Progress and opportunities in molecular pathological epidemiology of colorectal premalignant lesions

ATP6AP1 as a potential prognostic biomarker in CRC by comprehensive analysis and verification

The role of ATP6AP1 in colorectal cancer (CRC) remains elusive despite its observed upregulation in pan-cancer. Therefore, the current study aimed to assess the clinical significance of ATP6AP1 and its relationship with the immune infiltration in CRC. Transcriptome data of CRC were obtained from The Cancer Genome Atlas (TCGA) database and analyzed using the combination of R packages and tumor-related databases, including TIMER2, TISIDB, cBioPortal, and MethSurv. The tissue arrays and immunohistochemical staining were performed to verify the expression and clinical characteristics of ATP6AP1. The results revealed that ATP6AP1 expression was significantly elevated in CRC and associated with poor clinicopathological characteristics and prognosis. Furthermore, the analysis demonstrated ATP6AP1 expression was correlated with the infiltration of immune cells and cancer-associated fibroblasts in the microenvironment of CRC. Moreover, ATP6AP1 was found to be linked to various immune checkpoints and chemokines, with enrichment of cytoplasmic vesicle lumen, endopeptidase regulator activity, and endopeptidase inhibitor activity observed in the high ATP6AP1 expressional group. In conclusion, the findings of this study suggest that ATP6AP1 upregulation may serve as a biomarker for poor diagnosis in CRC and offer a potential target for immunotherapy in CRC.

Colorectal cancer: Genetic alterations, novel biomarkers, current therapeutic strategies and clinical trials

Colorectal cancer (CRC) is the third most commonly detected cancer with a serious global health issue. The rates for incidence and mortality for CRC are alarming, especially since the prognosis is abysmal when the CRC is diagnosed at an advanced or metastatic stage. Both type of (modifiable/ non-modifiable) types of risk factors are established for CRC. Despite the advances in recent technology and sophisticated research, the survival rate is still meager due to delays in diagnosis. Therefore, there is urgently required to identify critical biomarkers aiming at early diagnosis and improving effective therapeutic strategies. Additionally, a complete understanding of the dysregulated pathways like PI3K/Akt, Notch, and Wnt associated with CRC progression and metastasis is very beneficial in designing a therapeutic regimen. This review article focused on the dysregulated signaling pathways, genetics and epigenetics alterations, and crucial biomarkers of CRC. This review also provided the list of clinical trials targeting signaling cascades and therapies involving small molecules. This review discusses up-to-date information on novel diagnostic and therapeutic strategies alongside specific clinical trials.

Interaction between Gut Microbiota and Dendritic Cells in Colorectal Cancer

Colorectal cancer (CRC) is a malignancy that manifests in serial stages and has been observed to have an escalating incidence in modern societies, causing a significant global health problem. The development of CRC is influenced by various exogenous factors, including lifestyle, diet, nutrition, environment, and microbiota, that can affect host cells, including immune cells. Various immune dysfunctions have been recognized in patients with CRC at different stages of this disease. The signature of microbiota in the development of CRC-inflammation related to obesity, diet, and reactive host cells, such as dendritic cells (DCs)-has been highlighted by many studies. This study focuses on DCs, the primary cellular mediators linking innate and adaptive immune responses against cancer. In addition, this review focuses on the role of microbiota in dysbiosis and how it affects DCs and, in turn, the immune response and progression of CRC by stimulating different sets of T cells. Additionally, DCs' role in protecting this delicate balance is examined. This is to determine how gene yields of commensal microbiota may be critical in restoring this balance when disrupted. The stages of the disease and major checkpoints are discussed, as well as the role of the C-type lectin receptor of immature DCs pattern recognition receptor in CRC. Finally, based on a thorough examination of worldwide clinical studies and recent advancements in cancer immunotherapy, it is recommended that innovative approaches that integrate DC vaccination strategies with checkpoint inhibitors be considered. This approach holds great promise for improving CRC management.

Lactate metabolic pathway regulates tumor cell metastasis and its use as a new therapeutic target

Abnormal energy metabolism is one of the ten hallmarks of tumors, and tumor cell metabolism provides energy and a suitable microenvironment for tumorigenesis and metastasis. Tumor cells can consume large amounts of glucose and produce large amounts of lactate through glycolysis even in the presence of oxygen, a process called aerobic glycolysis, also known as the Warburg effect. Lactate is the end product of the aerobic glycolysis. Lactate dehydrogenase A (LDHA), which is highly expressed in cancer cells, promotes lactate production and transports lactate to the tumor microenvironment and is taken up by surrounding stromal cells under the action of monocarboxylate transporter 1/4 (MCT1/4), which in turn influences the immune response and enhances the invasion and metastasis of cancer cells. Therapeutic strategies targeting lactate metabolism have been intensively investigated, focusing on its metastasis-promoting properties and various target inhibitors; AZD3965, an MCT1 inhibitor, has entered phase I clinical trials, and the LDHA inhibitor N-hydroxyindole (NHI) has shown cancer therapeutic activity in pre-clinical studies. Interventions targeting lactate metabolism are emerging as a promising option for cancer therapy, with chemotherapy or radiotherapy combined with lactate-metabolism-targeted drugs adding to the effectiveness of cancer treatment. Based on current research, this article outlines the role of lactate metabolism in tumor metastasis and the potential value of inhibitors targeting lactate metabolism in cancer therapy.

Association of cigarette smoking with risk of colorectal cancer subtypes classified by gut microbiota

INTRODUCTION

Both cigarette smoking and gut microbiota play important roles in colorectal carcinogenesis. We explored whether the association between smoking and colorectal cancer (CRC) risk varies by gut microbial enterotypes and how smoking-related enterotypes promote colorectal carcinogenesis.

