Mutational signature profiling classifies subtypes of clinically different mismatch-repair-deficient tumours with a differential immunogenic response potential.

BACKGROUND: Mismatch repair (MMR) deficiency is the hallmark of tumours from Lynch syndrome (LS), sporadic MLH1 hypermethylated and Lynch-like syndrome (LLS), but there is a lack of understanding of the variability in their mutational profiles based on clinical phenotypes. The aim of this study was to perform a molecular characterisation to identify novel features that can impact tumour behaviour and clinical management. METHODS: We tested 105 MMR-deficient colorectal cancer tumours (25 LS, 35 LLS and 45 sporadic) for global exome microsatellite instability, cancer mutational signatures, mutational spectrum and neoepitope load. RESULTS: Fifty-three percent of tumours showed high contribution of MMR-deficient mutational signatures, high level of global exome microsatellite instability, loss of MLH1/PMS2 protein expression and included sporadic tumours. Thirty-one percent of tumours showed weaker features of MMR deficiency, 62% lost MSH2/MSH6 expression and included 60% of LS and 44% of LLS tumours. Remarkably, 9% of all tumours lacked global exome microsatellite instability. Lastly, HLA-B07:02 could be triggering the neoantigen presentation in tumours that show the strongest contribution of MMR-deficient tumours. CONCLUSIONS: Next-generation sequencing approaches allow for a granular molecular characterisation of MMR-deficient tumours, which can be essential to properly diagnose and treat patients with these tumours in the setting of personalised medicine.

Adenosquamous cancer of the pancreas: A multicenter retrospective study.

INTRODUCTION: Adenosquamous cancer of the pancreas (ASCP) is an aggressive, infrequent subtype of pancreatic cancer that combines a glandular and squamous component and is associated with poor survival. METHODS: Multicenter retrospective observational study carried out at three Spanish hospitals. The study period was: January 2010-August 2020. A descriptive analysis of the data was performed, as well as an analysis of global and disease-free survival using the Kaplan-Meier statistic. RESULTS: Of a total of 668 pancreatic cancers treated surgically, twelve were ASCP (1.8%). Patient mean age was 69.2±7.4 years. Male/female ratio was 1:1. The main symptom was jaundice (seven patients). Correct preoperative diagnosis was obtained in only two patients. Nine pancreatoduodenectomies and three distal pancreatosplenectomies were performed. 25% had major complications. Mean tumor size was 48.6±19.4mm. Nine patients received adjuvant chemotherapy. Median survival time was 5.9 months, and median disease-free survival was 4.6 months. 90% of patients presented recurrence. Ten of the twelve patients in the study (83.3%) died, with disease progression being the cause in eight. Of the two surviving patients, one is disease-free and the other has liver metastases. CONCLUSION: ASCP is a very rare pancreatic tumor with aggressive behavior. It is rarely diagnosed preoperatively. The best treatment, if feasible, is surgery followed by the standard chemotherapy regimens for pancreatic adenocarcinoma.

Main genetic differences in high-grade gliomas may present different MR imaging and MR spectroscopy correlates.

