Case Report: Durable therapy response to Osimertinib in rare EGFR Exon 18 mutated NSCLC.

Up to 20% of all non-small cell lung cancer patients harbor tumor specific driver mutations that are effectively treated with tyrosine kinase inhibitors. However, for the rare EGFR deletion-insertion mutation of exon 18, there is very little evidence regarding the effectiveness of tyrosine kinase inhibitors. A particular challenge for clinicians in applying tyrosine kinase inhibitors is not only diagnosing a mutation but also interpreting rare mutations with unclear therapeutic significance. Thus, we present the case of a 65-year-old Caucasian male lung adenocarcinoma patient with an EGFR Exon 18 p.Glu709_Thr710delinsAsp mutation of uncertain therapeutic relevance. This patient initially received two cycles of standard platinum-based chemotherapy without any therapeutic response. After administration of Osimertinib as second line therapy, the patient showed a lasting partial remission for 12 months. Therapy related toxicities were limited to mild thrombocytopenia, which ceased after dose reduction of Osimertinib. To our knowledge, this is the first report of effective treatment of this particular mutation with Osimertinib. Hence, we would like to discuss Osimertinib as a viable treatment option in EGFR Exon 18 p.Glu709_Thr710delinsAsp mutated lung adenocarcinoma.

Targeting miR-34a/Pdgfra interactions partially corrects alveologenesis in experimental bronchopulmonary dysplasia.

Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth characterized by arrested lung alveolarization, which generates lungs that are incompetent for effective gas exchange. We report here deregulated expression of miR-34a in a hyperoxia-based mouse model of BPD, where miR-34a expression was markedly increased in platelet-derived growth factor receptor (PDGFR)α-expressing myofibroblasts, a cell type critical for proper lung alveolarization. Global deletion of miR-34a; and inducible, conditional deletion of miR-34a in PDGFRα+ cells afforded partial protection to the developing lung against hyperoxia-induced perturbations to lung architecture. Pdgfra mRNA was identified as the relevant miR-34a target, and using a target site blocker in vivo, the miR-34a/Pdgfra interaction was validated as a causal actor in arrested lung development. An antimiR directed against miR-34a partially restored PDGFRα+ myofibroblast abundance and improved lung alveolarization in newborn mice in an experimental BPD model. We present here the first identification of a pathology-relevant microRNA/mRNA target interaction in aberrant lung alveolarization and highlight the translational potential of targeting the miR-34a/Pdgfra interaction to manage arrested lung development associated with preterm birth.