METHODS

A case-control study was conducted. Fecal microbiota was determined by 16S rDNA sequencing. The cases with CRC or adenoma were subclassified by gut microbiota enterotypes. Multivariate analyses were used to test associations between smoking and the odds of colorectal neoplasm subtypes. Mann-Whitney U tests were used to find differential genera, genes, and pathways between the subtypes.

RESULTS

Included in the study were 130 CRC patients (type I: n=77; type II: n=53), 120 adenoma patients (type I: n=66; type II: n=54), and 130 healthy participants. Smoking increased the odds for type II tumors significantly (all p for trend <0.05) but not for type I tumors. The associations of smoking with increased odds of colorectal neoplasm significantly differed by gut microbiota enterotypes (p<0.05 for heterogeneity). An increase in carcinogenic bacteria (genus Escherichia shigella) and a decrease in probiotics (family Lachnospiraceae and Ruminococcaceae) in type II tumors may drive disease progression by upregulating oncogenic signaling pathways and inflammatory/oxidative stress response pathways, as well as protein phospholipase D1/2, cytochrome C, and prostaglandin-endoperoxide synthase 2 expression.

CONCLUSIONS

Smoking was associated with a higher odds of type II colorectal neoplasms but not type I tumors, supporting a potential role for the gut microbiota in mediating the association between smoking and colorectal neoplasms.

An Overview of DNA Methylation Indicators for the Course of Oral Precancer

DNA methylation is a physiologically epigenetic alteration that happens when a methyl group is introduced to a CpG dinucleotide in the gene-regulating sequence of DNA. However, the majority of oral cancers have a well-defined precancerous stage; there are few clinical and morphological parameters for detecting and signalling the progression of precancerous to malignant tumours. DNA methylation forms are dynamic and reversible, allowing them to adjust to environmental or therapeutic changes. We did an extensive investigation to compile the data supporting aberrant DNA methylation forms as a possible biomarker for prediction. According to two longitudinal studies, p16 hypermethylation was considerably higher in precancerous lesions that progressed to cancer than in lesions that shrank. Most of the studies examined for this study were tiny cross-sectional research with scant validation and inadequately specified control groups. Existing evidence suggests that DNA methylation sequences can be relevant as a diagnostic biomarker for OPS development; however, sample size and research design restrictions make it difficult to draw definitive conclusions. Strong studies, including extensive epigenome-wide methylation scans of OPS with longitudinal monitoring, are necessary in this study in order to corroborate the recently discovered signals and discover new risk loci and disease progression molecular pathways.

Cancer Stem Cells in Tumor Microenvironment of Adenocarcinoma of the Stomach, Colon, and Rectum

Simple Summary

Gastrointestinal cancers have a high mortality rate worldwide, and the progression of the disease is related to cancer stem cells. Until now, its relationship with the microenvironment has been poorly understood. We describe the molecules and different pathways activated during this interaction and the new targeting therapies for cancer cells and microenvironment modulation. This approach could impact the way gastrointestinal cancers are managed.

Abstract

Gastrointestinal adenocarcinomas are one of the world’s deadliest cancers. Cancer stem cells and the tissue microenvironment are highly regulated by cell and molecular mechanisms. Cancer stem cells are essential for maintenance and progression and are associated with resistance to conventional treatments. This article reviews the current knowledge of the role of the microenvironment during the primary establishment of gastrointestinal adenocarcinomas in the stomach, colon, and rectum and its relationship with cancer stem cells. We also describe novel developments in cancer therapeutics, such as targeted therapy, and discuss the advantages and disadvantages of different treatments for improving gastrointestinal cancer prognosis.

Regulatory effect between HMGA2 and the Wnt/β-catenin signaling pathway in the carcinogenesis of sporadic colorectal tubular adenoma

Due to the high incidence of colorectal cancer worldwide, the underlying molecular mechanisms have been extensively investigated. The Wnt/β-catenin signaling pathway plays a key role in the carcinogenesis of colorectal adenoma. In addition, the high mobility group AT-hook 2 (HMGA2) protein, which is involved in several biological processes, such as proliferation, differentiation, transformation and metastasis, is expressed at significantly high levels in colorectal cancer tissues compared with adjacent normal tissues. Currently, the role of HMGA2 in the carcinogenesis of sporadic colorectal tubular adenoma remains unclear. The downstream Wnt/β-catenin signaling molecule, T-cell factor/lymphoid enhancing factor (TCF/LEF), shares a similar domain with HMGA2, which enhances β-catenin transcriptional activity and TCF/LEF binding. Thus, the present study investigated the association between HMGA2 and the Wnt/β-catenin signaling pathway, and their role in the carcinogenesis of sporadic colorectal tubular adenoma via immunohistochemistry, siRNA, quantitative PCR and western blot analyses. The results demonstrated that the positive rate of HMGA2 expression gradually increased during tumor progression. Furthermore, HMGA2 expression was positively correlated with Wnt/β-catenin signaling protein expression [Wnt, β-catenin, cyclin-dependent kinase 4 (CDK4) and cyclin D1], suggesting its involvement in the carcinogenesis of sporadic colorectal tubular adenoma and its potential to synergistically interact with the Wnt/β-catenin signaling pathway. HMGA2 knockdown in the human colorectal cancer cell line, HCT 116 decreased β-catenin expression and its downstream targets, CDK4 and cyclin D1. Furthermore, silencing of Wnt or β-catenin decreased HMGA2 expression. Taken together, the results of the present study suggest the coordinated regulation of HMGA2 and the Wnt/β-catenin signaling pathway in the carcinogenesis of sporadic colorectal tubular adenoma.