OBJECTIVE: To assess whether the main genetic differences observed in high-grade gliomas (HGG) will present different MR imaging and MR spectroscopy correlates that could be used to better characterize lesions in the clinical setting. METHODS: Seventy-nine patients with histologically confirmed HGG were recruited. Immunohistochemistry analyses for isocitrate dehydrogenase gene 1 (IDH1), alpha thalassemia mental retardation X-linked gene (ATRX), Ki-67, and p53 protein expression were performed. Tumour radiological features were examined on MR images. Metabolic profile and infiltrative pattern were assessed with MR spectroscopy. MR features were analysed to identify imaging-molecular associations. The Kaplan-Meier method and the Cox regression model were used to identify survival prognostic factors. RESULTS: In total, 17.7% of the lesions were IDH1-mutated, 8.9% presented ATRX-mutated, 70.9% presented p53 unexpressed, and 22.8% had Ki-67 > 5%. IDH1 wild-type tumours had higher levels of mobile lipids (p = 0.001). The tumour-infiltrative pattern was higher in HGG with unexpressed p53 (p = 0.009). Mutated ATRX tumours presented higher levels of glutamate and glutamine (Glx) (p = 0.001). An association was observed between Glx tumour levels (p = 0.038) and Ki-67 expression (p = 0.008) with the infiltrative pattern. Survival analyses identified IDH1 status, age, and tumour choline levels as independent predictors of prognostic significance. CONCLUSIONS: Our results suggest that IDH1-wt tumours are more necrotic than IDH1-mut. And that the presence of an infiltrative pattern in HGG is associated with loss of p53 expression, Ki-67 index, and Glx levels. Finally, tumour choline levels could be used as a predictive factor in survival in addition to the IDH1 status to provide a more accurate prediction of survival in HGG patients. KEY POINTS: • IDH1-wt tumours present higher levels of mobile lipids than IDH1-mut. • Mutated ATRX tumours exhibit higher levels of glutamate and glutamine. • Loss of p53 expression, Ki-67 expression, and glutamate and glutamine levels may contribute to the presence of an infiltrative pattern in HGG.

CLytA-DAAO Chimeric Enzyme Bound to Magnetic Nanoparticles. A New Therapeutical Approach for Cancer Patients?

D-amino acid oxidase (DAAO) is an enzyme that catalyzes the oxidation of D-amino acids generating H2O2. The enzymatic chimera formed by DAAO bound to the choline-binding domain of N-acetylmuramoyl-L-alanine amidase (CLytA) induces cytotoxicity in several pancreatic and colorectal carcinoma and glioblastoma cell models. In the current work, we determined whether the effect of CLytA-DAAO immobilized in magnetic nanoparticles, gold nanoparticles, and alginate capsules offered some advantages as compared to the free CLytA-DAAO. Results indicate that the immobilization of CLytA-DAAO in magnetic nanoparticles increases the stability of the enzyme, extending its time of action. Besides, we compared the effect induced by CLytA-DAAO with the direct addition of hydrogen peroxide, demonstrating that the progressive generation of reactive oxygen species by CLytA-DAAO is more effective in inducing cytotoxicity than the direct addition of H2O2. Furthermore, a pilot study has been initiated in biopsies obtained from pancreatic and colorectal carcinoma and glioblastoma patients to evaluate the expression of the main genes involved in resistance to CLytA-DAAO cytotoxicity. Based on our findings, we propose that CLytA-DAAO immobilized in magnetic nanoparticles could be effective in a high percentage of patients and, therefore, be used as an anti-cancer therapy for pancreatic and colorectal carcinoma and glioblastoma.

Clinical and Pathological Characterization of Lynch-Like Syndrome.

BACKGROUND & AIMS: Lynch syndrome is characterized by DNA mismatch repair (MMR) deficiency. Some patients with suspected Lynch syndrome have DNA MMR deficiencies but no detectable mutations in genes that encode MMR proteins-this is called Lynch-like syndrome (LLS). There is no consensus on management of patients with LLS. We collected data from a large series of patients with LLS to identify clinical and pathology features. METHODS: We collected data from a nationwide-registry of patients with colorectal cancer (CRC) in Spain. We identified patients whose colorectal tumors had loss of MSH2, MSH6, PMS2, or MLH1 (based on immunohistochemistry), without the mutation encoding V600E in BRAF (detected by real-time PCR), and/or no methylation at MLH1 (determined by methylation-specific multiplex ligation-dependent probe amplification), and no pathogenic mutations in MMR genes, BRAF, or EPCAM (determined by DNA sequencing). These patients were considered to have LLS. We collected data on demographic, clinical, and pathology features and family history of neoplasms. The χ2 test was used to analyze the association between qualitative variables, followed by the Fisher exact test and the Student t test or the Mann-Whitney test for quantitative variables. RESULTS: We identified 160 patients with LLS; their mean age at diagnosis of CRC was 55 years and 66 patients were female (41%). The Amsterdam I and II criteria for Lynch syndrome were fulfilled by 11% of cases and the revised Bethesda guideline criteria by 65% of cases. Of the patients with LLS, 24% were identified in universal screening. There were no proportional differences in sex, indication for colonoscopy, immunohistochemistry, pathology findings, or personal history of CRC or other Lynch syndrome-related tumors between patients who met the Amsterdam and/or Bethesda criteria for Lynch syndrome and patients identified in universal screening for Lynch syndrome, without a family history of CRC. CONCLUSIONS: Patients with LLS have homogeneous clinical, demographic, and pathology characteristics, regardless of family history of CRC.

