduce falls in the hospital setting. Patient falls are one of the main causes of lawsuits against hospitals, which has led to the development of validated instruments that are beneficial in treating the patient after the incident and effective in minimizing the frequency of falls. The aim of our study is to evaluate compensation claims asserting healthcare culpability in situations where a patient fell in a hospital setting. The collected data relate to judgments issued in Italy until December 2022 regarding 30 episodes of falls that occurred between 2003 and 2018. Our research revealed that approximately 50% of Italian healthcare organizations lose the case in court when a patient falls in a hospital setting and dies or is injured. In half of these cases, the failure of the medical staff to use protective equipment against falls is what led to the court's acceptance of the compensation claim. In order to improve the quality of healthcare services, fall prevention techniques must continue to be implemented.

Heat Stroke in the Work Environment: Case Report of an Underestimated Phenomenon.

Average global temperatures continue to trend upward, and this phenomenon is part of the more complex climate change taking place on our planet over the past century. Human health is directly affected by environmental conditions, not only because of communicable diseases that are clearly affected by climate, but also because of the relationship between rising temperatures and increased morbidity for psychiatric diseases. As global temperatures and the number of extreme days increase, so does the risk associated with all those acute illnesses related to these factors. For example, there is a correlation between out-of-hospital cardiac arrest and heat. Then, there are pathologies that recognize excessive heat as the main etiological agent. This is the case with so-called "heat stroke", a form of hyperthermia accompanied by a systemic inflammatory response, which causes multi-organ dysfunction and sometimes death. Starting with a case that came to their attention of a young man in good general health who died while working unloading fruit crates from a truck, the authors wanted to express some thoughts on the need to adapt the world of work, including work-specific hazards, in order to protect the worker exposed to this "new risk" and develop multidisciplinary adaptation strategies that incorporate climatology, indoor/building environments, energy use, regulatory perfection of work and human thermal comfort.

Diagnostic Methods in Forensic Pathology: A New Sign in Death from Hanging.

PURPOSE: To evaluate the usefulness of studying vital injuries at the sternal head insertion of the sternocleidomastoid muscle in the medico-legal assessment of death by hanging. MATERIALS AND METHODS: Study material was obtained from eight bodies of people who died from hanging. The control group included as many specimens collected from people who died from traumatic causes other than hanging (precipitation from medium to large heights and traffic accidents). The structures under study were examined histologically with a BX-51 light microscope (Olympus). An analysis of the extravasated erythrocytes was performed by counting the number per mm2 in the histologic section on 10 HPF (400×), and Student's t-test for a comparison of the averages was applied for all parametric values. The authors noted that the key finding, indicative of the subject's viability at the time of discontinuation, was the presence of recent hemorrhagic infiltrate (in the absence of hemosiderin) at the tendon insertion of the sternocleidomastoid muscle and the proximal part of the muscle itself. RESULTS: All specimens tested were positive for the presence of hemorrhagic infiltrate at the portions tested in a statistically significant manner. In contrast, in the control cases there was no or, where present, no statistically significant (p < 0.05) presence of recent hemorrhagic infiltrate. The limitation of the study is the low number of samples examined. In any case, the results obtained are strongly indicative of the possibility of using this type of forensic pathological investigation in cases where there is a doubt in terms of a differential diagnosis between hanging (suicidal type) and suspension of a corpse in a simulation of hanging.

SARM1 is a multi-functional NAD(P)ase with prominent base exchange activity, all regulated bymultiple physiologically relevant NAD metabolites.

SARM1 is an NAD(P) glycohydrolase and TLR adapter with an essential, prodegenerative role in programmed axon death (Wallerian degeneration). Like other NAD(P)ases, it catalyzes multiple reactions that need to be fully investigated. Here, we compare these multiple activities for recombinant human SARM1, human CD38, and Aplysia californica ADP ribosyl cyclase. SARM1 has the highest transglycosidation (base exchange) activity at neutral pH and with some bases this dominates NAD(P) hydrolysis and cyclization. All SARM1 activities, including base exchange at neutral pH, are activated by an increased NMN:NAD ratio, at physiological levels of both metabolites. SARM1 base exchange occurs also in DRG neurons and is thus a very likely physiological source of calcium-mobilizing agent NaADP. Finally, we identify regulation by free pyridines, NADP, and nicotinic acid riboside (NaR) on SARM1, all of therapeutic interest. Understanding which specific SARM1 function(s) is responsible for axon degeneration is essential for its targeting in disease.