Evaluation of global and intragenic hypomethylation in colorectal adenomas improves patient stratification and colorectal cancer risk prediction

Background

Aberrant DNA hypomethylation of the long interspersed nuclear elements (LINE-1 or L1) has been recognized as an early event of colorectal transformation. Simultaneous genetic and epigenetic analysis of colorectal adenomas may be an effective and rapid strategy to identify key biological features leading to accelerated colorectal tumorigenesis. In particular, global and/or intragenic LINE-1 hypomethylation of adenomas may represent a helpful tool for improving colorectal cancer (CRC) risk stratification of patients after surgical removal of polyps. To verify this hypothesis, we analyzed a cohort of 102 adenomas derived from 40 high-risk patients (who developed CRC in a post-polypectomy of at least one year) and 43 low-risk patients (who did not develop CRC in a post-polypectomy of at least 5 years) for their main pathological features, the presence of hotspot variants in driver oncogenes (KRAS, NRAS, BRAF and PIK3CA), global (LINE-1) and intragenic (L1-MET) methylation status.

Results

In addition to a significantly higher adenoma size and an older patients’ age, adenomas from high-risk patients were more hypomethylated than those from low-risk patients for both global and intragenic LINE-1 assays. DNA hypomethylation, measured by pyrosequencing, was independent from other parameters, including the presence of oncogenic hotspot variants detected by mass spectrometry. Combining LINE-1 and L1-MET analyses and profiling the samples according to the presence of at least one hypomethylated assay improved the discrimination between high and low risk lesions (p = 0.005). Remarkably, adenomas with at least one hypomethylated assay identified the patients with a significantly (p < 0.001) higher risk of developing CRC. Multivariable analysis and logistic regression evaluated by the ROC curves proved that methylation status was an independent variable improving cancer risk prediction (p = 0.02).

Conclusions

LINE-1 and L1-MET hypomethylation in colorectal adenomas are associated with a higher risk of developing CRC. DNA global and intragenic hypomethylation are independent markers that could be used in combination to successfully improve the stratification of patients who enter a colonoscopy surveillance program.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01135-0.

The Pivotal Player: Components of NF-κB Pathway as Promising Biomarkers in Colorectal Cancer

Over the last several decades, colorectal cancer (CRC) has been one of the most prevalent cancers. While significant progress has been made in both diagnostic screening and therapeutic approaches, a large knowledge gap still remains regarding the early identification and treatment of CRC. Specifically, identification of CRC biomarkers that can help with the creation of targeted therapies as well as increasing the ability for clinicians to predict the biological response of a patient to therapeutics, is of particular importance. This review provides an overview of CRC and its progression stages, as well as the basic types of CRC biomarkers. We then lay out the synopsis of signaling pathways related to CRC, and further highlight the pivotal and multifaceted role of nuclear factor (NF) κB signaling in CRC. Particularly, we bring forth knowledge regarding the tumor microenvironment (TME) in CRC, and its complex interaction with cancer cells. We also provide examples of NF-κB signaling-related CRC biomarkers, and ongoing efforts made at targeting NF-κB signaling in CRC treatment. We conclude and anticipate that with more emerging novel regulators of the NF-κB pathway being discovered, together with their in-depth characterization and the integration of large groups of genomic, transcriptomic and proteomic data, the day of successful development of more ideal NF-κB inhibitors is fast approaching.

Mucosal lesions of the upper gastrointestinal tract in patients with ulcerative colitis: A review

Ulcerative colitis (UC) is a chronic, nonspecific, relapsing inflammatory bowel disease. The colorectum is considered the chief target organ of UC, whereas upper gastrointestinal (UGI) tract manifestations are infrequent. Recently, emerging evidence has suggested that UC presents complications in esophageal, stomachic, and duodenal mucosal injuries. However, UC-related UGI tract manifestations are varied and frequently silenced or concealed. Moreover, the endoscopic and microscopic characteristics of UGI tract complicated with UC are nonspecific. Therefore, UGI involvement may be ignored by many clinicians. In addition, no standard criteria have been established for patients with UC who should undergo fibrogastroduodenoscopy. Furthermore, specific treatment recommendations may be needed for patients with UC-associated UGI lesions. Herein, we review the esophageal, gastric, and duodenal mucosal lesions of the UC-associated UGI tract, as well as the potential pathogenesis and therapy.

Steroid 5α-Reductase Type I Induces Cell Viability and Migration via Nuclear Factor-κB/Vascular Endothelial Growth Factor Signaling Pathway in Colorectal Cancer

Colorectal cancer (CRC) is a common malignant tumor of the digestive system. Steroid 5α-reductase type I (SRD5A1), as an important part of the steroid metabolism, converts testosterone to dihydrotestosterone and regulates sex hormone levels, which accommodates tumor occurrence or development. However, the underlying molecular mechanism of SRD5A1 in CRC remains unclear. We compared SRD5A1 expression in CRC tissues with normal controls by immunohistochemistry and found that elevated SRD5A1 in CRC was relevant for poor patient prognosis. Furthermore, inducible downregulation of SRD5A1 by small hairpin RNA reduced cell viability, promoted cell cycle arrest, and induced cell apoptosis and cellular senescence of CRC cells, as well as attenuated cell migration ability. In the following experiments, we used dutasteride (an inhibitor of SRD5A1/2) to explore its inhibitory effect on the biological processes of CRC cells, as mentioned earlier. Further mechanism study demonstrated that the repression of SRD5A1 abolished the expression of p65 and vascular endothelial growth factor, suggesting that SRD5A1 might regulate cell viability and migration through nuclear factor-κB/vascular endothelial growth factor signaling pathway. Collectively, these findings implicate SRD5A1 acting as a novel biomarker for CRC diagnosis and prognosis and provide compelling evidence for the future evaluation of dutasteride as a promising candidate for CRC treatment.

