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

[BACKGROUND] Extramural venous invasion (EMVI) is a critical prognostic factor in gastric cancer (GC); however, its detection and underlying molecular mechanisms remain underexplored.

[AIM] To investigate the relationship between EMVI and expression of the circular RNA hsa_circ_0097977 in orthotopic GC mouse models.

[METHODS] A retrospective analysis was conducted in addition to a preclinical animal study, involving 13 GC patients and 24 orthotopic GC mouse models, respectively. EMVI was assessed using axial T2-weighted fat suppression sequences on a 9.4T magnetic resonance imaging (MRI) with histopathological confirmation as the gold standard for EMVI. The impact of hsa_circ_0097977 on EMVI and GC cell function was evaluated. Statistical analyses comprised consistency, area under the curve analysis, correlation, /Fisher exact, and Mann-Whitney /-tests, with significance set at < 0.05.

[RESULTS] EMVI was accurately detected using 9.4T MRI in orthotopic mouse models with an area under the curve of 0.843 (sensitivity 78.6%, specificity 90.0%). MRI detected EMVI was the only imaging factor associated with distant metastasis ( = 0.04). Furthermore, knockdown of hsa_circ_0097977 was the only factor associated with EMVI ( = 0.043, 0.038) and led to reduced invasion and increased apoptosis in GC cells.

[CONCLUSION] EMVI, a risk factor for distant metastasis in GC, is detectable by 9.4T MRI and regulated by hsa_circ_0097977, making it a potential therapeutic target.