MSI/MMR-deficient tumor diagnosis: Which standard for screening and for diagnosis? Diagnostic modalities for the colon and other sites: Differences between tumors

Preoperative prediction of microsatellite instability status: development and validation of a pan-cancer PET/CT-based radiomics model

OBJECTIVE

The purpose of this study is to verify the feasibility of preoperative prediction of patients' microsatellite instability status by applying a PET/CT-based radiation model.

METHODS

This retrospective study ultimately included 142 patients. Three prediction models have been developed. The predictive performance of all models was evaluated by the receiver operating characteristic curve and area under the curve values. The PET/CT radiological histology score (Radscore) was calculated to evaluate the microsatellite instability status, and the corresponding nomogram was established. The correlation between clinical factors and radiological characteristics was analyzed to verify the value of radiological characteristics in predicting microsatellite instability status.

RESULTS

Twelve features were retained to establish a comprehensive prediction model of radiological and clinical features. M phase of the tumor has been proven to be an independent predictor of microsatellite instability status. The receiver operating characteristic results showed that the area under the curve values of the training set and the validation set of the radiomics model were 0.82 and 0.75, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the training set were 0.72, 0.78, 0.83 and 0.66, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the validation set were 1.00, 0.50, 0.76 and 1.00, respectively. The risk of patients with microsatellite instability was calculated by Radscore and nomograph, and the cutoff value was -0.4385. The validity of the results was confirmed by the decision and calibration curves.

CONCLUSION

Radiological models based on PET/CT can provide clinical and practical noninvasive prediction of microsatellite instability status of several different cancer types, reducing or avoiding unnecessary biopsy to a certain extent.

Predicting effect of anti-PD-1/PD-L1 inhibitors therapy for hepatocellular carcinoma by detecting plasma metabolite based on UHPLC-MS

Introduction

Anti-PD-1/PD-L1 inhibitors therapy has become a promising treatment for hepatocellular carcinoma (HCC), while the therapeutic efficacy varies significantly among effects for individual patients are significant difference. Unfortunately, specific predictive biomarkers indicating the degree of benefit for patients and thus guiding the selection of suitable candidates for immune therapy remain elusive.no specific predictive biomarkers are available indicating the degree of benefit for patients and thus screening the preferred population suitable for the immune therapy.

Methods

Ultra-high-pressure liquid chromatography-mass spectrometry (UHPLC-MS) considered is an important method for analyzing biological samples, since it has the advantages of high rapid, high sensitivity, and high specificity. Ultra-high-pressure liquid chromatography-mass spectrometry (UHPLC-MS) has emerged as a pivotal method for analyzing biological samples due to its inherent advantages of rapidity, sensitivity, and specificity. In this study, potential metabolite biomarkers that can predict the therapeutic effect of HCC patients receiving immune therapy were identified by UHPLC-MS.

Results

A partial least-squares discriminant analysis (PLS-DA) model was established using 14 glycerophospholipid metabolites mentioned above, and good prediction parameters (R2 = 0.823, Q2 = 0.615, prediction accuracy = 0.880 and p < 0.001) were obtained. The relative abundance of glycerophospholipid metabolite ions is closely related to the survival benefit of HCC patients who received immune therapy.

Discussion

This study reveals that glycerophospholipid metabolites play a crucial role in predicting the efficacy of immune therapy for HCC.

Pan-cancer analysis of the prognostic and immunological role of FKBP4

Objectives

Our previous studies revealed the significant roles of FK506-binding protein 4 (FKBP4) in tumorigenesis, however, there has been no pan-cancer analysis of FKBP4. Using bioinformatics, the current study reported the expression and prognostic role of FKBP4, and the correlation between FKBP4 and clinicopathological parameters, methylation, molecular network, immunological traits and drug sensitivity.

Methods

RNA sequencing data, somatic mutation, and related clinical information were obtained from TCGA using UCSC Xena. The association between FKBP4 expression and clinical features was assessed using TISIDB. The relationships between FKBP4 expression and tumour stage, OS, DSS, DFS, and PFS were analysed using univariate cox regression analysis. The radar plots for TMB and MSI were obtained using "Fmsb" R package. UALCAN was used to explore the effect of FKBP4 methylation on tumour and normal samples. CBioportal was used to analyse copy number mutations in FKBP4 Gene expression and drug sensitivity data were downloaded from the CellMiner database. GO analysis was performed for the high and the low expression of FKBP4 compared with the median level of FKBP4 using clusterProfiler4.0.

Results

FKBP4 expression is significantly upregulated in various types of cancers. Cox regression analysis showed that high FKBP4 levels were correlated with poor OS, DSS, DFS, and PFS in most patients with cancer. Methylation of FKBP4 DNA was upregulated in most cancers, and FKBP4 expression is positively associated with transmethylase expression. FKBP4 and its copy were significantly associated with the expression of immune-infiltrating cells, immune checkpoint genes, immune modulators, TMB, MMR, and MSI. FKBP4 expression levels significantly correlated with 16 different drug sensitivities (all p < 0.05).

Conclusions

Our pan-cancer bioinformatic analysis revealed a potential mechanism underlying the effects of FKBP4 on the prognosis and progression of various cancers.

Deficient mismatch repair/microsatellite unstable colorectal cancer: therapeutic advances and questions

The microsatellite instability (MSI) phenotype is related to a deficiency of the DNA mismatch repair (dMMR) system and is observed in 5% of metastatic colorectal cancers (mCRCs). MSI/dMMR phenotype testing should be routine for all CRCs regardless of stage. Two complementary techniques with a high concordance (90-97%) allow us to determine the MSI/dMMR status of a tumor: immunohistochemistry and polymerase chain reaction. Since 2020 and the results of the phase III KEYNOTE 177 trial, pembrolizumab [anti-programmed cell death protein 1 (PD1)] is the new standard of care in first-line MSI/dMMR mCRC. To date, no combination of chemtotherapy ± targeted therapy with immune checkpoint inhibitors (ICIs) has been validated in the management of MSI/dMMR mCRC, and it is not known whether this combination would be beneficial. It is also unclear whether dual therapy with two ICIs is more effective than monotherapy. Several phase III trials are ongoing to answer these questions. Despite a high response rate and long-term benefit of a first line by anti-PD1, 30-50% of patients with MSI/dMMR mCRC experience an early or secondary progression. There are currently no validated predictive biomarkers of anti-PD1 ± anti-cytotoxic T lymphocyte antigen-4 resistance in patients with MSI/dMMR mCRC. In case of early progression on ICIs, the first two questions to consider are the possibility of pseudoprogression and the correct diagnosis of MSI/dMMR status. To date, there are no data on the use of adjuvant ICIs for MSI/dMMR resected colon cancers. By contrast, data are accumulating regarding the efficacy of neoadjuvant ICIs, with at least two-thirds of patients in the different trials in pathological complete response, making it possible to envisage 'Watch and wait' strategies in future.

Beyond PD(L)-1 Blockade in Microsatellite-Instable Cancers: Current Landscape of Immune Co-Inhibitory Receptor Targeting

High microsatellite instability (MSI-H) derives from genomic hypermutability due to deficient mismatch repair function. Colorectal (CRC) and endometrial cancers (EC) are the tumor types that more often present MSI-H. Anti-PD(L)-1 antibodies have been demonstrated to be agnostically effective in patients with MSI-H cancer, but 50-60% of them do not respond to single-agent treatment, highlighting the necessity of expanding their treatment opportunities. Ipilimumab (anti-CTLA4) is the only immune checkpoint inhibitor (ICI) non-targeting PD(L)-1 that has been approved so far by the FDA for MSI-H cancer, namely, CRC in combination with nivolumab. Anti-TIM3 antibody LY3321367 showed interesting clinical activity in combination with anti-PDL-1 antibody in patients with MSI-H cancer not previously treated with anti-PD(L)-1. In contrast, no clinical evidence is available for anti-LAG3, anti-TIGIT, anti-BTLA, anti-ICOS and anti-IDO1 antibodies in MSI-H cancers, but clinical trials are ongoing. Other immunotherapeutic strategies under study for MSI-H cancers include vaccines, systemic immunomodulators, STING agonists, PKM2 activators, T-cell immunotherapy, LAIR-1 immunosuppression reversal, IL5 superagonists, oncolytic viruses and IL12 partial agonists. In conclusion, several combination therapies of ICIs and novel strategies are emerging and may revolutionize the treatment paradigm of MSI-H patients in the future. A huge effort will be necessary to find reliable immune biomarkers to personalize therapeutical decisions.

Comprehensive genomic profiling for oncological advancements by precision medicine

Considerable advancements in next generation sequencing (NGS) techniques have sparked the use of comprehensive genomic profiling (CGP) as a guiding tool for precision-centered oncological treatments. The past two decades have seen the completion of the human genome project, and the consequential invention of NGS. High-throughput sequencing technologies support the discovery and commonplace use of individualized cancer treatments, specifically immune-centered checkpoint inhibitor therapies, and oncogene and tumor suppressor gene targeted therapies. Nevertheless, CGP is not commonly used in all clinical settings. This review investigates the clinically relevant applications of CGP. Studies published between the years 2000-2023 have shown substantial evidence of the benefits of integrating CGP into routine care practice, while also making important comparisons to current-standard oncological treatment strategies. Findings of a comprehensive genomic profile includes predictive, prognostic, and diagnostic biomarkers, together with somatic mutation identification which can indicate the efficacy of immunotherapies and molecularly guided therapies. This review highlights the importance of CGP in identifying driver mutations in tumors that subsequently can be effectively targeted with molecular therapeutics and lead to drug discovery, allowing for increased precision in treating tumors selectively based on their specific genetic mutations, thereby improving patient outcomes.