Cell Death Mechanisms Induced by CLytA-DAAO Chimeric Enzyme in Human Tumor Cell Lines.

The combination of the choline binding domain of the amidase N-acetylmuramoyl-L-alanine (CLytA)-D-amino acid oxidase (DAAO) (CLytA-DAAO) and D-Alanine induces cell death in several pancreatic and colorectal carcinoma and glioblastoma cell lines. In glioblastoma cell lines, CLytA-DAAO-induced cell death was inhibited by a pan-caspase inhibitor, suggesting a classical apoptotic cell death. Meanwhile, the cell death induced in pancreatic and colon carcinoma cell lines is some type of programmed necrosis. In this article, we studied the mechanisms that trigger CLytA-DAAO-induced cell death in pancreatic and colorectal carcinoma and glioblastoma cell lines and we acquire a further insight into the necrotic cell death induced in pancreatic and colorectal carcinoma cell lines. We have analyzed the intracellular calcium mobilization, mitochondrial membrane potential, PARP-1 participation and AIF translocation. Although the mitochondrial membrane depolarization plays a crucial role, our results suggest that CLytA-DAAO-induced cell death is context dependent. We have previously detected pancreatic and colorectal carcinoma cell lines (Hs766T and HT-29, respectively) that were resistant to CLytA-DAAO-induced cell death. In this study, we have examined the putative mechanism underlying the resistance in these cell lines, evaluating both detoxification mechanisms and the inflammatory and survival responses. Overall, our results provide a better understanding on the cell death mechanism induced by CLytA-DAAO, a promising therapy against cancer.

The heritability and patterns of DNA methylation in normal human colorectum.

DNA methylation (DNAm) has been linked to changes in chromatin structure, gene expression and disease. The DNAm level can be affected by genetic variation; although, how this differs by CpG dinucleotide density and genic location of the DNAm site is not well understood. Moreover, the effect of disease causing variants on the DNAm level in a tissue relevant to disease has yet to be fully elucidated. To this end, we investigated the phenotypic profiles, genetic effects and regional genomic heritability for 196080 DNAm sites in healthy colorectum tissue from 132 unrelated Colombian individuals. DNAm sites in regions of low-CpG density were more variable, on average more methylated and were more likely to be significantly heritable when compared with DNAm sites in regions of high-CpG density. DNAm sites located in intergenic regions had a higher mean DNAm level and were more likely to be heritable when compared with DNAm sites in the transcription start site (TSS) of a gene expressed in colon tissue. Within CpG-dense regions, the propensity of the DNAm level to be heritable was lower in the TSS of genes expressed in colon tissue than in the TSS of genes not expressed in colon tissue. In addition, regional genetic variation was associated with variation in local DNAm level no more frequently for DNAm sites within colorectal cancer risk regions than it was for DNAm sites outside such regions. Overall, DNAm sites located in different genomic contexts exhibited distinguishable profiles and may have a different biological function.

Increased Risk of Colorectal Cancer in Patients With Multiple Serrated Polyps and Their First-Degree Relatives.

