Application of immune checkpoint inhibitors and microsatellite instability in gastric cancer

In this editorial we comment on the article by Li published in the recent issue of the World Journal of Gastroenterology.We focus specifically on the application of immune checkpoint inhibitors(ICIs)and microsatellite instability(MSI)in gastric cancer(GC).The four pillars of GC management have long been considered,including surgery,chemotherapy,radiotherapy and targeted therapy.However,immunotherapy has recently emerged as a“fifth pillar”,and its use is rapidly expanding.There are four principal strategies for tumor immunotherapy:ICIs,tumor vaccines,adoptive immunotherapy and nonspecific immunomodulators.Of them,ICIs are the most advanced and widespread type of cancer immunotherapy for GC.Recent breakthrough results for ICIs have paved the way to a new era of cancer immunotherapy.In particular,inhibition of the PD-1/PD-L1 axis with ICIs,including nivolumab and pembrolizumab,has emerged as a novel treatment strategy for advanced GC.Unfortunately,these therapies are sometimes associated with often subtle,potentially fatal immune-related adverse events(irAEs),including dermatitis,diarrhea,colitis,endocrinopathy,hepatotoxicity,neuropathy and pneumonitis.We must be aware of these irAEs and improve the detection of these processes to prevent inappropriate discharges,emergency department revisits,and downstream complications.Recent studies have revealed that MSI-high or mismatch-repair-deficient tumors,regardless of their primary site,have a promising response to ICIs.So,it is important to detect MSI before applying ICIs for treatment of GC.

Comparative effectiveness of immunotherapy and chemotherapy in patients with metastatic colorectal cancer stratified by microsatellite instability status

BACKGROUND Immunotherapy have demonstrated promising outcomes in patients with high microsatellite instability(MSI)(MSI-H)metastatic colorectal cancer.However,the comparative effectiveness of Immunotherapy and chemotherapy for patients with low MSI(MSI-L),and microsatellite stable(MSS)metastatic colorectal cancer remains unclear.AIM To investigate immunotherapy vs chemotherapy for treatment of MSI-L/MSS metastatic colorectal cancer,and to evaluate the success of immunotherapy against chemotherapy in managing MSI-H metastatic colorectal cancer during a follow-up of 50 months.METHODS We conducted a retrospective cohort study using the National Cancer Database(NCDB)to evaluate the overall survival(OS)of patients with metastatic colorectal cancer treated with immunotherapy or chemotherapy.The study population was stratified by MSI status(MSI-H,MSI-L,and MSS).Multivariable Cox proportional hazard models were used to assess the association between treatment modality and OS,adjusting for potential confounders.RESULTS A total of 21951 patients with metastatic colorectal cancer were included in the analysis,of which 2358 were MSI-H,and 19593 were MSI-L/MSS.In the MSI-H cohort,immunotherapy treatment(n=142)was associated with a significantly improved median OS compared to chemotherapy(n=860).After adjusting for potential confounders,immunotherapy treatment remained significantly associated with better OS in the MSI-H cohort[adjusted hazard ratio(aHR):0.57,95%confidence interval(95%CI):0.43-0.77,P<0.001].In the MSS cohort,no significant difference in median OS was observed between immunotherapy treatment and chemotherapy(aHR:0.94,95%CI:0.69-1.29,P=0.715).CONCLUSION In this population-based study using the NCDB,immunotherapy treatment was associated with significantly improved OS compared to chemotherapy in patients with MSI-H metastatic colorectal cancer,but not in those with MSI-L/MSS metastatic colorectal cancer.Further studies are warranted to determine the optimal therapeutic approach for patients with MSI-L/MSS metastatic colorectal cancer.

