Consensus Molecular Subtypes Subtypes Research Articles

Transcription factor expression repertoire basis for epigenetic and transcriptional subtypes of colorectal cancers

Colorectal cancers (CRCs) form a heterogenous group classified into epigenetic and transcriptional subtypes. The basis for the epigenetic subtypes, exemplified by varying degrees of promoter DNA hypermethylation, and its relation to the transcriptional subtypes is not well understood. We link cancer-specific transcription factor (TF) expression alterations to methylation alterations near TF-binding sites at promoter and enhancer regions in CRCs and their premalignant precursor lesions to provide mechanistic insights into the origins and evolution of the CRC molecular subtypes. A gradient of TF expression changes forms a basis for the subtypes of abnormal DNA methylation, termed CpG-island promoter DNA methylation phenotypes (CIMPs), in CRCs and other cancers. CIMP is tightly correlated with cancer-specific hypermethylation at enhancers, which we term CpG-enhancer methylation phenotype (CEMP). Coordinated promoter and enhancer methylation appears to be driven by downregulation of TFs with common binding sites at the hypermethylated enhancers and promoters. The altered expression of TFs related to hypermethylator subtypes occurs early during CRC development, detectable in premalignant adenomas. TF-based profiling further identifies patients with worse overall survival. Importantly, altered expression of these TFs discriminates the transcriptome-based consensus molecular subtypes (CMS), thus providing a common basis for CIMP and CMS subtypes.

Abstract A012: Transcription factor expression repertoire basis for epigenetic and transcriptional subtypes of colorectal cancers

Abstract Colorectal cancers (CRCs) form a heterogenous group classified into epigenetic and transcriptional subtypes. The basis for the epigenetic subtypes, exemplified by varying degrees of promoter DNA hypermethylation, and its relation to the transcriptional subtypes is not well understood. We now link cancer-specific transcription factor (TF) expression dysregulation to methylation alterations near TF-binding sites at promoter and enhancer regions in CRCs and their pre-malignant precursor lesions to provide mechanistic insights into the origins and evolution of the CRC molecular subtypes. A gradient of TF-expression changes forms a basis for the subtypes of abnormal DNA methylation, termed CpG-island promoter DNA methylation phenotypes (CIMP), in CRCs and other cancers. CIMP is tightly correlated with cancer-specific hypermethylation at enhancers, which we term CpG-enhancer methylation phenotype (CEMP). CIMP/CEMP coordination appears to be driven by augmented downregulation of TFs with common binding sites at the hypermethylated enhancers and promoters. The dysregulated expression of TFs related to CIMP/CEMP subtypes occurs early during CRC development, detectable in pre-malignant adenomas. TF-based profiling further identifies patients with worse overall survival. Importantly, altered expression of these TFs discriminates the transcriptome-based consensus molecular subtypes (CMS), thus providing a common basis for CIMP and CMS subtypes. Citation Format: Yuba R. Bhandari, Vinod Krishna, Rachael Powers, Sehej Parmar, Sara-Jayne Thursby, Ekta Gupta, Ozlem Kulak, Prashanth Gokare, Joke Reumers, Liesbeth Van Wesenbeeck, Kurtis E. Bachman, Stephen B. Baylin, Hariharan Easwaran. Transcription factor expression repertoire basis for epigenetic and transcriptional subtypes of colorectal cancers. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr A012.

Genetic and microenvironmental intra-tumor heterogeneity impacts colorectal cancer evolution and metastatic development

Colorectal cancer (CRC) is a highly diverse disease, where different genomic instability pathways shape genetic clonal diversity and tumor microenvironment. Although intra-tumor heterogeneity has been characterized in primary tumors, its origin and consequences in CRC outcome is not fully understood. Therefore, we assessed intra- and inter-tumor heterogeneity of a prospective cohort of 136 CRC samples. We demonstrate that CRC diversity is forged by asynchronous forms of molecular alterations, where mutational and chromosomal instability collectively boost CRC genetic and microenvironment intra-tumor heterogeneity. We were able to depict predictor signatures of cancer-related genes that can foresee heterogeneity levels across the different tumor consensus molecular subtypes (CMS) and primary tumor location. Finally, we show that high genetic and microenvironment heterogeneity are associated with lower metastatic potential, whereas late-emerging copy number variations favor metastasis development and polyclonal seeding. This study provides an exhaustive portrait of the interplay between genetic and microenvironment intra-tumor heterogeneity across CMS subtypes, depicting molecular events with predictive value of CRC progression and metastasis development.

