Microsatellite Instability Research Articles

Prognostic aging gene-based score for colorectal cancer: unveiling links to drug resistance, mutation burden, and personalized treatment strategies

ObjectiveColorectal cancer (CRC) is characterized by high incidence and mortality rates worldwide. In this study, we present a novel aging-related gene-based risk scoring system (Aging score) as a predictive tool for CRC prognosis. Method: We identified prognostic aging-related genes using univariate Cox regression analysis, revealing key biological processes in CRC progression. We then constructed a robust prognostic model using LASSO and multivariate Cox regression analyses, including four critical genes: CAV1, FOXM1, MAD2L1, and WT1. Result: The Aging score demonstrated high prognostic performance across the training, testing, and entire TCGA-CRC datasets, proving its reliability. High-risk patients identified by the Aging score had significantly shorter overall survival times than low-risk patients, indicating its potential for patient stratification and personalized treatment. The Aging score remained an independent prognostic factor compared to age, gender, and tumor stage. Additionally, the score was linked to tumor mutation burden and microsatellite instability, indicators of immune checkpoint inhibitor response. High-risk patients also showed higher estimated IC50 values for common chemotherapeutic drugs, suggesting possible treatment resistance. Conclusion: Our findings highlight the Aging score's potential to enhance clinical decision-making and pave the way for personalized CRC management.

Novel MLH1 nonsense variant in a patient with suspected Lynch syndrome

Loss-of-function germline variants of MLH1 cause Lynch syndrome. Here, we present the case of a 43-year-old male patient diagnosed with cecal and transverse colon adenocarcinomas. The characteristics of the case met the revised Bethesda guidelines, and the tumors demonstrated a high frequency of microsatellite instability. Genetic testing for mismatch repair genes (indicative of Lynch syndrome) revealed a novel heterozygous germline pathogenic variant, NM_000249.4:c.856A>T/NP_000240.1:p.(Lys286Ter), in MLH1.

From whole-slide image to biomarker prediction: end-to-end weakly supervised deep learning in computational pathology.

Hematoxylin- and eosin-stained whole-slide images (WSIs) are the foundation of diagnosis of cancer. In recent years, development of deep learning-based methods in computational pathology has enabled the prediction of biomarkers directly from WSIs. However, accurately linking tissue phenotype to biomarkers at scale remains a crucial challenge for democratizing complex biomarkers in precision oncology. This protocol describes a practical workflow for solid tumor associative modeling in pathology (STAMP), enabling prediction of biomarkers directly from WSIs by using deep learning. The STAMP workflow is biomarker agnostic and allows for genetic and clinicopathologic tabular data to be included as an additional input, together with histopathology images. The protocol consists of five main stages that have been successfully applied to various research problems: formal problem definition, data preprocessing, modeling, evaluation and clinical translation. The STAMP workflow differentiates itself through its focus on serving as a collaborative framework that can be used by clinicians and engineers alike for setting up research projects in the field of computational pathology. As an example task, we applied STAMP to the prediction of microsatellite instability (MSI) status in colorectal cancer, showing accurate performance for the identification of tumors high in MSI. Moreover, we provide an open-source code base, which has been deployed at several hospitals across the globe to set up computational pathology workflows. The STAMP workflow requires one workday of hands-on computational execution and basic command line knowledge.

Associations of SEMA7A, SEMA4D, ADAMTS10, and ADAM8 with KRAS, NRAS, BRAF, PIK3CA, and AKT Gene Mutations, Microsatellite Instability Status, and Cytokine Expression in Colorectal Cancer Tissue.

