Clinical Significance Of TFF2 And Claudin18.2 Expression Disorder In Gastric Cancer

BackgroundGastric cancer(GC)is one of the most common cancer types in the world,with a high mortality rate.Although with the continuous development of medical technology,new surgical,chemotherapy,and targeted therapy methods,the prognosis of GC patients is still not ideal,which brings significant economic and spiritual burdens to society,families,and individuals.In order to improve the prognosis of GC patients,first of all,the early diagnosis rate should be improved.Early gastric cancer(EGC)means that the cancer tissue is limited to the mucosa to the submucosa,with or without lymph node metastasis.Endoscopic resection is the first choice for EGC patients,and most cases can be cured without surgical operation,with a 5-year survival rate of more than 90%.Therefore,improving the early diagnosis rate can effectively improve the prognosis of GC patients.The diagnosis of GC relies on the pathological diagnosis.However,due to the limitation of biopsy specimens,diagnosis only by histology is highly subjective,and there is a risk of missed diagnosis.Therefore,it is necessary to use objective immunohistochemical indicators to assist in diagnosis.In previous studies,our research group found that MUC2,MUC5AC,and MUC6 showed abnormal expression patterns in EGC.Immunohistochemical detection of these mucins was helpful for the diagnosis of EGC.MUC2 is mainly expressed by intestinal goblet cells but is not expressed in normal gastric mucosa.When intestinal metaplasia occurs in gastric mucosa,the expression of MUC2 is up-regulated.MUC5AC is limited to the upper part of the gastric mucosa(the foveal epithelium of the stomach and the mucous cells of the glandular neck).MUC6 is mainly expressed in the fundus gland of the stomach,limited to the lower part of the gastric mucosa.As secretory mucins,both of them are essential components of the gastric mucus barrier.In GC patients,the expression of MUC2 was up-regulated,while the expression of MUC5AC was decreased.In contrast,the expression area of MUC6 rose to the upper part of the gastric mucosa.These expression disorders were helpful for the diagnosis and differential diagnosis of GC.However,it is difficult to observe the change of mucin expression area in GC biopsy specimens,so other immunohistochemical indicators are still needed.Trefoil factor(TFF)is a kind of small molecule polypeptide mainly expressed in gastrointestinal mucosa.It is synthesized and secreted by mucous-secreting cells and has a protective effect on the gastrointestinal mucosa.TFF2,also known as the spasmolytic polypeptide,is mainly expressed in the gastric foveal epithelium,the mucous cells of the glandular neck,and pyloric gland cells and is involved in the formation of the gastric mucus barrier.TFF2 is a marker of spasmolytic polypeptideexpressing metaplasia(SPEM).SPEM is one of the most commonly accepted precancerous lesions of GC.The main research direction of our group is early cancer of the digestive tract,so we also paid attention to the TFF2 molecule in our daily work and scientific research.We found that TFF2 was highly expressed in normal gastric mucosa but decreased in intestinal metaplasia,which was almost exclusively expressed in metaplasia goblet cells.However,TFF2 was almost not expressed in gastric mucosa dysplasia or adenocarcinoma.At the same time,we found that TFF2 was expressed in the same GC cells as MUC5AC and MUC6 in most cases.Therefore,TFF2 may be a promising immunohistochemical indicator to assist in the diagnosis of EGC.Purpose1.To explore the correlation between TFF2 and clinicopathological parameters in EGC patients.2.To explore the application significance of down-regulated TFF2 expression in the diagnosis of EGC.Methods1.163 endoscopic submucosal dissection(ESD)specimens were collected in the Second Hospital of Shandong University from January 1,2019 to December 31,2021,which were diagnosed pathologically at T1 stage gastric adenocarcinoma.Relevant clinicopathological data were collected,including age,gender,tumor size,tumor cell infiltration pattern,Vienna classification,T stage,and histological type.2.Immunohistochemical staining was used to detect the expression of TFF2,MUC2,MUC5AC,MUC6,mismatch repair protein(MLH1,MSH2,MSH6,PMS2),P53,and Ki67 in EGC.3.To analyze the correlation of TFF2 with clinicopathological data and immunohistochemical indicators in EGC patients.4.To compare and analyze the expression difference of TFF2 between EGC and adjacent tissues.Results1.In EGC,the expression of TFF2 was not significantly correlated with age,gender,tumor size,T stage,tumor cell infiltration pattern,and Vienna classification.2.The expression of TFF2 in EGC was correlated with histological type,and the expression of TFF2 was more common in papillary carcinoma or EGC containing papillary structure than that in tubular adenocarcinoma.3.In EGC,the expression of TFF2 was correlated with MUC5AC,MUC6,mismatch repair protein,and P53 but was not significantly associated with MUC2.4.In EGC,there was no significant difference in Ki67 index between TFF2positive group and TFF2-negative group.5.Compared with gastric mucosa adjacent to cancer,the expression of TFF2 was significantly down-regulated in EGC.Conclusion1.The absence of TFF2 expression contributed to the diagnosis of EGC.2.The dysregulation of TFF2 might be a necessary initiating stage of GC.3.The expression of TFF2 was different between intestinal type and gastric type GC,suggesting that TFF2 might play different roles in different histological types of GC through different pathways.BackgroundGC is the fourth leading cause of cancer death in the world.EGC patients’prognosis is good,and endoscopic resection is required for treatment.However,advanced GC patients’ prognosis is poor.They need surgical