The NAD+ precursor NMN activates dSarm to trigger axon degeneration in Drosophila.

Axon degeneration contributes to the disruption of neuronal circuit function in diseased and injured nervous systems. Severed axons degenerate following the activation of an evolutionarily conserved signaling pathway, which culminates in the activation of SARM1 in mammals to execute the pathological depletion of the metabolite NAD+. SARM1 NADase activity is activated by the NAD+ precursor nicotinamide mononucleotide (NMN). In mammals, keeping NMN levels low potently preserves axons after injury. However, it remains unclear whether NMN is also a key mediator of axon degeneration and dSarm activation in flies. Here, we demonstrate that lowering NMN levels in Drosophila through the expression of a newly generated prokaryotic NMN-Deamidase (NMN-D) preserves severed axons for months and keeps them circuit-integrated for weeks. NMN-D alters the NAD+ metabolic flux by lowering NMN, while NAD+ remains unchanged in vivo. Increased NMN synthesis by the expression of mouse nicotinamide phosphoribosyltransferase (mNAMPT) leads to faster axon degeneration after injury. We also show that NMN-induced activation of dSarm mediates axon degeneration in vivo. Finally, NMN-D delays neurodegeneration caused by loss of the sole NMN-consuming and NAD+-synthesizing enzyme dNmnat. Our results reveal a critical role for NMN in neurodegeneration in the fly, which extends beyond axonal injury. The potent neuroprotection by reducing NMN levels is similar to the interference with other essential mediators of axon degeneration in Drosophila.

Neurotoxin-mediated potent activation of the axon degeneration regulator SARM1.

Axon loss underlies symptom onset and progression in many neurodegenerative disorders. Axon degeneration in injury and disease is promoted by activation of the NAD-consuming enzyme SARM1. Here, we report a novel activator of SARM1, a metabolite of the pesticide and neurotoxin vacor. Removal of SARM1 completely rescues mouse neurons from vacor-induced neuron and axon death in vitro and in vivo. We present the crystal structure of the Drosophila SARM1 regulatory domain complexed with this activator, the vacor metabolite VMN, which as the most potent activator yet known is likely to support drug development for human SARM1 and NMNAT2 disorders. This study indicates the mechanism of neurotoxicity and pesticide action by vacor, raises important questions about other pyridines in wider use today, provides important new tools for drug discovery, and demonstrates that removing SARM1 can robustly block programmed axon death induced by toxicity as well as genetic mutation.

Severe biallelic loss-of-function mutations in nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) in two fetuses with fetal akinesia deformation sequence.

The three nicotinamide mononucleotide adenylyltransferase (NMNAT) family members synthesize the electron carrier nicotinamide adenine dinucleotide (NAD+) and are essential for cellular metabolism. In mammalian axons, NMNAT activity appears to be required for axon survival and is predominantly provided by NMNAT2. NMNAT2 has recently been shown to also function as a chaperone to aid in the refolding of misfolded proteins. Nmnat2 deficiency in mice, or in its ortholog dNmnat in Drosophila, results in axon outgrowth and survival defects. Peripheral nerve axons in NMNAT2-deficient mice fail to extend and innervate targets, and skeletal muscle is severely underdeveloped. In addition, removing NMNAT2 from established axons initiates axon death by Wallerian degeneration. We report here on two stillborn siblings with fetal akinesia deformation sequence (FADS), severely reduced skeletal muscle mass and hydrops fetalis. Clinical exome sequencing identified compound heterozygous NMNAT2 variant alleles in both cases. Both protein variants are incapable of supporting axon survival in mouse primary neuron cultures when overexpressed. In vitro assays demonstrate altered protein stability and/or defects in NAD+ synthesis and chaperone functions. Thus, both patient NMNAT2 alleles are null or severely hypo-morphic. These data indicate a previously unknown role for NMNAT2 in human neurological development and provide the first direct molecular evidence to support the involvement of Wallerian degeneration in a human axonal disorder. SIGNIFICANCE: Nicotinamide Mononucleotide Adenylyltransferase 2 (NMNAT2) both synthesizes the electron carrier Nicotinamide Adenine Dinucleotide (NAD+) and acts a protein chaperone. NMNAT2 has emerged as a major neuron survival factor. Overexpression of NMNAT2 protects neurons from Wallerian degeneration after injury and declining levels of NMNAT2 have been implicated in neurodegeneration. While the role of NMNAT2 in neurodegeneration has been extensively studied, the role of NMNAT2 in human development remains unclear. In this work, we present the first human variants in NMNAT2 identified in two fetuses with severe skeletal muscle hypoplasia and fetal akinesia. Functional studies in vitro showed that the mutations impair both NMNAT2 NAD+ synthase and chaperone functions. This work identifies the critical role of NMNAT2 in human development.

