A promising and due to their non-invasive nature favorable concept in biomarker exploration is liquid biopsy. Micro RNAs (miRNAs) are a preferred target due to their stability. Various miRNAs are known to be dysregulated in colorectal cancers (CRC) where they take part in oncogenesis by acting as tumor suppressor or oncogene by silencing of target genes. The aim of this study is to explore a set of differentially expressed plasma cell-free miRNAs as potential biomarkers for CRC dynamic response to chemotherapy. Plasma samples from 51 patients with histologically confirmed primary metastatic CRC were obtained before and during the FOLFOX chemotherapy with/without targeted treatment every 2 weeks. Six retrospective patients were chosen for the discovery set. Per patient a plasma sample before treatment (control), a sample at remission after the start of chemotherapy (group 1) and relapse (group 2) was selected based on clinical data including serum carcinoembryonic antigen levels if informative.
Hemolytic samples were identified via ΔCT of miRNA-23a and miRNA-451 and excluded from the sample set. Each sample was analyzed for 752 selected miRNAs using miRNome PCR Panel (Qiagen). For normalization a set of preselected miRNAs were used. The Fold changes and p-values of each miRNA between the 3 timepoints and level of differential expression were detected with the analysis tool of the GeneGlobe Data Analysis Center (Qiagen). 22 miRNAs were found to have a significant (p<0.05) fold change >2.0 between control and relapse samples versus remission. In 11 miRNAs an uniform expression pattern between diagnosis, remission and relapse in 4 or more patients were found. Five miRNAS were chosen for further validation in a larger sample set as promising biomarkers. Changes in miRNA expression levels in plasma are a potentially promising biomarkers for CRC response to chemotherapy.
- 3.4. Other publications in conference proceedings (including local)