Discrepancy among microsatellite instability detection methodologies in non-colorectal cancer:Report of 3 cases

BACKGROUND Microsatellite instability(MSI)is a predictive biomarker for cancer immunotherapy.The tumor-agnostic nature of MSI makes it a denominator for immunotherapy in several solid tumors.It can be assessed using next-generation sequencing(NGS),fluorescent multiplex PCR,and immunohistochemistry(IHC).CASE SUMMARY Here,we report 3 cases with discordant MSI results detected using different methods.A cholangiocellular carcinoma case revealed proficient mismatch repair(MMR)by IHC but high MSI(MSI-H)by liquid NGS.A cervical cancer case revealed deficient MMR by IHC,microsatellite stable by PCR,and MSI-H by NGS.Lastly,an endometrial cancer case revealed proficient MMR by IHC but MSI-H by NGS.CONCLUSION IHC for MMR status is the first choice due to several advantages.However,in cases of indeterminate IHC results,molecular testing by MSI-PCR is preferred.Recently,NGS-based MSI assays are being widely used to detect MSI-H tumors.All three methods have high accuracy;however,the inconsistencies between them may lead to misdiagnosis.

Bat 26 Microsatellite Instability in Oral Cavity Cancers in Senegal

Oral cavity cancers are part of head and neck cancers. They have become frequent in the world in general and Senegal in particular. This study evaluates microsatellite instability tumors in oral cavity cancers in Senegal. Forty cancerous tissues, 20 healthy tissues, and 12 blood tissues were included in this study. These tissues were collected from each patient during the biopsy after obtaining consent. DNA extraction, Polymerase Chain Reaction (PCR) and sequencing were carried out to obtain sequences. Mutation surveyor, Bioedit and Dnasp software were used to perform our analyses. High instability was found in 57.5% of patients with cancer. Moreover, 90% of the patients had the same motif on healthy and cancerous tissue. Furthermore, 26.12%, 20.72%, and 11.71% polymorphic sites were found in cancerous, healthy and blood tissue respectively. Thus, a similarity between cancerous and healthy tissues seems to exist. This implies that instability of the Bat 26 microsatellite could occur early in the occurrence of oral cavity cancers.

Causes and consequences of microsatellite instability in gastric carcinogenesis

Loss of DNA mismatch repair(MMR) function, due to somatic or germline epi/genetic alterations of MMR genes leads to the accumulation of numerous mutations across the genome, creating a molecular phenotype known as microsatellite instability(MSI). In gastric cancer(g C), MSI occurs in about 15% to 30% of the cases. This review summarizes the current knowledge on the molecular mechanisms underlying the acquisition of MSI in g C as well as on the clinic, pathologic and molecular consequences of the MSI phenotype. Additionally, current therapeutic strategies for g C and their applicability in the MSI subset are also discussed.

Helicobacter pylori and EBV in gastric carcinomas:Methylation status and microsatellite instability

AIM:To verify the methylation status of CDH1, DAPK, COX2, hMLH1 and CDKN2A genes and to evaluate their association with Helicobacter pylori (H. pylori)-cagA+ and Epstein Barr virus (EBV) infections in gastric adenocarcinomas.METHODS: Methylation-specific PCR (MSP) assay was performed in 89 primary gastric carcinomas (intestinal and diffuse types). Microsatellite instability (MSI) analysis was performed using the BAT26 primer set and PCR products were analyzed with the ABI PRISM 3100 Genetic Analyzer using Genescan 3.7 software (Applied Biosystems). Detection of H. pylori and genotyping were performed by PCR, using specifi c primers for ureaseC and cagA genes. The presence of EBV was assessed by in situ hybridization. Statistical analyses were performed using the χ2 or Fisher's exact test.RESULTS: The most frequent hypermethylated gene was COX-2 (63.5%) followed by DAPK (55.7%), CDH1 (51%), CDKN2A (36%) and hMLH1 (30.3%). Intestinal and diffuse adenocarcinomas showed different methylation profiles and there was an association between methylation of E-CDH1 and H. pylori-cagA+ in the intestinal adenocarcinoma type. MSI was correlated with hMLH1 methylation. There was an inverse correlation between DAPK hypermethylation and MSI.CONCLUSION: We found a strong association between CDH1 methylation and H. pylori-cagA+ in intestinal-type gastric cancer, association of MSI and better prognosis and an heterogeneous COX-2 overexpression.