Intratumor CMS Heterogeneity Impacts Patient Prognosis in Localized Colon Cancer.

The consensus molecular subtypes (CMS) represent a significant advance in the understanding of intertumor heterogeneity in colon cancer. Intratumor heterogeneity (ITH) is the new frontier for refining prognostication and understanding treatment resistance. This study aims at deciphering the transcriptomic ITH of colon cancer and understanding its potential prognostic implications. We deconvoluted the transcriptomic profiles of 1,779 tumors from the PETACC8 trial and 155 colon cancer cell lines as weighted sums of the four CMSs, using the Weighted In Silico Pathology (WISP) algorithm. We assigned to each tumor and cell line a combination of up to three CMS subtypes with a threshold above 20%. Over 55% of tumors corresponded to mixtures of at least two CMSs, demonstrating pervasive ITH in colon cancer. Of note, ITH was associated with shorter disease-free survival (DFS) and overall survival, [HR, 1.34; 95% confidence interval (CI; 1.12-1.59), 1.40, 95% CI (1.14-1.71), respectively]. Moreover, we uncovered specific combinations of CMS associated with dismal prognosis. In multivariate analysis, ITH represents the third parameter explaining DFS variance, after T and N stages. At a cellular level, combined WISP and single-cell transcriptomic analysis revealed that most colon cancer cell lines are a mixture of cells falling into different CMSs, indicating that ITH may correspond to distinct functional statuses of colon cancer cells. This study shows that CMS-based transcriptomic ITH is frequent in colon cancer and impacts its prognosis. CMS-based transcriptomic ITH may correspond to distinct functional statuses of colon cancer cells, suggesting plasticity between CMS-related cell populations. Transcriptomic ITH deserves further assessment in the context of personalized medicine.

Interconnectivity between molecular subtypes and tumor stage in colorectal cancer

BackgroundThere are profound individual differences in clinical outcomes between colorectal cancers (CRCs) presenting with identical stage of disease. Molecular stratification, in conjunction with the traditional TNM staging, is a promising way to predict patient outcomes. We investigated the interconnectivity between tumor stage and tumor biology reflected by the Consensus Molecular Subtypes (CMSs) in CRC, and explored the possible value of these insights in patients with stage II colon cancer.MethodsWe performed a retrospective analysis using clinical records and gene expression profiling in a meta-cohort of 1040 CRC patients. The interconnectivity of tumor biology and disease stage was assessed by investigating the association between CMSs and TNM classification. In order to validate the clinical applicability of our findings we employed a meta-cohort of 197 stage II colon cancers.ResultsCMS4 was significantly more prevalent in advanced stages of disease (stage I 9.8% versus stage IV 38.5%, p < 0.001). The observed differential gene expression between cancer stages is at least partly explained by the biological differences as reflected by CMS subtypes. Gene signatures for stage III-IV and CMS4 were highly correlated (r = 0.77, p < 0.001). CMS4 cancers showed an increased progression rate to more advanced stages (CMS4 compared to CMS2: 1.25, 95% CI: 1.08–1.46). Patients with a CMS4 cancer had worse survival in the high-risk stage II tumors compared to the total stage II cohort (5-year DFS 41.7% versus 100.0%, p = 0.008).ConclusionsConsiderable interconnectivity between tumor biology and tumor stage in CRC exists. This implies that the TNM stage, in addition to the stage of progression, might also reflect distinct biological disease entities. These insights can potentially be utilized to optimize identification of high-risk stage II colon cancers.

A novel mesenchymal-associated transcriptomic signature for risk-stratification and therapeutic response prediction in colorectal cancer.

