AIM:To investigate expression of microRNA(miRNA)and potential targets in chemotherapy resistant esoph-ageal cancer cell lines.METHODS:An in-vitro model of acquired chemotherapy resistance in esophageal adeno-(EAC)and squamous cell carcinoma(ESCC)cells was used,and microRNA expression profiles for cisplatin or 5-fluorouracil(5-FU)resistant variants vs chemotherapy sensitive controls were compared using microarray and quantitative real-time polymerase chain reaction(PCR).The expression of chemotherapy-relevant genes potentially targeted by the dysregulated microRNAs in the chemotherapy resistant variants was also evaluated.RESULTS:Chemotherapy resistant sublines were found to have specific miRNA signatures,and these miRNA signatures were different for the cisplatin vs 5-FU resistant cells from the same tumor cell line,and also for EAC vs ESCC cells with resistance to the same specific chemotherapy agent.Amongst others,miR-27b-3p,miR-193b-3p,miR-192-5p,miR-378 a-3p,miR-125a-5p and miR-18a-3p were dysregulated,consistent with negative posttranscriptional control of KRAS,TYMS,ABCC3,CBL-B and ERBB2 expression via these miRNAs.CONCLUSION:The current study supports the hypothesis that microRNA expression has an impact on chemotherapy resistance in esophageal cancer. AIM: To investigate expression of microRNA (miRNA) and potential targets in chemotherapy resistant esoph-ageal cancer cell lines. METHODS: An in-vitro model of acquired chemotherapy resistance in esophageal adeno- (EAC) and squamous cell carcinoma (ESCC) cells was used, and microRNA expression profiles for cisplatin or 5-fluorouracil (5-FU) resistant variants versus chemotherapy sensitive controls were compared using microarray and quantitative real-time polymerase chain reaction (PCR). The expression of chemotherapy-relevant genes potentially targeted by the Results: Chemotherapy resistant sublines were found to have specific miRNA signatures, and these miRNA signatures were different for the cisplatin vs 5-FU resistant cells from the same tumor cell line, and also for EAC vs ESCC cells with resistance to the same specific chemotherapy agent. Amongst others, miR-27b-3p, miR-193b-3p, miR- 192-5p, miR- 378 a- 3p, miR- 125a-5p and miR- 18a -3p were dysregulated, consistent with negative posttranscriptional control of KRAS, TYMS, ABCC3, CBL-B and ERBB2 expression via these miRNAs.CONCLUSION: The current study supports the hypothesis that microRNA expression has an impact on chemotherapy resistance in esophageal cancer.