Search

Purpose: To evaluate current MRI-based criteria for malignancy in mesorectal nodal structures in rectal cancer., Method: Mesorectal nodal structures identified on baseline MRI as lymph nodes were anatomically compared to their corresponding structures histopathologically, reported as lymph nodes, tumour deposits or extramural venous invasion. All anatomically matched nodal structures from patients with primary surgery and all malignant nodal structures from patients with neoadjuvant treatment were included. Mixed-effects logistic regression models were used to evaluate the morphological criteria irregular margin, round shape, heterogeneous signal and nodal size, as well as the combined 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus criteria, with histopathological nodal status as the gold standard., Results: In total, 458 matched nodal structures were included from 46 patients (mean age, 67.7 years ± 1.5 [SD], 27 men), of which 19 received neoadjuvant treatment. The strongest associations in the univariable model were found for short-axis diameter ≥ 5 mm (OR 21.43; 95% CI: 4.13-111.29, p < 0.001) and heterogeneous signal (OR 9.02; 95% CI: 1.33-61.08, p = 0.024). Only size remained significant in multivariable analysis (OR 12.32; 95% CI: 2.03-74.57, p = 0.006). When applying the ESGAR consensus criteria to create a binary classification of nodal status, the OR of malignant outcome for nodes with positive ESGAR was 8.23 (95% CI: 2.15-31.50, p = 0.002), with corresponding sensitivity and specificity of 54% and 85%, respectively., Conclusion: The results confirm the role of morphological and size criteria in predicting lymph node metastases. However, the current criteria might not be accurate enough for nodal staging., Key Points: Question Pretreatment lymph node staging in rectal cancer is challenging, and the ESGAR consensus criteria are not fully validated. Findings Although the ESGAR criteria correlated with malignant outcomes, diagnostic performance in terms of particular sensitivity, but also specificity, was not high. Clinical relevance Accurate nodal staging in rectal cancer is crucial for individual treatment planning. However, this validation of the current ESGAR consensus criteria suggests that these should be used with caution., Competing Interests: Compliance with ethical standards. Guarantor: The scientific guarantor of this publication is Katrine Riklund. Conflict of interest: The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article. Statistics and biometry: One of the authors, Wendy Wu, a statistician at the Department of Diagnostics and Intervention, Oncology, Umeå University, kindly provided the statistical expertise for this manuscript. Informed consent: Written informed consent was obtained from all subjects (patients) in this study. Ethical approval: Ethical approval (dnr: 2015/417-31) was obtained from the Regional Ethical Review Board in Umeå, Sweden. Study subjects or cohorts overlap: Nine study subjects (patients) have been previously reported in our published initial findings and method description of the RECTOPET study (NCT03846882) [7, 15]. Methodology: Prospective observational study Performed at one institution, (© 2025. The Author(s).)

The systemic inflammatory response (SIR), defined as elevated levels of circulating C-reactive protein (CRP), is an important predictor of impaired survival in colorectal cancer. The aim of this study was to explore the prognostic role of SIR and its association with tumour mismatch repair status and the immune response. Immune activity profiles of mononuclear cells isolated from CRC tissues and blood in the U-CAN exploration cohort (n = 69), were analysed by flow cytometry. In the U-CAN validation cohort (n = 257), T-helper cells (T-bet + ), cytotoxic T cells (CD8 + ), regulatory T cells (FoxP3 + ), B cells (CD20 + ), and macrophages (CD68 + ) were analysed by multispectral imaging. Microsatellite instability was determined using five mononucleotide-repeat microsatellite markers. Patients with high CRP levels (> 10 mg/l) were significantly more often diagnosed with high-grade tumours and tumours exhibiting microsatellite instability. However, some patients with high CRP levels were found to have microsatellite-stable tumours. Furthermore, high CRP levels were associated with specific tumour immune traits including an augmented macrophage response and were significantly linked to poorer cancer-specific survival, particularly in patients with microsatellite-stable tumours. In conclusion, our findings suggest an interplay between SIR and mismatch repair status in CRC prognosis which needs to be further explored., Competing Interests: Declarations. Competing interests: The authors declare no competing interests. Supplementary Information accompanies this paper. Supplementary Table S1: Multivariable Cox regression analysis in Stage I-III patients from the U-CAN validation cohort., (© 2024. The Author(s).)