Type 2 diabetes impacts colorectal adenoma detection in screening colonoscopy

Background: Diabetes is associated with an increased risk of colorectal cancer (CRC). We conducted a retrospective analysis of adenoma detection rates (ADR) in initial screening colonoscopies to further investigate the role of diabetes in adenoma detection. Methods: A chart review was performed on initial average risk screening colonoscopies (ages 45–75) during 2012–2015. Data collected included basic demographics, insurance, BMI, family history of CRC, smoking, diabetes, and aspirin use. Multivariable generalized linear mixed models for binary outcomes were used to examine the relationship between diabetes and variables associated with CRC risk and ADR. Results: Of 2865 screening colonoscopies, 282 were performed on patients with type 2 diabetes (T2DM). Multivariable analysis suggested that T2DM (OR = 1.49, 95% CI:1.13–1.97, p = 0.0047) was associated with an increased ADR, as well as smoking, older age, higher BMI and male sex (all p < 0.05). For patients with T2DM, those not taking diabetes medications were more likely to have an adenoma than those taking medication (OR = 2.38, 95% CI:1.09–5.2, p = 0.03). Conclusion: T2DM has an effect on ADR after controlling for multiple confounding variables. Early interventions for prevention of T2DM and prescribing anti-diabetes medications may reduce development of colonic adenomas and may contribute to CRC prevention.

Decreased vitamin D receptor protein expression is associated with progression and poor prognosis of colorectal cancer patients

This study aimed to investigate vitamin D receptor (VDR) expression levels and evaluate their clinical significance in patients with colorectal cancer (CRC). VDR protein expression was validated by immunohistochemistry in 188 CRC tissues and 134 normal colorectal tissues. The associations between VDR expression and clinicopathologic characteristics, including prognostic outcomes, were analyzed. VDR expression in normal colorectal tissue was higher than that in CRC (83.6% versus 34.6%, P = 4.489 × 10^-20) and generated moderate diagnostic performance for CRC detection (AUC = 0.88, sensitivity = 0.87, specificity = 0.84). Low VDR expression was associated with invasion depth (P = 0.001) and poor survival in CRC (P = 0.031). Univariate Cox analysis demonstrated VDR expression (P = 0.036) was a significant prognostic predictor for survival in patients with CRC. Low VDR expression could be a valuable diagnostic and prognostic biomarker for CRC patients. Targeting VDR may offer a potential therapeutic strategy for blocking CRC.

Screen detection is a survival predictor independent of pathological grade in colorectal cancer. A prospective cohort study

INTRODUCTION

Patients with screened detected colorectal cancer (CRC) have a better survival than patients referred with symptoms. This may be because of cancers being identified in a younger population and at an earlier stage. In this study, we assess whether screened detected CRC has an improved outcome after controlling for key pathological and patient factors known to influence prognosis.

METHOD

This is a cohort study of all CRC patients diagnosed in NHS Grampian. Patients aged 51-75 years old between June 2007 and July 2017 were included. Data were obtained from a prospectively maintained regional pathology database and outcomes from ISD records. All-cause mortality rates at 1 and 5 years were examined. A Cox proportional hazards regression model was used to estimate the effect of screening status, age, gender, Duke stage, tumour location, extramural venous invasion (EMVI) status and lymph node ratio (LNR) on overall survival.

RESULTS

Of 1618 CRC cases, 449 (27.8%) were screened and 1169 (72.2%) were symptomatic. Screened CRC patients had improved survival compared to non-screened CRC at 1 year (88.9% vs 83.9% p < 0.001) and 5-years (42.5% vs 36.2%; p < 0.001). On multivariable analysis of patients who had no neoadjuvant therapy (n = 1272), screening had better survival (HR 0.57; 95% CI 0.44-0.74; p < 0.001). EMVI (HR 2.22; CI 1.76 to 2.79; p < 0.001) and tumour location were found to affect outcome.

CONCLUSION

Patients referred through screening had improved survival compared with symptomatic patients. Further research could be targeted to determine if screened CRC cases are pathologically different to symptomatic cancers or if the screening cohort is inherently more healthy.

Significance of gene mutations in the Wnt signaling pathway in traditional serrated adenomas of the colon and rectum

Recent studies have shown that colorectal serrated lesions, which include sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs), are precursors of colorectal cancer. However, the molecular mechanisms underlying the carcinogenesis, particularly in TSAs, remain largely uncharacterized. To clarify their molecular and clinicopathological characteristics, we performed mutation and methylation analyses of cancer-associated genes in 78 serrated lesions, including TSAs, SSAs and microvesicular hyperplastic polyps. Target exon sequence analysis was performed with 39 genes, including genes known to be frequently mutated in colorectal cancers and/or serrated lesions. We also used bisulfite pyrosequencing to assess the methylation status of various cancer-associated genes and marker genes of the CpG island methylator phenotype (CIMP). The prevalence of mutations in genes associated with Wnt signaling was significantly higher in TSAs than SSAs (65% vs. 28%, p < 0.01). Among those, RNF43 mutations were observed in 38% of TSAs and 17% of SSAs. In immunohistochemical studies of 39 serrated lesions, the prevalence of abnormal nuclear β-catenin accumulation was significantly higher in TSAs (57%) than SSAs (8%) (P = 0.01). SMOC1 methylation was detected in 54% of TSAs but in no SSAs (p < 0.01). Additionally, SMOC1 methylation was more prevalent among TSAs with KRAS mutation (82%) than with BRAF mutation (38%, p = 0.03). Lesions with CIMP-high or RNF43 mutations were detected only in TSAs with BRAF mutation, suggesting two distinct carcinogenic pathways in TSAs. Mutations in genes associated with Wnt signaling play a greater role in the carcinogenesis of TSAs than SSAs.