BACKGROUND & AIMS: We investigated whether patients with multiple serrated polyps, but not meeting the World Health Organization criteria for serrated polyposis syndrome, and their relatives have similar risks for colorectal cancer (CRC) as those diagnosed with serrated polyposis. METHODS: We collected data from patients with more than 10 colonic polyps, recruited in 2008-2009 from 24 hospitals in Spain for a study of causes of multiple colonic polyps. We analyzed data from 53 patients who met the criteria for serrated polyposis and 145 patients who did not meet these criteria, but who had more than 10 polyps throughout the colon, of which more than 50% were serrated. We calculated age- and sex-adjusted standardized incidence ratios (SIRs) for CRC in both groups, as well as in their first-degree relatives. RESULTS: The prevalence of CRC was similar between patients with confirmed serrated polyposis and multiple serrated polyps (odds ratio, 1.35; 95% confidence interval [CI], 0.64-2.82; P = .40). The SIR for CRC in patients with serrated polyposis (0.51; 95% CI, 0.01-2.82) did not differ significantly from the SIR for CRC in patients with multiple serrated polyps (0.74; 95% CI, 0.20-1.90; P = .70). The SIR for CRC also did not differ significantly between first-degree relatives of these groups (serrated polyposis: 3.28, 95% CI, 2.16-4.77; multiple serrated polyps: 2.79, 95% CI, 2.10-3.63; P = .50). Kaplan-Meier analysis showed no differences in the incidence of CRC between groups during the follow-up period (log-rank, 0.6). CONCLUSIONS: The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.

Lack of cytomegalovirus detection in human glioma.

Gliomas are the most common brain tumors and include a variety of histologic types and grades of malignancy. They arise from glial cells and represent approximately 70% of the primary brain tumors. According to the criteria of the World Health Organization (WHO), the majority of gliomas can be classified into four grades of malignancy (I-IV). Virus infection, especially by DNA viruses and retroviruses, which may cause insertion of viral DNA sequences into the host genome, often triggers the host defense mechanisms. Particularly, the DNA methylation machinery can be activated to cause the methylation of foreign movable viral sequences and, therefore, silence viral gene expression. Several studies have shown the presence of Human Cytomegalovirus (HCMV) in glioblastoma, suggesting that the virus may participate in tumor pathogenesis. But this relationship is controversial because many other studies did not detect HCMV in these tumors. This study aims to detect the presence of HCMV in several samples of human glioma (94 formalin-fixed, paraffin-embedded samples and 28 snap-frozen samples) by different sensitive techniques. We have been unable to detect HCMV DNA and proteins in glioma samples. Therefore, arguments used so far to conclude that HCMV is an oncomodulator virus in gliomas must be, in our view, seriously reconsidered.

Association of a let-7 miRNA binding region of TGFBR1 with hereditary mismatch repair proficient colorectal cancer (MSS HNPCC).

The purpose of this study was to identify novel colorectal cancer (CRC)-causing alleles in unexplained familial CRC cases. In order to do so, coding regions in five candidate genes (MGMT, AXIN2, CTNNB1, TGFBR1 and TGFBR2) were sequenced in 11 unrelated microsatellite-stable hereditary non-polyposis CRC (MSS HNPCC) cases. Selected genetic variants were genotyped in a discovery set of 27 MSS HNPCC cases and 85 controls. One genetic variant, rs67687202, in TGFBR1 emerged as significant (P = 0.002), and it was genotyped in a replication set of 87 additional MSS HNPCC-like cases and 338 controls where it was also significantly associated with MSS HNPCC cases (P = 0.041). In the combined genotype data, rs67687202 was associated with a moderate increase in CRC risk (OR = 1.68; 95% CI = 1.13-2.50; P = 0.010). We tested a highly correlated SNP rs868 in 723 non-familial CRC cases compared with 629 controls, and it was not significantly associated with CRC risk (P = 0.370). rs868 is contained in a let-7 miRNA binding site in the 3'UTR of TGFBR1, which might provide a functional basis for the association in MSS HNPCC. In luciferase assays, the risk-associated allele for rs868 was associated with half the luciferase expression in the presence of miRNA let-7b-5p compared with protective allele, suggesting more binding of let-7b-5p and less TGFBR1 expression. Thus, rs868 potentially is a CRC risk-causing allele. Our results support the concept that rs868 is associated with lower TGFBR1 expression thereby increasing CRC risk.

