Correlation Of Tigar Expression With Clinicopathology,prognosis And ¹⁸F-FDG PET/CT Parameters In Patients With Pancreatic Ductal Adenocarcinoma

Objective:Pancreatic cancer is one of the leading causes of cancer-related death in the abdomen.TP53-induced glycolysis and apoptosis regulator（TIGAR）is the target gene of tumor suppressor gene p53,and its expression is different in different tumor tissues,and its correlation with prognosis is not consistent.We studied the expression of TIGAR in pancreatic ductal adenocarcinoma tissue and its relationship with clinicopathological parameters and prognosis,and analyzed the relationship between TIGAR expression and¹⁸F-FDG PET/CT related indicators in patients with pancreatic ductal adenocarcinoma（PDAC）.Methods:Part I:Collected medical records of patients from January 2009 to December2016 in our hospital of PET/CT,with postoperative pathology confirmed for PDAC,evaluation the correlation between TIGAR expression and clinical data,prognosis and PET/CT parameters in PDAC,including the maximum standardized uptake values（SUVmax）,mean standardized uptake values（SUVmean）,peak standardized uptake values（SUVpeak）,metabolic tumor volume（MTV）,total lesion glycolysis（TLG）,maximum standardized uptake normalized to lean body mass（SULmax）,peak standardized uptake normalized to lean body mass（SULpeak）and mean standardized uptake normalized to lean body mass（SULmean）.Part II:Medical records of pancreatic cancer patients who underwent pancreatic cancer surgery in our hospital from January 1,2015 to December 31,2016 were collected to evaluate the expression of TIGAR in pancreatic ductal adenocarcinoma（PDAC）,the correlation between TIGAR expression and clinical data and its value on prognosis.Part III,subcutaneous and orthotopic xenografts in nude mice of SW1990 overexpression group,silent group and control group were constructed.Micro PET/CT examination was performed to observe the correlation between TIGAR gene and tumor volume and SUVmax.Results:Part I:The medical records of 23 patients with pancreatic ductal adenocarcinoma confirmed by postoperative pathology after PET/CT were collected.Immunohistochemical results indicated high TIGAR expression in 15 patients,and TIGAR expression was not correlated with age,gender,tumor differentiation,tumor location,maximum diameter,lymph node metastasis,and CA19-9 level of patients.The overall survival time of patients with high TIGAR expression was significantly shorter than those with low TIGAR expression.¹⁸F-FDG PET/CT parameters SUVmax,SUVmean,SUVpeak,MTV,TLG,SULmax,SULpeak and SULmean were positively correlated with TIGAR expression,and only MTV and TIGAR expression showed statistical significance.Part II:The clinicopathological data of a total of 110 patients with pancreatic ductal adenocarcinoma confirmed pathologically after surgery were collected.The expression of TIGAR in pancreatic ductal adenocarcinoma tissues was significantly higher than that in paracancerous tissues.The expression of TIGAR was not related to gender,age,tumor location,tumor differentiation degree,and tumor maximum diameter,but was related to lymph node metastasis,and patients with high TIGAR expression had poor prognosis.Part III:subcutaneous and orthotopic xenografts in nude mice of SW1990 overexpressed group,silent group and control group were successfully constructed.Micro CT indicated that the tumor volume of the overexpressed group was significantly higher than that of the control group,the tumor volume of the silent group was lower than that of the control group,and the SUVmax value of the control group was higher than that of the silent group,while the SUVmax value of the overexpressed group was lower than that of the control group.Conclusions:TIGAR is highly expressed in pancreatic cancer tissues and is related to clinical indicators.TIGAR can be used as a prognostic predictor.TIGAR expression is positively correlated with ¹⁸F-FDG PET/CT parameters and has a statistical difference with MTV,and MTV and TLG are correlated with the prognosis of pancreatic duct adenocarcinoma patients.Although SUVmax is a commonly used ¹⁸F-FDG PET/CT metabolic index,SUVmax cannot absolutely reflect the expression of TIGAR and glucose metabolism within the tumor.