Functional polymorphisms of the lncRNA H19 promoter region contribute to the cancer risk and clinical outcomes in advanced colorectal cancer

Background

The long non-coding RNA H19 plays critical roles in cancer occurrence, development, and progression. The present study is for the first time to evaluate the association of genetic variations in the H19 promoter region with advanced colorectal cancer (CRC) susceptibility, environmental factors, and clinical outcomes.

Methods

16 single-nucleotide polymorphisms (SNPs) were identified in the H19 gene promoter by DNA sequencing, and 3 SNPs among which including rs4930101, rs11042170, and rs2735970 further expanded samples with 572 advanced CRC patients and 555 healthy controls.

Results

We found that harboring SNP [rs4930101 (P = 0.009), rs2735970 (P = 0.003), and rs11042170 (P = 0.003)] or carrying more than one combined risk genotypes significantly increased the risk for CRC [P < 0.0001, adjusted OR (95% CI) 6.48 (2.97–14.15)]. In the correlation analysis with environmental factors, rs2735970 and gender, combined risk genotypes (> 1 vs. ≤ 1) and family history of cancer demonstrated significant interactions. Furthermore, a remarkably worse clinical outcome was found in combined risk genotypes (> 1 vs. ≤ 1), especially in CRC patients with body weight ≥ 61 kg, smoking, and first-degree family history of cancer (Log-rank test: P = 0.006, P = 0.018, and P = 0.013, respectively). More importantly, the multivariate Cox regression analyses further verified that combined risk genotypes > 1 showed a prognostic risk factor for CRC patients with body weight ≥ 61 kg (P = 0.002), smoking (P = 0.008), and family history of cancer (P = 0.006). In addition, MDR analysis consistently revealed that the combination of selected SNPs and nine known risk factors showed a better prediction prognosis and represented the best model to predict advanced CRC prognosis.

Conclusion

3 SNPs of rs4930101, rs11042170, and rs27359703 among 16 identified SNPs of H19 gene remarkably increased CRC risk. Furthermore, the combined risk genotypes had a significant impact on environmental factors and clinical outcomes in the advanced CRC patients with body weight ≥ 61 kg, ever-smoking, and first-degree family history of cancer. These data suggest that H19 promoter SNPs, especially these combined SNPs might be more potentially functional biomarkers in the prediction of advanced CRC risk and prognosis.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0895-x) contains supplementary material, which is available to authorized users.

CpG Island Methylation in Sessile Serrated Adenoma/Polyp of the Colorectum: Implications for Differential Diagnosis of Molecularly High-Risk Lesions among Non-dysplastic Sessile Serrated Adenomas/Polyps

Background

Although colorectal sessile serrated adenomas/polyps (SSA/Ps) with morphologic dysplasia are regarded as definite high-risk premalignant lesions, no reliable grading or risk-stratifying system exists for non-dysplastic SSA/Ps. The accumulation of CpG island methylation is a molecular hallmark of progression of SSA/Ps. Thus, we decided to classify non-dysplastic SSA/Ps into risk subgroups based on the extent of CpG island methylation.

Methods

The CpG island methylator phenotype (CIMP) status of 132 non-dysplastic SSA/Ps was determined using eight CIMP-specific promoter markers. SSA/Ps with CIMP-high and/or MLH1 promoter methylation were regarded as a high-risk subgroup.

Results

Based on the CIMP analysis results, methylation frequency of each CIMP marker suggested a sequential pattern of CpG island methylation during progression of SSA/P, indicating MLH1 as a late-methylated marker. Among the 132 non-dysplastic SSA/Ps, 34 (26%) were determined to be high-risk lesions (33 CIMP-high and 8 MLH1-methylated cases; seven cases overlapped). All 34 high-risk SSA/Ps were located exclusively in the proximal colon (100%, p = .001) and were significantly associated with older age (≥ 50 years, 100%; p = .003) and a larger histologically measured lesion size (> 5 mm, 100%; p = .004). In addition, the high-risk SSA/Ps were characterized by a relatively higher number of typical base-dilated serrated crypts.

Conclusions

Both CIMP-high and MLH1 methylation are late-step molecular events during progression of SSA/Ps and rarely occur in SSA/Ps of young patients. Comprehensive consideration of age (≥ 50), location (proximal colon), and histologic size (> 5 mm) may be important for the prediction of high-risk lesions among non-dysplastic SSA/Ps.

