Fat1 deletion promotes hybrid EMT state, tumour stemness and metastasis.

FAT1, which encodes a protocadherin, is one of the most frequently mutated genes in human cancers1-5. However, the role and the molecular mechanisms by which FAT1 mutations control tumour initiation and progression are poorly understood. Here, using mouse models of skin squamous cell carcinoma and lung tumours, we found that deletion of Fat1 accelerates tumour initiation and malignant progression and promotes a hybrid epithelial-to-mesenchymal transition (EMT) phenotype. We also found this hybrid EMT state in FAT1-mutated human squamous cell carcinomas. Skin squamous cell carcinomas in which Fat1 was deleted presented increased tumour stemness and spontaneous metastasis. We performed transcriptional and chromatin profiling combined with proteomic analyses and mechanistic studies, which revealed that loss of function of FAT1 activates a CAMK2-CD44-SRC axis that promotes YAP1 nuclear translocation and ZEB1 expression that stimulates the mesenchymal state. This loss of function also inactivates EZH2, promoting SOX2 expression, which sustains the epithelial state. Our comprehensive analysis identified drug resistance and vulnerabilities in FAT1-deficient tumours, which have important implications for cancer therapy. Our studies reveal that, in mouse and human squamous cell carcinoma, loss of function of FAT1 promotes tumour initiation, progression, invasiveness, stemness and metastasis through the induction of a hybrid EMT state.

Identification of the tumour transition states occurring during EMT.

In cancer, the epithelial-to-mesenchymal transition (EMT) is associated with tumour stemness, metastasis and resistance to therapy. It has recently been proposed that, rather than being a binary process, EMT occurs through distinct intermediate states. However, there is no direct in vivo evidence for this idea. Here we screen a large panel of cell surface markers in skin and mammary primary tumours, and identify the existence of multiple tumour subpopulations associated with different EMT stages: from epithelial to completely mesenchymal states, passing through intermediate hybrid states. Although all EMT subpopulations presented similar tumour-propagating cell capacity, they displayed differences in cellular plasticity, invasiveness and metastatic potential. Their transcriptional and epigenetic landscapes identify the underlying gene regulatory networks, transcription factors and signalling pathways that control these different EMT transition states. Finally, these tumour subpopulations are localized in different niches that differentially regulate EMT transition states.

Treatment of solitary thyroid nodules according to size, preoperative fine-needle aspiration cytology and frozen section: a retrospective single centre study.

Background: In order to avoid unnecessary thyroidectomies, it is important to predict the nature of thyroid nodules the more accurately possible. The size of the nodule as a predictive factor for malignancy is very controversial. Another point of debate is the accuracy of preoperative fine-needle aspiration cytology (FNAC) and frozen section (FS). The aim of our study is to correlate the nodule size with the final histological diagnosis and to estimate the accuracy of preoperative FNAC and FS. Methods: Retrospective study including 387 operated patients with ultrasound-detected solitary thyroid nodules from 01 January 2001 to 31 December 2013. The following data were collected: patient age and sex, nodule size, FNAC, FS and final histology results. Results: The odds ratio for malignancy within nodules <40 mm was 2.12 (95% CI: 1.104-4.084). The specificity of FNAC was 97.78% and the negative predictive value (NPV) was 97.78% for nodules ≥40 mm and 93.2% and 96.5% for nodules <40 mm, respectively. The observed specificity and NPV of FS ranged from 98% to 100% and from 87.4% to 98%, respectively. When combining FNAC and FS, the specificity and the NPV were 99% and 98%, respectively. Conclusions: The nodule size is not a predictive factor for thyroid cancer and therefore nodules ≥40 mm should not be routinely resected. A lege artis preparation and performance of FNAC along with an expertise on cytological interpretation can considerably diminish false-negative rate. FS can offer additional accuracy on FNAC results and should, therefore, be a part of patient treatment.

Thyroid lobectomy is an effective option for unilateral benign nodular disease.

