BackgroundSeveral c-MET targeting inhibitory molecules have already shown promising results in the treatment of patients with Non-small Cell Lung Cancer (NSCLC). Combination of EGFR- and c-MET-specific molecules may overcome EGFR tyrosine kinase inhibitor (TKI) resistance. The aim of this study was to allow for the identification of patients who might benefit from TKI treatments targeting MET and to narrow in on the diagnostic assessment of MET.Methods222 tumor tissues of patients with NSCLC were analyzed concerning c-MET expression and activation in terms of phosphorylation (Y1234/1235 and Y1349) using a microarray format employing immunohistochemistry (IHC). Furthermore, protein expression and MET activation was correlated with the amplification status by Fluorescence in Situ Hybridization (FISH).ResultsCorrelation was observed between phosphorylation of c-MET at Y1234/1235 and Y1349 (spearman correlation coefficient rs = 0.41; p < 0.0001). No significant correlation was shown between MET expression and phosphorylation (p > 0.05). c-MET gene amplification was detected in eight of 214 patients (3.7 %). No significant association was observed between c-MET amplification, c-MET protein expression and phosphorylation.ConclusionOur data indicate, that neither expression of c-MET nor the gene amplification status might be the best way to select patients for MET targeting therapies, since no correlation with the activation status of MET was observed. We propose to take into account analyzing the phosphorylation status of MET by IHC to select patients for MET targeting therapies. Signaling of the receptor and the activation of downstream molecules might be more crucial for the benefit of therapeutics targeting MET receptor tyrosine kinases than expression levels alone.

Long segment malacia of the trachea or main stem bronchi in children is not always suitable for surgical correction; patients may therefore remain ventilator-dependent and/or experience severe obstructive crises. We treated 7 children (ages, 4 months to 9 years) with extreme structural central airway obstruction with stent implantations. Six were mechanically ventilated; 5 had frequent life-threatening obstructive spells requiring deep sedation or paralysis. Diagnoses were: syndrome-associated tracheobronchomalacia (n = 4), malignancy infiltrating the carina (n = 1), congenital tracheal stenosis (n = 1), and tracheobronchial compression by a malpositioned aorta (n = 1). Six tracheal and 13 bronchial stents were endoscopically placed. The prostheses included mesh titan (n = 5), the newer shape memory material nitinol (n = 13), and 1 Y-shaped carina stent. Follow-up was reported for 7 weeks to 72 months. All patients showed marked improvement of their respiratory obstruction. Six children were weaned at least temporarily from ventilation. No significant bleeding, stenosis, or perforation was observed. Seven stents were changed after up to 14 months. Three children are well and at home. In 2 children airway stabilization was successful, but they later died from causes unrelated to stent placement, and 2 children died due to generalized airway disease. Soft metal mesh airway stents can offer a therapeutic option in life-threatening inoperable obstruction of the trachea and main stem bronchi in children.

Over the last few years various types of metal wire stents have been increasingly employed in the treatment of both malignant and benign tracheobronchial obstruction. To date, however, few studies have investigated the in vivo properties of different stent types. We implanted 26 balloon-expandable tantalum Strecker stents (18 patients) and 18 self-expandable Wallstents (16 patients) into the tracheobronchial system of 30 patients with combined stenting in 4 patients. Mean age was 51 years (range: 0.5-79 years). Malignant disease was present in 23 patients, benign disease in seven patients. Both patients and individual stents were monitored clinically and radiographically. The probability of stents remaining within the tracheobronchial system, and of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for both stent types. Average stent follow-up time was 112 days until explantation and 115 days until patients' death or discharge. Kaplan-Meier analysis revealed a higher probability for the Wallstent to remain within the tracheobronchial system. Dislocation and compression occurred more rarely. Explantation, however, if desired, was more difficult compared to the Strecker stent. The Wallstent also led to the formation of granulation tissue, especially at the proximal stent end, frequently requiring reintervention. Both stent types proved to be effective therapeutic options in the management of obstructive tracheobronchial disease. The mechanical properties of the Strecker stent seem to be less favorable compared to the Wallstent but removal is easy. For benign disease, however, the Wallstent reveals limitations due to significant side effects.

Tracheobronchial endoluminal reconstruction and stenting has become a valuable palliative tool in adults with intrathoracic tumors compromising the airways. Tracheobronchial balloon dilatation has been recently used in children and even neonates. We report a case of severe airway obstruction requiring emergency intubation and artificial ventilation in a 5-year-old child with intrathoracic recurrence of a rhabdomyosarcoma. Endoscopic balloon dilatation through the endotracheal tube with subsequent implantation of a non self-expanding metal mesh stent was used successfully, allowing extubation and discharge of the child from ICU.