Risk stratification in Stage II and III colorectal cancer (CRC) patients is critical, as it allows patient selection for adjuvant chemotherapy. In view of the inadequacy of current clinicopathological features for risk-stratification, we undertook a systematic and comprehensive biomarker discovery effort to develop a risk-assessment signature in CRC patients. The biomarker discovery phase examined 853 CRC patients, and identified a gene signature for predicting recurrence-free survival (RFS). This signature was validated in a meta-analysis of 1212 patients from nine independent datasets, and its performance was compared against established prognostic signatures and consensus molecular subtypes (CMS). In addition, a risk-prediction model was trained (n = 142), and subsequently validated in an independent clinical cohort (n = 286). As a result, this mesenchymal-associated transcriptomic signature (MATS) identified high-risk CRC patients with poor RFS in the discovery (hazard ratio [HR]: 1.79), and nine validation cohorts (HR: 1.86). In multivariate analysis, MATS was the most significant predictor of RFS compared to established prognostic signatures and CMS subtypes. Intriguingly, MATS robustly identified CMS4-subtype in multiple CRC cohorts (AUC = 0.92-0.99). In the two clinical cohorts, MATS stratified low and high-risk groups with a 5-year RFS in the training (HR: 4.11) and validation cohorts (HR: 2.55), as well as predicted response to adjuvant therapy in Stage II and III CRC patients. We report a novel prognostic and predictive biomarker signature in CRC, which is superior to currently used approaches and have the potential for clinical translation in near future.

Analysis of consensus molecular subtypes (CMS) classification in the TRICOLORE trial: A randomized phase III trial of S-1 and irinotecan (IRI) plus bevacizumab (Bmab) versus mFOLFOX6 or CapeOX plus Bmab as first-line treatment for metastatic colorectal cancer (mCRC).

169 Background: The TRICOLORE trial previously demonstrated that S-1+IRI+Bmab (Arm B) was non-inferior to mFOLFOX6/CapeOX+Bmab (Arm A) in terms of progression-free survival (PFS) as first-line treatment for mCRC, irrespective of RAS status. CMS was reported to be a prognostic factor for mCRC. Previously, it was reported that the CMS could be a predictive factor for the efficacy of oxaliplatin (OX) and IRI (Okita A, et al. Oncotarget. 2018). In this exploratory study of TRICOLORE trial, we examined if the CMS could be a predictive factor of OX and IRI regimen. Methods: We collected formalin-fixed paraffin-embedded (FFPE) primary tumor tissues and performed gene expression analysis by microarray. The subtype of CMS was determined by the CMS classifier (Guinney et al. Nature Med. 2015). PFS and overall survival (OS) were compared between arm A and B in each subtypes of CMS. Results: Total of 308 FFPE samples from 487 cases who were enrolled in the TRICOLORE study were collected. Number of patients classified into CMS1 to CMS4 were 47, 72, 99 and 90, respectively. Similar to the previous reports, the proportion of RAS mutant cases was highest in CMS3 and the most of BRAF mutant cases were classified into CMS1. The median PFS (mPFS) of arm A and B were almost same in CMS2 (16.1m vs. 17.6m, HR = 1.10, p = 0.79) and CMS3 (10.6 vs. 11.4, HR = 0.95, p = 0.81). In CMS1, mPFS of arm A was worse than that of arm B, although not statistically significant (7.4m vs. 13.2m, HR = 0.73, p = 0.35). In CMS4, mPFS of arm B was better than that of arm A, although not statistically significant again (9.7m vs. 14.1m, HR = 0.72, p = 0.15). The median OS (mOS) of both arm in CMS2-CMS4 and arm B in CMS1 were good and were 29.0m or more. On the other hand, mOS of arm A in CMS1 (18.1m) was worse than the others. Conclusions: From these results, it was not concluded that CMS was a predictor of mFOLFOX6/CapeOX+Bmab and S-1+IRI+Bmab. However, mPFS and mOS of mFOLFOX6/CapeOX+Bmab in CMS1 were poor unlike other CMS subtypes, and these were consistent with a previous report. Whereas S-1+IRI+Bmab was effective in all subtypes of CMS. Clinical trial information: UMIN000007834.