Background: Mounting evidence suggests a significant role of the gut microbiota in the development and progression of colorectal cancer (CRC). In particular, an over-representation of oral pathogens has been linked to CRC. The aim of this study was to further investigate the faecal microbial landscape of CRC patients, with a focus on the oral pathogens Parvimonas micra and Fusobacterium nucleatum., Methods: In this study, 16S rRNA sequencing was conducted using faecal samples from CRC patients (n = 275) and controls without pathological findings (n = 95)., Results: We discovered a significant difference in microbial composition depending on tumour location and microsatellite instability (MSI) status, with P. micra, F. nucleatum, and Peptostreptococcus stomatis found to be more abundant in patients with MSI tumours. Moreover, P. micra and F. nucleatum were associated with a cluster of CRC-related bacteria including Bacteroides fragilis as well as with other oral pathogens such as P. stomatis and various Porphyromonas species. This cluster was distinctly different in the control group, suggesting its potential linkage with CRC., Conclusions: Our results suggest a similar distribution of several CRC-associated bacteria within CRC patients, underscoring the importance of considering the concomitant presence of bacterial species in studies investigating the mechanisms of CRC development and progression., (© 2024. The Author(s).)

Colorectal cancer is caused by a sequence of somatic genomic alterations affecting driver genes in core cancer pathways 1 . Here, to understand the functional and prognostic impact of cancer-causing somatic mutations, we analysed the whole genomes and transcriptomes of 1,063 primary colorectal cancers in a population-based cohort with long-term follow-up. From the 96 mutated driver genes, 9 were not previously implicated in colorectal cancer and 24 had not been linked to any cancer. Two distinct patterns of pathway co-mutations were observed, timing analyses identified nine early and three late driver gene mutations, and several signatures of colorectal-cancer-specific mutational processes were identified. Mutations in WNT, EGFR and TGFβ pathway genes, the mitochondrial CYB gene and 3 regulatory elements along with 21 copy-number variations and the COSMIC SBS44 signature correlated with survival. Gene expression classification yielded five prognostic subtypes with distinct molecular features, in part explained by underlying genomic alterations. Microsatellite-instable tumours divided into two classes with different levels of hypoxia and infiltration of immune and stromal cells. To our knowledge, this study constitutes the largest integrated genome and transcriptome analysis of colorectal cancer, and interlinks mutations, gene expression and patient outcomes. The identification of prognostic mutations and expression subtypes can guide future efforts to individualize colorectal cancer therapy., (© 2024. The Author(s).)

Background and Objectives: Disparities between tumors arising via different sporadic carcinogenetic pathways have not been studied systematically. This retrospective multicenter cohort study evaluated the differences in the risk for non-colorectal malignancy between sporadic colorectal cancer (CRC) patients from different DNA mismatch repair status., Methods: A retrospective European multicenter cohort study including in total of 1706 CRC patients treated between 1996 and 2019 in three different countries. The proficiency (pMMR) or deficiency (dMMR) of mismatch repair was determined by immunohistochemistry. Cases were analyzed for tumor BRAF V600E mutation, and BRAF mutated tumors were further analyzed for hypermethylation status in the promoter region of MLH1 to distinguish between sporadic and hereditary cases. Swedish and Finish patients were matched with their respective National Cancer Registries. For the Czech cohort, thorough scrutiny of medical files was performed to identify any non-colorectal malignancy within 20 years before or after the diagnosis of CRC. Poisson regression analysis was performed to identify the incidence rates of non-colorectal malignancies. For validation purposes, standardized incidence ratios were calculated for the Swedish cases adjusted for age, year, and sex., Results: Of the 1706 CRC patients included in the analysis, 819 were female [48%], median age at surgery was 67 years [interquartile range: 60-75], and sporadic dMMR was found in 188 patients (11%). Patients with sporadic dMMR CRC had a higher incidence rate ratio (IRR) for non-colorectal malignancy before and after diagnosis compared to patients with a pMMR tumor, in both uni- (IRR = 2.49, 95% confidence interval [CI] = 1.89-3.31, p = 0.003) and multivariable analysis (IRR = 2.24, 95% CI = 1.67-3.01, p = 0.004). This association applied whether or not the non-colorectal tumor developed before or after the diagnosis of CRC in both uni- (IRR = 1.91, 95% CI = 1.28-2.98, p = 0.004), (IRR = 2.45, 95% CI = 1.72-3.49, p = 0.004) and multivariable analysis (IRR = 1.67,95% CI = 1.05-2.65, p = 0.029), (IRR = 2.35, 95% CI = 1.63-3.42, p = 0.005), respectively., Conclusion: In this retrospective European multicenter cohort study, patients with sporadic dMMR CRC had a higher risk for non-colorectal malignancy than those with pMMR CRC. These findings indicate the need for further studies to establish the need for and design of surveillance strategies for patients with dMMR CRC., (© 2024 The Authors. Journal of Surgical Oncology published by Wiley Periodicals LLC.)