Cytotoxic CD8+ T cells and tissue resident memory cells in colorectal cancer based on microsatellite instability and BRAF status

BACKGROUND Recent studies in non-colorectal malignancy have associated T resident memory(T_(RM)) cells with improved patient survival. It is unknown if T_(RM) plays a role in colorectal cancer(CRC).AIM To examine the potential role of T_(RM) cells in providing immunogenicity in CRC stratified by microsatellite instability(MSI) and BRAF status.METHODS Patients with known MSI and BRAF mutation status were eligible for inclusion in this study. CRC tumour sections stained with haematoxylin and eosin were microscopically reviewed and the images scanned prior to assessment for location of invading edge and core of tumour. Sequential sections were prepared for quantitative multiplex immunohistochemistry(IHC) staining. Opal Multiplex IHC staining was performed with appropriate positive and negative controls and imaged using a standard fluorescent microscope fitted with a spectral scanning camera(Mantra) in conjunction with Mantra snap software. Images were unmixed and annotated in in Form 2.2.0. Statistical analysis was performed using Graphpad Prism Version 7 and Stata Version 15.RESULTS Seventy-two patients with known MSI and BRAF status were included in the study. All patients were assessed for MSI by IHC and high resolution capillary electrophoresis testing and 44 of these patients successfully underwent quantitative multiplex IHC staining. Overall, there was a statistically significant increase in CD8+ T_(RM) cells in the MSI(BRAF mutant and wild type) group over the microsatellite stable(MSS) group. There was a statistically significant difference in CD8+ T_(RM) between high level MSI(MSI-H):BRAF mutant [22.57, 95% confidence interval(CI): 14.31-30.84] vs MSS [8.031(95%CI: 4.698-11.36)], P = 0.0076 and MSI-H:BRAF wild type [16.18(95%CI: 10.44-21.93)] vs MSS [8.031(95%CI: 4.698-11.36)], P = 0.0279. There was no statistically significant difference in CD8 T cells(both CD8+CD103-and CD8+CD103+T_(RM)) between MSI-H: BRAF mutant and wild type CRC.CONCLUSION This study has shown that CD8+ T_(RM) are found in greater abundance in MSI-H CRC, both BRAF mutant and MSI-H:BRAF wild type, when compared with their MSS counterpart. CD8+ T_(RM) may play a role in the immunogenicity in MSI-H CRC(BRAF mutant and BRAF wild type). Further studies should focus on the potential immunogenic qualities of T_(RM) cells and investigate potential immunotherapeutic approaches to improve treatment and survival associated with CRC.

Microsatellite instability and expression of DNA mismatch repair genes in malignant astrocytic tumors from adult and pediatric patients

Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO grade Ⅳ) of pediatric patients (2-21 years) and 12 GBM from adults (44-68 years) by comparative analysis of BAT25/BAT26 loci and 10 other microsatellite markers. High-level microsatellite instability (MSI-H) occurred in 4 of the 15 pediatric cases (26.7%) and in 1 of the 12 adult GBM cases (8.3%). Low-level mi-

MutL homolog 1 methylation and microsatellite instability in sporadic colorectal tumors among Filipinos

BACKGROUND Colorectal cancer(CRC)ranks third in terms of incidence and second in mortality worldwide.In CRC,the silencing of mismatch repair genes,including the mutL homolog 1(hMLH1)has been linked to microsatellite instability(MSI),the lengthening or shortening of microsatellite repeats.Very limited data have been presented so far on the link of hMLH1 methylation and MSI in Southeast Asia populations with sporadic CRC,and on its clinical significance.AIM To investigate the significance of the MSI status and hMLH1 methylation in CRC Filipino patients.METHODS Fifty-four sporadic CRC patients with complete clinical data were included in this study.Genomic DNA from CRC tumor biopsies and their normal tissue counterparts were profiled for MSI by high resolution melting(HRM)analysis using the Bethesda Panel of Markers(BAT25,BAT26,D2S123,D5S346,and D17S250).hMLH1 methylation screening was performed using bisulfite conversion and methylation specific polymerase chain reaction.Statistical analysis was conducted to calculate their associations to clinicopathological characteristics and survival relevance(Kaplan-Meier curves and the log-rank test).RESULTS hMLH1 methylation was observed in 9%and 35%of CRC and normal samples,respectively.Higher incidence of consistently methylated hMLH1 found in both normal and CRC was noticed for relation to location of tumor(P<0.05).As for MSI status,D2S123 the most common unstable microsatellite and MSI-high(MSIH)was the most common MSI profile,counted for 46%and 50%of normal and CRC tissues,respectively.The presence of MSI-low(MSI-L)and microsatellite stable(MSS)was 43%and 11%for normal,and 31%and 19%for CRC samples.The mean month of patients’survival was shorter in patients whose normal and tumor tissues had methylated compared to those with unmethylated hMLH1 and with MSI-H compared to those with MSI-L/MSS(P<0.05).This was supported by significant difference in Kaplan-Meier with log-rank analysis.This data indicated that hMLH1 methylation and high MSI status have prognostic value.CONCLUSION This study showed the clinical significance of hMLH1 methylation and MSI status in sporadic CRC Filipino patients,especially in the normal part of the tumor.

