Extramural venous invasion in gastric cancer: 9.4T magnetic resonance imaging assessment and circular RNA functional analysis

Figure 1 The overall workflow. CT: Computed tomography; MRI: Magnetic resonance imaging.

Figure 2 The expression of hsa_circ_0097977 in gastric cancer cell lines. A: The expression of hsa_circ_0097977 in normal gastric mucosal epithelial cells and six human gastric cancer cell lines. The relative value (RV) of expression of each circRNA was determined by the 2-Δct method using glyceraldehyde-3-phosphate dehydrogenase as a normalizer. The expression value of each circRNA was scaled to a reasonable range with the following equation: Log2 (RV × 10000 + 1); B: The relative expression level of hsa_circ_0097977 in cells after transfection. The relative expression level was calculated as 2^-∆∆Ct × 100%. KD: Knockdown; NC: Negative control.

Figure 3 Monitoring of tumor growth in the NCI-N87 orthotopic mouse model. A: The tumor growth of the orthotopic model, gross pathology and hematoxylin & eosin staining (10 ×) in the negative control group and knockdown group; B: Long diameter, short diameter, vertical diameter and volume change curve. KD: Knockdown; NC: Negative control; HE staining: Hematoxylin & eosin staining.

Figure 4 Extramural venous invasion in gastric cancer orthotopic mouse model perpendicular to the plane of magnetic resonance imaging axial image. A: T2-weighted fat-suppressed images, gastric cancer is manifested as a significant thickening of the gastric wall with heterogeneous signal intensity (within the red circle); B: Extramural venous invasion-detected detected on magnetic resonance imaging (mrEMVI) is visible as a tubular structure with a slightly high signal (orange arrow); C: This tubular structure can be observed in continuous layers and is connected to both the tumor and nearby blood vessels (white arrow); D: Hematoxylin and eosin staining of tumor (10 × and 200 ×); E: Alpha-smooth muscle actin staining (200 ×); F: CD34 staining (200 ×). ¹Extramural venous invasion; T: Tumor; red dashed line: Tumor boundary.

Figure 5 Extramural venous invasion in a gastric cancer orthotopic mouse model visualized parallel to the plane of magnetic resonance imaging axial imaging. A: T2-weighted fat-suppressed images showing gastric cancer, characterized by a thickened gastric wall with homogeneous signal intensity (within the red circle). Extramural venous invasion appears as a tubular structure with slightly high signal (orange arrow), connected to the tumor and adjacent vessels (white arrow); B: Hematoxylin & eosin staining of the tumor (200 ×); C: Smooth muscle actin staining (200 ×); D: CD34 staining (200 ×). ¹Extramural venous invasion; T: Tumor; red dashed line: Tumor boundary.

Figure 6 Heatmap features in the knockdown and negative control groups. pEMVI: Pathological extramural venous invasion; mrEMVI: Magnetic resonance imaging-detected extramural venous invasion; KD: Knockdown; NC: Negative control.

Figure 7 Results of the cell function test. A: Cell apoptosis of BGC-823, MKN-74 and NCI-N87 cells transfected with negative control or knockdown lentivirus; B: Cell invasion of BGC-823, MKN-74 and NCI-N87 cells transfected with negative control or knockdown lentivirus; C: Cell proliferation of BGC-823, MKN-74 and NCI-N87 cells transfected with negative control or knockdown lentivirus. KD: Knockdown; NC: Negative control.