Gut barrier dysfunction and related inflammation are known to be associated with the development and progression of colorectal cancer (CRC). We investigated associations of 292 single-nucleotide polymorphisms (SNPs) from 27 genes related to endotoxins/lipopolysaccharide (LPS) sensing and tolerance, mucin synthesis, inflammation, and Crohn's disease with colon and rectal cancer risks. Incident CRC cases (N=1,374; colon=871, rectum=503) were matched 1:1 to controls nested within the European Prospective Investigation into Cancer and Nutrition cohort. Previously measured serum concentrations of gut barrier function and inflammation biomarkers (flagellin/LPS-specific immunoglobulins and C-reactive protein [CRP]) were available for a sub-set of participants (Ncases=1,001; Ncontrols=667). Forty-two unique SNPs from 19 different genes were associated with serum biomarkers at Punadjusted≤0.05 among controls. Among SNPs associated with a gut permeability score, 24 SNPs were in genes related to LPS sensing and mucin synthesis. Nine out of 12 SNPs associated with CRP were in genes related to inflammation or Crohn's disease. TLR4 was associated with colon cancer at the SNP level (nine SNPs, all Punadjusted≤0.04) and at the gene level (Punadjusted≤0.01). TLR4 rs10759934 was associated with rectal cancer but not colon cancer. Similarly, IL10 was associated with rectal cancer risk at a SNP and gene level (both Punadjusted ≤ 0.01), but not colon cancer. Genes and SNPs were selected a priori therefore we present unadjusted P-values. However, no association was statistically significant after multiple testing correction. This large and comprehensive study has identified gut barrier function and inflammation-related genes possibly contributing to CRC risk in European populations and is consistent with potential etiological links between host genetic background, gut barrier permeability, microbial endotoxemia and CRC development., (© The Author(s) 2024. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The immune response has important clinical value in colorectal cancer (CRC) in both prognosis and response to immunotherapy. This study aims to explore tumour immune cell infiltration in relation to clinically well-established molecular markers of CRC., Methods: Multiplex immunohistochemistry and multispectral imaging was used to evaluate tumour infiltration of cytotoxic T cells (CD8 + ), Th1 cells (T-bet + ), T regulatory cells (FoxP3 + ), B cells (CD20 + ), and macrophages (CD68 + ) in a cohort of 257 CRC patients., Results: We found the expected association between higher immune-cell infiltration and microsatellite instability. Also, whereas BRAF-mutated tumours displayed increased immune-cell infiltration compared to BRAF wild-type tumours, the opposite was seen for KRAS-mutated tumours, differences that were most prominent for cytotoxic T cells and Th1 cells. The opposing relationships of BRAF and KRAS mutations with tumour infiltration of cytotoxic T cells was validated in an independent cohort of 608 CRC patients. A positive prognostic importance of cytotoxic T cells was found in wild-type as well as KRAS and BRAF-mutated CRCs in both cohorts., Conclusion: A combined evaluation of MSI status, KRAS and BRAF mutational status, and immune infiltration (cytotoxic T cells) may provide important insights to prognosis and response to immunotherapy in CRC., (© 2023. The Author(s).)

