MicroRNA analysis of microdissected normal squamous esophageal epithelium and tumor cells

Previous studies have identified several dysregulated microRNAs in esophageal squamous cell carcinoma (ESCC); however, to date there are no ex vivo analyses comparing expression levels of these regulatory molecules in esophageal squamous cell tumors versus patient-matched normal epithelium. We describe here a technical strategy to evaluate microRNAs in normal esophageal basal cells (NB), normal esophageal differentiated cells (ND), and tumor cells (T). Laser capture microdissection was used to procure target populations from five cases and 18 ESCC-associated microRNAs were measured by RT-qPCR. Five microRNAs (miR-25, miR-106b, miR-21, miR-203, and miR-145) demonstrated consistent differential expression in at least one of the three comparisons: T vs. NB, T vs. ND, or NB vs. ND. The potential regulatory role of the microRNAs in ESCC was further evaluated by correlating their expression with a matched mRNA dataset, which included the same five cases and cell populations. In conclusion, the present work demonstrates the feasibility of studying microRNA levels in precisely dissected cell populations from clinical samples, and sheds light on the molecular mechanisms associated with ESCC.