Semaphorins (SEMAs), ADAM, and ADAMTS family members are implicated in various cancer progression events within the tumor microenvironment across different cancers. In this study, we aimed to evaluate the expression of SEMA7A, SEMA4D, ADAM8, and ADAMTS10 in colorectal cancer (CRC) in relation to the mutational landscape of KRAS, NRAS, BRAF, PIK3CA, and AKT genes, microsatellite instability (MSI) status, and clinicopathological features. We also examined the associations between the expression of these proteins and selected cytokines, chemokines, and growth factors, assessed using a multiplex assay. Protein concentrations were quantified using ELISA in CRC tumors and tumor-free surgical margin tissue homogenates. Gene mutations were evaluated via RT-PCR, and MSI status was determined using immunohistochemistry (IHC). GSEA and statistical analyses were performed using R Studio. We observed a significantly elevated expression of SEMA7A in BRAF-mutant CRC tumors and an overexpression of ADAM8 in KRAS 12/13-mutant tumors. The expression of ADAMTS10 was decreased in PIK3CA-mutant CRC tumors. No significant differences in the expression of the examined proteins were observed based on MSI status. The SEMA7A and SEMA4D expressions were correlated with the expression of numerous cytokines associated with various immune processes. The potential immunomodulatory functions of these molecules and their suitability as therapeutic targets require further investigation.

Abstract PR-02: Uncovering molecular differences in pancreatic ductal adenocarcinoma tissues from Black and White patients in the US

Abstract Background: Pancreatic cancer (PC) is among the leading causes of cancer-related deaths in the United States, with a 5-year survival rate of approximately 13%. Previous studies reported higher PC incidence and mortality rates among Black or African American (BAA) patients in comparison to White patients. Disadvantaged socioeconomic status (SES) and environmental exposure to chemicals are factors contributing to racial disparities in pancreatic cancer. Whether and how biological pathways play roles in disparities in pancreatic cancer is unclear. The understanding of molecular features associated racial backgrounds in pancreatic cancer will have significant impacts on both scientific inquiry on cancer biology and clinical management of pancreatic malignancy. In this study, we examined oncogene alterations and PD-L1 expression in pancreatic cancer patients of diverse racial backgrounds. Methods: We conducted our study by analyzing clinical test results of patients through a collaboration with Tempus Labs. In total, 4,249 pancreatic cancer patients’ (White: 3797 and BAA: 452) information were included in this study. DNA target panel sequencing was performed to identify genomic mutations. Genomic microsatellite instability (MSI) and tumor mutational burdens (TMB) were assessed. We also evaluated PD-L1 expression by immunohistochemistry. Results: DNA sequencing analysis revealed differential gene mutation profiles between White and BAA patients. We observed higher rates of KRAS (79.2% vs. 74.2%, q=0.14), TP53 (69.9% vs. 61.9%, q=0.014), KMT2C (6.9% vs. 2.3%, q=0.001), RNF43 (6% vs. 3.7%, q=0.14), and KMT2D (4.4% vs. 2.8%, q=0.3) mutations among BAA patients compared to White patients whereas fewer GNAS (0.2% vs 1.6%, q=0.14) mutation occur in the BAA group. Importantly, the KRAS mutant allele KRASG12R was significantly enriched in BAA compared to White patients (14.4% vs. 10.1%). Next, we compared the TMB levels and found that BAA patients showed higher average TMB levels when compared to White patients. Further, we determined the expression of PD-L1 between the two racial groups and observed BAA patients had more frequent PD-L1 overexpression than White patients (13.2% vs. 8.6%, p<0.05). Interestingly, the race associated difference in PD-L1 expression was even more remarkable in female groups (14.1% vs. 8%, p<0.05). Conclusion: We observed differences in mutation profiles of oncogenes between BAA and White patients, suggesting that such molecular-level changes may contribute to the higher incidence among BAA patients. Additionally, higher frequencies of PD-L1 upregulation in BAA patients implicate racial backgrounds influence tumor microenvironment regulation in pancreatic cancer patients. It is imperative to improve racial diversity in translational and clinical studies. Citation Format: Saurabh Mandal, Emily A Teslow, Minxuan Huang, Swathi Sridhar, Howard Crawford, Melissa C Stoppler, Albert Levin, Ling Huang. Uncovering molecular differences in pancreatic ductal adenocarcinoma tissues from Black and White patients in the US [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-02.

Advancing Cancer Care in Colombia: Results of the First In Situ Implementation of Comprehensive Genomic Profiling.