Microsatellite Instability in Intestinal Metaplasia and Gastric Cancer

Objective: To investigate the changeable patterns of microsatellite instability(MSI)in intestinal metaplasia(IM)and gastric cancer(GC)and the role of MSI in gastric carcinogenesis. Methods: Silver staining single strand conformation polymorphism-polymeriase chain reaction(PCR-SSCP)was used to screen MSI markers at 5 loci in formalin-fixed,paraffin-embedded tissues of GC(n=30),IM(n=40)and corresponding normal gastric tissues. Results: The abnormal shifting of the single-strand DNA was identified in 7(23.3%)out of GC and in 8(20%)out of IM samples.Three(10%)tumors and one(2.5%)IM displayed high-frequency MSI(two or more loci altered).Low-frequency MSI(one loci altered)was detected in 4(13.3%)of the tumors and in 7(17.5%)IM samples.GC with MSI was associated with distal location of the tumors but age,sex,differentiation,lymph nodes metastasis and TNM stage(P=0.044).MSI was more likely detected in moderate-grade IM than in mild-grade IM tissues(34.8% versus 0; P=0.013); and MSI had a tendency to be easily detected in female with IM. Conclusion: The progressive accumulation of MSI in areas of IM may contribute to GC development,representing an important molecular event in the multistep gastric carcinogenesis.

Analysis of Microsatellite Instability in Colorectal Cancer and Precursor Lesions

In many countries,colorectal cancer is one of the common cancers.It has been confirmed that microsatellite instability(MSI)is one of the most important molecular changes in colorectal cancer.As the recognized precursor lesions of colorectal cancer,adenomas and some polyps also have MSI phenomenon.This article analyzes the MSI of colorectal cancer and its closely related adenomas and polyps in domestic and foreign literature,and further discusses how to identify colorectal cancer at an early stage and the impact of MSI on the prognosis and treatment of colorectal cancer.

Inhibitory Effect of Sodium Selenite on Microsatellite Instability of RER^+ Colorectal Cancer Cells

Objective Investigation of the effects of sodium selenite on genetic instability of human tumor cells via its role in alteration of microsatellite sequence(MS) of RER + (replication error) colon cancer cell line. Methods RER + and RER - human colon cancer cell lines, RKO or SW480, were used as hosts for lipofection with pcmv car in which a foreign(CA) 14 repeat was inserted in the coding sequence of LacZ reporter gene, resulting in misreading LacZ frame. Any mutation which makes the base number of (CA) 14 tract to be 3 fold will resume the normal reading frame of the reporter gene, and thus lead to expression and production of bioactive β galactosidase. To test the effect of selenite on MI(microsatellite instability) of tumor cells, a series of concentrations of selenite were administered in cell culture in vitro. Variable expression of bioactive β galactosidase of transfectant cells resulted from selenite administration was measured by A reading at λ410 after X gal staining; Results Mutations of the exogenous(CA) 14 developed and maintained in pcmv car transfectant RKO cells but not in SW480 cells. It was found that blue cell frequency of RKO transfectant cells was markedly reduced after incubation of cells with 5 μmol/L of selenite for 5 days, at which concentration it was not toxic to cell growth. However, selenite at lower concentration of 1μmol/L didn′t exhibit suppression of blue cell rate until cell′s exposure to it for a longer period up to 5 weeks or more. Conclusion Our data showed that selenite displayed inhibitory effect on MI of human cancer cells and thus demonstrated its beneficial role in stabilization of human genomic DNA.

