Association between Helicobacter pylori infection,mismatch repair,HER2 and tumor-infiltrating lymphocytes in gastric cancer

BACKGROUND The influence of Helicobacter-pylori(H.pylori)infection and the characteristics of gastric cancer(GC)on tumor-infiltrating lymphocyte(TIL)levels has not been extensively studied.Analysis of infiltrating-immune-cell subtypes as well as survival is necessary to obtain comprehensive information.AIM To determine the rates of deficient mismatch-repair(dMMR),HER2-status and H.pylori infection and their association with TIL levels in GC.METHODS Samples from 503 resected GC tumors were included and TIL levels were evaluated following the international-TILs-working-group recommendations with assessment of the intratumoral(IT),stromal(ST)and invasive-border(IB)compartments.The density of CD3,CD8 and CD163 immune cells,and dMMR and HER2-status were determined by immunohistochemistry(IHC).H.pylori infection was evaluated by routine histology and quantitative PCR(qPCR)in a subset of samples.RESULTS dMMR was found in 34.4%,HER2+in 5%and H.pylori-positive in 55.7%of samples.High IT-TIL was associated with grade-3(P=0.038),while ST-TIL with grade-1(P<0.001),intestinal-histology(P<0.001)and no-recurrence(P=0.003).dMMR was associated with high TIL levels in the ST(P=0.019)and IB(P=0.01)compartments,and STCD3(P=0.049)and ST-CD8(P=0.05)densities.HER2-was associated with high IT-CD8(P=0.009).H.pylorinegative was associated with high IT-TIL levels(P=0.009)when assessed by routine-histology,and with high TIL levels in the 3 compartments(P=0.002-0.047)and CD8 density in the IT and ST compartments(P=0.001)when assessed by qPCR.A longer overall survival was associated with low IT-CD163(P=0.003)and CD8/CD3(P=0.001 in IT and P=0.002 in ST)and high IT-CD3(P=0.021),ST-CD3(P=0.003)and CD3/CD163(P=0.002).CONCLUSION TIL levels were related to dMMR and H.pylori-negativity.Low CD8/CD3 and high CD163/CD3 were associated with lower recurrence and longer survival.

Survival after curative pancreaticoduodenectomy for ampullary adenocarcinoma in a South American population:A retrospective cohort study

BACKGROUND Ampullary adenocarcinoma(AAC)is a rare neoplasm that accounts for only 0.2%of all gastrointestinal cancers.Its incidence rate is lower than 6 cases per million people.Different prognostic factors have been described for AAC and are associated with a wide range of survival rates.However,these studies have been exclusively conducted in patients originating from Asian,European,and North American countries.AIM To evaluate the histopathologic predictors of overall survival(OS)in South American patients with AAC treated with curative pancreaticoduodenectomy(PD).METHODS We analyzed retrospective data from 83 AAC patients who underwent curative(R0)PD at the National Cancer Institute of Peru between January 2010 and October 2020 to identify histopathologic predictors of OS.RESULTS Sixty-nine percent of patients had developed intestinal-type AAC(69%),23%had pancreatobiliary-type AAC,and 8%had other subtypes.Forty-one percent of patients were classified as Stage I,according to the AJCC 8 th Edition.Recurrence occurred primarily in the liver(n=8),peritoneum(n=4),and lung(n=4).Statistical analyses indicated that T3 tumour stage[hazard ratio(HR)of 6.4,95%confidence interval(CI)of 2.5-16.3,P<0.001],lymph node metastasis(HR:4.5,95%CI:1.8-11.3,P=0.001),and pancreatobiliary type(HR:2.7,95%CI:1.2-6.2,P=0.025)were independent predictors of OS.CONCLUSION Extended tumour stage(T3),pancreatobiliary type,and positive lymph node metastasis represent independent predictors of a lower OS rate in South American AAC patients who underwent curative PD.