Deep Learning Can Predict Bevacizumab Therapeutic Effect and Microsatellite Instability Directly from Histology in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) remains a significant cause of mortality among gynecologic cancers, with the majority of cases being diagnosed at an advanced stage. Before targeted therapies were available, EOC treatment relied largely on debulking surgery and platinum-based chemotherapy. Vascular endothelial growth factors have been identified as inducing tumor angiogenesis. According to several clinical trials, anti-vascular endothelial growth factor-targeted therapy with bevacizumab was effective in all phases of EOC treatment. However, there are currently no biomarkers accessible for regular therapeutic use despite the importance of patient selection. Microsatellite instability (MSI), caused by a deficiency of the DNA mismatch repair system, is a molecular abnormality observed in EOC associated with Lynch syndrome. Recent evidence suggests that angiogenesis and MSI are interconnected. Developing predictive biomarkers, which enable the selection of patients who might benefit from bevacizumab-targeted therapy or immunotherapy, is critical for realizing personalized precision medicine. In this study, we developed 2 improved deep learning methods that eliminate the need for laborious detailed image-wise annotations by pathologists and compared them with 3 state-of-the-art methods to not only predict the efficacy of bevacizumab in patients with EOC using mismatch repair protein immunostained tissue microarrays but also predict MSI status directly from histopathologic images. In prediction of therapeutic outcomes, the 2 proposed methods achieved excellent performance by obtaining the highest mean sensitivity and specificity score using MSH2 or MSH6 markers and outperformed 3 state-of-the-art deep learning methods. Moreover, both statistical analysis results, using Cox proportional hazards model analysis and Kaplan-Meier progression-free survival analysis, confirm that the 2 proposed methods successfully differentiate patients with positive therapeutic effects and lower cancer recurrence rates from patients experiencing disease progression after treatment (P < .01). In prediction of MSI status directly from histopathology images, our proposed method also achieved a decent performance in terms of mean sensitivity and specificity score even for imbalanced data sets for both internal validation using tissue microarrays from the local hospital and external validation using whole section slides from The Cancer Genome Atlas archive.

Immune checkpoint therapy for solid tumours: clinical dilemmas and future trends

Immune-checkpoint inhibitors (ICBs), in addition to targeting CTLA-4, PD-1, and PD-L1, novel targeting LAG-3 drugs have also been approved in clinical application. With the widespread use of the drug, we must deeply analyze the dilemma of the agents and seek a breakthrough in the treatment prospect. Over the past decades, these agents have demonstrated dramatic efficacy, especially in patients with melanoma and non-small cell lung cancer (NSCLC). Nonetheless, in the field of a broad concept of solid tumours, non-specific indications, inseparable immune response and side effects, unconfirmed progressive disease, and complex regulatory networks of immune resistance are four barriers that limit its widespread application. Fortunately, the successful clinical trials of novel ICB agents and combination therapies, the advent of the era of oncolytic virus gene editing, and the breakthrough of the technical barriers of mRNA vaccines and nano-delivery systems have made remarkable breakthroughs currently. In this review, we enumerate the mechanisms of each immune checkpoint targets, associations between ICB with tumour mutation burden, key immune regulatory or resistance signalling pathways, the specific clinical evidence of the efficacy of classical targets and new targets among different tumour types and put forward dialectical thoughts on drug safety. Finally, we discuss the importance of accurate triage of ICB based on recent advances in predictive biomarkers and diagnostic testing techniques.

Immunotherapy for Colorectal Cancer with High Microsatellite Instability: The Ongoing Search for Biomarkers

Microsatellite instability (MSI) is a biological condition associated with inflamed tumors, high tumor mutational burden (TMB), and responses to immune checkpoint inhibitors. In colorectal cancer (CRC), MSI tumors are found in 5% of patients in the metastatic setting and 15% in early-stage disease. Following the impressive clinical activity of immune checkpoint inhibitors in the metastatic setting, associated with deep and long-lasting responses, the development of immune checkpoint inhibitors has expanded to early-stage disease. Several phase II trials have demonstrated a high rate of pathological complete responses, with some patients even spared from surgery. However, in both settings, not all patients respond and some responses are short, emphasizing the importance of the ongoing search for accurate biomarkers. While various biomarkers of response have been evaluated in the context of MSI CRC, including B2M and JAK1/2 mutations, TMB, WNT pathway mutations, and Lynch syndrome, with mixed results, liver metastases have been associated with a lack of activity in such strategies. To improve patient selection and treatment outcomes, further research is required to identify additional biomarkers and refine existing ones. This will allow for the development of personalized treatment approaches and the integration of novel therapeutic strategies for MSI CRC patients with liver metastases.

Assessment of the reliability of MSI status and dMMR proteins deficiency screening on endoscopic biopsy material in esophagus and gastric adenocarcinoma

BACKGROUND

Microsatellite instability (MSI) is a negative predictive factor for neoadjuvant chemotherapy in resectable oesogastric adenocarcinoma and a crucial determinant for immunotherapy. We aimed to evaluate reliability of dMMR/MSI status screening performed on preoperative endoscopic biopsies.

METHODS

Paired pathological samples from biopsies and surgical specimen of oesogastric adenocarcinoma were retrospectively collected between 2009 and 2019. We compared dMMR status obtained by immunohistochemistry (IHC) and MSI status by PCR. dMMR/MSI status on surgical specimen was considered as reference.

RESULTS

PCR and IHC were conclusive on biopsies respectively for 53 (96.4%) and 47 (85.5%) of the 55 patients enrolled. IHC was not contributive for 1 surgical specimen. A third reading of IHC was carried out for 3 biopsies. MSI status was observed in 7 (12.5%) surgical specimens. When analyses were contributive, sensitivity and specificity of biopsies for dMMR/MSI were respectively 85% and 98% for PCR vs. 86% and 98% for IHC. Concordance rate between biopsies and surgical specimen was 96.2% for PCR and 97.8% for IHC.

CONCLUSIONS

Endoscopic biopsies are a suitable source of tissue for dMMR/MSI status determination in oesogastric adenocarcinoma which should be routinely performed at diagnosis to better adapt neoadjuvant treatment.

MINIABSTRACT

By comparison of dMMR phenotype obtained by immunohistochemistry and MSI status by PCR between match-paired samples of oesogastric cancer's endoscopic biopsies and surgical specimen, we observed that biopsies are a suitable source of tissue for dMMR/MSI status determination.

Concordance between microsatellite instability and mismatch repair protein expression in colorectal cancer and their clinicopathological characteristics: a retrospective analysis of 502 cases

Microsatellite instability (MSI) is one of the hallmarks of colorectal cancer (CRC). Mismatch repair (MMR) protein expression may reflect MSI status. To analyze the concordance between MSI and MMR expression in CRC and their clinicopathological characteristics, 502 CRC patients were retrospectively collected in this study. Polymerase chain reaction-capillary electrophoresis (PCR-CE) was used to measure MSI, and MMR expression was determined by immunohistochemistry (IHC). The causes of non-concordance were analyzed. Chi-square test was used to find the correlation between MSI and various clinicopathological parameters. PCR-CE results showed 64 (12.7%) patients had high microsatellite instability (MSI-H); low microsatellite instability (MSI-L) and microsatellite stable (MSS) cases were 19 (3.8%)and 419 (83.5%), respectively. With regard to IHC, 430 (85.7%) showed proficient mismatch repair (pMMR) and 72 (14.3%) showed deficient mismatch repair (dMMR). The coincidence rate of MSI and MMR expression in CRC was 98.4% (494/502), with good concordance (Kappa = 0.932). Using PCR-CE as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of IHC were 100%, 98.2%, 88.9%, and 100%, respectively. MSI-H was more common in women, right colon, tumors ≥ 5 cm, ulcerative type, mucinous adenocarcinoma, poor differentiation, T stage I/II, and without lymph node or distant metastasis for CRC patients. In summary, MSI exhibited some typical clinicopathological characteristics. MSI and MMR expression in CRC had good concordance. However, it is still extremely necessary to perform PCR-CE. We recommend that testing packages of different sizes should be developed in clinical practice to create a testing echelon, to facilitate comprehensive selection according to experimental conditions, clinical diagnosis, and treatment needs.

Special features of sarcomas developed in patients with Lynch syndrome: a systematic review

Lynch syndrome (LS) is a genetic predisposition leading to colorectal and non-colorectal tumors such as endometrial, upper urinary tract, small intestine, ovarian, gastric, biliary duct cancers and glioblastoma. Though not classically associated with LS, growing literature suggests that sarcomas might develop in patients with LS. This systematic review of literature identified 44 studies (N=95) of LS patients who developed sarcomas. It seems that most sarcomas developed in patients with a germline mutation of MSH2 (57%) exhibit a dMMR (81%) or MSI (77%) phenotype, as in other LS-tumors. Although undifferentiated pleomorphic sarcoma (UPS), leiomyosarcoma, and liposarcoma remain the most represented histologic subtype, a higher proportion of rhabdomyosarcoma (10%, especially pleomorphic rhabdomyosarcoma) is reported. Further studies are required to better characterize this sub-population.