New insights into POLE and POLD1 germline mutations in familial colorectal cancer and polyposis.

Germline mutations in DNA polymerase ɛ (POLE) and δ (POLD1) have been recently identified in families with multiple colorectal adenomas and colorectal cancer (CRC). All reported cases carried POLE c.1270C>G (p.Leu424Val) or POLD1 c.1433G>A (p.Ser478Asn) mutations. Due to the scarcity of cases reported so far, an accurate clinical phenotype has not been defined. We aimed to assess the prevalence of these recurrent mutations in unexplained familial and early-onset CRC and polyposis, and to add additional information to define the clinical characteristics of mutated cases. A total of 858 familial/early onset CRC and polyposis patients were studied: 581 familial and early-onset CRC cases without mismatch repair (MMR) deficiency, 86 cases with MMR deficiency and 191 polyposis cases. Mutation screening was performed by KASPar genotyping assays and/or Sanger sequencing of the involved exons. POLE p.L424V was identified in a 28-year-old polyposis and CRC patient, as a de novo mutation. None of the 858 cases studied carried POLD1 p.S478N. A new mutation, POLD1 c.1421T>C (p.Leu474Pro), was identified in a mismatch repair proficient Amsterdam II family. Its pathogenicity was supported by cosegregation in the family, in silico predictions, and previously published yeast assays. POLE and POLD1 mutations explain a fraction of familial CRC and polyposis. Sequencing the proofreading domains of POLE and POLD1 should be considered in routine genetic diagnostics. Until additional evidence is gathered, POLE and POLD1 genetic testing should not be restricted to polyposis cases, and the presence of de novo mutations, considered.

Endoscopic surveillance in patients with multiple (10-100) colorectal polyps.

BACKGROUND AND STUDY AIMS: Endoscopic surveillance in patients with multiple colorectal polyps aims to reduce colorectal cancer (CRC) incidence and mortality, as well as the need for colorectal surgery. The aim of this study was to determine the risk of developing CRC or the need for surgery during endoscopic surveillance in a cohort of patients with multiple (10 - 100) colorectal polyps. PATIENTS AND METHODS: This was a multicentrer, longitudinal, observational study in 15 CRC high risk clinics in Spain, carried out between January 2009 and December 2010. Patients who were included in the EPIPOLIP trial and had at least 1 year of follow-up were included in the study. The primary outcome of interest was the incidence of CRC at least 1 year following the initial colonoscopy. The secondary outcome was the need for colorectal surgery. RESULTS: A total of 265 patients were followed for a median of 3.8 years. Patients underwent a median of 5 colonoscopies, and 17 patients (6.4 %) were diagnosed with CRC. A total of 32 patients (12.1 %) underwent surgery, including 15 (5.7 %) for prophylaxis without a diagnosis of CRC. The corresponding incidence density rates for CRC and colorectal surgery were 1.4 (95 % confidence interval [CI] 0.7 to 2.1) and 2.7 (95 %CI 1.7 to 3.6) per 100 patient-years, respectively. Only the presence of symptoms at first colonoscopy was independently associated with CRC diagnosis (hazard ratio [HR] 7.7, 95 %CI 1.1 to 59.3) and colorectal surgery (HR 4.6, 95 %CI 1.02 to 20.6). CONCLUSIONS: Patients with more than 10 neoplastic polyps required frequent colonoscopies within a short follow-up period. More than 10 % of patients required colorectal surgery within 4 years, more than half for incident CRC.