Comprehensive genomic profiling (CGP) identifies genetic alterations and patterns that are crucial for therapy selection and precise treatment development. In Colombia, limited access to CGP tests underscores the necessity of documenting the prevalence of treatable genetic alterations. This study aimed to describe the somatic genetic profile of specific cancer types in Colombian patients and assess its impact on treatment selection. A retrospective cohort study was conducted at Clínica Colsanitas S.A. from March 2023 to June 2024. Sequencing was performed on the NextSeq2000 platform with the TruSight Oncology 500 (TSO500) assay, which simultaneously evaluates 523 genes for DNA analysis and 55 for RNA; additionally, analyses were performed with the SOPHiA DDM software. The tumor mutational burden (TMB), microsatellite instability (MSI), and programmed cell death ligand 1 (PDL1) were assessed. Among 111 patients, 103 were evaluated, with gastrointestinal (27.93%), respiratory (13.51%), and central nervous system cancers (10.81%) being the most prevalent. TP53 (37%), KMT2C (28%), and KRAS (21%) were frequent mutations. Actionable findings were detected in 76.7% of cases, notably in digestive (20 patients) and lung cancers (8 patients). MSI was stable at 82.52% and high at 2.91%, whilst TMB was predominantly low (91.26%). The test has facilitated access to targeted therapies, improving clinical outcomes in Colombian patients. This profiling test is expected to increase opportunities for personalized medicine in Colombia.

Molecular, Socioeconomic, and Clinical Factors Affecting Racial and Ethnic Disparities in Colorectal Cancer Survival

Disparity in overall survival (OS) and differences in the frequency of driver gene variants by race and ethnicity have been separately observed in patients with colorectal cancer; however, how these differences contribute to survival disparity is unknown. To quantify the association of molecular, socioeconomic, and clinical covariates with racial and ethnic disparities in overall survival among patients with colorectal cancer. This single-center cohort study was conducted at a tertiary-level cancer center using relevant data on all patients diagnosed with colorectal cancer from January 1, 1973, to March 1, 2023. The relative contribution of variables to the disparity was determined using mediation analysis with sequential multivariate Cox regression models. OS, from diagnosis date and from start of first-line chemotherapy. The study population of 47 178 patients (median [IQR] age, 57.0 [49-66] years; 20 465 [43.4%] females and 26 713 [56.6%] males; 3.0% Asian, 8.7% Black, 8.8% Hispanic, and 79.4% White individuals) had a median (IQR) follow-up from initial diagnosis of 124 (174) months and OS of 55 (145) months. Compared with White patients, Black patients had worse OS (hazard ratio [HR], 1.16; 95% CI, 1.09-1.24; P <.001), whereas Asian and Hispanic patients had better OS (HR, 0.66; 95% CI, 0.59-0.74; P <.001; and 0.86; 95% CI, 0.81-0.92; P <.001, respectively). When restricted to patients with metastatic disease, the greatest disparity was between Black patients compared with White patients (HR, 1.2; 95% CI, 1.06-1.37; P <.001). Evaluating changes in OS disparity over 20 years showed disparity decreasing among Asian, Hispanic, and White patients, but increasing between Black patients and White patients (HRs, 1.18; 95% CI, 1.07-1.31 for 2008-2012; 1.24, 95% CI, 1.08-1.42 for 2013-2017; and 1.50; 95% CI, 1.20-1.87 for 2018-2023). Survival outcomes for first-line chemotherapy were worse for Black patients compared with White patients (median OS, 18 vs 26 months; HR, 1.30; 95% CI, 1.01-1.70). Among 7628 patients who had clinical molecular testing, APC, KRAS, and PIK3CA showed higher variant frequency in Black patients (false discovery rate [FDR], 0.01; < 0.001; and 0.01, respectively), whereas BRAF and KIT were higher among White patients (FDR, 0.001 and 0.01). Mediation analysis identified neighborhood socioeconomic status as the greatest contributor to OS disparity (29%), followed by molecular characteristics (microsatellite instability status, KRAS variation and BRAF variation, 10%), and tumor sidedness (9%). This single-center cohort study identified substantial OS disparity and differing frequencies of driver gene variations by race and ethnicity. Socioeconomic status had the largest contribution but accounted for less than one-third of the disparity, with substantial contribution from tumor molecular features. Further study of the associations of genetic ancestry and the molecular pathogenesis of colorectal cancer with chemotherapy response is needed.