Prediction of Response to Immune Checkpoint Blockade in Patients with Metastatic Colorectal Cancer with Microsatellite Instability

BACKGROUND

Mismatch repair deficient (dMMR) tumors displaying microsatellite instability (MSI) represent a paradigm for the success of immune checkpoint inhibitor (ICI)-based immunotherapy, particularly in patients with metastatic colorectal cancer (mCRC). However, a proportion of patients with dMMR/MSI mCRC exhibit resistance to ICI. Identification of tools predicting MSI mCRC patient response to ICI are required for the design of future strategies further improving this therapy.

PATIENTS AND METHODS

We combined high-throughput DNA and RNA sequencing of tumors from 116 patients with MSI mCRC treated with anti-PD-1 +/- anti-CTLA-4 of the NIPICOL phase II trial (C1, NCT03350126, discovery set) and the IMMUNOMSI prospective cohort (C2, validation set). The DNA/RNA predictors whose status was significantly associated with ICI status of response in C1 were subsequently validated in C2. Primary endpoint was iPFS (progression-free survival by iRECIST).

RESULTS

Analyses showed no impact of previously suggested DNA/RNA indicators of resistance to ICI, e.g., MSISensor score, tumor mutational burden, or specific cellular and molecular tumoral contingents. By contrast, iPFS under ICI was shown in C1 and C2 to depend both on a multiplex MSI signature involving the mutations of 19 microsatellites (HR_C2 = 3.63; 95% CI [1.65-7.99] ; p = 1.4x10^-3) and the expression of a set of 182 RNA markers with a non-epithelial TGFB-related desmoplastic orientation (HR_C2 = 1.75 ; 95% CI [1.03-2.98] ; p = 0.035). Both DNA and RNA signatures were independently predictive of iPFS.

CONCLUSIONS

iPFS in patients with MSI mCRC can be predicted by simply analyzing the mutational status of DNA microsatellite-containing genes in epithelial tumor cells together with nonepithelial TGFB-related desmoplastic RNA markers.

Pancreatic Ductal Adenocarcinoma and Immune Checkpoint Inhibitors: The Gray Curtain of Immunotherapy and Spikes of Lights

Pancreatic ductal adenocarcinoma (PDAC) is a dismal disease with a poor 5-year overall survival rate (~10%). The revolution of immunotherapy in clinical oncology has not substantially changed clinical outcome for patients with PDAC. Despite outstanding efforts, neither immune checkpoint inhibitors (ICIs) alone, nor in combination with chemotherapy or targeted therapies have shown encouraging results. This failure mirrors the lack of knowledge about the real key players of immune system senescence and the complexity of the tumor microenvironment in PDAC. However, some hope can be derived from PARP-inhibitor combinations, vaccines, and CAR-T-cells therapy. In this review, we comprehensively summarize the latest updates about the use of ICIs in PDAC, focusing on clinical evidence and ongoing studies highlighting explanations for the failure of immunotherapy and possible solutions.

Immunotherapy in the Management of Esophagogastric Cancer: A Practical Review

Recent data support incorporation of immune checkpoint inhibitors into the treatment armamentarium for esophageal, gastroesophageal junction, and gastric (esophagogastric) cancer. This practical review focuses on clinical trials that influenced US Food and Drug Administration approvals and treatment guidelines in esophagogastric cancer, including the impact of location, stage, histology, human epidermal growth factor receptor 2 status, and PD-(L)1 expression on these guidelines. The role of immunotherapy in the locally advanced and metastatic setting is constantly expanding. Over the next few years, the many ongoing trials exploring immunotherapy are anticipated to bring new treatment regimens into the frontline setting with the potential to improve survival in patients with advanced disease.

Mismatch repair deficiency, chemotherapy and survival for resectable gastric cancer: an observational study from the German staR cohort and a meta-analysis

PURPOSE

In a post hoc analysis of the MAGIC trial, patients with curatively resected gastric cancer (GC) and mismatch repair (MMR) deficiency (MMRd) had better median overall survival (OS) when treated with surgery alone but worse median OS when treated with additional chemotherapy. Further data are required to corroborate these findings.

METHODS

Between April 2013 and December 2018, 458 patients with curatively resected GC, including cancers of the esophagogastric junction Siewert type II and III, were identified in the German centers of the staR consortium. Tumor sections were assessed for expression of MLH1, MSH2, MSH6 and PMS2 by immunohistochemistry. The association between MMR status and survival was assessed. Similar studies published up to January 2021 were then identified in a MEDLINE search for a meta-analysis.

RESULTS

MMR-status and survival data were available for 223 patients (median age 66 years, 62.8% male), 23 patients were MMRd (10.3%). After matching for baseline clinical characteristics, median OS was not reached in any subgroup. Compared to perioperative chemotherapy, patients receiving surgery alone with MMRd and MMRp had a HR of 0.67 (95% CI 0.13-3.37, P = 0.63) and 1.44 (95% CI 0.66-3.13, P = 0.36), respectively. The meta-analysis included pooled data from 385 patients. Compared to perioperative chemotherapy, patients receiving surgery alone with MMRd had an improved OS with a HR of 0.36 (95% CI 0.14-0.91, P = 0.03), whereas those with MMRp had a HR of 1.18 (95% CI 0.89-1.58, P = 0.26).

CONCLUSION

Our data support a positive prognostic effect for MMRd in GC patients treated with surgery only and a differentially negative prognostic effect in patients treated with perioperative chemotherapy. MMR status determined by preoperative biopsies may be used as a predictive biomarker to select patients for perioperative chemotherapy in curatively resectable GC.

Fast and label-free automated detection of microsatellite status in early colon cancer using artificial intelligence integrated infrared imaging

PURPOSE

Microsatellite instability (MSI) due to mismatch repair (MMR) defects accounts for 15-20% of colon cancers (CC). MSI testing is currently standard of care in CC with immunohistochemistry of the four MMR proteins representing the gold standard. Instead, label-free quantum cascade laser (QCL) based infrared (IR) imaging combined with artificial intelligence (AI) may classify MSI/microsatellite stability (MSS) in unstained tissue sections user-independently and tissue preserving.

METHODS

Paraffin-embedded unstained tissue sections of early CC from patients participating in the multicentre AIO ColoPredict Plus (CPP) 2.0 registry were analysed after dividing into three groups (training, test, and validation). IR images of tissue sections using QCL-IR microscopes were classified by AI (convolutional neural networks [CNN]) using a two-step approach. The first CNN (modified U-Net) detected areas of cancer while the second CNN (VGG-Net) classified MSI/MSS. End-points were area under receiver operating characteristic (AUROC) and area under precision recall curve (AUPRC).

RESULTS

The cancer detection in the first step was based on 629 patients (train n = 273, test n = 138, and validation n = 218). Resulting classification AUROC was 1.0 for the validation dataset. The second step classifying MSI/MSS was performed on 547 patients (train n = 331, test n = 69, and validation n = 147) reaching AUROC and AUPRC of 0.9 and 0.74, respectively, for the validation cohort.

CONCLUSION

Our novel label-free digital pathology approach accurately and rapidly classifies MSI vs. MSS. The tissue sections analysed were not processed leaving the sample unmodified for subsequent analyses. Our approach demonstrates an AI-based decision support tool potentially driving improved patient stratification and precision oncology in the future.

Scoring Systems for Immunohistochemistry in Urothelial Carcinoma

Immunohistochemistry is widely used in diagnostic and scientific analysis of urothelial carcinoma. Objective interpretation of staining results is mandatory for accuracy and comparability in diagnostic and therapeutic patient care as well as research.Herein we summarize and explain standardized microscopic evaluation and scoring approaches for immunohistochemical stainings. We focus on commonly used and generally feasible approaches for different cellular compartments and comment on their utility in diagnostics and research practice.

Controversies and management of deficient mismatch repair gastrointestinal cancers in the neoadjuvant setting

High microsatellite instability (MSI-H)/deficient mismatch repair (dMMR) phenotype is a distinct molecular signature across gastrointestinal cancers characterized by high tumor mutational burden and high neoantigen load. Tumors harboring dMMR are highly immunogenic and heavily infiltrated by immune cells; consequently, they are uniquely vulnerable to therapeutic strategies enhancing immune antitumor response such as checkpoint inhibitors. The MSI-H/dMMR phenotype arose as a powerful predictor of response to immune checkpoint inhibitors with evidence supporting significantly improved outcomes in the metastatic setting. On the other hand, the genomic instability characteristic of MSI-H/dMMR tumors appears to be associated with decreased sensitivity to chemotherapy, and the benefits of standard adjuvant or neoadjuvant chemotherapy approaches in this subtype are being increasingly questioned. Here, we review the prognostic and predictive impact of MMR status in localized gastric and colorectal cancers, and highlight the emerging clinical data incorporating checkpoint inhibitors in the neoadjuvant setting.