A robust microsatellite instability detection model for unpaired colorectal cancer tissue samples

Background:Microsatellite instability(MSI)is a key biomarker for cancer immunotherapy and prognosis.Integration of MSI testing into a next-generation-sequencing(NGS)panel could save tissue sample,reduce turn-around time and cost,and provide MSI status and comprehensive genomic profiling in single test.We aimed to develop an MSI calling model to detect MSI status along with the NGS panel-based profiling test using tumor-only samples.Methods:From January 2019 to December 2020,a total of 174 colorectal cancer(CRC)patients were enrolled,including 31 MSI-high(MSI-H)and 143 microsatellite stability(MSS)cases.Among them,56 paired tumor and normal samples(10 MSI-H and 46 MSS)were used for modeling,and another 118 tumor-only samples were used for validation.MSI polymerase chain reaction(MSI-PCR)was performed as the gold standard.A baseline was built for the selected microsatellite loci using the NGS data of 56 normal blood samples.An MSI detection model was constructed by analyzing the NGS data of tissue samples.The performance of the model was compared with the results of MSI-PCR.Results:We first intersected the target genomic regions of the NGS panels used in this study to select common microsatellite loci.A total of 42 loci including 23 mononucleotide repeat sites and 19 longer repeat sites were candidates for modeling.As mononucleotide repeat sites are more sensitive and specific for detecting MSI status than sites with longer length motif and the mononucleotide repeat sites performed even better than the total sites,a model containing 23 mononucleotide repeat sites was constructed and named Colorectal Cancer Microsatellite Instability test(CRC-MSI).The model achieved 100%sensitivity and 100%specificity when compared with MSI-PCR in both training and validation sets.Furthermore,the CRC-MSI model was robust with the tumor content as low as 6%.In addition,8 out of 10 MSI-H samples showed alternations in the four mismatch repair genes(MLH1,MSH2,MSH6,and PMS2).Conclusion:MSI status can be accurately determined along the targeted NGS panels using only tumor samples.The performance of mononucleotide repeat sites surpasses loci with longer repeat motif in MSI calling.

MSIsensor-pro: Fast, Accurate, and Matched-normal-sample-free Detection of Microsatellite Instability

Microsatellite instability(MSI)is a key biomarker for cancer therapy and prognosis.Traditional experimental assays are laborious and time-consuming,and next-generation sequencingbased computational methods do not work on leukemia samples,paraffin-embedded samples,or patient-derived xenografts/organoids,due to the requirement of matched normal samples.Herein,we developed MSIsensor-pro,an open-source single sample MSI scoring method for research and clinical applications.MSIsensor-pro introduces a multinomial distribution model to quantify polymerase slippages for each tumor sample and a discriminative site selection method to enable MSI detection without matched normal samples.We demonstrate that MSIsensor-pro is an ultrafast,accurate,and robust MSI calling method.Using samples with various sequencing depths and tumor purities,MSIsensor-pro significantly outperformed the current leading methods in both accuracy and computational cost.MSIsensor-pro is available at https://github.com/xjtu-omics/msisensor-pro and free for non-commercial use,while a commercial license is provided upon request.

Relationship between microsatellite instability and hepatocyte growth factor expression and their prognostic significance in colorectal cancer

Objective To investigate the expression of hepatocyte growth factor(HGF)and its relationship with microsatellite instability(MSI)and their influence on survival in patients with colorectal cancer.Methods Immunohistochemistry(IHC)was used to detect the expression of HGF and MSI in 98 specimens of colorectal cancer.Tumors lacking protein expression of any of the our mis-

Molecular insights into clinical trials for immune checkpoint inhibitors in colorectal cancer:Unravelling challenges and future directions