Endogenous sex hormones and DNA methylation both play important roles in various diseases. However, their interplay is largely unknown. A deeper understanding of their interrelationships could provide new insights into the pathology of disease development. We, therefore, investigated associations between circulating sex hormones, sex hormone binding globulin (SHBG), and DNA methylation in blood, using samples from 77 men (65 with repeated samples), from the population-based Northern Sweden Health and Disease Study (NSHDS). DNA methylation was measured in buffy coat using the Infinium Methylation EPIC BeadChip (Illumina). Sex hormone (oestradiol, oestrone, testosterone, androstenedione, dehydroepiandrosterone, and progesterone) and SHBG concentrations were measured in plasma using a high-performance liquid chromatography tandem mass spectrometry (LC/MS-MS) method and an enzyme-linked immunoassay, respectively. Associations between sex hormones, SHBG, and DNA methylation were estimated using both linear regression and mixed-effects models. Additionally, we used the comb-p method to identify differentially methylated regions based on nearby P values. We identified one novel CpG site (cg14319657), at which DNA methylation was associated with dehydroepiandrosterone, surpassing a genome-wide significance level. In addition, more than 40 differentially methylated regions were associated with levels of sex hormones and SHBG and several of these mapped to genes involved in hormone-related diseases. Our findings support a relationship between circulating sex hormones and DNA methylation and suggest that further investigation is warranted, both for validation, further exploration and to gain a deeper understanding of the mechanisms and potential consequences for health and disease.

Background: Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide, but if discovered at an early stage, the survival rate is high. The aim of this study was to identify novel markers predictive of future CRC risk using untargeted metabolomics., Methods: This study included prospectively collected plasma samples from 902 CRC cases and 902 matched cancer-free control participants from the population-based Northern Sweden Health and Disease Study (NSHDS), which were obtained up to 26 years prior to CRC diagnosis. Using reverse-phase liquid chromatography-mass spectrometry (LC-MS), data comprising 5015 metabolic features were obtained. Conditional logistic regression was applied to identify potentially important metabolic features associated with CRC risk. In addition, we investigated if previously reported metabolite biomarkers of CRC risk could be validated in this study population., Results: In the univariable analysis, seven metabolic features were associated with CRC risk (using a false discovery rate cutoff of 0.25). Two of these could be annotated, one as pyroglutamic acid (odds ratio per one standard deviation increase = 0.79, 95% confidence interval, 0.70-0.89) and another as hydroxytigecycline (odds ratio per one standard deviation increase = 0.77, 95% confidence interval, 0.67-0.89). Associations with CRC risk were also found for six previously reported metabolic biomarkers of prevalent and/or incident CRC: sebacic acid (inverse association) and L-tryptophan, 3-hydroxybutyric acid, 9,12,13-TriHOME, valine, and 13-OxoODE (positive associations)., Conclusions: These findings suggest that although the circulating metabolome may provide new etiological insights into the underlying causes of CRC development, its potential application for the identification of individuals at higher risk of developing CRC is limited., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Purpose: Sarcopenia and myosteatosis, quantified via computed tomography (CT), are associated with poor colorectal cancer outcomes. These body composition estimates can be influenced by physical exercise. We explored the correlation between pre-diagnostic physical exercise, body composition close to diagnosis, and the combined prognosis impact of these factors., Methods: We studied 519 stage I-III colorectal cancer (CRC) cases diagnosed 2000-2016 with pre-diagnostic self-reported recreational physical exercise data collected in the prospective, population-based Northern Sweden Health and Disease Study, and CT-estimated skeletal muscle index (SMI) or skeletal muscle density (SMD). Risk estimates were calculated by multivariable logistic regression and Cox proportional hazards models., Results: No association was seen between low pre-diagnostic physical exercise and sarcopenia/myosteatosis in the multivariable model adjusted for age, sex, educational level, tumor stage, and tumor location. In multivariable Cox regression models, the combination of low pre-diagnostic physical exercise and either sarcopenia or myosteatosis at the time of diagnosis was associated with cancer-specific mortality compared to the reference group of high physical exercise combined with no sarcopenia/myosteatosis (adjusted HR 1.94 95% CI 1.00-3.76 for sarcopenia and adjusted HR 2.39 95% CI 1.16-4.94 for myosteatosis)., Conclusions: The combined presence of low pre-diagnostic physical exercise and sarcopenia or myosteatosis was associated with increased CRC-specific mortality. Despite the positive effect on prognosis, physical exercise did not alter body composition estimates at diagnosis, which could indicate attenuation from other factors., (© 2023. The Author(s).)