OBJECTIVE: The use of thyroid lobectomy in the treatment of unilateral, benign nodules is limited by the potential of nodular recurrence in the remaining lobe. This study aimed to assess the rate and clinical impact of nodular recurrence in the contralateral lobe after thyroid lobectomy and to identify predictive factors of recurrence. DESIGN: Single-centre retrospective study. PATIENTS: Records of patients that underwent lobectomy for unilateral thyroid nodules between 1991 and 2010 were reviewed and 270 patients were included. Exclusion criteria were: presence of contralateral nodule(s) ≥5 mm on preoperative ultrasound, diagnosis of cancer necessitating completion thyroidectomy or pseudonodules. Recurrence was defined as the occurrence of nodule(s) ≥5 mm in the remaining lobe on at least one postoperative ultrasound. A set of clinical, imaging, histological and biochemical parameters was tested as predictors of recurrence using logistic regression. RESULTS: After a median follow-up of 78 months (range, 12-277 months), the global recurrence rate was 42% and recurrence of nodules of a size ≥1 cm occurred in 19%. Reoperation rate was 1·1%. 90% of patients were treated postoperatively by levothyroxine. Median time to nodular recurrence was 4 years. Preoperative contralateral lobe volume and resected thyroid weight were identified as significant predictors of recurrence (P = 0·045 and P = 0·03 respectively). CONCLUSIONS: Thyroid lobectomy is an effective therapeutic strategy for unilateral, benign nodules, resulting in a low rate of clinically relevant nodular relapse in a mildly iodine-deficient area. Patients with uninodular disease and a contralateral lobe of normal size are particularly good candidates for lobectomy.

FDG uptake at the bronchial stump after curative lobectomy for non-small cell lung cancer.

PURPOSE: Focal areas of FDG uptake may occur at the bronchial stump following curative lobectomy for non-small-cell lung carcinoma (NSCLC), even in the absence of suspicious CT changes. The purpose of our study was to investigate the significance of such PET/CT findings. METHODS: FDG-PET/CT scans performed in 54 patients after lobectomy for NSCLC were reviewed. The presence of focal areas of FDG uptake at the bronchial stump, associated CT abnormalities, SUVmax, and normalized SUV (SUVnorm = SUVmax/mean liver SUV) were recorded. Final diagnosis was based on biopsy or imaging follow-up. RESULTS: Focal areas of FDG uptake at the bronchial stump were detected in 30 patients (56 %). Mean SUVmax was 4.0 ± 1.9 (range; 2.2-12.1) and mean SUVnorm was 1.8 ± 0.8 (range; 0.9-4.5). Biopsy showed recurrence in two patients. In these patients, SUVnorm was respectively 4.4 and 4.5 (with SUVmax of 8.8 and 12.1), whereas SUVnorm was lower than 4.0 in those without recurrence, with mean SUVnorm of 1.6 ± 0.5 (range; 0.9-3.4) and mean SUVmax of 3.6 ± 0.9 (range; 2.2-5.8). The CT component of the PET/CT revealed ill-defined peribronchial soft tissue opacity only in both patients with recurrence. CONCLUSION: FDG uptake at the bronchial stump is a frequent finding after pulmonary lobectomy. Moderate levels of FDG uptake (i.e., SUVnorm < 4.0) without corresponding abnormal CT findings might be a dual criterion for diagnosing benign post-surgical changes.

Linking clinical phenotypes of chronic lung allograft dysfunction to changes in lung structure.

Chronic lung allograft dysfunction (CLAD) remains the major barrier to long-term success after lung transplantation. This report compares gross and microscopic features of lungs removed from patients receiving a redo-transplant as treatment for CLAD. Lungs donated by patients with either the bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS) phenotype of CLAD and appropriate control lungs (eight per group) were air-inflated, frozen solid and kept frozen while a multi-detector computed tomography (MDCT) was obtained. The lung was then cut into 2-cm thick transverse slices and sampled for micro-CT and histopathology. The MDCT showed reduced lung volume with increased lung weight and density in RAS versus BOS and control (p<0.05). Although pre-terminal bronchioles were obstructed in both phenotypes, RAS lungs showed a reduction of pre-terminal bronchioles (p<0.01). Micro-CT and matched histopathology showed that RAS was associated with reduced numbers of terminal bronchioles/lung compared to BOS and controls (p<0.01), with expansion of the interstitial compartment and obliteration of the alveolar airspaces by fibrous connective tissue. RAS is associated with greater destruction of both pre-terminal and terminal bronchioles. Additionally, the interstitial compartments are expanded and alveolar airspaces are obliterated by accumulation of fibrous connective tissue.