Prevalence of MLH1 constitutional epimutations as a cause of Lynch syndrome in unselected versus selected consecutive series of patients with colorectal cancer.

BACKGROUND: The prevalence of MLH1 constitutional epimutations in the general population is unknown. We sought to analyse the prevalence of MLH1 constitutional epimutations in unselected and selected series of patients with colorectal cancer (CRC). METHODS: Patients with diagnoses of CRC (n=2123) were included in the unselected group. For comparison, a group of 847 selected patients with CRC who fulfilled the revised Bethesda guidelines (rBG) were also included. Somatic and constitutional MLH1 methylation was assayed via methylation-specific multiplex ligation-dependent probe amplification of cases lacking MLH1 expression. Germline alterations in mismatch-repair (MMR) genes were assessed via Sanger sequencing and methylation-specific multiplex ligation-dependent probe amplification. RESULTS: Loss of MLH1 expression occurred in 5.5% of the unselected series and 12.5% of the selected series (p<0.0001). No constitutional epimutations in MLH1 were detected in the unselected population (0/62); five cases from the selected series were positive for MLH1 epimutations (15.6%, 5/32; p=0.004). CONCLUSIONS: Our results suggest a negligible prevalence of MLH1 constitutional epimutations in unselected cases of CRC. Therefore, MLH1 constitutional epimutation analysis should be conducted only for patients who fulfil the rBG and who lack MLH1 expression with methylated MLH1.

Risk of cancer in cases of suspected lynch syndrome without germline mutation.

BACKGROUND & AIMS: Colorectal cancers (CRCs) with microsatellite instability (MSI) and a mismatch repair (MMR) immunohistochemical deficit without hypermethylation of the MLH1 promoter are likely to be caused by Lynch syndrome. Some patients with these cancers have not been found to have pathogenic germline mutations and are considered to have Lynch-like syndrome (LLS). The aim of this study was to determine the risk of cancer in families of patients with LLS. METHODS: We studied a population-based cohort of 1705 consecutive patients, performing MSI tests and immunohistochemical analyses of MMR proteins. Patients were diagnosed with Lynch syndrome when they were found to have pathogenic germline mutations. Patients with MSI and loss of MSH2 and/or MSH6 expression, isolated loss of PMS2 or loss of MLH1 without MLH1 promoter hypermethylation, and no pathogenic mutation were considered to have LLS. The clinical characteristics of patients and the age- and sex-adjusted standardized incidence ratios (SIRs) of cancer in families were compared between groups. RESULTS: The incidence of CRC was significantly lower in families of patients with LLS than in families with confirmed cases of Lynch syndrome (SIR for Lynch syndrome, 6.04; 95% confidence interval [CI], 3.58-9.54; SIR for LLS, 2.12; 95% CI, 1.16-3.56; P < .001). However, the incidence of CRC was higher in families of patients with LLS than in families with sporadic CRC (SIR for sporadic CRC, 0.48; 95% CI, 0.27-0.79; P < .001). CONCLUSIONS: The risk of cancer in families with LLS is lower that of families with Lynch syndrome but higher than that of families with sporadic CRC. These results confirm the need for special screening and surveillance strategies for these patients and their relatives.

Clinical subtypes and molecular characteristics of serrated polyposis syndrome.