Clinical Interest in Exome-Based Analysis of Somatic Mutational Signatures for Non-Small Cell Lung Cancer.

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related mortality. This study investigates the clinical interest of whole exome sequencing (WES) for analyzing somatic mutational signatures in patients with advanced or metastatic NSCLC treated with the current standard of care. Exome sequencing data and clinical characteristics from 132 patients with advanced or metastatic NSCLC were analyzed. Somatic mutational signatures including single base substitutions (SBSs), double base substitutions (DBSs), and copy number signatures were evaluated. Structural variations including tumor mutational burden (TMB), the number of neoantigens, TCR clonality, homologous recombination deficiency (HRD), copy number alterations (CNAs), and microsatellite instability (MSI) score were determined. The association between these genomic features, NSCLC subtypes, and patient outcomes (progression-free and overall survival) was evaluated. Exome sequencing offers valuable insights into somatic mutational signatures in NSCLC. This study identified specific signatures associated with a poor response to immune checkpoint inhibitor (ICI) therapy and chemotherapy, potentially aiding treatment selection and identifying patients unlikely to benefit from these approaches.

A comprehensive prognostic and immunological implications of PFKP in pan-cancer

BackgroundPhosphofructokinase P (PFKP) is a key rate-limiting enzyme in glycolysis, playing a crucial role in various pathophysiological processes. However, its specific function in tumors remains unclear. This study aims to evaluate the expression and specific role of PFKP across multiple tumor types (Pan-cancer) and to explore its potential clinical significance as a therapeutic target in cancer treatment.MethodsWe analyzed the expression of PFKP, immune cell infiltration, and patient prognosis across various cancers using data from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Additionally, we conducted a series of experiments in lung cancer cells, including Western blot, CCK-8 assay, colony formation assay, transwell migration assay, scratch wound healing assay, LDH release assay, and flow cytometry, to evaluate the impact of PFKP on tumor cells.ResultsPFKP was found to be highly expressed in most cancers and identified as a prognostic risk factor. Elevated PFKP expression is associated with poorer clinical outcomes, particularly in lung adenocarcinoma (LUAD). Receiver operating characteristic (ROC) curve analysis indicated that PFKP can effectively differentiate between cancerous and normal tissues. The expression of PFKP in most tumors showed significant correlations with tumor mutational burden (TMB), microsatellite instability (MSI), immune score, and immune cell infiltration. In vitro experiments demonstrated that PFKP overexpression promotes lung cancer cell proliferation and migration while inhibiting apoptosis, whereas PFKP deficiency results in the opposite effects.ConclusionPFKP acts as an oncogene involved in tumorigenesis and may influence the immune microenvironment within the tumor. Our findings suggest that PFKP could serve as a potential biomarker for predicting prognosis and the efficacy of immunotherapy in tumors.

Benchmarking whole exome sequencing in the German network for personalized medicine

IntroductionWhole Exome Sequencing (WES) has emerged as an efficient tool in clinical cancer diagnostics to broaden the scope from panel-based diagnostics to screening of all genes and enabling robust determination of complex biomarkers in a single analysis. MethodsTo assess concordance, six formalin-fixed paraffin-embedded (FFPE) tissue specimens and four commercial reference standards were analyzed by WES as matched tumor-normal DNA at 21 NGS centers in Germany, each employing local wet-lab and bioinformatics. Somatic and germline variants, copy-number alterations (CNAs), and complex biomarkers were investigated. Somatic variant calling was performed in 494 diagnostically relevant cancer genes. The raw data were collected and re-analyzed with a central bioinformatic pipeline to separate wet- and dry-lab variability. ResultsThe mean positive percentage agreement (PPA) of somatic variant calling was 76 % while the positive predictive value (PPV) was 89 % in relation to a consensus list of variants found by at least five centers. Variant filtering was identified as the main cause for divergent variant calls. Adjusting filter criteria and re-analysis increased the PPA to 88 % for all and 97 % for the clinically relevant variants. CNA calls were concordant for 82 % of genomic regions. Homologous recombination deficiency (HRD), tumor mutational burden (TMB), and microsatellite instability (MSI) status were concordant for 94 %, 93 %, and 93 % of calls, respectively. Variability of CNAs and complex biomarkers did not decrease considerably after harmonization of the bioinformatic processing and was hence attributed mainly to wet-lab differences. ConclusionContinuous optimization of bioinformatic workflows and participating in round robin tests are recommended.