Microbiota dysbiosis may affect both the development and progression of colorectal cancer (CRC). Large metagenomic studies have highlighted specific oral bacteria linked to CRC including Porphyromonas gingivalis . Few studies have however analysed the implications of this bacterium in CRC progression and survival. In this study, we investigated the intestinal presence of P. gingivalis by qPCR in both faecal and mucosal samples from two different patient cohorts, including patients with precancerous dysplasia or CRC, as well as controls. P. gingivalis was detected in 2.6-5.3% of CRC patients and significantly different levels of P. gingivalis were found in faeces of CRC patients compared to controls ( P = 0.028). Furthermore, an association was found between the presence of P. gingivalis in faeces and tumour tissue ( P < 0.001). Our findings further suggested a potential link between mucosal P. gingivalis and tumours of MSI subtype ( P = 0.040). Last but not least, patients with faecal P. gingivalis were found to have a significantly decreased cancer-specific survival ( P = 0.040). In conclusion, P. gingivalis could be linked to patients with CRC and to a worse patient prognosis. Further studies are needed to elucidate the role of P. gingivalis in CRC pathogenesis., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Obesity and metabolic dysfunction are implicated in colorectal cancer development. Appetite-regulating gut hormones might have a role in colorectal cancer risk. We investigated whether circulating levels of the gut hormones ghrelin (analyzed as acyl ghrelin) and Peptide YY (PYY) were associated with subsequent colorectal cancer risk, including clinical and molecular tumor subtypes. We also provide descriptive data on these hormones in relation to background participant characteristics and metabolic biomarkers. This population-based study included 1,010 matched case-control pairs with a median of 12.3 years of follow-up. Acyl ghrelin and PYY were measured by multiplex immunoassay. Data on KRAS and BRAF mutations and microsatellite instability (MSI) status were available for 704 and 708 cases, respectively. Conditional logistic regression models estimated association to colorectal cancer risk. Partial correlation and linear regression were used to investigate relationships between background and metabolic variables and variation in plasma gut hormone concentrations. Acyl ghrelin was not clearly associated with colorectal cancer risk (multivariable OR per 1 SD increase: 1.11; 95% CI, 1.00-1.23). Positive associations were observed for specific subtypes, in particular BRAF-mutated colorectal cancer and right-sided colon cancer, although with nonsignificant heterogeneity. PYY was not related to colorectal cancer risk (multivariable OR per 1 SD: 1.04; 95% CI, 0.95-1.14) or any tumor subtype. In the control participants, ghrelin was inversely correlated with BMI, and PYY was positively correlated with C-peptide and insulin levels. These findings provide limited support for a possible role for ghrelin in colorectal cancer development, primarily in specific anatomical and molecular tumor subtypes., Prevention Relevance: The findings of this study do not support a major role for the metabolic gut hormones ghrelin and PYY in colorectal cancer development but suggest the possibility of an involvement for ghrelin in specific tumor subtypes. Elucidating subtype-specific risk factors and mechanisms of carcinogenesis may have implications for precision prevention., (©2022 The Authors; Published by the American Association for Cancer Research.)

Increasing evidence suggests that the gut microbiota may impact colorectal cancer (CRC) development and progression. In this study, the tumour colonisation of two CRC-associated bacteria, Parvimonas micra and Fusobacterium nucleatum , was studied in relation to patient survival in a cohort of 257 CRC patients. Colonisation of P. micra and F. nucleatum was analysed in fresh frozen tumour tissue (n = 112) and in faeces (n = 250) by qPCR. When analysing tumour tissues, both P. micra and F. nucleatum were found to be associated with decreased five-year cancer-specific survival, an association that remained significant in multivariable analysis for P. micra . Furthermore, we found significant associations of high levels of P. micra and F. nucleatum with tumour molecular characteristics, i.e., tumours mutated in BRAF V600E , and tumours of the MSI subtype. The analysis of faecal samples showed weaker associations with prognosis and tumour molecular characteristics. In conclusion, our findings support a novel association of tumour colonisation of P. micra with decreased patient survival. A better understanding of the role of the gut microbiota in CRC might contribute to the advancement of prognostic tools and new targets for therapy., Competing Interests: The authors declare no conflict of interest.