BACKGROUND & AIMS: We investigated clinical and molecular differences between the different phenotypes of serrated polyposis syndrome (SPS) and the frequency of mutations in BRAF or KRAS in polyps from patients with SPS. METHODS: We collected data on clinical and demographic characteristics of 50 patients who fulfilled the criteria for SPS. Polymerase chain reaction and sequence analysis were used to identify BRAF and KRAS mutations in 432 polyps collected from 37 patients; we analyzed CpG island methylator phenotypes in 272 of these polyps. RESULTS: Fifteen patients (30%) had type 1 SPS and 35 had type 2 SPS. There were no significant differences in age at diagnosis, sex, smoking frequency, body mass index, or colorectal cancer predisposition between groups of patients, or in the pathologic or molecular characteristics of their polyps. A familial history of colorectal cancer or colonic polyps was reported more frequently by patients with type 2 SPS. BRAF mutations were found in 63% of polyps and KRAS mutations were found in 9.9%; 43.4% of polyps had the CpG island methylator phenotype-high phenotype. A per-patient analysis revealed that all patients had a BRAF or KRAS mutation in more than 25% of their polyps; 84.8% of patients had a mutation in BRAF or KRAS in more than 50% of their polyps. CONCLUSIONS: Except for a greater likelihood of familial history of colorectal cancer or colonic polyps in patients with type 2 SPS, we found no significant demographic, pathologic, or molecular differences between types 1 and 2 SPS. All patients had a BRAF or KRAS mutation in at least 25% of their polyps.

Comparison between universal molecular screening for Lynch syndrome and revised Bethesda guidelines in a large population-based cohort of patients with colorectal cancer.

BACKGROUND: The selection of patients for genetic testing to rule out Lynch syndrome is currently based on fulfilment of at least one of the revised Bethesda criteria followed by mismatch repair (MMR) status analysis. A study was undertaken to compare the present approach with universal MMR study-based strategies to detect Lynch syndrome in a large series of patients with colorectal cancer (CRC). METHODS: 2093 patients with CRC from the EPICOLON I and II cohorts were included. Immunohistochemistry for MMR proteins and/or microsatellite instability (MSI) analysis was performed in tumour tissue. Germline MLH1 and MSH2 mutation analysis was performed in patients whose tumours showed loss of MLH1 or MSH2 staining, respectively. MSH6 genetic testing was done in patients whose tumours showed lack of MSH6 expression or a combined lack of MSH2 and MSH6 expression but did not have MSH2 mutations. PMS2 genetic testing was performed in patients showing isolated loss of PMS2 expression. In patients with MSI tumours and normal or not available MMR protein expression, all four MMR genes were studied. RESULTS: A total of 180 patients (8.6%) showed loss of expression of some of the MMR proteins and/or MSI. Four hundred and eighty-six patients (23.2%) met some of the revised Bethesda criteria. Of the 14 (0.7%) patients who had a MMR gene mutation, 12 fulfilled at least one of the revised Bethesda criteria and two (14.3%) did not. CONCLUSIONS: Routine molecular screening of patients with CRC for Lynch syndrome using immunohistochemistry or MSI has better sensitivity for detecting mutation carriers than the Bethesda guidelines.

Rationale for combined therapies in severe-to-critical COVID-19 patients.

An unprecedented global social and economic impact as well as a significant number of fatalities have been brought on by the coronavirus disease 2019 (COVID-19), produced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Acute SARS-CoV-2 infection can, in certain situations, cause immunological abnormalities, leading to an anomalous innate and adaptive immune response. While most patients only experience mild symptoms and recover without the need for mechanical ventilation, a substantial percentage of those who are affected develop severe respiratory illness, which can be fatal. The absence of effective therapies when disease progresses to a very severe condition coupled with the incomplete understanding of COVID-19's pathogenesis triggers the need to develop innovative therapeutic approaches for patients at high risk of mortality. As a result, we investigate the potential contribution of promising combinatorial cell therapy to prevent death in critical patients.

5-Fluorouracil adjuvant chemotherapy does not increase survival in patients with CpG island methylator phenotype colorectal cancer.