Insights into Pathogenic Interactions Among Environment, Host, and Tumor at the Crossroads of Molecular Pathology and Epidemiology

Evidence indicates that diet, nutrition, lifestyle, the environment, the microbiome, and other exogenous factors have pathogenic roles and also influence the genome, epigenome, transcriptome, proteome, and metabolome of tumor and nonneoplastic cells, including immune cells. With the need for big-data research, pathology must transform to integrate data science fields, including epidemiology, biostatistics, and bioinformatics. The research framework of molecular pathological epidemiology (MPE) demonstrates the strengths of such an interdisciplinary integration, having been used to study breast, lung, prostate, and colorectal cancers. The MPE research paradigm not only can provide novel insights into interactions among environment, tumor, and host but also opens new research frontiers. New developments-such as computational digital pathology, systems biology, artificial intelligence, and in vivo pathology technologies-will further transform pathology and MPE. Although it is necessary to address the rarity of transdisciplinary education and training programs, MPE provides an exemplary model of integrative scientific approaches and contributes to advancements in precision medicine, therapy, and prevention.

Characterization of cancer genomic heterogeneity by next-generation sequencing advances precision medicine in cancer treatment

Cancer is a heterogeneous disease with unique genomic and phenotypic features that differ between individual patients and even among individual tumor regions. In recent years, large-scale genomic studies and new next-generation sequencing technologies have uncovered more scientific details about tumor heterogeneity, with significant implications for the choice of specific molecular biomarkers and clinical decision making. Genomic heterogeneity significantly contributes to the generation of a diverse cell population during tumor development and progression, representing a determining factor for variation in tumor treatment response. It has been considered a prominent contributor to therapeutic failure, and increases the likelihood of resistance to future therapies in most common cancers. The understanding of molecular heterogeneity in cancer is a fundamental component of precision oncology, enabling the identification of genomic alteration of key genes and pathways that can be targeted therapeutically. Here, we review the emerging knowledge of tumor genomics and heterogeneity, as well as potential implications for precision medicine in cancer treatment and new therapeutic discoveries. An analysis and interpretation of the TCGA database was included.

Integrative analysis of exogenous, endogenous, tumour and immune factors for precision medicine

Immunotherapy strategies targeting immune checkpoints such as the CTLA4 and CD274 (programmed cell death 1 ligand 1, PD-L1)/PDCD1 (programmed cell death 1, PD-1) T-cell coreceptor pathways are revolutionising oncology. The approval of pembrolizumab use for solid tumours with high-level microsatellite instability or mismatch repair deficiency by the US Food and Drug Administration highlights promise of precision immuno-oncology. However, despite evidence indicating influences of exogenous and endogenous factors such as diet, nutrients, alcohol, smoking, obesity, lifestyle, environmental exposures and microbiome on tumour-immune interactions, integrative analyses of those factors and immunity lag behind. Immune cell analyses in the tumour microenvironment have not adequately been integrated into large-scale studies. Addressing this gap, the transdisciplinary field of molecular pathological epidemiology (MPE) offers research frameworks to integrate tumour immunology into population health sciences, and link the exposures and germline genetics (eg, HLA genotypes) to tumour and immune characteristics. Multilevel research using bioinformatics, in vivo pathology and omics (genomics, epigenomics, transcriptomics, proteomics and metabolomics) technologies is possible with use of tissue, peripheral blood circulating cells, cell-free plasma, stool, sputum, urine and other body fluids. This immunology-MPE model can synergise with experimental immunology, microbiology and systems biology. GI neoplasms represent exemplary diseases for the immunology-MPE model, given rich microbiota and immune tissues of intestines, and the well-established carcinogenic role of intestinal inflammation. Proof-of-principle studies on colorectal cancer provided insights into immunomodulating effects of aspirin, vitamin D, inflammatory diets and omega-3 polyunsaturated fatty acids. The integrated immunology-MPE model can contribute to better understanding of environment-tumour-immune interactions, and effective immunoprevention and immunotherapy strategies for precision medicine.

I-scan optical enhancement for the in vivo prediction of diminutive colorectal polyp histology: Results from a prospective three-phased multicentre trial

Background and aims

Dye-less chromoendoscopy is an emerging technology for colorectal polyp characterization. Herein, we investigated whether the newly introduced I-scan optical enhancement (OE) can accurately predict polyp histology in vivo in real-time.

Methods

In this prospective three-phased study, 84 patients with 230 diminutive colorectal polyps were included. During the first two study phases, five endoscopists assessed whether analysis of polyp colour, surface and vascular pattern under i-scan OE can differentiate in vivo between adenomatous and hyperplastic polyps. Finally, junior and experienced endoscopists (JE, EE, each n = 4) not involved in the prior study phases made a post hoc diagnosis of polyp histology using a static i-scan OE image database. Histopathology was used as a gold-standard in all study phases.

Results

The overall accuracy of i-scan OE for histology prediction was 90% with a sensitivity, specificity, positive (PPV) and negative prediction value (NPV) of 91%, 90%, 86% and 94%, respectively. In high confidence predictions, the diagnostic accuracy increased to 93% with sensitivity, specificity, PPV and NPV of 94%, 91%, 89% and 96%. Colonoscopy surveillance intervals were predicted correctly in ≥ 90% of patients. In the post hoc analysis EE predicted polyp histology under i-scan OE with an overall accuracy of 91%. After a single training session, JE achieved a comparable diagnostic performance for predicting polyp histology with i-scan OE.

Conclusion

The histology of diminutive colorectal polyps can be accurately predicted with i-scan OE in vivo in real-time. Furthermore, polyp differentiation with i-scan OE appears to require only a short learning curve.

Loss of ZG16 is associated with molecular and clinicopathological phenotypes of colorectal cancer

Background

Zymogen granule protein 16 (ZG16) is one of the most significantly down-regulated genes in colorectal cancer (CRC) tissues. This study aimed to further evaluate its expression changes and investigate its association with molecular and clinicopathological characteristics of CRC.