treatment,chemotherapy,targeted therapy,and other measures.Therefore,to improve the prognosis of GC patients,it is necessary to find effective therapeutic targets for advanced GC apart from improving the early diagnosis rate of GC.Advanced GC means that the cancer tissue has infiltrated beyond the submucosa.Advanced GC can be further divided into resectable and unresectable GC.Although advanced resectable GC can be treated by surgery,the prognosis is still not ideal,and it is prone to recurrence and metastasis.Chemotherapy,human epidermal growth factor receptor 2(HER2)-targeting drugs,and immunotherapy are the main treatments for advanced unresectable GC.But chemotherapy has low efficiency and high side effects.The positive rate of HER2 in GC is only about 15%,and the efficacy of its targeted drugs in GC patients is far less than that in breast cancer.Besides,immunosuppressive drugs are lacking in clinical application data in China,with few drug types and expensive prices.Therefore,in order to improve the prognosis of patients with advanced GC,therapeutic targets and targeted drugs are urgent to be studied.Claudin18.2,a member of the Claudins protein family,is an ideal target for the treatment of GC.The Claudins protein family is one of the main components of intercellular tight junctions.The primary function of the Claudins protein family is to maintain the mechanical junctions and participate in the formation of intercellular selective pores.Claudin18.2 is expressed explicitly in the gastric epithelium,and its expression changes during the development and progression of GC.This molecule has attracted wide attention as an emerging target for advanced GC.Currently,Zolbetuximab(IMAB362),which targets Claudin18.2,and chimeric antigen receptor(CAR)T cell therapy are in clinical trials,showing significant efficacy and few side effects.However,statistical analysis of Claudin18.2 expression in GC patients in China is lacking,and the correlation between Claudin18.2 and the prognosis of GC patients is still controversial.Therefore,we analyzed the correlation of Claudin18.2 with clinicopathological data and the prognosis of GC patients.In addition,it has been suggested that TFF protein has a regulatory effect on Claudins,and the expression loss of Claudin18.2 is related to the SPEM.Therefore,we also analyzed the correlation between TFF2 and Claudin18.2 in GC,providing ideas for the subsequent specific mechanism research.Purpose1.To explore the correlation of Claudin18.2 and TFF2 with clinicopathological parameters in advanced GC patients.2.To explore the correlation between Claudin18.2 and TFF2 in GC.3.To analyze the correlation of Claudin18.2 and TFF2 with the prognosis of GC patients.Methods1.269 radical gastrectomy specimens were collected in the Second Hospital of Shandong University from January 1,2013 to December 31,2017,which were pathologically diagnosed as primary gastric adenocarcinoma.None of these patients received preoperative neoadjuvant chemoradiotherapy.All cases were followed up until April 2021.Relevant clinicopathologic data were collected and sorted out,including age,gender,tumor size,TNM stage,and Lauren classification of GC.2.Immunohistochemical staining was used to detect the expression of TFF2,Claudin18.2,MUC2,MUC5AC,MUC6,mismatch repair protein(MLH1,MSH2,MSH6,PMS2),P53,E-cadherin and HER2.3.In situ hybridization was used to detect Epstein-Barr virus(EBV)infection in GC patients.4.To analyze the correlation of TFF2 and Claudin18.2 with clinicopathological parameters,immunohistochemical indexes,and EBV infection in GC patients.5.TCGA database was used to verify the correlation of Claudin18.2 and TFF2 with MUC2,MUC5AC,and MUC6 in GC at the RNA level.6.To analyze the correlation between the expression of TFF2 and Claudin18.2 in advanced gastric cancer.TCGA database was used to verify the correlation of TFF2 with Claudin18.2 in GC at the RNA level.7.To analyze the correlation of TFF2 and Claudin18.2 with the prognosis of GC patients.Results1.The expression of TFF2 and Claudin18.2 was correlated with the T stage of GC patients but had no significant correlation with age,gender,tumor size,N stage,M stage,TNM stage,and Lauren classification.2.TFF2 was correlated with the expression of MUC5AC,P53 and Claudin18.2 in GC patients but had no significant correlation with MUC2,MUC6,mismatch repair protein,HER2,E-cadherin and EBV infection.3.Immunohistochemistry and in situ hybridization showed that Claudin18.2 was correlated with the expression of MUC2,MUC5AC,MUC6,and P53 in GC but had no significant correlation with HER2,E-cadherin,mismatch repair protein,and EBV infection.4.Database analysis indicated that TFF2 was positively correlated with the expression of MUC5AC and Claudin18.2 in GC at the RNA level.Claudin18.2 was significantly positively correlated with MUC5AC and MUC6 in GC at the RNA level.5.The expression of Claudin18.2 was correlated with the prognosis of GC patients,and the prognosis of patients with positive expression of Claudin18.2 was better.However,there was no significant correlation between the expression of TFF2 and the prognosis of GC patients.Conclusion1.The loss of Claudin18.2 and TFF2 might promote the proliferation of GC cells instead of metastasis.2.The antitumor effect of P53 might be related to the TFF2 or Claudin18.2 in GC.3.The expression of Claudin18.2 was higher in gastric-type GC,and gastric-type GC patients were more likely to benefit from targeted therapy against Claudin18.2.4.TFF2 and Claudin18.2 might interact or regulate each other in the occurrence and development of GC.5.Grouping GC patients according to the expression of Claudin18.2 was conducive to the clinical judgment of the prognosis of GC patients.And it was helpful to develop personalized treatments and follow-up measures to achieve proper treatment of GC.