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Rationale: Chronic infection and inflammation shapes the airway microbiome in bronchiectasis. Utilizing whole-genome shotgun metagenomics to analyze the airway resistome provides insight into interplay between microbes, resistance genes, and clinical outcomes. Objectives: To apply whole-genome shotgun metagenomics to the airway microbiome in bronchiectasis to highlight a diverse pool of antimicrobial resistance genes: the "resistome," the clinical significance of which remains unclear. Methods: Individuals with bronchiectasis were prospectively recruited into cross-sectional and longitudinal cohorts (n = 280), including the international multicenter cross-sectional Cohort of Asian and Matched European Bronchiectasis 2 (CAMEB 2) study (n = 251) and two independent cohorts, one describing patients experiencing acute exacerbation and a further cohort of patients undergoing Pseudomonas aeruginosa eradication treatment. Sputum was subjected to metagenomic sequencing, and the bronchiectasis resistome was evaluated in association with clinical outcomes and underlying host microbiomes. Measurements and Main Results: The bronchiectasis resistome features a unique resistance gene profile and increased counts of aminoglycoside, bicyclomycin, phenicol, triclosan, and multidrug resistance genes. Longitudinally, it exhibits within-patient stability over time and during exacerbations despite between-patient heterogeneity. Proportional differences in baseline resistome profiles, including increased macrolide and multidrug resistance genes, associate with shorter intervals to the next exacerbation, whereas distinct resistome archetypes associate with frequent exacerbations, poorer lung function, geographic origin, and the host microbiome. Unsupervised analysis of resistome profiles identified two clinically relevant "resistotypes," RT1 and RT2, the latter characterized by poor clinical outcomes, increased multidrug resistance, and P. aeruginosa. Successful targeted eradication in P. aeruginosa-colonized individuals mediated reversion from RT2 to RT1, a more clinically favorable resistome profile demonstrating reduced resistance gene diversity. Conclusions: The bronchiectasis resistome associates with clinical outcomes, geographic origin, and the underlying host microbiome. Bronchiectasis resistotypes link to clinical disease and are modifiable through targeted antimicrobial therapy.

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BACKGROUND: In non-small cell lung cancer (NSCLC), there may be a relationship between programmed death-ligand 1 (PD-L1) expression, driver mutations and cigarette smoking. METHODS: In this single-center retrospective study, the relationship between common driver mutations (EGFR mutation and ALK rearrangement) and PD-L1 expression in advanced NSCLC according to the patients' smoking history was examined. Light, moderate and heavy smokers had smoked < 20, 20-39, and ≥ 40 pack-years, respectively. The level of PD-L1 expression, assessed using Ventana SP263 monoclonal antibody assay, was defined by the tumor proportion score (TPS) as high expression (TPS ≥ 50%), low expression (TPS 1%-49%) and no expression (TPS < 1%). RESULTS: 101 (52.9%) of 191 advanced NSCLC patients were never smokers. EGFR mutations were more common in never smokers (64.4%) than in smokers (17.8%) with advanced NSCLC (P < 0.0001). A higher proportion of smokers (26.7%) had high PD-L1 expression compared to never smokers (13.9%) (P = 0.042). There was a trend for a higher proportion of male NSCLC patients [28 of 115 (24.3%)] than female patients [10 of 76 (13.2%)] to have high PD-L1 expression (P = 0.087]. High PD-L1 expression was seen in 32 of 110 (29.1%) patients with EGFR wild-type NSCLC but only in 6 of 81 (7.4%) patients with EGFR-mutant tumors (P < 0.0001). Among the 90 smokers with NSCLC, a higher proportion of heavy smokers (35.8%) than non-heavy smokers (13.5%) had high PD-L1 expression (P = 0.034). In patients with adenocarcinoma, high PD-L1 expression was seen in 25 of 77 (32.5%) patients with EGFR wild-type tumors but only in 4 of 70 (5.7%) patients with EGFR-mutant tumors (P < 0.0001). Among patients with adenocarcinoma, a significantly higher proportion of ever smokers (29.3%) than never smokers (13.5%) had high PD-L1 expression (P = 0.032). Among smokers with adenocarcinoma, a significantly higher proportion of heavy smokers (44.1%) than non-heavy smokers (8.3%) had high PD-L1 expression (P = 0.004). On multivariate analysis, after adjusting for gender and smoking status, heavy smoking and EGFR wild-type tumors remained significantly associated with high PD-L1 expression in NSCLCs and also in adenocarcinoma. CONCLUSIONS: Heavy smoking and EGFR wild-type tumors were significantly associated with high PD-L1 expression in NSCLCs and also in adenocarcinoma.

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Neoadjuvant chemotherapy is a therapeutic option for potentially resectable non-small cell lung cancer (NSCLC). The role of neoadjuvant targeted therapy (NTT) remains less explored. This case highlights the use of neoadjuvant osimertinib in a case of advanced NSCLC. A 67-year-old woman had a left lower lobe lung mass measuring 5.0 × 5.1 × 7.0 cm with an enlarged subcarinal lymph node (LN) on her positron emission tomography scan. Following biopsy, a diagnosis of stage IIIB N2 (cT3N2M0) EGFR exon 19 deletion mutation-positive lung adenocarcinoma was established. NTT using osimertinib 80 mg once daily was commenced. Subsequent re-imaging at 3 months (ycT2bN2M0), 6 months (ycT1cN2M0) and 9 months showed tumour downstaging and resolution of the subcarinal LN (ycT1cN0M0). She underwent left lower lobectomy with systematic nodal dissection. All surgical specimens demonstrated no evidence of malignant cells (ypT0N0). Osimertinib could be the preferred NTT for potentially resectable NSCLC.

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Adjuvant chemotherapy has long been indicated to extend survival in completely resected stage IB to IIIA non-small cell lung cancer (NSCLC). However, there is accumulating evidence that chemotherapy or chemoradiotherapy can induce epithelial-to-mesenchymal transition (EMT) in disseminated or circulating NSCLC cells. Here, we describe the first case of EMT as the cause of recurrence and metastasis in a patient with resected stage IIB lung adenosquamous carcinoma after adjuvant chemotherapy. We review the literature and explore the possible mechanisms by which EMT occurs in disseminated tumor cells (DTC) or circulating tumor cells (CTC) in response to adjuvant chemotherapy (cisplatin) as a stressor. We also explore the possible therapeutic strategies to reverse EMT in patients with recurrence. In summary, although adjuvant cisplatin-based chemotherapy in resected NSCLC does extend survival, it may lead to the adverse phenomenon of EMT in disseminated tumor cells (DTC) or circulating tumor cells (CTC) causing recurrence and metastasis.

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