PROTAC-mediated conditional degradation of the WRN helicase as a potential strategy for selective killing of cancer cells with microsatellite instability

Multiple studies have demonstrated that cancer cells with microsatellite instability (MSI) are intolerant to loss of the Werner syndrome helicase (WRN), whereas microsatellite-stable (MSS) cancer cells are not. Therefore, WRN represents a promising new synthetic lethal target for developing drugs to treat cancers with MSI. Given the uncertainty of how effective inhibitors of WRN activity will prove in clinical trials, and the likelihood of tumours developing resistance to WRN inhibitors, alternative strategies for impeding WRN function are needed. Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that target specific proteins for degradation. Here, we engineered the WRN locus so that the gene product is fused to a bromodomain (Bd)-tag, enabling conditional WRN degradation with the AGB-1 PROTAC specific for the Bd-tag. Our data revealed that WRN degradation is highly toxic in MSI but not MSS cell lines. In MSI cells, WRN degradation caused G2/M arrest, chromosome breakage and ATM kinase activation. We also describe a multi-colour cell-based platform for facile testing of selective toxicity in MSI versus MSS cell lines. Together, our data show that a degrader approach is a potentially powerful way of targeting WRN in MSI cancers and paves the way for the development of WRN-specific PROTAC compounds.

Locally advanced rectal cancer in a young adult affected with dyskeratosis congenita (Zinsser–Cole–Engman syndrome): a case report

BackgroundDyskeratosis congenita (DKC), also known as Zinsser–Cole–Engman syndrome, is a progressive genetic disease with a triad of reticulate skin pigmentation, nail dystrophy, and leukoplakia. Approximately 8–10% of patients with DKC develop malignancies, and cases of colorectal cancer with DKC in young people have been reported previously.Case presentationA 25-year-old man with DKC since approximately 10 years of age developed fever and lower abdominal discomfort. Diagnostic imaging revealed locally advanced rectal cancer with lymph node metastasis, direct invasion of the prostate, and pelvic abscess due to tumor microperforation (cT4bN2M0 cStage IIIC). Biopsy showed well to moderately differentiated ductal adenocarcinoma. Genetic testing was negative for RAS and BRAF gene mutations, and microsatellite instability (MSI) testing was also negative. After sigmoid colostomy, the patient was treated with total neoadjuvant therapy (TNT) with systemic chemotherapy (six courses of FOLFOX + panitumumab) followed by chemoradiation therapy (50.4 Gy with capecitabine). After TNT, the primary tumor and metastatic lymph nodes shrank. According to the findings of colonoscopy and magnetic resonance image (MRI), we diagnosed near complete response (near-CR) and decided to follow the patient without surgery by every 3 months re-evaluation. However, 5 months after TNT, tumor regrowth was detected on colonoscopy and imaging, and the patient underwent total pelvic exenteration. He developed paralytic ileus as a postoperative complication, and was discharged on the 38th postoperative day. Pathological examination revealed a residual tumor with invasion of the periprostatic tissue. There was no metastasis in the pararectal and lateral pelvic lymph nodes, but one extramural non-contiguous cancerous extension (tumor deposit) was observed (ypT4bN1cM0 ypStage IIIC). The patient has been free of recurrence for one year after surgery.ConclusionsDKC often develops into various tumors in the digestive system at an early age; therefore, appropriate surveillance may be required. In addition, considering that cancers in patients with DKC occur at a young age, fertility preservation and survivorship are also important, and adequate explanations and care should be provided to patients before and after treatment.

Predictive Biomarkers and Resistance Mechanisms of Checkpoint Inhibitors in Malignant Solid Tumors.