Monocentric, Retrospective Study on Infectious Complications within One Year after Solid-Organ Transplantation at a Belgian University Hospital.

The epidemiology, diagnostic methods and management of infectious complications after solid-organ transplantation (SOT) are evolving. The aim of our study is to describe current infectious complications in the year following SOT and risk factors for their development and outcome. We conducted a retrospective study in adult SOT recipients in a Belgian university hospital between 2018 and 2019. We gathered demographic characteristics, comorbidities leading to transplantation, clinical, microbiological, surgery-specific and therapeutic data concerning infectious episodes, and survival status up to one year post-transplantation. Two-hundred-and-thirty-one SOT recipients were included (90 kidneys, 79 livers, 35 lungs, 19 hearts and 8 multiple organs). We observed 381 infections in 143 (62%) patients, due to bacteria (235 (62%)), viruses (67 (18%)), and fungi (32 (8%)). Patients presented a median of two (1-5) infections, and the first infection occurred during the first six months. Nineteen (8%) patients died, eleven (58%) due to infectious causes. Protective factors identified against developing infection were obesity [OR [IC]: 0.41 [0.19-0.89]; p = 0.025] and liver transplantation [OR [IC]: 0.21 [0.07-0.66]; p = 0.007]. Risk factors identified for developing an infection were lung transplantation [OR [IC]: 6.80 [1.17-39.36]; p = 0.032], CMV mismatch [OR [IC]: 3.53 [1.45-8.64]; p = 0.006] and neutropenia [OR [IC]: 2.87 [1.27-6.47]; p = 0.011]. Risk factors identified for death were inadequate cytomegalovirus prophylaxis, infection severity and absence of pneumococcal vaccination. Post-transplant infections were common. Addressing modifiable risk factors is crucial, such as pneumococcal vaccination.

Cryobiopsy and dye marking guided by electromagnetic navigation bronchoscopy before resection of pulmonary nodule.

BACKGROUND: Our aims were to explore the feasibility, safety, and efficacy of peroperative transbronchial lung cryobiopsy (TBLC) guided by electromagnetic navigation bronchoscopy (ENB) and ENB-guided methylene blue marking of presumably non-palpable pulmonary nodules, and to assess its impact on video-assisted thoracoscopic surgery (VATS) and postoperative lung function. METHODS: This approach was applied to 16 consecutive patients (Group A, mean age 64 years) who were compared retrospectively to a historical group of 49 patients (Group B, mean age 62 years) with similar nodules resected without guidance. The usefulness of dye marking was graded. The success rates of both ENB-guided TBLC and nodule localization through dye marking were computed. The type of resection, volume of resected parenchyma, duration of procedures, and postoperative lung function were compared between groups. Unpaired t-test, chi-square test, unpaired Wilcoxon test, and exact Fisher test were used when appropriate. RESULTS: Malignancy was pathologically proven in all patients. TBLC revealed malignancy in 9 patients in Group A. The success rate of ENB-guided dye marking was 94%. Lobectomy was less frequently performed in Group A than in Group B (p = 0.022). Forced expiratory volume in 1 s and total lung capacity were significantly less reduced in Group A than in Group B (p = 0.006 and p = 0.019, respectively). Combined procedure was longer than surgery alone (p<0.001), but its surgical part was shorter than VATS without guidance (p < 0.001). CONCLUSION: Peroperative ENB-guided TBLC with methylene blue marking of non-palpable lung nodules is feasible. A sparing lung parenchyma procedure could be achieved thanks to the ENB-guided dye marking before VATS.

Multicentric evaluation of the impact of central tumour location when comparing rates of N1 upstaging in patients undergoing video-assisted and open surgery for clinical Stage I non-small-cell lung cancer†.

