Examination of microRNA expression in pre- and post-treatment plasma samples of 3 patients

Drug resistance often tempers the clinical benefit of chemotherapy in human malignant tumors. The potential chemosensitization of low-dose decitabine has been evident both preclinically and in previous phase I trials. Emerging data showed that miRNAs play an important role as a prognostic factor for cancer survival. Given that the biopsy tumor tissue was often not available, especially for patients with relapsed or refractory cancer, plasma RNA provided a valuable source for biomarker development. In order to establish predictive biomarker signature for the clinical efficacy of the decitabine-primed chemotherapy, we evaluated the expression of plasma miRNAs via high throughput microRNA sequencing. We performed miRNA-seq on a training set of 2 partial response (PR) patients and 1 progressive disease (PD) patients, and revealed preliminary data that plasma miRNA expression signature may serve as putative predictive markers of the low-dose decitabine primed chemotherapy. The clinical responses were assessed in a blinded manner according to the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Overall design: miRNA-seq of plasma from cancer patients before (day0) and after (day28) decitabine-primed chemotherapy for two patients with partial response (PR) and one patient with progressive disease (PD).