Comprehensive analysis of immune-related gene signature based on ssGSEA algorithms in the prognosis and immune landscape of hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is a malignancy with a poor prognosis. This study aimed to distinguish patients with HCC having distinct tumour immune microenvironment (TIME) features and construct an immune-related gene signature (IRGs) to assess prognosis and provide a basis for personalised therapies. Methods: Transcriptomic data of patients with HCC were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We assessed the immune cell infiltration in each HCC specimen using single sample gene set enrichment analysis (ssGSEA) and classified all patients with HCC into high- and low-immune clusters using a hierarchical clustering algorithm. The ESTIMATE and CIBERSORT computational methods were employed to verify the stability and effectiveness of the immune clusters. Subsequently, the differentially expressed genes (DEGs) of the high- and low-immune clusters and the immune-related genes intersected to obtain the immune-related DEGs. The least absolute shrinkage and selection operator (LASSO) was then employed to screen the optimal genes for the construction of a prognostic predictive signature and to divide patients into high- and low-risk subgroups. The predictive efficacy of the IRGs was further confirmed using Kaplan-Meier survival curves, univariate and multifactorial Cox regression and time-dependent ROC curves in the TCGA and GSE14520 validation cohorts. Furthermore, we developed a nomogram to predict the prognosis. Tumour mutation burden (TMB) was also analysed in the risk groups. Additionally, gene ontology and gene set variation analysis were used for biological function and pathway exploration. Lastly, drug sensitivity analyses were employed to investigate prospective therapeutics in the two risk populations. Results: Immune cluster analysis based on ssGSEA could well distinguish the TIME characteristics of patients with HCC. The stromal score, immune score and ESTIMATE score were all lower in the low-immune cluster. Meanwhile, most of the immune checkpoint-related genes and HLA family genes were overexpressed in the high-immune cluster, suggesting that this cluster could be a beneficial population for immune checkpoint inhibitors therapy. There were 1,617 DEGs between the two immune clusters, of which 414 genes intersected with immune-associated genes. Furthermore, Cox regression analysis revealed 49 DEGs that were associated with survival. Then, 19 DEGs were screened using the LASSO algorithm for IRGs construction and patients were classified into high- and low-risk groups. Both the constructed signature and nomogram had good prognostic predictive efficacy. The signature-based risk score was an independent prognostic predictor in both the TCGA and GSE14520 cohorts. Additionally, there was no significant difference in TMB between the two risk populations. Lastly, the half-maximal inhibitory concentrations of certain chemotherapeutic and targeted therapeutic agents differed between the two risk groups. Conclusion: Our study provides a personalized tool for predicting the prognosis and TIME landscape of HCC and a basis for developing personalised treatment regimens.

Deficient mismatch repair/microsatellite unstable colorectal cancer: Diagnosis, prognosis and treatment

Microsatellite unstable (MSI) colorectal cancers (CRCs) are due to DNA mismatch repair (MMR) deficiency and occurs in15% of non-metastatic diseases and 5% in the metastatic setting. Nearly 30% of MSI CRCs occur in a context of constitutional mutation of the MMR system (Lynch syndrome). Others are sporadic cancers linked to a hypermethylation of the MLH-1 promoter. The pathogenic alterations of MMR genes lead to the accumulation of frequent somatic mutational events and these tumours arbour a high antigen burden and are highly infiltrated with cytotoxic T-cell lymphocytes. Microsatellite instability/DNA mismatch repair deficiency (MSI/dMMR) status has prognostic and predictive implications in non-metastatic and metastatic CRCs. The prognostic value of MSI status in non-metastatic CRCs has been studied extensively, yet the data are more limited for its predictive value in terms of adjuvant chemotherapy efficacy. In both cases (metastatic and non-metastatic settings) treatment with immune check-point inhibitors (ICIs) have shown a remarkable effectiveness in the context of MSI/dMMR status. Indeed, recent data from prospective cohorts and randomised trials have shown a dramatical improvement of survival with immunotherapy (programmed death-ligand 1 [PD-(L)1]   cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] blockage) in metastatic or non-metastatic MSI/dMMR CRC. In this review we report and discuss how and for whom to test for the MSI/dMMR phenotype, as well as the prognostic value of this phenotype and the new treatment recommendations options for this unique CRC population. Despite their efficacy, primary and secondary resistance to immune checkpoint inhibitors (ICIs) are observed in more than 50% MSI-H/dMMR CRC patients and in the future how to identify these patients and to overcome resistance will be an important challenge.

Fertility-sparing treatment for endometrial cancer and atypical endometrial hyperplasia in patients with Lynch Syndrome: Molecular diagnosis after immunohistochemistry of MMR proteins

Introduction

Lynch Syndrome (LS) represents the hereditary condition that is most frequently associated with endometrial cancer (EC). The aim of this study is to assess the presence of Lynch Syndrome (LS) in young women with mismatch repair (MMR)-deficient atypical endometrial hyperplasia (AEH) and non-myoinvasive FIGO G1 endometrioid EC and its possible impact on the outcome of conservative treatment.

Methods

Six MMR-deficient cases identified from a previous cohort of 69 conservatively treated patients were selected to be screened for germline mutations in MMR genes. In each patient, the outcomes of conservative treatment for AEH and EEC, including response, relapse, progression, and pregnancy, were assessed.

Results

Five out of 6 patients underwent genetic test for LS. Three out of these 5 patients showed a positive genetic test. Patient 1 showed the c.942 + 2 T>A heterozygous variant of MSH2 mutation; after 12 months of complete response, she had relapse and progression of disease. Patient 4 showed the c.2459-1G>C variant of MSH2 mutation; after complete response, she failed to achieve pregnancy; she had relapse after 24 months and underwent hysterectomy. Patient 6 showed the c.803 + 1 heterozygous variant of PMS2 mutation; she had relapse of disease after 18 months from the first complete response and then underwent hysterectomy.

Conclusions

In this series, 3 out of 6 women with MMR-deficiency had LS. None of the patients achieved pregnancy, and those who responded to treatment had subsequent relapse of disease. Patients undergoing fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer should perform MMR immunohistochemical analysis in order to screen LS.

PMS2 Expression With Combination of PD-L1 and TILs for Predicting Survival of Esophageal Squamous Cell Carcinoma

Background

DNA mismatch repair (MMR) deficiency (dMMR) has been recognized as an important biomarker for immunotherapy in esophageal squamous cell carcinoma (ESCC), along with programmed death ligand 1 (PD-L1) expression and/or tumor-infiltrated lymphocytes (TILs). However, in ESCC, MMR protein assessment has not been well studied at present.

Methods

A total of 484 ESCC tissues treated between 2007 and 2010, in our hospital, were enrolled. Immunohistochemical expression of MLH1, MSH2, MSH6, PMS2, and PD-L1 on tissue microarray specimens and clinicopathological features, including TILs, were analyzed retrospectively.

Results

Out of the 484 studied cases, loss of MLH1, MSH2, MSH6, and PMS2 expression were found in 6.8%, 2.1%, 8.7%, and 4.8% patients, respectively. dMMR was found in 65 patients, 37 cases involved in one MMR protein, 17 cases involved in two proteins, 7 cases involved in three proteins, and 4 cases involved in four proteins. There was no significant survival difference between pMMR (MMR-proficient) and dMMR patients (P>0.05). However, 224 patients with low PMS2 expression had better DFS and OS than 260 patients with high PMS2 expression (P=0.006 for DFS and 0.008 for OS), which was identified as an independent prognostic factor in multivariate analyses. Positive PD-L1 expression was detected in 341 (70.5%) samples. In stage I-II disease, patients with PD-L1 expression had better DFS and OS than those without PD-L1 expression(P<0.05), which was not found in stage III-IV disease. With the ITWG system, 40.1% of cases were classified as high TILs. Patients in the high-TILs group tended to have better DFS (P=0.055) and OS (P=0.070) than those in the low-TILs group and the differences were statistically significant in pMMR, high MSH6, or PMS2 expression cases (P<0.05). Also, high PMS2 expression patients with both PD-L1 expression and high TILs, had similar DFS and OS compared with low PMS2 expression patients (P>0.05), which were much better than other high PMS2 expression patients.

Conclusion

The expression level of MMR proteins could also be used as a prognostic factor in ESCC and PMS2 expression outperformed other MMR proteins for predicting survival. The combination of PD-L1 expression and TILs may lead to more efficient risk stratification of ESCC.

Consequences of the Hsp110DE9 mutation in tumorigenesis and the 5-fluorouracil-based chemotherapy response in Msh2-deficient mice

Heat shock proteins (HSPs) play oncogenic roles in human tumours. We reported a somatic inactivating mutation of HSP110 (HSP110DE9) in mismatch repair-deficient (dMMR) cancers displaying microsatellite instability (MSI) but did not assess its impact. We evaluated the impact of the Hsp110DE9 mutation on tumour development and the chemotherapy response in a dMMR knock-in mouse model (Hsp110DE9KIMsh2KO mice). The effect of the Hsp110DE9 mutation on tumorigenesis and survival was evaluated in Msh2KO mice that were null (Hsp110wt), heterozygous (Hsp110DE9KI/+), or homozygous (Hsp110DE9KI/KI) for the Hsp110DE9 mutation by assessing tumoral syndrome (organomegaly index, tumour staging) and survival (Kaplan-Meier curves). 5-Fluorouracil (5-FU), which is the backbone of chemotherapy regimens in gastrointestinal cancers and is commonly used in other tumour types but is not effective against dMMR cells in vivo, was administered to Hsp110DE9KI/KI, Hsp110DE9KI/+, and Hsp110wtMsh2KO mice. Hsp110, Ki67 (proliferation marker) and activated caspase-3 (apoptosis marker) expression were assessed in normal and tumour tissue samples by western blotting, immunophenotyping and cell sorting. Hsp110wt expression was drastically reduced or totally lost in tumours from Msh2KOHsp110DE9KI/+ and Msh2KOHsp110DE9KI/KI mice. The Hsp110DE9 mutation did not affect overall survival or tumoral syndrome in Msh2KOHsp110DE9KI/+ and Msh2KOHsp110DE9KI/KI mice but drastically improved the 5-FU response in all cohorts (Msh2KOHsp110DE9KI/KI: P5fu = 0.001; Msh2KOHsp110DE9KI/+: P5fu = 0.005; Msh2KOHsp110wt: P5fu = 0.335). Histopathological examination and cell sorting analyses confirmed major hypersensitization to 5-FU-induced death of both Hsp110DE9KI/KI and Hsp110DE9KI/+ dMMR cancer cells. This study highlights how dMMR tumour cells adapt to HSP110 inactivation but become hypersensitive to 5-FU, suggesting Hsp110DE9 as a predictive factor of 5-FU efficacy.

