A lab-on-a-disc platform enables serial monitoring of individual CTCs associated with tumor progression during EGFR-targeted therapy for patients with NSCLC

Rationale: Unlike traditional biopsy, liquid biopsy, which is a largely non-invasive diagnostic and monitoring tool, can be performed more frequently to better track tumors and mutations over time and to validate the efficiency of a cancer treatment. Circulating tumor cells (CTCs) are considered promising liquid biopsy biomarkers; however, their use in clinical settings is limited by high costs and a low throughput of standard platforms for CTC enumeration and analysis. In this study, we used a label-free, high-throughput method for CTC isolation directly from whole blood of patients using a standalone, clinical setting-friendly platform. Methods: A CTC-based liquid biopsy approach was used to examine the efficacy of therapy and emergent drug resistance via longitudinal monitoring of CTC counts, DNA mutations, and single-cell-level gene expression in a prospective cohort of 40 patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer. Results: The change ratio of the CTC counts was associated with tumor response, detected by CT scan, while the baseline CTC counts did not show association with progression-free survival or overall survival. We achieved a 100% concordance rate for the detection of EGFR mutation, including emergence of T790M, between tumor tissue and CTCs. More importantly, our data revealed the importance of the analysis of the epithelial/mesenchymal signature of individual pretreatment CTCs to predict drug responsiveness in patients. Conclusion: The fluid-assisted separation technology disc platform enables serial monitoring of CTC counts, DNA mutations, as well as unbiased molecular characterization of individual CTCs associated with tumor progression during targeted therapy

An Esophageal Leiomyoma Mistaken as an Esophageal Duplication Cyst

Esophageal leiomyoma is a benign tumor that accounts for two-thirds of esophageal benign tumors. In general, patients with esophageal leiomyoma are asymptomatic; however, as the tumor grows in size, symptoms such as dysphagia, chest discomfort, obstruction, or bleeding can appear. A 65-year-old man visited our clinic to receive treatment for a subepithelial tumor in the lower esophagus, which was incidentally found during endoscopy for work-up of chest discomfort and indigestion. On endoscopic ultrasonography (EUS), the tumor was 2.6×1.9 cm in size, with a cystic lesion located in the submucosal and proper muscle layers and thick cystic wall. Therefore, it was highly likely to be a duplication cyst. As the patient had symptoms such as chest discomfort, surgical resection was performed. The tumor was finally diagnosed as a leiomyoma with cystic degeneration. Leiomyoma with cystic change that has similar EUS features to duplication cyst is rare. Thus, we report the case with a literature review