Homozygous NMNAT2 mutation in sisters with polyneuropathy and erythromelalgia.

We identified a homozygous missense mutation in the gene encoding NAD synthesizing enzyme NMNAT2 in two siblings with childhood onset polyneuropathy with erythromelalgia. No additional homozygotes for this rare allele, which leads to amino acid substitution T94M, were present among the unaffected relatives tested or in the 60,000 exomes of the ExAC database. For axons to survive, axonal NMNAT2 activity has to be maintained above a threshold level but the T94M mutation confers a partial loss of function both in the ability of NMNAT2 to support axon survival and in its enzymatic properties. Electrophysiological tests and histological analysis of sural nerve biopsies in the patients were consistent with loss of distal sensory and motor axons. Thus, it is likely that NMNAT2 mutation causes this pain and axon loss phenotype making this the first disorder associated with mutation of a key regulator of Wallerian-like axon degeneration in humans. This supports indications from numerous animal studies that the Wallerian degeneration pathway is important in human disease and raises important questions about which other human phenotypes could be linked to this gene.

Expression of 90K (Mac-2 BP) correlates with distant metastasis and predicts survival in stage I non-small cell lung cancer patients.

90K, also known as Mac-2 binding protein, is a secreted glycoprotein that binds galectins, beta1-integrins, collagens, and fibronectin, and has some relevance in cell-cell and cell-extracellular matrix adhesion. Previous studies have shown that serum levels of 90K have prognostic value in several neoplasms. In the present study, the role of the expression of 90K as an adverse prognostic indicator in 72 pathological stage I non-small cell lung cancer patients was investigated immunohistochemically. All of the patients underwent complete surgical removal of the tumor. The median length of follow-up care was 54 months. High level of 90K expression (90K staining of > or =50% of the neoplastic cells) was observed in 20 of the 72 (28%) tumors. Expression of 90K was confirmed by ELISA. The results showed that a high expression of 90K correlates with adverse prognosis. Among patients with high 90K expression, the disease-free and overall survival rates were significantly lower than the same rates of those with low expression (P = 0. 0001 and P = 0. 0003, respectively). The incidence of distant metastases in the patients with high 90K expression (60%; 12 of 20 patients) was significantly higher than that of in the patients with low expression (21%; 11 of 53 patients; P = 0.0038). The results of multivariate analysis confirmed that a high 90K expression was a significant factor to predict poor prognosis. We suggest that 90K expression could be a useful prognostic factor in patients with stage I non-small cell lung cancer, likely as an indicator of the metastatic propensity of the tumor.

Small cell lung carcinoma (SCLC): the angiogenic phenomenon.

OBJECTIVES: Tumor angiogenesis, expressed by the microvessel count (MVC), and its mediators (i.e. vascular endothelial growth factor) significantly correlate with metastases in surgically treated non-small cell lung carcinoma/cancer (NSCLC). SCLC is rarely treated by surgery, as a consequence, few specimens are available to perform a biological characterization. We reviewed our experience in the surgical treatment of SCLC with particular reference to the angiogenetic expression and its correlation to the stage of disease and prognosis. METHODS: We retrospectively investigated a homogenous cohort of 87 patients with SCLC, who were primarily operated on and then underwent adjuvant chemotherapy between 1980 and 1998. Their median age was 62 years (range 34-73). All the patients were completely staged. The surgical procedures included: 32 pneumonectomies and 55 lobectomies. There were 46 N0, 17 N1 and 24 N2-disease. The adjuvant chemotherapy consisted of four to six courses of cyclophosphamide, epidoxorubicine and etoposide. The MVC was determined highlighting the microvessels with anti-CD34 monoclonal antibodies. Immunostaining for VEGF was performed using the ABC method with anti-VEGF monoclonal antibodies. The p53 protein expression was assessed by NCL-DO7 anti-p53 monoclonal antibody. RESULTS: With a median follow-up of 109.6 months (range 25-238), 37 patients are alive and well, two are alive with systemic metastases. Forty-four patients died of local (n=5) or systemic (n=39) relapse, while four patients died from other causes. The median MVC was 59 (range 18-145). Among the clinico-pathological parameters, metastatic nodal-involvement (P=0.002) and advanced stage of disease (P=0.005) were associated with a worse overall survival (OS). MVC and VEGF protein expression significantly affected the survival (P<0.001 and P=0.0008, respectively). No statistical association was found between p53 alterations and OS as well as no association was found among p53 alterations, MVC and VEGF expression. On multivariate analysis only the VEGF expression (P=0.003) was an independent prognostic factor. CONCLUSIONS: Angiogenesis plays a role in the metastatic process of the SCLC as well as NSCLC. SCLC has a higher vascularization than NSCLC as results from the higher number of microvessels; however, tumor angiogenesis tested by the MVC and the VEGF protein expression correlates with the prognosis also in SCLC. SCLC may be an ideal field to test new antiangiogenic drugs associated to chemotherapy.