Immune Checkpoint Blockade Therapy in Patients With Colorectal Cancer Harboring Microsatellite Instability/Mismatch Repair Deficiency in 2022

Immune checkpoint inhibitors (ICIs) are shown to be effective among patients with metastatic colorectal cancer (mCRC) harboring high microsatellite instability (MSI-H) and/or mismatch repair deficiency (dMMR), with U.S. Food and Drug Administration approvals for all lines of therapy. In Europe, only pembrolizumab in the first line and the combination of nivolumab and ipilimumab beyond the first line are approved. Many questions remain about the clinical management of MSI-H/dMMR CRC. Biomarkers predictive of immune checkpoint inhibitor resistance among MSI-H/dMMR tumors are needed (1) to select the best treatment for patients with CRC (anti-PD-[L]1 monotherapy alone or combined with anti-CTLA-4 or chemotherapy) and (2) to develop new treatment strategies for patients whose disease progressed after immune checkpoint inhibitor monotherapy. The development of immune checkpoint inhibitors in the adjuvant and neoadjuvant settings is also of great interest for patients harboring MSI-H/dMMR, especially as a substantial proportion have Lynch syndrome or are at high risk of developing cancers in their lifetime and sporadic MSI-H/dMMR cancers occur most frequently in elderly and frail patients. Thus, CRC is not one, but two different diseases: (1) MSI-H/dMMR CRC (seen in 5% of mCRC and 15% of non-mCRC), which is genetically unstable with a high mutational load and many neoantigens, and for which immune checkpoint inhibitors radically changed clinical management, and (2) microsatellite stable CRC with chromosomal instability, for which immune checkpoint inhibitors are not proven efficient.

Which role for predictors of response to immune checkpoint inhibitors in hepatocellular carcinoma?

INTRODUCTION

Hepatocellular carcinoma (HCC) remains a frequently diagnosed malignancy worldwide, still representing an important cause of cancer-related death. Recent years have seen the emergence of novel systemic treatments for HCC patients, including immune checkpoint inhibitors (ICIs). Nonetheless, several questions regarding HCC immunotherapy remain unanswered, especially in terms of biochemical predictors of response.

AREAS COVERED

In the current paper, we will discuss available evidence regarding predictive biomarkers of response to HCC immunotherapy. A literature search was conducted in January 2022 of Pubmed/Medline, Cochrane library, and Scopus databases.

EXPERT OPINION

The identification of predictive biomarkers represents an unmet need in HCC patients receiving ICIs. The HCC medical community is called to further efforts aimed to elucidate the effective role of PD-L1 expression, TMB, MSI, gut microbiota, and other emerging biomarkers.

Mismatch repair deficiency in early‐onset duodenal, ampullary, and pancreatic carcinomas is a strong indicator for a hereditary defect

Mismatch repair deficiency (dMMR) is a hallmark of Lynch syndrome (LS), but its prevalence in early‐onset (diagnosed under the age of 50 years) duodenal, ampullary, and pancreatic carcinomas (DC, AC, and PC, respectively) is largely unknown. We explored the prevalence of dMMR and the underlying molecular mechanisms in a retrospectively collected cohort of 90 early‐onset carcinomas of duodenal, ampullary, and pancreatic origin. dMMR was most prevalent in early‐onset DCs (47.8%); more than half of those were associated with hereditary cancer syndromes (LS or constitutional mismatch repair deficiency syndrome). All dMMR AC and PC were due to LS. Concordance of dMMR with underlying hereditary condition warrants ubiquitous dMMR testing in all early‐onset DC, AC, and PC.

Biomarkers for response to immune checkpoint inhibitors in gastrointestinal cancers

Gastrointestinal (GI) cancers account for a large proportion of cancer deaths worldwide and pose a major public health challenge. Immunotherapy is considered to be one of the prominent and successful approaches in cancer treatment in recent years. Among them, immune checkpoint inhibitor (ICI) therapy, has received widespread attention, and many clinical findings support the feasibility of ICIs, with sustained responses and significantly prolonged lifespan observed in a wide range of tumors. However, patients treated with ICIs have not fully benefited, and therefore, the identification and development of biomarkers for predicting ICI treatment response have received further attention and exploration. From tumor genome to molecular interactions in the tumor microenvironment, and further expanding to circulating biomarkers and patient characteristics, the exploration of biomarkers is evolving with high-throughput sequencing as well as bioinformatics. More large-scale prospective and specific studies are needed to explore biomarkers in GI cancers. In this review, we summarize the known biomarkers used in ICI therapy for GI tumors. In addition, some ICI biomarkers applied to other tumors are included to provide insights and further validation for GI tumors. Moreover, we present single-cell analysis and machine learning approaches that have emerged in recent years. Although there are no clear applications yet, it can be expected that these techniques will play an important role in the application of biomarker prediction.

Prognostic Impact of An Integrative Landscape of Clinical, Immune, and Molecular Features in Non-Metastatic Rectal Cancer

Rectal Cancer (RC) is a complex disease that involves highly variable treatment responses. Currently, there is a lack of reliable markers beyond TNM to deliver a personalized treatment in a cancer setting where the goal is a curative treatment. Here, we performed an integrated characterization of the predictive and prognostic role of clinical features, mismatch-repair deficiency markers, HER2, CDX2, PD-L1 expression, and CD3-CD8+ tumor-infiltrating lymphocytes (TILs) coupled with targeted DNA sequencing of 76 non-metastatic RC patients assigned to total mesorectal excision upfront (TME; n = 15) or neoadjuvant chemo-radiotherapy treatment (nCRT; n = 61) followed by TME. Eighty-two percent of RC cases displayed mutations affecting cancer driver genes such as TP53, APC, KRAS, ATM, and PIK3CA. Good response to nCRT treatment was observed in approximately 40% of the RC cases, and poor pathological tumor regression was significantly associated with worse disease-free survival (DFS, HR = 3.45; 95%CI = 1.14-10.4; p = 0.028). High neutrophils-platelets score (NPS) (OR = 10.52; 95%CI=1.34-82.6; p = 0.025) and KRAS mutated cases (OR = 5.49; 95%CI = 1.06-28.4; p = 0.042) were identified as independent predictive factors of poor response to nCRT treatment in a multivariate analysis. Furthermore, a Cox proportional-hazard model showed that the KRAS mutational status was an independent prognostic factor associated with higher risk of local recurrence (HR = 9.68; 95%CI = 1.01-93.2; p <0.05) and shorter DFS (HR = 2.55; 95%CI = 1.05-6.21; p <0.05), while high CEA serum levels were associated with poor DFS (HR = 2.63; 95%CI = 1.01-6.85; p <0.05). Integrated clinical and molecular-based unsupervised analysis allowed us to identify two RC prognostic groups (cluster 1 and cluster 2) associated with disease-specific OS (HR = 20.64; 95%CI = 2.63-162.2; p <0.0001), metastasis-free survival (HR = 3.67; 95%CI = 1.22-11; p = 0.012), local recurrence-free survival (HR = 3.34; 95%CI = 0.96-11.6; p = 0.043) and worse DFS (HR = 2.68; 95%CI = 1.18-6.06; p = 0.012). The worst prognosis cluster 2 was enriched by stage III high-risk clinical tumors, poor responders to nCRT, with low TILs density and high frequency of KRAS and TP53 mutated cases compared with the best prognosis cluster 1 (p <0.05). Overall, this study provides a comprehensive and integrated characterization of non-metastatic RC cases as a new insight to deliver a personalized therapeutic approach.

Predictive Biomarkers for Checkpoint Inhibitor-Based Immunotherapy in Hepatocellular Carcinoma: Where Do We Stand?

Hepatocellular carcinoma (HCC) remains the sixth most commonly diagnosed malignancy worldwide, still representing an important cause of cancer-related death. Over the next few years, novel systemic treatment options have emerged. Among these, immune checkpoint inhibitors (ICIs) have been widely evaluated and are under assessment, as monotherapy or in combination with other anticancer agents in treatment-naïve and previously treated patients. In particular, the approval of the PD-L1 inhibitor atezolizumab plus the antiangiogenic agent bevacizumab as front-line treatment for advanced HCC has led to the adoption of this combination in this setting, and the IMbrave 150 phase III trial has established a novel standard of care. However, several questions remain unanswered, including the identification of reliable predictors of response to ICIs in HCC patients. In the current paper, we will provide an updated overview of potentially useful predictive biomarkers of response to immunotherapy in advanced HCC. A literature search was conducted in September 2021 of Pubmed/Medline, Cochrane library and Scopus databases.

