Serum and FFPE RNA Isolation

As previously described (Zhou et al., 2017b (link)), total RNA was isolated from 200 µl serum or exosome samples using mirVana Paris Kit (Ambion, Austin, TX, USA) under the manufacturer’s protocol instruction. We added 5 µl of synthetic C. elegans miR-39 (5nM/L, RiboBio, Guangzhou, China) to each sample after denaturing the solution (Ambion, Austin, TX, USA) for sample-to-sample normalization. We extracted total RNA from FFPE specimens via the High Pure FFPE RNA Micro Kit (Ambion Austin, TX, USA). Then, we dissolved RNA in 100 µl RNAse-free water and stored these RNA samples at −80 °C until use. Nanodrop 2000 Thermo scientific spectrophotometer (NanoDrop Technologies, Wilmington, DE, USA) was used to evaluate the total RNA’s concentration and purity.