Objective  To investigate the value of exosomal miRNAs in predicting the efficacy of chemotherapy in patients with advanced gastric cancer.

  Methods  Overall, 36 patients with stage Ⅳgastric adenocarcinoma at The First Affiliated Hospital of Soochow University between April 2018 and November 2020 were included and administered at least two cycles of Xelox or SOX chemotherapy. According to the RECIST criteria, patients were assigned into the sensitive group and resistant group. Serum samples before the first chemotherapy were collected, and serum exosomal RNA was extracted. miRNA sequencing was performed, and miRNAs with significant differential expression were included. Polymerase chain reaction (PCR) was used to verify the screened miRNAs. Receiver operating characteristic curve (ROC) analysis was used to determine the value of the validated exosomal miRNAs for efficacy prediction.

  Results  The drug-sensitive group had 15 patients, and the drug-resistant group had 21 patients. Overall, 527 differentially expressed miRNAs were included, and only three exosomal miRNAs were significant after qRT-PCR verification. Areas under the ROC curve of miRNA-106a-5p, miRNA-1323, and miRNA-202-3p for predicting fluorouracil’s efficacy were 0.952, 0.949, and 0.946, respectively. The sensitivity was 90.5%, 90.1%, and 85.7%, and the specificity was 93.3%, 86.7%, and 93.1%, respectively.

  Conclusions  Detection of serum exosomal miRNA-106a-5p, miRNA-1323, and miRNA-202-3p in patients with advanced gastric cancer may have a certain predictive value for the efficacy of chemotherapy.