Colorectal cancer(CRC)is a complex disease with diverse etiologies and clinical outcomes.Despite considerable progress in development of CRC therapeutics,challenges remain regarding the diagnosis and management of advanced stage metastatic CRC(mCRC).In particular,the five-year survival rate is very low since mCRC is currently rarely curable.Over the past decade,cancer treatment has significantly improved with the introduction of cancer immunotherapies,specifically immune checkpoint inhibitors.Therapies aimed at blocking immune checkpoints such as PD-1,PD-L1,and CTLA-4 target inhibitory pathways of the immune system,and thereby enhance anti-tumor immunity.These therapies thus have shown promising results in many clinical trials alone or in combination.The efficacy and safety of immunotherapy,either alone or in combination with CRC,have been investigated in several clinical trials.Clinical trials,including KEYNOTE-164 and CheckMate 142,have led to Food and Drug Administration approval of the PD-1 inhibitors pembrolizumab and nivolumab,respectively,for the treatment of patients with unresectable or metastatic microsatellite instability-high or deficient mismatch repair CRC.Unfortunately,these drugs benefit only a small percentage of patients,with the benefits of immunotherapy remaining elusive for the vast majority of CRC patients.To this end,primary and secondary resistance to immunotherapy remains a significant issue,and further research is necessary to optimize the use of immunotherapy in CRC and identify biomarkers to predict the response.This review provides a comprehensive overview of the clinical trials involving immune checkpoint inhibitors in CRC.The underlying rationale,challenges faced,and potential future steps to improve the prognosis and enhance the likelihood of successful trials in this field are discussed.

Immune signature of small bowel adenocarcinoma and the role of tumor microenvironment

In this editorial we comment on the article published“Clinical significance of programmed cell death-ligand expression in small bowel adenocarcinoma is determined by the tumor microenvironment”.Small bowel adenocarcinoma(SBA)is a rare gastrointestinal neoplasm and despite the small intestine's significant surface area,SBA accounts for less than 3%of such tumors.Early detection is challenging and the reason arises from its asymptomatic nature,often leading to late-stage discovery and poor prognosis.Treatment involves platinum-based chemotherapy with a 5-fluorouracil combination,but the lack of effective chemotherapy contributes to a generally poor prognosis.SBAs are linked to genetic disorders and risk factors,including chronic inflammatory conditions.The unique characteristics of the small bowel,such as rapid cell renewal and an active immune system,contributes to the rarity of these tumors as well as the high intratumoral infiltration of immune cells is associated with a favorable prognosis.Programmed cell death-ligand 1(PD-L1)expression varies across different cancers,with potential discrepancies in its prognostic value.Microsatellite instability(MSI)in SBA is associated with a high tumor mutational burden,affecting the prognosis and response to immunotherapy.The presence of PD-L1 and programmed cell death 1,along with tumor-infiltrating lymphocytes,plays a crucial role in the complex microenvironment of SBA and contributes to a more favorable prognosis,especially in the context of high MSI tumors.Stromal tumor-infiltrating lymphocytes are identified as independent prognostic indicators and the association between MSI status and a favorable prognosis,emphasizes the importance of evaluating the immune status of tumors for treatment decisions.

Comprehensive analysis of gene mutations and mismatch repair in Chinese colorectal cancer patients

BACKGROUND RAS,BRAF,and mismatch repair(MMR)/microsatellite instability(MSI)are crucial biomarkers recommended by clinical practice guidelines for colorectal cancer(CRC).However,their characteristics and influencing factors in Chinese patients have not been thoroughly described.AIM To analyze the clinicopathological features of KRAS,NRAS,BRAF,and PIK3CA mutations and the DNA MMR status in CRC.METHODS We enrolled 2271 Chinese CRC patients at the China-Japan Friendship Hospital.MMR proteins were tested using immunohistochemical analysis,and the KRAS/NRAS/BRAF/PIK3CA mutations were determined using quantitative polymerase chain reaction.Microsatellite status was determined using an MSI detection kit.Statistical analyses were conducted using SPSS software and logistic regression.RESULTS The KRAS,NRAS,BRAF,and PIK3CA mutations were detected in 44.6%,3.4%,3.7%,and 3.9% of CRC patients,respectively.KRAS mutations were more likely to occur in patients with moderate-to-high differentiation.BRAF mutations were more likely to occur in patients with right-sided CRC,poorly differentiated,or no perineural invasion.Deficient MMR(dMMR)was detected in 7.9% of all patients and 16.8% of those with mucinous adenocarcinomas.KRAS,NRAS,BRAF,and PIK3CA mutations were detected in 29.6%,1.1%,8.1%,and 22.3% of patients with dMMR,respectively.The dMMR was more likely to occur in patients with a family history of CRC,aged<50 years,right-sided CRC,poorly differentiated histology,no perineural invasion,and with carcinoma in situ,stage I,or stage II tumors.CONCLUSION This study analyzed the molecular profiles of KRAS,NRAS,BRAF,PIK3CA,and MMR/MSI in CRC,identifying key influencing factors,with implications for clinical management of CRC.

