Table 1.
Clinicopathological characteristics of patients with gastric cancer.
Well-differentiated adenocarcinoma (well); moderately differentiated adenocarcinoma (mod); poorly differentiated adenocarcinoma (poor). Malignant ascites (MA); Peritoneal lavage fluid (PLF); TMN stage (UICC 7th edition); Present (P) Absent (A); Peritoneal lavage cytology (CY);
Fig 1.
Exosomal miRNA expression in malignant ascites (MA), peritoneal lavage fluid (PLF), and cell culture media (CM).
Variation and commonality between the samples were examined. Evaluation of total exosomal RNA used a Bioanalyzer 2100. The electropherograms show the size distribution (nucleotides, nt) and fluorescence intensity (FU) of total exosomal RNA isolated from CM, MA, and PLF. The lowest spike (around 25 nt) in each sample is the marker of the Agilent RNA 6000 Pico kit.
Fig 2.
The number of detected miRNA species in 14 samples.
Fig 3.
Signal intensity distribution among MA (A), PLF (B), and CM (C) samples and among the groups (D).
Fig 4.
The number of miRNA species detected in malignant ascites, peritoneal lavage fluids, and cell culture media groups; 196 miRNAs were common to all groups.
Table 2.
Coefficient of correlation between samples. MA, Malignant ascites; PLF, Peritoneal lavage fluid; CM, Cell culture medium
Fig 5.
Identification of five exosomal miRNAs related to peritoneal dissemination.
Schematic representation of the step-wise approach to screening miRNAs related to peritoneal dissemination. Step 1: selection of miRNAs differentially expressed (fold-change, >2) in culture medium (CM) of the highly metastatic peritoneal cell line OCUM-2MD3 (OCUM-2M parental cell line was used as control). Step 2: six peritoneal lavage fluid (PLF) samples were divided into T4 (n = 4) and T1–T3 groups according to gastrointestinal cancer stage; miRNAs differentially expressed (fold-change, >2) in the T4 group were selected. Step 3: the selected miRNA species common for Steps 1 and 2 and expressed in malignant ascites (MA) with signal intensity > log2 10 in MA and PLF were considered as candidate miRNAs related to peritoneal metastases.
Table 3.
Signal intensity and fold-change of the miRNAs.
Malignant ascites (MA); Peritoneal lavage fluid (PLF); Condition medium (CM), T stage UICC 7th edition (T4, T1-3); OCUM-2M (2M); OCUM-2MD3 (D3).
Fig 6.
Relative expression levels of exosomal miRNAs in intraoperative peritoneal lavage fluid of T4 and T1–T3 gastric cancer patients.
An asterisk indicates P < 0.05.
Table 4.
Clinicopathological parameters and microRNA expression.