BACKGROUND & AIMS: 5-Fluorouracil (5-FU)-based adjuvant chemotherapy does not increase survival times of patients with colorectal tumors with microsatellite instability. We determined the response of patients with colorectal tumors with the CpG island methylator phenotype (CIMP) to 5-FU-based therapy. METHODS: We analyzed a population-based cohort of 302 patients with colorectal cancer (CRC) for a median follow-up time of 50.7 months. CIMP status was determined by analysis of the CACNAG1, SOCS1, RUNX3, NEUROG1, and MLH1 promoters; tumors were considered to be CIMP positive if at least 3 promoters were methylated. RESULTS: Tumors from 29.5% of patients (89/302) were CIMP positive; CIMP status did not influence disease-free survival (DFS; log-rank = 0.3). Of tumors of TNM stages II-III (n = 196), 32.7% were CIMP positive. Among patients with stages II-III CRC who did not receive adjuvant 5-FU chemotherapy, those with CIMP-positive tumors had longest times of DFS (log-rank = 0.04); In patients who received chemotherapy, those with CIMP-positive tumors had shorter times of DFS (log-rank = 0.02). In patients with CIMP-negative tumors, adjuvant 5-FU chemotherapy significantly increased time of DFS (log-rank = 0.00001). However, in patients with CIMP-positive tumors, adjuvant 5-FU chemotherapy did not affect time of DFS (log-rank = 0.7). Multivariate analysis showed a significant, independent interaction between 5-FU treatment and CIMP status (hazard ratio [HR], 0.6; 95% confidence interval [CI], 0.5-0.8). Among patients with CIMP-positive tumors, adjuvant chemotherapy was not an independent predictor of outcome (HR, 0.8; 95% CI, 0.3-2.0). In patients who did not receive adjuvant 5-FU chemotherapy, CIMP status was the only independent predictor of survival (HR, 2.0; 95% CI, 1.1-3.8). CONCLUSIONS: Patients with CIMP-positive colorectal tumors do not benefit from 5-FU-based adjuvant chemotherapy.

Pathological Findings Associated With SARS-CoV-2 on Postmortem Core Biopsies: Correlation With Clinical Presentation and Disease Course.

Background: Autopsies can shed light on the pathogenesis of new and emerging diseases. Aim: To describe needle core necropsy findings of the lung, heart, and liver in decedents with COVID-19. Material: Cross-sectional study of needle core necropsies in patients who died with virologically confirmed COVID-19. Histopathological analyses were performed, and clinical data and patient course evaluated. Results: Chest core necropsies were performed in 71 decedents with a median age of 81 years (range 52-97); 47 (65.3%) were men. The median interval from symptoms onset to death was 17.5 days (range 1-84). Samples of lung (n = 62, 87.3%), heart (n = 48, 67.6%) and liver (n = 39, 54.9%) were obtained. Fifty-one lung samples (82.3%) were abnormal: 19 (30.6%) showed proliferative diffuse alveolar damage (DAD), 12 (19.4%) presented exudative DAD, and 10 (16.1%) exhibited proliferative plus exudative DAD. Of the 46 lung samples tested for SARS-CoV-19 by RT-PCR, 39 (84.8%) were positive. DAD was associated with premortem values of lactate dehydrogenase of 400 U/L or higher [adjusted odds ratio (AOR) 21.73; 95% confidence interval (CI) 3.22-146] and treatment with tocilizumab (AOR 6.91; 95% CI 1.14-41.7). Proliferative DAD was associated with an onset-to-death interval of over 15 days (AOR 7.85, 95% CI 1.29-47.80). Twenty-three of the 48 (47.9%) heart samples were abnormal: all showed fiber hypertrophy, while 9 (18.8%) presented fibrosis. Of the liver samples, 29/39 (74.4%) were abnormal, due to steatosis (n = 12, 30.8%), cholestasis (n = 6, 15.4%) and lobular central necrosis (n = 5, 12.8%). Conclusion: Proliferative DAD was the main finding on lung core needle necropsy in people who died from COVID-19; this finding was related to a longer disease course. Changes in the liver and heart were common.