Predictive molecular markers for the treatment with immune checkpoint inhibitors in colorectal cancer

Colorectal cancer is one of the most common malignant tumors and, hence, has become one of the most important public health issues in the world. Treatment with immune checkpoint inhibitors (ICIs) successfully improves the survival rate of patients with melanoma, non-small-cell lung cancer, and other malignancies, and its application in metastatic colorectal cancer is being actively explored. However, a few patients develop drug resistance. Predictive molecular markers are important tools to precisely screen patient groups that can benefit from treatment with ICIs. The current article focused on certain important predictive molecular markers for ICI treatment in colorectal cancer, including not only some of the mature molecular markers, such as deficient mismatch repair (d-MMR), microsatellite instability-high (MSI-H), tumor mutational burden (TMB), programmed death-ligand-1 (PD-L1), tumor immune microenvironment (TiME), and tumor-infiltrating lymphocytes (TILs), but also some of the novel molecular markers, such as DNA polymerase epsilon (POLE), polymerase delta 1 (POLD1), circulating tumor DNA (ctDNA), and consensus molecular subtypes (CMS). We have reviewed these markers in-depth and presented the results from certain important studies, which suggest their applicability in CRC and indicate their advantages and disadvantages. We hope this article is helpful for clinicians and researchers to systematically understand these markers and can guide the treatment of colorectal cancer.

An unusual phenotype occurs in 15% of mismatch repair-deficient tumors and is associated with non-colorectal cancers and genetic syndromes

Immunohistochemistry (IHC) and/or MSI-PCR (microsatellite instability-polymerase chain reaction) tests are performed routinely to detect mismatch repair deficiency (MMR-D). Classical MMR-D tumors present a loss of MLH1/PMS2 or MSH2/MSH6 with MSI-High. Other profiles of MMR-D tumors have been described but have been rarely studied. In this study, we established a classification of unusual MMR-D tumors and determined their frequency and clinical impact. All MMR-D tumors identified between 2007 and 2017 were selected. Any profile besides the classical MMR-D phenotype was defined as unusual. For patients with unusual MMR-D tumors, IHC, and PCR data were reviewed, the tumor mutation burden (TMB) was evaluated and clinical and genetic features were collected. Of the 4948 cases of MMR testing, 3800 had both the available IHC and MSI-PCR results and 585 of these had MMR-D. After reviewing the IHC and PCR, 21% of the cases initially identified as unusual MMR-D were reclassified, which resulted in a final identification of 89 unusual MMR-D tumors (15%). Unusual MMR-D tumors were more often associated with non-CRC than classical MMR-D tumors. Unusual MMR-D tumors were classified into four sub-groups: i) isolated loss of PMS2 or MSH6, ii) classical loss of MLH1/PMS2 or MSH2/MSH6 without MSI, iii) four MMR proteins retained with MSI and, iv) complex loss of MMR proteins, with clinical characteristics for each sub-group. TMB-high or -intermediate was shown in 96% of the cancers studied (24/25), which confirmed MMR deficiency. Genetic syndromes were identified in 44.9% (40/89) and 21.4% (106/496) of patients with unusual and classical MMR-D tumors, respectively (P < 0.001). Five patients treated with an immune checkpoint inhibitor (ICI) had a prolonged clinical benefit. Our classification of unusual MMR-D phenotype helps to identify MMR deficiency. Unusual MMR-D phenotype occurs in 15% of MMR-D tumors. A high frequency of genetic syndromes was noted in these patients who could benefit from ICI.

Biomarkers for breast cancer immunotherapy: PD-L1, TILs, and beyond

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have recently entered into the therapeutic scenario of metastatic breast cancer. However, only a proportion of patients benefit from ICIs and immune-based combinations, so the identification of reliable predictors of response remains an unmet need.

AREAS COVERED

We discuss potential predictors of response to ICIs in breast cancer, including PD-L1 expression, tumor-infiltrating lymphocytes (TILs), tumor mutational burden (TMB), and several other biomarkers and suggest future directions of research in this setting. A literature search was conducted in October 2021 of Pubmed/Medline, Cochrane library and Scopus databases; in addition, abstract of international cancer meetings were reviewed.

EXPERT OPINION

In terms of predictors of response to immunotherapy in TNBC patients, several biomarkers are being evaluated. Valuable data on predictive biomarkers have recently emerged, including host-related factors, immune-related cells, and protein and genetic markers. Data supporting immunotherapy in the metastatic triple-negative breast cancer setting are not concordant, but there have been some positive phase III trials including IMpassion130 and KEYNOTE-355. Phase II and III (neo)adjuvant trials are supportive of this therapeutic strategy. Further investigations are warranted in this challenging area.

A novel mouse model of PMS2 founder mutation that causes mismatch repair defect due to aberrant splicing

Hereditary non-polyposis colorectal cancer, now known as Lynch syndrome (LS) is one of the most common cancer predisposition syndromes and is caused by germline pathogenic variants (GPVs) in DNA mismatch repair (MMR) genes. A common founder GPV in PMS2 in the Canadian Inuit population, NM_000535.5: c.2002A>G, leads to a benign missense (p.I668V) but also acts as a de novo splice site that creates a 5 bp deletion resulting in a truncated protein (p.I668*). Individuals homozygous for this GPV are predisposed to atypical constitutional MMR deficiency with a delayed onset of first primary malignancy. We have generated mice with an equivalent germline mutation (Pms2c.1993A>G) and demonstrate that it results in a splicing defect similar to those observed in humans. Homozygous mutant mice are viable like the Pms2 null mice. However, unlike the Pms2 null mice, these mutant mice are fertile, like humans homozygous for this variant. Furthermore, these mice exhibit a significant increase in microsatellite instability and intestinal adenomas on an Apc mutant background. Rectification of the splicing defect in human and murine fibroblasts using antisense morpholinos suggests that this novel mouse model can be valuable in evaluating the efficacy aimed at targeting the splicing defect in PMS2 that is highly prevalent among the Canadian Inuits.

Performance of Next-Generation Sequencing for the Detection of Microsatellite Instability in Colorectal Cancer With Deficient DNA Mismatch Repair

BACKGROUND & AIMS

Next-generation sequencing (NGS) was recently approved by the United States Food and Drug Administration to detect microsatellite instability (MSI) arising from defective mismatch repair (dMMR) in patients with metastatic colorectal cancer (mCRC) before treatment with immune checkpoint inhibitors (ICI). In this study, we aimed to evaluate and improve the performance of NGS to identify MSI in CRC, especially dMMR mCRC treated with ICI.

METHODS

CRC samples used in this post hoc study were reassessed centrally for MSI and dMMR status using the reference methods of pentaplex polymerase chain reaction and immunohistochemistry. Whole-exome sequencing (WES) was used to evaluate MSISensor, the Food and Drug Administration-approved and NGS-based method for assessment of MSI. This was performed in (1) a prospective, multicenter cohort of 102 patients with mCRC (C1; 25 dMMR/MSI, 24 treated with ICI) from clinical trials NCT02840604 and NCT033501260, (2) an independent retrospective, multicenter cohort of 113 patients (C2; 25 mCRC, 88 non-mCRC, all dMMR/MSI untreated with ICI), and (3) a publicly available series of 118 patients with CRC from The Cancer Genome Atlas (C3; 51 dMMR/MSI). A new NGS-based algorithm, namely MSICare, was developed. Its performance for assessment of MSI was compared with MSISensor in C1, C2, and C3 at the exome level or after downsampling sequencing data to the MSK-IMPACT gene panel. MSICare was validated in an additional retrospective, multicenter cohort (C4) of 152 patients with new CRC (137 dMMR/MSI) enriched in tumors deficient in MSH6 (n = 35) and PMS2 (n = 9) after targeted sequencing of samples with an optimized set of microsatellite markers (MSIDIAG).

RESULTS

At the exome level, MSISensor was highly specific but failed to diagnose MSI in 16% of MSI/dMMR mCRC from C1 (4 of 25; sensitivity, 84%; 95% confidence interval [CI], 63.9%-95.5%), 32% of mCRC (8 of 25; sensitivity, 68%; 95% CI, 46.5%-85.1%), and 9.1% of non-mCRC from C2 (8 of 88; sensitivity, 90.9%; 95% CI, 82.9%-96%), and 9.8% of CRC from C3 (5 of 51; sensitivity, 90.2%; 95% CI, 78.6%-96.7%). Misdiagnosis included 4 mCRCs treated with ICI, of which 3 showed an overall response rate without progression at this date. At the exome level, reevaluation of the MSI genomic signal using MSICare detected 100% of cases with true MSI status among C1 and C2. Further validation of MSICare was obtained in CRC tumors from C3, with 96.1% concordance for MSI status. Whereas misdiagnosis with MSISensor even increased when analyzing downsampled WES data from C1 and C2 with microsatellite markers restricted to the MSK-IMPACT gene panel (sensitivity, 72.5%; 95% CI, 64.2%-79.7%), particularly in the MSH6-deficient setting, MSICare sensitivity and specificity remained optimal (100%). Similar results were obtained with MSICare after targeted NGS of tumors from C4 with the optimized microsatellite panel MSIDIAG (sensitivity, 99.3%; 95% CI, 96%-100%; specificity, 100%).

CONCLUSIONS

In contrast to MSISensor, the new MSICare test we propose performs at least as efficiently as the reference method, MSI polymerase chain reaction, to detect MSI in CRC regardless of the defective MMR protein under both WES and targeted NGS conditions. We suggest MSICare may rapidly become a reference method for NGS-based testing of MSI in CRC, especially in mCRC, where accurate MSI status is required before the prescription of ICI.

