Abstract: Objective To explore the prognostic value of the long noncoding RNA plasmacytoma variant translocation 1(lncRNA PVT1)nomogram model in predicting postoperative survival in patients with gastric cancer(GC), and to investigate the effects of lncRNA PVT1 on the proliferation and invasion of GC cells. Methods A quantitative real-time polymerase chain reaction(RT-qPCR)was employed to measure the expression levels of lncRNA PVT1 and c-Myc in GC tissues and paired gastric mucosa tissues from 196 patients. The expression of c-Myc protein in GC tissues was detected using the western blotting technique. The investigation involved the implementation of survival analysis and Cox regression analysis, with the objective of elucidating the clinicopathological factors associated with GC and the construction of a prognostic model. In vitro, MGC-803 cells were subjected to transfection with a specific interfering RNA(siRNA)designed to target lncRNA PVT1. The experimental design involved the establishment of three distinct groups: the experimental group, which received the targeted knockdown via the PVT1-siRNA, the control group, which received a non-specific negative control via the PVT1-siRNA, and a third group that served as a blank control, receiving no transfection. The expression of c-Myc protein in GC cells was measured using Western blotting, while cell proliferation and invasion were evaluated using CCK-8 and Transwell assays, respectively. Results The expression of lncRNA PVT1(P=0.002), along with c-Myc mRNA expression(P=0.013)and protein levels(P=0.024), was significantly elevated in GC tissues compared to adjacent normal tissues. Univariate survival analysis and multivariate Cox regression analysis identified several factors significantly correlated with overall survival(OS)in GC patients, including age(P=0.004), and Laurens classification(P=0.021). The following factors were found to be statistically significant: local tumor invasion(P<0.001), pTNM stage(P=0.020), local lymph node metastasis(P=0.002), and the expression level of lncRNA PVT1(P<0.001). The expression level of lncRNA PVT1 was found to be an independent risk factor. The nomogram model based on lncRNA PVT1 predicted 1-year, 2-year, and 3-year OS probabilities of 0.997, 0.937, and 0.828, respectively. Furthermore, following the silencing of lncRNA PVT1, a significant reduction in both c-Myc mRNA(P<0.001)and protein levels(P=0.006)was observed, as well as a reduction in cell proliferation(P<0.001)and invasion ability(P=0.028)in the siPVT1-1907 group compared to the siNC group. Conclusion The present study has showed that the expression of lncRNA PVT1 is elevated in cases of gastric cancer, and that this elevation is associated with a poor prognosis for patients. The lncRNA PVT1-based nomogram model demonstrates good predictive capability for postoperative survival in GC. Additionally, lncRNA PVT1 appears to promote carcinogenesis by upregulating c-Myc expression in GC cells. This finding indicates that the lncRNA PVT1-Myc regulatory network may represent a viable target for the clinical management of gastric cancer.

Key words: Plasmacytoma variant translocation 1, Gastric cancer, Prognosis, Nomogram, Oncogene Myc, RNA interference