OBJECTIVES: Large retrospective series have indicated lower rates of cN0 to pN1 nodal upstaging after video-assisted thoracic surgery (VATS) compared with open resections for Stage I non-small-cell lung cancer (NSCLC). The objective of our multicentre study was to investigate whether the presumed lower rate of N1 upstaging after VATS disappears after correction for central tumour location in a multivariable analysis. METHODS: Consecutive patients operated for PET-CT based clinical Stage I NSCLC were selected from prospectively managed surgical databases in 11 European centres. Central tumour location was defined as contact with bronchovascular structures on computer tomography and/or visibility on standard bronchoscopy. RESULTS: Eight hundred and ninety-five patients underwent pulmonary resection by VATS (n = 699, 9% conversions) or an open technique (n = 196) in 2014. Incidence of nodal pN1 and pN2 upstaging was 8% and 7% after VATS and 15% and 6% after open surgery, respectively. pN1 was found in 27% of patients with central tumours. Less central tumours were operated on by VATS compared with the open technique (12% vs 28%, P < 0.001). Logistic regression analysis showed that only tumour location had a significant impact on N1 upstaging (OR 6.2, confidence interval 3.6-10.8; P < 0.001) and that the effect of surgical technique (VATS versus open surgery) was no longer significant when accounting for tumour location. CONCLUSIONS: A quarter of patients with central clinical Stage I NSCLC was upstaged to pN1 at resection. Central tumour location was the only independent factor associated with N1 upstaging, undermining the evidence for lower N1 upstaging after VATS resections. Studies investigating N1 upstaging after VATS compared with open surgery should be interpreted with caution due to possible selection bias, i.e. relatively more central tumours in the open group with a higher chance of N1 upstaging.

Influence of Donor Lung Surfactant-A and -B Protein Expression on the Development of Primary Graft Dysfunction After Lung Transplantation: A Pilot Study.

BACKGROUND Primary graft dysfunction (PGD) is responsible of high early mortality in lung transplanted patients. We measured the rate of surfactant proteins in the organ donor, and we observed the occurrence of lung PGD in the recipient. The co-relation between these two parameters was evaluated. MATERIAL AND METHODS In this pilot study, we prospectively collected blood samples and lung biopsies in thirteen donors at the time of recovery of organs before preservation. Gene expression of SP-A, SP-B, SP-D, and CC16 was evaluated by real-time quantitative PCR. Surfactant proteins plasma levels were evaluated by ELISA. Post-transplant assessments included hemodynamic, arterial blood gas measurements, and radiographic evaluation to determine PGD and lung biopsies. RESULTS Nine of the thirteen recipients (69%) developed lung infiltrates and four (31%) developed PGD at either stages 2 or 3. SP-A and SP-B expressions were dramatically reduced in lung allografts of these patients, while lung expression of SP-D and CC16 remained unchanged. Plasma levels of SP-A, SP-B, SP-D, and CC16 did not differ. CONCLUSIONS Primary graft dysfunction may be initiated in the donor. Lung allografts with low lung SP-A and SP-B gene expression prior to implantation are associated with increased incidence of lung infiltrates after transplantation.

Stent-in-Stent Technique for the Treatment of Proximal Bronchial Restenosis after Insertion of Metallic Stents: A Report of Two Cases.

Endoscopic treatment of a bronchial restenosis previously treated by insertion of a partially covered self-expandable metallic stent (SEMS) can be difficult. Classically, after recanalization of the bronchus, the stent is removed and replaced by a more adapted one. We report on two cases of proximal bronchial restenosis treated by insertion of an additional stent inside the lumen of the previously inserted stent using the stent-in-stent (SIS) technique. The indications for the initial stent were malignancy in Patient 1 and posttransplant bronchial stenosis in Patient 2. Restenosis occurred at the proximal end of the stent within months in both cases. Stent removal and insertion of a new stent were considered, but this option was discarded because of an excessive risk of bronchial perforation and preference towards an alternative approach. In both cases, a second customized SEMS was placed using the SIS technique after ablation of the proximal end stenosis of the stent by argon plasma coagulation and/or dilation with a balloon. Recanalization of the bronchus was achieved in both cases without complications. The SIS technique is a valuable alternative to removal of SEMS in case of proximal bronchial restenosis.