PD-L1, TMB, and other potential predictors of response to immunotherapy for hepatocellular carcinoma: how can they assist drug clinical trials?

INTRODUCTION

Hepatocellular carcinoma (HCC) represents the sixth most commonly diagnosed malignancy worldwide, accounting for millions of deaths annually. Despite immune checkpoint inhibitors (ICIs) reported important results, only a minority of HCC patients benefit from these treatments, and the identification of predictive biomarkers of response still remains a highly unmet need.

AREAS COVERED

Herein, we provide a timely overview of available evidence on biochemical predictors of response to immunotherapy in advanced HCC patients; we speculate on how PD-L1, TMB, and other emerging biomarkers could assist drug clinical trials in the near future. A literature search was conducted in June 2021 using Pubmed/Medline, Cochrane library, and Scopus databases.

EXPERT OPINION

Reliable predictors of response to ICIs are of pivotal importance to allow a proper stratification and selection of HCC patients that could derive more benefit from immunotherapy. Well-designed, multicenter clinical trials specifically focused on predictive biomarkers are warranted in this setting, where most of evidence currently derives from retrospective, single-center studies with small sample size.

Quantitative Prediction of Microsatellite Instability in Colorectal Cancer With Preoperative PET/CT-Based Radiomics

OBJECTIVES

Microsatellite instability (MSI) status is an important hallmark for prognosis prediction and treatment recommendation of colorectal cancer (CRC). To address issues due to the invasiveness of clinical preoperative evaluation of microsatellite status, we investigated the value of preoperative 18F-FDG PET/CT radiomics with machine learning for predicting the microsatellite status of colorectal cancer patients.

METHODS

A total of 173 patients that underwent 18F-FDG PET/CT scans before operations were retrospectively analyzed in this study. The microsatellite status for each patient was identified as microsatellite instability-high (MSI-H) or microsatellite stable (MSS), according to the test for mismatch repair gene proteins with immunohistochemical staining methods. There were 2,492 radiomic features in total extracted from 18F-FDG PET/CT imaging. Then, radiomic features were selected through multivariate random forest selection and univariate relevancy tests after handling the imbalanced dataset through the random under-sampling method. Based on the selected features, we constructed a BalancedBagging model based on Adaboost classifiers to identify the MSI status in patients with CRC. The model performance was evaluated by the area under the curve (AUC), sensitivity, specificity, and accuracy on the validation dataset.

RESULTS

The ensemble model was constructed based on two radiomic features and achieved an 82.8% AUC for predicting the MSI status of colorectal cancer patients. The sensitivity, specificity, and accuracy were 83.3, 76.3, and 76.8%, respectively. The significant correlation of the selected two radiomic features with multiple effective clinical features was identified (p < 0.05).

CONCLUSION

18F-FDG PET/CT radiomics analysis with the machine learning model provided a quantitative, efficient, and non-invasive mechanism for identifying the microsatellite status of colorectal cancer patients, which optimized the treatment decision support.

The association between the histopathological features and microsatellite instability in young patients with urothelial carcinoma of the bladder

OBJECTIVE

Bladder cancer under the age of 40 is extremely rare. Bladder cancer development involves complex and multi-stage processes, one of which is the DNA damage repair mechanism. In this retrospective study, we aimed to evaluate the histopathological features of bladder urothelial carcinoma seen in patients under 40 years of age and tumor microsatellite instability status using immunohistochemistry.

METHODS

A total of 50 patients under the age of 40 with urothelial bladder carcinoma from two different centers in the same country were included. Expression of the mismatch repair proteins MLH1, MSH2, MSH6, and PMS2 was analyzed by immunohistochemistry.

RESULTS

Age at the time of diagnosis ranged from 17 to 40 years old. Most tumors were non-invasive papillary urothelial carcinoma. Two cases had nuclear loss of MSH-6 and PMS-2. We observed that tumor grade, tumor stage, presence of tumor differentiation, and infiltrative growth pattern of the tumor have significant impact on prognosis, but microsatellite instability does not have an effective role in bladder carcinogenesis in young patients.

CONCLUSIONS

Our results indicate that the presence of microsatellite instability is not related to the low tumor grade and stage in urothelial neoplasms in young patients, suggesting that urothelial carcinoma of the bladder in young patients may represent a genetically stable form of neoplasia.

WRN Germline Mutation Is the Likely Inherited Etiology of Various Cancer Types in One Iranian Family

Background

Familial cancers comprise a considerable distribution of colorectal cancers (CRCs), of which only about 5% occurs through well-established hereditary syndromes. It has been demonstrated that deleterious variants at the newly identified cancer-predisposing genes could describe the etiology of undefined familial cancers.

Methods

The present study aimed to identify the genetic etiology in a 32-year-old man with early onset familial CRC employing several molecular diagnostic techniques. DNA was extracted from tumoral and normal formalin-fixed-paraffin-embedded (FFPE) blocks, and microsatellite instability (MSI) was evaluated. Immunohistochemistry staining of MMR proteins was performed on tumoral FFPE blocks. Next-generation sequencing (NGS), multiplex ligation-dependent amplification (MLPA) assay, and Sanger sequencing were applied on the genomic DNA extracted from peripheral blood. Data analysis was performed using bioinformatics tools. Genetic variants interpretation was based on ACMG.

Results

MSI analysis indicated MSI-H phenotype, and IHC staining proved no expressions of MSH2 and MSH6 proteins. MLPA and NGS data showed no pathogenic variants in MMR genes. Further analysis of NGS data revealed a candidate WRN frameshift variant (p.R389Efs*3), which was validated with Sanger sequencing. The variant was interpreted as pathogenic since it met the criteria based on the ACMG guideline including very strong (PVS1), strong (PS3), and moderate (PM2).

Conclusion

WRN is a DNA helicase participating in DNA repair pathways to sustain genomic stability. WRN deficient function may contribute to CRC development that is valuable for further investigation as a candidate gene in hereditary cancer syndrome diagnosis.

Discordance between immunochemistry of mismatch repair proteins and molecular testing of microsatellite instability in colorectal cancer

Background

DNA mismatch repair system deficiency (dMMR) is found in 15% of colorectal cancers (CRCs). Two methods are used to determine dMMR, immunohistochemistry (IHC) of MMR proteins and molecular testing of microsatellite instability (MSI). Only studies with a low number of patients have reported rates of discordance between these two methods, ranging from 1% to 10%.

Materials and methods

Overall, 3228 consecutive patients with CRCs from two centers were included. Molecular testing was carried out using the Pentaplex panel and IHC evaluated four (MLH1, MSH2, MSH6, and PMS2; cohort 1; n = 1085) or two MMR proteins (MLH1 and MSH2; cohort 2; n = 2143). The primary endpoint was the rate of discordance between MSI and MMR IHC tests.

Results

Fifty-one discordant cases (1.6%) were initially observed. Twenty-nine out of 51 discordant cases were related to IHC misclassifications. In cohort 1, after re-reading IHC and/or carrying out new IHC, 16 discordant cases were reclassified as nondiscordant. In cohort 2, after the addition of MSH6/PMS2 IHC and re-examination, 13 were reclassified as nondiscordant. In addition, 10 misclassifications of molecular tests were identified. Finally, only 12 discordant cases (0.4%) remained: 5 were proficient MMR/MSI and 7 were dMMR/microsatellite stable.

Conclusions

Our study confirmed the high degree of concordance between MSI and MMR IHC tests. Discordant cases must be reviewed, and if needed, tests must be repeated and analyzed by an expert team.

•

Concordance between MMR IHC (four proteins) and MSI molecular testing (Pentaplex) is superior to 98% in CRC cases

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Most discordant cases are related to misinterpretation of the tests, which may lead to clinical management errors.

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Discordant cases must be reviewed and tests must be repeated because most cases will be reclassified as nondiscordant.

T-cell immunoglobulin and ITIM domain, as a potential immune checkpoint target for immunotherapy of colorectal cancer

The importance of the tumor microenvironment in cancer progression has been well studied for many years. Immune checkpoint inhibitors (ICIs) are regarded as potential strategies in enhancing the immune responses in patients with cancer, particularly colorectal cancer (CRC). Notably, CRCs are extraordinarily heterogeneous and mostly are microsatellite-stable (MSS) or cold tumors, which means that the immune response is not usually as strong as that of foreign cells. T-cell immunoglobulin and ITIM domain (TIGIT) is a new immune checkpoint receptor overexpressed inside the CRC tumor-immune microenvironments. Moreover, several studies have shown that TIGIT in combination with other ICIs and/or conventional treatments, can lead to a robust anti-tumor response in CRC. This review looks deep inside TIGIT expression patterns, their various functions, and possible immunotherapy strategies to increase survival rates and decrease immune-related adverse events.

Immune Checkpoint Inhibition in Colorectal Cancer: Microsatellite Instability and Beyond

Immune checkpoints inhibitors (ICIs) have been a breakthrough, with unique response and survival patterns compared with chemotherapy for patients with advanced Mismatch Repair-deficient/Microsatellite instable (dMMR/MSI) colorectal cancer, but have shown disappointing results in Mismatch Repair-proficient/Microsatellite stable (pMMR/MSS) colorectal cancer. As up to 50% of patients harboring dMMR/MSI advanced cancers will ultimately progress after PD-1 blockade, biomarkers are needed to predict response/resistance to immunotherapy and to select patients for immunomodulating combination therapies. Patients with pMMR/MSS colorectal cancer present with distinct immune profiles compared to dMMR/MSI tumors, giving evidence of different immune escape mechanisms, which could be overcome through individualized immunotherapeutic strategies. In this review we discuss the latest developments in the field of immunotherapy for dMMR/MSI and pMMR/MSS colorectal cancers, and unresolved questions and considerations concerning the use of ICI therapies in this population. Future immunomodulation strategies based on biomarker selection (tumor mutational burden, Immunoscore^®, mutational profile) are discussed.