Predictive biomarkers for immune checkpoint inhibitors (ICIs) in solid tumors such as melanoma, hepatocellular carcinoma (HCC), colorectal cancer (CRC), non-small cell lung cancer (NSCLC), endometrial carcinoma, renal cell carcinoma (RCC), or urothelial carcinoma (UC) include programmed cell death ligand 1 (PD-L1) expression, tumor mutational burden (TMB), defective deoxyribonucleic acid (DNA) mismatch repair (dMMR), microsatellite instability (MSI), and the tumor microenvironment (TME). Over the past decade, several types of ICIs, including cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, anti-programmed cell death 1 (PD-1) antibodies, anti-programmed cell death ligand 1 (PD-L1) antibodies, and anti-lymphocyte activation gene-3 (LAG-3) antibodies have been studied and approved by the Food and Drug Administration (FDA), with ongoing research on others. Recent studies highlight the critical role of the gut microbiome in influencing a positive therapeutic response to ICIs, emphasizing the importance of modeling factors that can maintain a healthy microbiome. However, resistance mechanisms can emerge, such as increased expression of alternative immune checkpoints, T-cell immunoglobulin (Ig), mucin domain-containing protein 3 (TIM-3), LAG-3, impaired antigen presentation, and alterations in the TME. This review aims to synthesize the data regarding the interactions between microbiota and immunotherapy (IT). Understanding these mechanisms is essential for optimizing ICI therapy and developing effective combination strategies.

Universal screening of colorectal tumors for lynch syndrome: a survey of patient experiences and opinions

BackgroundLynch syndrome represents the most common hereditary cause of both colorectal and endometrial cancer. It is caused by defects in mismatch repair genes, as well as EPCAM. Universal screening of colon tumors for Lynch syndrome via microsatellite instability (MSI) and/or immunohistochemistry (IHC) can identify patients and families at risk to develop further cancers and potentially impact surveillance and treatment options. The approach to implementation of universal screening, taking ethical considerations into account, is critical to its effectiveness, with patient perspectives providing valuable insight.MethodsPatients whose colon tumors underwent universal screening at Penn State Hershey Medical Center over a period of 2.5 years were mailed a survey on universal screening in 2017. Along with the survey, they received a recruitment letter and a summary explanation of research. The survey included both multiple choice and free-response questions that covered topics including respondent knowledge of Lynch syndrome, attitudes toward universal screening and experiences with the screening protocol as implemented.ResultsSixty-six of 297 possible patients (22.2%) responded to the survey, including 13 whose screening results raised concern for Lynch syndrome. 75.8% of respondents supported universal tumor screening without informed consent. 92.4% preferred receiving screening results regardless of outcome. Respondents described benefits to screening for themselves and their families.ConclusionsWhile broadly supporting universal tumor screening without informed consent, respondents also wanted more information shared about the screening policy, as well as their results. These patient preferences should be one of many factors considered when implementing universal screening and can also inform practices regarding both tumor profiling and universal genetic testing, which is becoming more prevalent.

Consensus molecular subtyping of metastatic colorectal cancer expands biomarker-directed therapeutic benefit for patients with CMS1 and CMS2 tumors.

We developed a whole transcriptome sequencing (WTS)-based Consensus Molecular Subtypes (CMS) classifier using FFPE tissue and investigated its prognostic and predictive utility in a large clinico-genomic database of CRC patients (n = 24,939). The classifier was trained against the original CMS datasets using an SVM model and validated in an independent blinded TCGA dataset (88.0% accuracy). Kaplan-Meier estimates of overall survival (OS) and time-on-treatment (TOT) were calculated for each CMS (p < 0.05 considered significant). CMS2 tumors were enriched on left-side of colon and conferred the longest median OS. In RAS-wildtype mCRC, left-sided tumors and CMS2 classification were associated with longer TOT with anti-EGFR antibodies (cetuximab and panitumumab). When restricting to only CMS2, there was no significant difference in TOT between right- versus left-sided tumors. CMS1 tumors were associated with a longer median TOT with pembrolizumab relative to other CMS groups, even when analyzing only microsatellite stable (MSS) tumors. A WTS-based CMS classifier allowed investigation of a large multi-institutional clinico-genomic mCRC cohort, suggesting anti-EGFR therapy benefit for right-sided RAS-WT CMS2 tumors and immune checkpoint inhibitor benefit for MSS CMS1. Routine CMS classification of CRC provides important treatment associations that should be further investigated.