Pan-Cancer dissection of ORAI1:prognostic implications and immune landscapecorrelation

Background:The ORAI1 gene,central to store-operated calcium entry(SOCE),is increasingly recognized for its pivotal role in cancer progression and patient prognosis across a broad spectrum of malignancies.Despite its critical involvement in calcium signaling pathways that are essential for cellular functions such as proliferation,migration,and apoptosis,the comprehensive impacts of ORAI1 within the tumor microenvironment(TME)and its modulation across various cancers have not been fully elucidated.Methods:We conducted a pan-cancer analysis leveraging data from The Cancer Genome Atlas(TCGA)and Genotype-Tissue Expression(GTEx)to assess ORAI1 expression.Differential expression analyses were performed,complemented by correlative studies with tumor mutation burden(TMB),microsatellite instability(MSI),immune infiltration,and key biological processes and pathways.Results:Our results demonstrate that ORAI1 is consistently upregulated in a range of cancer types,associated with aggressive tumor characteristics and poor patient outcomes.Significantly,ORAI1 upregulation correlates with increased tumor mutation burden(TMB)and microsatellite instability(MSI),markers of genomic instability that are predictive of response to immunotherapy,underscoring its potential utility in clinical stratification and treatment decision-making.ORAI1's influence extended to the immune landscape,showing associations with immune cell infiltration and both immunosuppressive and immunostimulatory gene sets,thereby affecting the TME and possibly the efficacy of immunotherapeutic interventions.Conclusions:The multifaceted nature of ORAI1's involvement in cancer pathophysiology positions it as a prospective biomarker and therapeutic target.Its expression dynamics and correlative significance with prognostic and immune regulatory elements underscore its potential in guiding therapeutic strategies and improving clinical outcomes.This study lays a foundation for future research,aiming to leverage ORAI1's biological significance in cancer prognosis and therapy optimization.

Prognostic values of chromosome 18q microsatellite alterations in stage Ⅱ colonic carcinoma

AIM: To investigate the prognostic value of chromosome 18q microsatellite alterations (MA) in stage Ⅱ colon cancer. METHODS: One hundred and six patients with sporadic stage Ⅱ colon cancer were enrolled in this study. DNA was extracted from formalin-fixed, paraffin-embedded tumor and adjacent normal mucosal tissue samples. MA, including loss of heterozygosity (LOH) and microsatellite instability (MSI), was analyzed by polymerase chain reaction, polyacrylamide gel-electrophoresis and DNA sequencing at 5 microsatellite loci on chromosome 18q (D18S474, D18S55, D18S58, D18S61 and D18S64).RESULTS: Among the 102 patients eligible for MA information, the overall frequencies of LOH, high and low frequency MSI/microsatellite stable were 49.0%, 17.6% and 82.4%, respectively. The high frequency of 18q-LOH was signif icantly associated with the poor 5-year overall survival (OS) (P=0.008) and disease free survival (P=0.006). High levels of MSI were significantly associated with a longer 5-year OS (P=0.045) while the higher frequency of 18q-LOH at the loci of D18S474 and D18S61 was significantly associated with a poorer 5-year OS (P=0.010 and 0.005, respectively). But multivariate analysis showed that only the frequency of 18q-LOH was significantly associated with the prognosis of the disease. CONCLUSION: High frequency of 18q-LOH is an independent prognostic factor indicating poor prognosis of the patients with stage Ⅱ colon cancer.