Biochemical predictors of response to immune checkpoint inhibitors in unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the most commonly diagnosed liver cancer worldwide, and the overall survival of patients with unresectable disease is poor. In the last five years, immune checkpoint inhibitors (ICIs) have revolutionized the treatment scenario of several hematological and solid tumors, and these agents have been actively explored in unresectable HCC. Firstly, promising findings of phase I and II clinical studies reporting durable responses and a tolerable safety profile have led to the assessment of ICIs as single agents in phase III clinical studies; however, the latter have provided controversial results, and the activity of ICI monotherapy seems limited to a small subgroup of patients. Conversely, the IMbrave150 trial recently showed that, among patients with previously untreated unresectable HCC, treatment with atezolizumab plus bevacizumab resulted in significantly longer overall survival and progression-free survival compared to sorafenib monotherapy. In addition, the activity of several other ICIs is under investigation, as combination immunotherapy as well as combinations of immunotherapy with antiangiogenic agents. Nonetheless, there are currently no validated predictive biomarkers able to guide treatment choice in this setting, where the identification of specific predictors of response to ICIs represents a major challenge. In this review, we aim to provide a critical overview of recent evidence on biochemical predictors of response to ICIs in patients with unresectable HCC, especially focusing on PD-L1, TMB, MSI, and other emerging biomarkers.

Investigation of an Alternative Marker for Hypermutability Evaluation in Different Tumors

A growing number of studies have shown immunotherapy to be a promising treatment strategy for several types of cancer. Short tandem repeats (STRs) have been proven to be alternative markers for the evaluation of hypermutability in gastrointestinal (GI) cancers. However, the status of STRs and microsatellite instability (MSI) in other tumors have not yet been investigated. To further compare STR and MSI alterations in different tumors, a total of 407 paired DNAs were analyzed from the following eight tumor types: breast cancer (BC), hepatocellular cancer (HCC), pancreatic cancer (PC), colorectal cancer (CRC), gastric cancer (GC), lung cancer (LC), esophageal cancer (EC), and renal cell cancer (RCC). The STR alteration frequencies varied in different tumors as expected. Interestingly, none of the patients possessed MSI-low (MSI-L) or MSI-high (MSI-H), except for the GI patients. The highest STR alteration was detected in EC (77.78%), followed by CRC (69.77%), HCC (63.33%), GC (54.55%), LC (48.00%), RCC (40.91%), BC (36.11%), and PC (25.71%). The potential cutoff for hypermutability was predicted using the published objective response rate (ORR), and the cutoff of LC and HCC was the same as that of GI cancers (26.32%). The cutoffs of 31.58% and 10.53% should be selected for BC and RCC, respectively. In summary, we compared MSI and STR status in eight tumor types, and predicted the potential threshold for hypermutability of BC, HCC, CRC, GC, LC, EC, and RCC.

Mutational Signatures Driven by Epigenetic Determinants Enable the Stratification of Patients with Gastric Cancer for Therapeutic Intervention

DNA mismatch repair deficiency (dMMR) is associated with the microsatellite instability (MSI) phenotype and leads to increased mutation load, which in turn may impact anti-tumor immune responses and treatment effectiveness. Various mutational signatures directly linked to dMMR have been described for primary cancers. To investigate which mutational signatures are associated with prognosis in gastric cancer, we performed a de novo extraction of mutational signatures in a cohort of 787 patients. We detected three dMMR-related signatures, one of which clearly discriminates tumors with MLH1 gene silencing caused by promoter hypermethylation (area under the curve = 98%). We then demonstrated that samples with the highest exposure of this signature share features related to better prognosis, encompassing clinical and molecular aspects and altered immune infiltrate composition. Overall, the assessment of the prognostic value and of the impact of modifications in MMR-related genes on shaping specific dMMR mutational signatures provides evidence that classification based on mutational signature exposure enables prognosis stratification.

Mismatch Repair Proteins in Oropharyngeal Squamous Cell Carcinoma: A Retrospective Observational Study

Cases of oropharyngeal squamous cell carcinoma are on the rise and the disease now ranks as the most common human papillomavirus-related cancer. Although risk factors have been extensively discussed in the literature, the role of the DNA mismatch repair system remains unanswered. To evaluate the impact of the DNA mismatch repair (MMR) protein immunostaining on the tumor progression and prognosis of oropharyngeal squamous cell carcinoma (OPSCC). This retrospective observational study comprised 50 cases of OPSCC. Immunohistochemistry for MSH2, MSH6, PMS2, MLH1, Ki67, p16 and caspase-3 was performed. The expression of these proteins was assessed in surgical resection margins, primary tumor (PT), and lymph node metastasis (LNM) of p16+ and p16- OPSCC. Clinical-pathological involvement in immunostaining was evaluated with Kruskal-Wallis/Dunn or Mann-Whitney test, Wilcoxon test and Spearman's correlation. Overall survival (OS) was analyzed with Log-Rank Mantel-Cox and Cox regression. MSH6 and caspase-3 showed high expression in PT (p16+ and p16 -) and in LNM (p16+ and p16-), and high levels of MSH2 were found in LNM (p16+ and p16 -). An imbalance in MutSα also was observed. PMS2 and caspase-3 expression was associated with poor survival in p16- OPSCC and, in multivariate analysis, MSH2, MSH6 and MLH1 had the poorest prognostic impact in p16+ OPSCC. MMR protein immunostaining is involved in OPSCC progression, dissemination and prognosis. The overexpression of MMR proteins as a response to increased DNA mismatch caused by cell proliferation and MSH2, MSH6 and MLH1 proteins might constitute a prognostic marker in p16+ OPSCC.

Microsatellite Instability in Patients With Stage III Colon Cancer Receiving Fluoropyrimidine With or Without Oxaliplatin: An ACCENT Pooled Analysis of 12 Adjuvant Trials

PURPOSE

In patients with stage III colon cancer (CC) whose tumors demonstrate microsatellite instability (MSI), the efficacy of adjuvant fluoropyrimidine (FP) with or without oxaliplatin has not been clearly demonstrated and the prognostic value of MSI remains uncertain.

MATERIALS AND METHODS

Individual patient data from the ACCENT database were used to evaluate the effect of FP with or without oxaliplatin on disease-free survival (DFS) and overall survival (OS) among patients with MSI stage III CC and the prognostic value of MSI in patients treated with FP plus oxaliplatin, by stratified Cox models adjusted for demographic and clinicopathological factors.

RESULTS

MSI status was available for 5,457 patients (609 MSI, 11.2%; 4848 microsatellite stable [MSS], 88.8%) from 12 randomized clinical trials (RCTs). Oxaliplatin significantly improved OS of MSI patients from the two RCTs testing FP with or without oxaliplatin (n = 185; adjusted hazard ratio [aHR] = 0.52, 95% CI, 0.28 to 0.93). Among the 4,250 patients treated with FP plus oxaliplatin (461 MSI and 3789 MSS), MSI was associated with better OS in the N1 group compared with MSS (aHR = 0.66; 95% CI, 0.46 to 0.95) but similar survival in the N2 population (aHR = 1.13; 95% CI, 0.86 to 1.48; P interaction = .029). The main independent prognosticators of MSI patients treated with FP plus oxaliplatin were T stage (aHR = 2.09; 95% CI, 1.29 to 3.38) and N stage (aHR = 3.57; 95% CI, 2.32 to 5.48). Similar results were observed for DFS in all analyses.

CONCLUSION

Adding oxaliplatin to FP improves OS and DFS in patients with MSI stage III CC. Compared with MSS, MSI patients experienced better outcomes in the N1 group but similar survival in the N2 group.

Diagnostics of Mutations in MMR/EPCAM Genes and Their Role in the Treatment and Care of Patients with Lynch Syndrome

Lynch syndrome (LS), also known as hereditary nonpolyposis colorectal cancer (HNPCC), is a disorder caused by an autosomal dominant heterozygous germline mutation in one of the DNA mismatch repair (MMR) genes. Individuals with LS are at an increased risk of developing colorectal and extracolonic cancers, such as endometrial, small bowel, or ovarian. In this review, the mutations involved with LS and their diagnostic methods are described and compared, as are their current uses in clinical decision making. Nowadays, LS diagnosis is based on a review of family medical history, and when necessary, microsatellite instability (MSI) or/and immunohistochemistry (IHC) analyses should be performed. In the case of a lack of MMR protein expression (dMMR) or MSI-H (MSI-High) detection in tumor tissue, molecular genetic testing can be undertaken. More and more genetic testing for LS is based mainly on next-generation sequencing (NGS) and multiplex ligation-dependent probe amplification (MLPA), which provide better and quicker information about the molecular profile of patients as well as individuals at risk. Testing based on these two methods should be the standard and commonly used. The identification of individuals with mutations provides opportunities for the detection of cancer at an early stage as well as the introduction of proper, more effective treatment, which will result in increased patient survival and reduced costs of medical care.