Risk of metachronous neoplasia in early-onset colorectal cancer: meta-analysis.

Metachronous colorectal cancer refers to patients developing a second colorectal neoplasia diagnosed at least 6 months after the initial cancer diagnosis, excluding recurrence. The aim of this systematic review is to assess the incidence of metachronous colorectal cancer in early-onset colorectal cancer (defined as age at diagnosis of less than 50 years) and to identify risk factors. This is a systematic review and meta-analysis performed following the PRISMA statement and registered on PROSPERO. The literature search was conducted in PubMed and Embase. Only studies involving patients with early-onset colorectal cancer (less than 50 years old) providing data on metachronous colorectal cancer were included in the analysis. The primary endpoint was the risk of metachronous colorectal cancer in patients with early-onset colorectal cancer. Secondary endpoints were association with Lynch syndrome, family history and microsatellite instability. Sixteen studies met the inclusion criteria. The incidence of metachronous colorectal cancer was 2.6% (95% c.i. 2.287-3.007). The risk of developing metachronous colorectal cancer in early-onset colorectal cancer versus non-early-onset colorectal cancer patients demonstrated an OR of 0.93 (95% c.i. 0.760-1.141). The incidence of metachronous colorectal cancer in patients with Lynch syndrome was 18.43% (95% c.i. 15.396-21.780), and in patients with family history 10.52% (95% c.i. 5.555-17.659). The proportion of metachronous colorectal cancer tumours in the microsatellite instability population was 19.7% (95% c.i. 13.583-27.2422). The risk of metachronous colorectal cancer in patients with early-onset colorectal cancer is comparable to those with advanced age, but it is higher in patients with Lynch syndrome, family history and microsatellite instability. This meta-analysis demonstrates the need to personalize the management of patients with early-onset colorectal cancer according to their risk factors.

The Relationship Between DNA Mismatch Repair Status and Clinicopathologic Characteristics in Colon Cancer.

DNA mismatch repair (MMR) proteins are essential for repairing genetic mutations that occur during DNA replication. Deficiency of MMR proteins results in a phenotype called microsatellite instability (MSI), which occurs in Lynch syndrome as well as sporadic colorectal cancers (CRC), and it is associated with several clinicopathological features. We aimed to investigate the association of the loss of MMR proteins with clinicopathologic considerations in our CRC series. In this retrospective study, DNA MMR protein status in CRC is evaluated in a total of 200 colorectal resection specimens by immunohistochemistry (IHC) for MLH1, MSH2, MSH6 and PMS2 protein expression. The BRAF mutation was investigated by the real-time PCR in cases with loss of MLH1 protein expression. The relationship between MMR status and clinicopathological parameters was investigated statistically. Loss of MMR protein expression was detected in 26 of 200 CRC cases. The BRAFV600E mutation was detected in 2 of the cases with MLH1 loss and accepted as sporadic. The remaining 24 cases (12%) were identified as Lynch syndrome candidates. There were statistical differences observed regarding the presence of tumor-infiltrating lymphocytes (P < .001), Crohn's-like reaction (P = .001), expansile growth (P < .001), tumor heterogeneity (P < .001), mucinous differentiation (P < .001), and presence of metastatic lymph nodes (P = .045) between sporadic cases with preserved MMR and Lynch candidates. However, difference in the survival rates between sporadic cases and Lynch candidates was not significant. Immunohistochemical staining for MMR is a practical method for predicting MSI phenotype as well as Lynch candidates. MMR expression status was found to be associated with certain clinicopathological features some of which also have prognostic significance.

