Characterization and Mapping of a Rolling Leaf Mutant Allele rlT73 on Chromosome 1BL of Wheat.

Leaf rolling is regarded as an important morphological trait in wheat breeding. Moderate leaf rolling is helpful to keep leaves upright and improve the photosynthesis of plants, leading to increased yield. However, studies on the identification of genomic regions/genes associated with rolling leaf have been reported less frequently in wheat. In this study, a rolling leaf mutant, T73, which has paired spikelets, dwarfism, and delayed heading traits, was obtained from a common wheat landrace through ethyl methanesulfonate mutagenesis. The rlT73 mutation caused an increase in the number of epidermal cells on the abaxial side and the shrinkage of bulliform cells on the adaxial side, leading to an adaxially rolling leaf phenotype. Genetic analysis showed that the rolling leaf phenotype was controlled by a single recessive gene. Further Wheat55K single nucleotide polymorphism array-based bulked segregant analysis and molecular marker mapping delimited rlT73 to a physical interval of 300.29-318.33 Mb on the chromosome arm 1BL in the Chinese Spring genome. We show that a point mutation at the miRNA165/166 binding site of the HD zipper class III transcription factor on 1BL altered its transcriptional level, which may be responsible for the rolling leaf phenotype. Our results suggest the important role of rlT73 in regulating wheat leaf development and the potential of miRNA-based gene regulation for crop trait improvement.

Combination of Cytologic Findings and Circulating Tumor DNA From Cerebrospinal Fluid Revealed SCLC Transformation in Patients With Leptomeningeal Metastases of Lung Adenocarcinoma.

Introduction: Transformation to SCLC is a resistance mechanism to tyrosine kinase inhibitor in EGFR-mutated lung adenocarcinoma (LUAD). Nevertheless, the clinical and molecular features of SCLC transformation in LUAD with leptomeningeal metastases (LM) are scarce. Methods: We retrospectively collected 237 patients with NSCLC who underwent lumbar puncture owing to suggestion of LM. All SCLC transformation in cerebrospinal fluid (CSF) was confirmed by two experienced pathologists using cytologic evaluation. CSF circulating tumor DNA (ctDNA) was tested by next-generation sequencing. Results: Tumor cells in CSF samples were found in 111 patients (111 of 237, 46.8%), and eight cases (eight of 111, 7.2%) were identified as having SCLC cells in CSF. Seven patients carried the EGFR mutation, including four patients with EGFR exon 19 deletion and three patients with EGFR exon 21 L858R mutation. Another patient harbored ERBB2 insertion. Seven of these patients were resistant to targeted therapy. CSF ctDNA analysis reported that TP53 and RB1 mutations were common. The median time from the diagnosis of advanced NSCLC to SCLC transformation found in CSF was 9.7 months (95% confidence interval [CI]: 4.0-17.5 mo). The median overall survival since the initial diagnosis of metastatic NSCLC was 15.3 months (95% CI: 1.2-29.4 mo). The median overall survival after SCLC transformation detected in CSF was 5.0 months (95% CI: 4.0-5.9 mo). Conclusions: SCLC transformation may be revealed in CSF by both cytologic evaluation and ctDNA, not just in tissue that underwent rebiopsy. SCLC transformation of CSF is informative for resistance mechanism in patients with LUAD with LM on tyrosine kinase inhibitor progression, which was associated with poor survival.

Perioperative targeted therapy for oncogene-driven NSCLC.

Targeted therapy has stepped into the perioperative treatment arena and launched a radical revolution in the treatment of early-stage oncogene-driven non-small-cell lung cancer (NSCLC). A series of practice-changing clinical trials has enriched the therapeutic perspectives of potentially curable NSCLC. While the CTONG1104 trial took the first step in investigating the adjuvant gefitinib - a first-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), for the treatment of resected EGFR-mutated NSCLC - the subsequent ADAURA study marked adjuvant osimertinib as the standard of care for resected EGFR-mutant NSCLC. Other targeted agents matched for ALK, ROS1, NTRK, BRAF V600, and RET molecular alterations are also currently being evaluated in the adjuvant and neoadjuvant settings, and there is an urgent need to study biomarker selection, optimal duration, and paradigm making. All these efforts are intended to hit the same target, which is to treat patients on a more personalized level. We review herein the recent major breakthroughs in perioperative targeted therapy for oncogene-driven NSCLC, focusing especially on data from published clinical trials. We discuss challenges from surgical, pathological, and oncological perspectives, and provide recommended strategies for the clinical management of early-stage NSCLC patients.