Abstract C132: Fusobacterium nucleatum in colorectal carcinoma and expression of multiple immune checkpoint molecules on T cells

Abstract Background: Fusobacterium nucleatum (Fn) appears to play a role in colorectal cancer carcinogenesis through suppression of antitumor immune response. This study aims to characterize immune-related signatures, including the expression of multiple immune checkpoint molecules in tumor-infiltrating T cells. Methods: We measured Fn DNA by quantitative PCR in a total of 155 colorectal cancer tissues. Gene expression profile was studied using microarray technology to determine the consensus molecular subtypes (CMS) and immune-related signatures using CIBERSORT and Gene Set Enrichment Analysis (GSEA), respectively. Expression of immune checkpoint molecules (PD-1, TIM-3, and TIGIT) on CD8+ cytotoxic T cells and the ratio of FOXP3-CD4-/FOXP3+CD4 were examined using multicolor flow cytometric analysis. Results: All patients had stage III disease underwent curative surgery. Fn infection was observed in 43% of patients and was associated with recurrence (Fisher’ exact test, P=0.002) and decreased overall survival (log-rank test, P&amp;lt;0.001). The distribution of CMS subtypes was CMS1/2/3/4/mixed (14%/24%/15%/27%/20%), which is comparable to previous data. Fn infection was associated with the platinum-resistant signature, hypoxia pathway, and stem cell pathways in the GSEA. Interestingly, Patients with Fn infection showed a trend toward enrichment in CMS4, mesenchymal subtype with the inflamed immune phenotype (9% vs. 17% with Fn-infection, P=0.24). The number of cytotoxic CD8+ T cells showed a trend toward decreased expression in patients with Fn infection. Furthermore, higher expression of inhibitory immune checkpoints (PD-1, P&amp;lt;0.01; TIM-3, P&amp;lt;0.05; TIGIT, P&amp;lt;0.05) was observed on CD8+ cytotoxic T cells of patients with Fn infection, compared to that of Fn negative cases. Besides, the regulatory FOXP3+CD4+ cells were increased in patients with Fn infection, supporting the suppressive role of Fn infection in the tumor immune microenvironment (P&amp;lt;0.05). Conclusions: The adverse prognostic impact of Fn infection depends on the suppression of T cell-mediated immune response by increased expression of inhibitory immune checkpoints on cytotoxic T cell and by increased regulatory T cells. Citation Format: Han Sang Kim, Wonkyu Kim, Chang Gon Kim, Jinseon Yoo, Soonmyung Paik, Eui-Cheol Shin, Tae-Min Kim, Hoguen Kim, Joong Bae Ahn. Fusobacterium nucleatum in colorectal carcinoma and expression of multiple immune checkpoint molecules on T cells [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr C132. doi:10.1158/1535-7163.TARG-19-C132

1931P - Hyaluronan (HA) accumulation in the tumor microenvironment (TME) is increased in colorectal cancer (CRC) and associated with consensus molecular subtypes (CMS) 4 molecular subtype