CD24 affects the immunosuppressive effect of tumor-infiltrating cells and tumor resistance in a variety of cancers

BackgroundCluster of differentiation 24 (CD24) is a highly glycosylated glycosylphosphatidylinositol (GPI)-anchored surface protein, expressed in various tumor cells, as a "don't eat me" signaling molecule in tumor immune. This study aimed to investigate the potential features of CD24 in pan-cancer.MethodsThe correlations between 22 immune cells and CD24 expression were using TIMER analysis. R package “ESTIMATE” was used to predict the proportion of immune and stromal cells in pan-cancer. Spearman's correlation analysis was performed to evaluate the relationships between CD24 expression and immune checkpoints, chemokines, mismatch repair, tumor mutation burden and microsatellite instability, and qPCR and western blot were conducted to assess CD24 expression levels in liver hepatocellular carcinoma (LIHC). In addition, loss of function was performed for the biological evaluation of CD24 in LIHC.ResultsCD24 expression was positively correlated with myeloid cells, including neutrophils and myeloid-derived suppressor cells, in various tumors, such as BLCA, HNSC-HPV, HNSC, KICH, KIRC, KIRP, TGCT, THCA, THYM, and UCEC. In contrast, anti-tumor NK cells and NKT cells showed a negative association with CD24 expression in BRCA-Her2, ESCA, HNSC-HPV, KIRC, THCA, and THYM. The top three tumors with the highest correlation between CD24 and ImmuneScore were TGCT, THCA, and SKCM. Functional enrichment analysis revealed CD24 expression was negatively associated with various immune-related pathways. Immune checkpoints and chemokines also exhibited inverse correlations with CD24 in CESC, CHOL, COAD, ESCA, READ, TGCT, and THCA. Additionally, CD24 was overexpressed in most tumors, with high CD24 expression in BRCA, LIHC, and CESC correlating with poor prognosis. The TIDE database indicated tumors with high CD24 expression, particularly melanoma, were less responsive to PD1/PD-L1 immunotherapy. Finally, CD24 knockdown resulted in impaired proliferation and cell cycle progression in LIHC.ConclusionCD24 participates in regulation of immune infiltration, influences patient prognosis and serves as a potential tumor marker.

Investigation of the Relationship Between DNA Mismatch Repair Genes and Microsatellite Instability in Solid Tumors

Aim: In this study, we aimed to detect the MSI status and somatic mutations in MMR genes (MSH2, MSH6, MLH1, PMS2) of a total of 55 solid tumors diagnosed with colorectal, endometrium and ovarian cancer by NGS method and to reveal the relationship between them. Material and Method: DNA isolation was performed by taking 10-micron sections from paraffin-embedded tissue samples of 55 patients diagnosed with kolorektal, endometrium ve ovarian solid tümörlerinin and Kapa NGS DNA extraction kit was used for sequence analysis. The purity and concentration of the DNA obtained was measured by Qubit fluoremeter, and NadPrep DNA Universal Library Preparation Kit was used for high quality library preparation. Bioinformatics analyses were performed on the Genomize Seq platform. The MSI value was analysed by Roche Navify Mutation Caller software and percentage MSI values were determined using the MSIsensor2 pipeline for secondary analysis of NGS. Results: All ovarian tumors were in the MSI-Stable category. The average MSI value was 2.01. One sample had an MSI of zero. In addition, no mutations in the MSH2 and MLH1 genes were detected in any of the ovarian tumors. 3 of 4 endometrial tumors were in the MSI-Stable category, and 1 tumor was in the MSI-low (MSI value: 13.2) category. No variants were detected in the MSH2 and PMS2 genes in endometrial tumors. 2 of the 41 colorectal tumors (Case4, Case16) were in the MSI-High category. No variants were detected in the MMR genes in 19 tumors. Conclusion: Although frame-shift and stop-gain mutations were detected in 23 tumors that would cause protein deficiency in MMR genes, MSI-H was not detected, as expected, except for two colorectal tumors. Therefore, the results of our study emphasise the need to define new predictive biomarkers clinically within the framework of algorithms to predict response to immunotherapy and determine prognosis.

Enhanced Sensitivity and Specificity for Microsatellite Instability in Colorectal Cancer Using a Novel PCR-HRM Technique

Enhanced Sensitivity and Specificity for Microsatellite Instability in Colorectal Cancer Using a Novel PCR-HRM Technique