Early experience with robotic technology for thoracoscopic surgery.

OBJECTIVE: Recently, robots have been introduced into surgical procedures in an attempt to facilitate surgical performance. The purpose of this study was to develop a technique to perform thoracoscopic lung resection using a telemanipulation system. METHODS: We have used a robotic system to perform thoracoscopic surgery in 12 cases: five lobectomies, three tumor enucleations, three excisions and one bulla stitching completed with fibrin glue for spontaneous pneumothorax. The operations were performed using the Intuitive Microsurgical system (Da Vinci System) through three ports and, a fourth space 'service entrance' incision, in the major lung resection. RESULTS: Three procedures begun with the robotic technique were completed by a minimal thoracotomy. No technical operative mishaps were associated with the manoeuvres of robotic arms. In all manoeuvres (up, down, insertion, extraction, etc.), the robotic arms moved appropriately in the favorable operative fields. All patients tolerated the procedure well and the post-operative course was satisfactory, requiring few analgesics. CONCLUSIONS: Although further studies on robotically assisted procedures are needed to clarify the clinical feasibility of this procedure, the results in our cases are encouraging. We believe that thoracoscopic procedures using a robotic manipulation system may be technically feasible in selected cases and in the hands of experienced thoracic surgeons.

The management of malignant pericardial effusions using permanently implanted devices.

We present a new approach utilising VATS and a Port-system (Medi-Port MP-GS9; IAP-HMP) that allows home management of pericardial effusion in patients with advanced malignancy and recurrent effusion. All patients underwent thoracoscopic pericardial window under general anaesthesia. On completion of this procedure a Port-system was permanently implanted with the reservoir body placed in a subcutaneous pocket and the outlet catheter inserted into the pleural cavity which allows aspiration of the effusion at home, on becoming symptomatic.

Intraoperative radioguided sentinel lymph node biopsy in non-small cell lung cancer.

OBJECTIVES: The aim of this study was to determine the accuracy and the role of the sentinel lymph node (SLN) technique in patients with early non-small cell lung cancer (NSCLC). METHODS: This study was carried out on 29 consecutive patients (M/F = 24:5, mean age 65.9 +/- 7.1 years) with resectable NSCLC (Stage IA-IB). Intraoperative injection with a (99m)Tc-nanocolloid suspension was performed in the first ten patients; the following patients were injected under computed tomography scan guidance. A total dose of 37 MBq (1 ml) was administered in two to four divided aliquots (depending on the size), injected in the periphery of the tumour. Intraoperative radioactivity counting started a mean of 1 h (range 50-70 min) after the injection. The SLN was defined as the node with the highest count rate using a handheld gamma probe counter. Resection with mediastinal node dissection was performed and findings were correlated with histologic and immunohistochemistry (IHC) examination. RESULTS: Three of the 29 patients did not have NSCLC (two benign lesions, and one metastatic breast tumour) and were excluded. The SLN was identified in 25/26 (96.1%) patients (a total of 31 SLNs); 7/31 (22.5%) of the SLNs were positive for metastatic involvement after histologic and IHC examination. One inaccurately identified SLN was encountered (3.8%). CONCLUSIONS: These preliminary results demonstrate the feasibility of this procedure in identifying the first site of potential nodal metastases of NSCLC. The actual clinical impact of this procedure remains to be elucidated by further investigation in larger groups of patients.