BackgroundHA, a secreted large, megadalton glycosaminoglycan, is a major component of the extracellular matrix. Its accumulation in the TME increases interstitial pressure, induces vascular collapse and hypoperfusion, and may be a potential barrier to therapeutic access and immune infiltration. Enzymatic breakdown of HA by PEGPH20 alters the TME. PEGPH20 + chemotherapy or checkpoint inhibitor combinations are currently in clinical development. We examined the prevalence profile of HA in a large CRC cohort and report the relationship between HA accumulation and CRC molecular subtypes. MethodsHA accumulation was quantified in 115 CRC tumor samples using the Ventana Class I CDx HA assay, which scores the % of stromal HA at any intensity greater than background over the entire tumor tissue surface area. RNAseq transcriptome analysis was carried out and CMSs were determined, implemented by using the CMScaller R package. ResultsCRC samples had increased HA accumulation (HA score 20%-90%) compared with normal colon tissue (HA score 20%). HA localized predominantly to stroma in CRC samples and to lamina propria in normal colon tissue. Increased HA accumulation in CRC tumors was accompanied by increased desmoplastic stroma. We classified the 115 CRC tumors into 4 CMSs with distinct underlying biology and clinical outcomes (table). The CMS4 subtype, which has the worst prognosis, had significantly higher HA content compared with the other CMS subtypes as determined by Tukey’s honest significance test (p=0.0052 CMS4 vs CMS1; p<0.0001 CMS4 vs CMS2 and CMS3).Table: 1931PCMS Type and OutcomesTable: 1931PCMS TypePercent (Out of 115 Total SamplesBiological Characteristics and Clinical OutcomesCMS118%- Highly immunogenic - HypermutatedCMS 239%- Wingless/integrated (WNT)-β-catenin pathway activation - Good prognosisCMS314%- Metabolic cancer phenotypeCMS429%- Strong stromal gene signature - Worst prognosis ConclusionsHA accumulation is increased in CRC pts, suggesting PEGPH20 may be a promising therapeutic agent in this indication. There are potential links between HA accumulation, CRC disease biology, and clinical outcomes. Investigation of HA accumulation in association with additional molecular and clinical features of CRC is ongoing. Editorial acknowledgementElizabeth L. Pham of Halozyme Therapeutics, Inc. provided editorial support for this abstract. Legal entity responsible for the studyHalozyme Therapeutics, Inc. and Genentech, Inc. FundingHalozyme Therapeutics, Inc. and Genentech Inc. DisclosureB. Blouw: Shareholder / Stockholder / Stock options, Full / Part-time employment: Halozyme Therapeutics, Inc.. L. Ryner: Shareholder / Stockholder / Stock options, Full / Part-time employment: Genentech, Inc.. R. Johnson: Shareholder / Stockholder / Stock options, Full / Part-time employment: Genentech, Inc.. D. Taverna: Shareholder / Stockholder / Stock options, Full / Part-time employment: Halozyme Therapeutics, Inc.. Y. Wang: Shareholder / Stockholder / Stock options, Full / Part-time employment: Genentech, Inc.

Analytical Validation of Multiplex Biomarker Assay to Stratify Colorectal Cancer into Molecular Subtypes

Previously, we classified colorectal cancers (CRCs) into five CRCAssigner (CRCA) subtypes with different prognoses and potential treatment responses, later consolidated into four consensus molecular subtypes (CMS). Here we demonstrate the analytical development and validation of a custom NanoString nCounter platform-based biomarker assay (NanoCRCA) to stratify CRCs into subtypes. To reduce costs, we switched from the standard nCounter protocol to a custom modified protocol. The assay included a reduced 38-gene panel that was selected using an in-house machine-learning pipeline. We applied NanoCRCA to 413 samples from 355 CRC patients. From the fresh frozen samples (n = 237), a subset had matched microarray/RNAseq profiles (n = 47) or formalin-fixed paraffin-embedded (FFPE) samples (n = 58). We also analyzed a further 118 FFPE samples. We compared the assay results with the CMS classifier, different platforms (microarrays/RNAseq) and gene-set classifiers (38 and the original 786 genes). The standard and modified protocols showed high correlation (> 0.88) for gene expression. Technical replicates were highly correlated (> 0.96). NanoCRCA classified fresh frozen and FFPE samples into all five CRCA subtypes with consistent classification of selected matched fresh frozen/FFPE samples. We demonstrate high and significant subtype concordance across protocols (100%), gene sets (95%), platforms (87%) and with CMS subtypes (75%) when evaluated across multiple datasets. Overall, our NanoCRCA assay with further validation may facilitate prospective validation of CRC subtypes in clinical trials and beyond.

Explaining the unexplainable: discrepancies in results from the CALGB/SWOG 80405 and FIRE-3 studies.