Methods

We applied quantitative RT-PCR to determine expression difference between tumor and matched normal tissues from 23 CRC patients. To further validate the down-regulation in tumor tissues, we performed immunohistochemistry (IHC) analysis in 40 paraffin-embedded normal-tumor pairs and 22 colon tissues with a variety of diseases. To evaluate if the ZG16 gene changes were associated with clinicopathological characteristics, we further analyzed the gene expression and copy number changes from The Cancer Genome Atlas (TCGA) and Oncomine datasets.

Results

Quantitative RT-PCR confirmed significant down-regulation (~ 130-fold) of ZG16 in all tumor tissues. ZG16 expression was in an organ-specific manner with an extremely high expression in normal epithelial cells of small intestine, colon and rectum. IHC analysis showed that ZG16 protein was completely lost in all of 40 CRC tissues, and partially lost in premalignant adenomatous polyps (adenomas) and chronic ulcerative colitis tissues. Gene expression and copy number changes were significantly associated with multiple molecular and clinicopathological features of CRC including microsatellite instability (MSI), MLH1 silencing, CpG island methylator phenotype, hyper-mutation status, gender, presence of synchronous adenomas, and histological type (P < 0.05). Patients with lower ZG16 gene expression showed shorter progression-free survival and overall survival than those with relatively higher expression (P < 0.05). Multivariate analysis suggested that the ZG16 expression was an independent prognosis factor (P = 0.012, HR = 6.286, 95% CI = 0.816–0.975).

Conclusion

For the first time, our study demonstrated that ZG16 expression was sequentially reduced from normal, adenoma, to carcinoma. Association with multiple clinicopathological features indicates that ZG16 may play an important role in cancer initiation and progression. ZG16 may serve as a potential biomarker for diagnosis and prognosis of CRC.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4337-2) contains supplementary material, which is available to authorized users.

An evidence-based treatment algorithm for colorectal polyp cancers: results from the Scottish Screen-detected Polyp Cancer Study (SSPoCS)

OBJECTIVES

Colorectal polyp cancers present clinicians with a treatment dilemma. Decisions regarding whether to offer segmental resection or endoscopic surveillance are often taken without reference to good quality evidence. The aim of this study was to develop a treatment algorithm for patients with screen-detected polyp cancers.

DESIGN

This national cohort study included all patients with a polyp cancer identified through the Scottish Bowel Screening Programme between 2000 and 2012. Multivariate regression analysis was used to assess the impact of clinical, endoscopic and pathological variables on the rate of adverse events (residual tumour in patients undergoing segmental resection or cancer-related death or disease recurrence in any patient). These data were used to develop a clinically relevant treatment algorithm.

RESULTS

485 patients with polyp cancers were included. 186/485 (38%) underwent segmental resection and residual tumour was identified in 41/186 (22%). The only factor associated with an increased risk of residual tumour in the bowel wall was incomplete excision of the original polyp (OR 5.61, p=0.001), while only lymphovascular invasion was associated with an increased risk of lymph node metastases (OR 5.95, p=0.002). When patients undergoing segmental resection or endoscopic surveillance were considered together, the risk of adverse events was significantly higher in patients with incomplete excision (OR 10.23, p<0.001) or lymphovascular invasion (OR 2.65, p=0.023).

CONCLUSION

A policy of surveillance is adequate for the majority of patients with screen-detected colorectal polyp cancers. Consideration of segmental resection should be reserved for those with incomplete excision or evidence of lymphovascular invasion.

Review Article: The Role of Molecular Pathological Epidemiology in the Study of Neoplastic and Non-neoplastic Diseases in the Era of Precision Medicine

Molecular pathology diagnostics to subclassify diseases based on pathogenesis are increasingly common in clinical translational medicine. Molecular pathological epidemiology (MPE) is an integrative transdisciplinary science based on the unique disease principle and the disease continuum theory. While it has been most commonly applied to research on breast, lung, and colorectal cancers, MPE can investigate etiologic heterogeneity in non-neoplastic diseases, such as cardiovascular diseases, obesity, diabetes mellitus, drug toxicity, and immunity-related and infectious diseases. This science can enhance causal inference by linking putative etiologic factors to specific molecular biomarkers as outcomes. Technological advances increasingly enable analyses of various -omics, including genomics, epigenomics, transcriptomics, proteomics, metabolomics, metagenomics, microbiome, immunomics, interactomics, etc. Challenges in MPE include sample size limitations (depending on availability of biospecimens or biomedical/radiological imaging), need for rigorous validation of molecular assays and study findings, and paucities of interdisciplinary experts, education programs, international forums, and standardized guidelines. To address these challenges, there are ongoing efforts such as multidisciplinary consortium pooling projects, the International Molecular Pathological Epidemiology Meeting Series, and the Strengthening the Reporting of Observational Studies in Epidemiology-MPE guideline project. Efforts should be made to build biorepository and biobank networks, and worldwide population-based MPE databases. These activities match with the purposes of the Big Data to Knowledge (BD2K), Genetic Associations and Mechanisms in Oncology (GAME-ON), and Precision Medicine Initiatives of the United States National Institute of Health. Given advances in biotechnology, bioinformatics, and computational/systems biology, there are wide open opportunities in MPE to contribute to public health.

