Identification of differentially expressed miRNAs in PD vs. nonPD in cancer samples

Lack of a standard method for stratifying advanced-stage NSCLC patients receiving platinum combination therapy often results in a number of patients that do not derive benefit yet are still exposed to treatment toxicity. We hypothesized that miRNAs in pre-treatment serum and/or plasma could be used to differentiate non-small cell lung cancer (NSCLC) patients who would have disease progression to first-line carboplatin and gemcitabine chemotherapy at first response assessment. miRNA profiling of mature and precursor miRNAs was performed on total RNA isolated from the pre-treatment serum and plasma of 24 NSCLC patients. Single validated candidates or combinations thereof were selected based on specificity and sensitivity to segregate patients with disease progression at first radiologic response (PD) vs. those without progressed disease (nonPD). Two precursor miRNA were significantly over-expressed in serum (but not plasma) of PD patients: pre-miR-518b and pre-miR-598. Serum miRNAs may serve as a screening tool in predicting chemoresistance to platinum-based combination chemotherapy. miRNA microarray was performed on RNA extracted from matched human serum or plasma obtained from NSCLC patients