We propose a working hypothesis that integrates data from the CALGB/SWOG 80405 and FIRE-3 studies to explain apparent discrepancies in their results. Both trials assessed the combination of either cetuximab or bevacizumab with a different chemotherapy backbone: irinotecan in all patients in the FIRE-3 study, or oxaliplatin in 75% of the patients in the CALGB/SWOG 80405 study. The hypothesis is divided into three parts. Firstly, in addition to the biology or microenvironment of the tumour and the selection of the biologically targeted agents common to both trials, chemotherapy itself is an important variable that determines treatment efficacy because of a complex interplay between the biological therapy, the chemotherapy, and the microenvironment. Secondly, the tumour microenvironment, as defined by the Consensus Molecular Subtypes (CMS) classification, determines the interaction of chemotherapeutic agents with biologically targeted agents such as bevacizumab and cetuximab. Whereas irinotecan synergises with cetuximab across all CMS subtypes, oxaliplatin might have variable effects, synergising with cetuximab in fibroblast-poor microenvironments, such as CMS2 and CMS3, but activating fibroblast-rich microenvironments, such as CMS1 and CMS4, to release cytokines that might antagonise some of the cetuximab effects. Thirdly, the previous assumptions integrate into a final concept, which is that overall survival is determined not only by the biological therapy or the first-line treatment, but specifically by the sequence of first-line and second-line regimens, and the degree of synergism between them. In a clinical setting, the optimal first-line combination of biological therapy and chemotherapy predetermines the crossover to a specific second-line treatment, which affects the overall survival of a patient with a specific tumour subtype. Our working hypothesis suggests that the CALGB/SWOG 80405 and FIRE-3 studies are complementary rather than discrepant, and it provides an explanation for their opposing interpretations. In conclusion, proper interpretation of the CALGB/SWOG 80405 and FIRE-3 results requires an in-depth examination of the complex interplay, not only between the targeted biological agents and chemotherapeutic drugs, but also between therapies and the tumour biology and microenvironment, for each line of treatment.

Selective Inhibition of a Panel of Cancer Stem Cell Lines by Novel Glycosaminoglycan Mimetics

PurposeTo characterize the anti‐cancer stem cell (CSC) properties of non‐saccharide glycosaminoglycan mimetics (NSGMs) and their lipid‐modified analogs in a panel of colon cancer cells.MethodFour novel NSGMs were screened for their ability to inhibit the formation of 1° spheroids in 12 intestinal tumor cells belonging to one of four consensus molecular subtypes (CMS) for intestinal cancers and were chosen to be representative of common genetic variants in colon cancer. Spheroid were grown by suspending monolayer cancer cells in stem cell media in low‐adhesion plates and the number of spheroids was measured with light microscopy. Spheroid forming cell frequency (SFF) was determined in the 1° spheroids by plating them at varying concentration 1→124 cells/well and recording 2° spheroids (present or absent) in each well using http://bioinf.wehi.edu.au/software/elda web tool. Dose‐response curves were generated by examining 1° spheroid formation following treatment with increasing concentration of NSGMs (0→5000 μM). The IC50 values for each of the NSGMs were determined using the standard sigmoidal regression equation. Inhibition of monolayers of corresponding cancer cells by NSGMs was assessed through a colorimetric MTT assay.ResultsThe MTT assay in monolayer conditions revealed no or minimal cytotoxicity with all the NSGMs at concentrations &gt;300μM, suggesting selective targeting of CSCs. Screening for primary spheroid inhibition revealed three distinct responses concerning the lead NSGM G2.2. G2.2 showed a mean IC50 of 225 μM across all cell lines (range 134 – 252 μM). Intriguingly, CMS1, CMS2, and neuroendocrine cells were either moderately resistant or highly resistant. On the other hand, none of the CMS3 and CMS4 cell lines were highly resistant, and a majority (4/8) were sensitive to G2.2. Intriguingly, we observed a significant inverse correlation (r = −0.56, p= 0.06) between SFF and IC50 for G2.2, suggesting that the level of pre‐existing CSCs could determine G2.2's efficacy. Interestingly, the lipid‐modified analogs showed higher potency in comparison with the parent molecule G2.2. Of the three lipid‐modified analogs, G8C was the most potent inhibitor of CSC's (with a mean IC50 of 11 μM) against intestinal cancer spheroids. In fact, G8C displayed sub‐micromolar inhibition (IC50 = 0.73 μM) against the most sensitive colorectal cell line HT‐29 (CMS3). Except for one case, the resistant cell lines turned sensitive or less resistant to treatment with the three lipid analogs.ConclusionsG2.2 (and related NSGMs) selectively inhibit CSCs and its efficacy strongly correlates with the levels of pre‐existing CSCs and/or CMS subtypes 3 (KRAs activation) and 4 (TGF‐β pathway activation) providing valuable clues about their mechanism. Lipid‐modified NSGMs represent potent and selective anti‐CSCs agents with paradigm‐shifting implications for colorectal cancer treatment.Support or Funding InformationGrant support from the following sources:1P01 HL1071521R25 HL1286391R01 HL090586This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.