Thoracoscopic tunnel technique for anatomical lung resections: a 'fissure first, hilum last' approach with staplers in the fissureless patient.

OBJECTIVES: To minimize air leak after anatomical lung resections, many video-assisted thoracic surgery (VATS) surgeons use a 'fissureless' technique, using staplers to divide the hilar bronchovascular structures first and the main part of the fissure last. We describe a cohort of 198 consecutive patients operated with an alternative fissureless technique, opening the fissure completely with staplers at an early stage of the VATS anatomical lung resection. METHODS: To open the incomplete fissure first and with staplers, a tunnel dissection is started anterior between the triangle of pulmonary veins and the parenchyma. After identification of the pulmonary artery, the anvil of a first stapler is placed on top of the artery and the anterior part of the fissure is divided. Dissection between artery and parenchyma is continued until the fissure is completely stapled. From a prospectively managed single institution database, we retrieved 405 patients scheduled for VATS anatomical resection between October 2009 and December 2014. The patients were categorized in four consecutive periods: a learning curve with the first 50 cases of VATS lobectomy technique (LC), a period of consecutive 'hilum first, fissure last' (HF), a transition group (TG) during which both techniques were used and a period of consecutive 'fissure first, hilum last' (FF). RESULTS: No significant differences in operating time, frequency of prolonged air leak or hospital stay were observed between HF (n = 45) and FF (n = 198). Chest tubes were removed earlier in the FF period (6.9 vs 5.2 days, P = 0.025). Excluding the learning curve, we found 2 patients (2.8%) operated 'hilum first' with an intraoperative complication that potentially could have been avoided by a 'fissure first' technique. CONCLUSIONS: By making a tunnel between the bronchovascular structures and parenchyma from anteriorly to posteriorly, one can open the fissure completely with staplers at an early stage of an anatomical lung resection. This combines the advantages of both the 'fissureless' hilum first technique and classic (open) fissure first dissection, i.e. minimal air leak and optimal anatomical overview before bronchovascular structures are divided, potentially avoiding inadvertent transections. A cohort of 198 consecutive patients operated with this alternative fissureless technique demonstrates the feasibility and non-inferiority regarding hospital stay, chest tube duration, operation time and complications in comparison with the hilum first technique.

Prospective European multicenter randomized trial of PleuraSeal for control of air leaks after elective pulmonary resection.

OBJECTIVES: We sought to evaluate the efficacy and safety of a synthetic bioresorbable pleural sealant (PleuraSeal; Covidien, Bedford, Mass) to treat air leaks after pulmonary resection. METHODS: Patients with air leaks after lung resection were randomized to treatment with pleural sealant on air leak sites after standard methods of lung closure or standard lung closure only. The primary outcome variable was the percentage of patients remaining air leak free until discharge. The secondary outcome variables were the proportion of patients with successful intraoperative air leak sealing, time to last air leak, and durations of chest tube drainage and hospitalization. RESULTS: The sealant group comprised 62 subjects, and the control group comprised 59 subjects. Most patients (98.3%) underwent open lobectomy for bronchogenic carcinoma. The overall success rates for intraoperative air leak sealing were as follows: sealant group, 71.0%; control group, 23.7% (P < .001). For grade 2 and 3 air leaks (n = 77), the intraoperative sealing rates were as follows: sealant group, 71.7%; control group, 9.1% (P < .001). More patients with grade 2 and 3 air leaks had their leaks remain sealed in the sealant group (43.5% vs 15.2%, P = .013). The median time from skin closure to last observable air leak was 6 hours (sealant group) versus 42 hours (control group, P = .718). No treatment-related complications were reported. No differences in drainage or hospitalization were observed. CONCLUSIONS: In this multicenter study the pleural sealant was safe and effective treatment for intraoperative air leaks after lung resection. Significantly fewer patients with surgically relevant intraoperative air leaks had postoperative air leaks when the pleural sealant was applied.