These new guidelines are based on the recommendations published by European Society of Gastrointestinal Endoscopy (ESGE) in 2020. Low risk patients, i.e. after removal of 1-4 <10 mm adenomas with low grade dysplasia (irrespective of villous components), or any serrated lesion (hyperplastic polyp, sessile serrated lesion, or traditional serrated adenoma) <10 mm without dysplasia, are not recommended a surveillance colonoscopy. High-risk patients, i.e. after removal of at least one adenoma ≥10 mm or with high grade dysplasia or any serrated lesion ≥10 mm or with dysplasia, should undergo a surveillance colonoscopy after 3 years. If high-risk lesions are detected at surveillance colonoscopy, a 3-year repetition of the next endoscopic examination is recommended. If a high-risk patient has no high-risk lesions at surveillance colonoscopy, a 5-year period is recommended until the next surveillance colonoscopy. In general, follow-up should be terminated at 80 years of age.

The importance of the tumour microbiome in different aspects of colorectal cancer (CRC) has been increasingly recognised, but many questions remain. The aim of this study was to explore the effect of specific CRC associated microbes on the tumour immune response, which has a considerable prognostic value in CRC. We applied specific qPCR to detect Parvimonas micra and Fusobacterium nucleatum in tumour tissues from an immunologically well-characterised cohort of 69 CRC patients. This cohort included detailed analyses of immune profiles based on flow cytometry and transcriptomics in tumour tissue and blood, along with comprehensive analyses of molecular subtypes. P. micra and F. nucleatum were detected in 24% and 64% of tumour tissues, respectively. We found a significant association of P. micra with high-grade tumours and tumours of CMS1 subtype. F. nucleatum was significantly associated with right-sided tumours, microsatellite instability, and CMS1 tumours. The immunological analyses revealed significant associations of P. micra with activated CD69 + T lymphocytes and increased antigen-presenting HLA-DR + B lymphocytes. P. micra was also positively associated with M1 and M2 macrophage traits. The impact of P. micra tumour colonisation on the immune response was further assessed using transcriptomics in validation of our findings. No associations were found between F. nucleatum and immune profiles in this study. Our findings support novel associations between P. micra and the immune response in CRC. A better understanding of these interactions might help to identify important predictive and prognostic tools as well as new targets for therapy., (© 2022. The Author(s).)

Background: Faecal calprotectin (FC) is a potential biomarker for colorectal cancer (CRC) screening. There is uncertainty if tumor characteristics are associated with FC levels. We investigated how tumor stage and tumor localization influence the extent of FC levels in patients with CRC in clinical practice., Methods: In two cohorts of patients with CRC, we retrospectively analyzed FC tests (CALPRO®) performed within three months prior to diagnosis. One hundred twenty-four patients with CRC were included (mean age 68 years, 44% women)., Results: Ninety-eight patients with CRC (79%) had a FC ≥ 50 µg/g. FC correlated positively with tumor stage (UICC based on WHO TNM classification) (r s 0.24; p = 0.007) and with CRP levels (r s 0.31, p = 001), and a negatively with B-haemoglobin (r s -0.21; p = 0.019). The patients with right-sided CRC had significantly more often a FC ≥ 50 µg/g than patients with left-sided CRC (92% vs 74% p = 0.027). In a binary logistic regression analysis, tumor stage III/IV (adjusted OR 3.47; CI 1.27-9.42) and right-sided tumor localization (adjusted OR 3.80; CI 1.01-14.3) were associated with FC ≥ 50 µg/g. Tumor stage III/IV (adjusted OR 2.30; CI 1.04-5.10) and acetylsalicylic use (adjusted OR 3.54; CI 1.03-12.2) were associated with FC ≥ 100 µg/g. In a cox regression analysis, a FC ≥ 100 µg/g was not associated with survival (Hazard OR 0.61; CI 0.24-1.52)., Conclusions: Elevated pre-diagnostic FC levels were common in patients with CRC in close proximity to diagnosis. Right-sided localization and tumor stage were significantly associated with a rise in FC levels., (© 2022. The Author(s).)