Assessment of epigenetic alterations in early colorectal lesions containing BRAF mutations

To clarify the molecular and clinicopathological characteristics of colorectal serrated lesions, we assessed the DNA methylation of cancer-associated genes in a cohort of BRAF-mutant precancerous lesions from 94 individuals. We then compared those results with the lesions' clinicopathological features, especially colorectal subsites. The lesions included hyperplastic polyps (n = 16), traditional serrated adenomas (TSAs) (n = 15), TSAs with sessile serrated adenomas (SSAs) (n = 6), SSAs (n = 49) and SSAs with dysplasia (n = 16). The prevalence of lesions exhibiting the CpG island methylator phenotype (CIMP) was lower in the sigmoid colon and rectum than in other bowel subsites, including the cecum, ascending, transverse and descending colon. In addition, several cancer-associated genes showed higher methylation levels within lesions in the proximal to sigmoid colon than in the sigmoid colon and rectum. These results indicate that the methylation status of lesions with BRAF mutation is strongly associated with their location, histological findings and neoplastic pathways. By contrast, no difference in aberrant DNA methylation was observed in normal-appearing background colonic mucosa along the bowel subsites, which may indicate the absence of an epigenetic field defect.

Tumor-associated DNA mutation detection in individuals undergoing colonoscopy

The majority of colorectal cancers (CRC) harbor somatic mutations and epigenetic modifications in the tumor tissue, and some of these mutations can be detected in plasma as circulating tumor DNA (ctDNA). Precancerous colorectal lesions also contain many of these same mutations. This study examined plasma for ctDNA from patients undergoing a screening or diagnostic colonoscopy to determine the sensitivity and specificity of the ctDNA panel for detecting CRC and precancerous lesions. Two hundred patients without a history of nonskin cancer had blood drawn before a colonoscopy. Plasma ctDNA was measured with a 96 mutation panel for nine cancer driver genes. The ctDNA results were correlated with the findings at colonoscopy. Of the 200 patients, 176 (88%) had wild‐type DNA, 12 (6%) had mutations detected, and 12 (6%) had indeterminate results. Colonoscopy was normal in 80% of the patients and 20% were found to have polyps. No CRC was found in this study, precluding a determination of true‐positive rate for CRC detection. Our ctDNA panel was positive in 13.2% of patients with colonic polyps found at colonoscopy, while 4.7% of patients with normal colonoscopy also had ctDNA detected, which may represent ctDNA released from a benign process, an occult tumor, or an acquired somatic mutation from clonal hematopoiesis.

Molecular pathological epidemiology: new developing frontiers of big data science to study etiologies and pathogenesis

Molecular pathological epidemiology (MPE) is an integrative field that utilizes molecular pathology to incorporate interpersonal heterogeneity of a disease process into epidemiology. In each individual, the development and progression of a disease are determined by a unique combination of exogenous and endogenous factors, resulting in different molecular and pathological subtypes of the disease. Based on "the unique disease principle," the primary aim of MPE is to uncover an interactive relationship between a specific environmental exposure and disease subtypes in determining disease incidence and mortality. This MPE approach can provide etiologic and pathogenic insights, potentially contributing to precision medicine for personalized prevention and treatment. Although breast, prostate, lung, and colorectal cancers have been among the most commonly studied diseases, the MPE approach can be used to study any disease. In addition to molecular features, host immune status and microbiome profile likely affect a disease process, and thus serve as informative biomarkers. As such, further integration of several disciplines into MPE has been achieved (e.g., pharmaco-MPE, immuno-MPE, and microbial MPE), to provide novel insights into underlying etiologic mechanisms. With the advent of high-throughput sequencing technologies, available genomic and epigenomic data have expanded dramatically. The MPE approach can also provide a specific risk estimate for each disease subgroup, thereby enhancing the impact of genome-wide association studies on public health. In this article, we present recent progress of MPE, and discuss the importance of accounting for the disease heterogeneity in the era of big-data health science and precision medicine.

Malignant Colorectal Polyps; Pathological Consideration (A review)

BACKGROUND

Routine screening colonoscopy is on the rise and pathologists have to deal with the ever larger numbers of excised colonic polyps. It is very important to optimize the patients' individual treatment and further surveillance. Pathologists play a critical role in management, as most of the clinical decisions concerning colonic polyp management are based on pathologic findings. One of the most important clinical issues in colonic adenomas is the diagnosis of malignancy and reporting its different aspects by the pathologist. The histologic type and the extent of carcinoma within a malignant polyp have considerable impact on the decisions of gastroenterologists and surgeons for further management. Therefore, the most recent literature regarding the diagnosis and reporting of the different features of malignant polyps was reviewed.

DATA ACQUISITION

There is growing literature regarding the different pathologic features and reporting of malignant colonic polyps, and in this review, published articles that are listed on Google Scholar and Pub Med are discussed.

CONCLUSION

Diagnosis of malignant colon polyp requires the presence of tumor cells that are penetrating beyond the muscular mucosa into submucosa (pT1). As well as establishing a diagnosis of malignant polyp, it is very important to report the size of the invasive component, the presence or absence of lymphovascular invasion, the degree of tumor differentiation and the distance of the carcinoma from the line of resection. Other important features that may be reported include: the presence or absence of tumor budding, the depth of tumor cell penetration into the submucosa, and results of immunohistochemistry for mismatch repair proteins and BRAF.

Developing drugs that target the Wnt pathway: recent approaches in cancer and neurodegenerative diseases

INTRODUCTION

Wnt/β-catenin signaling is an evolutionarily conserved pathway that has a crucial role in embryonic and adult life. Dysregulation of Wnt/β-catenin pathway has been associated with various diseases, including cancer and neurodegenerative disorders, including Parkinson's disease (PD). Several molecular components of the signaling have been proposed as innovative targets for cancer therapy, and very recently, some of them have been also evaluated as potential therapeutic targets for PD. Areas covered: This review focuses on the role of Wnt/β-catenin pathway in the pathogenensis of cancer and PD, examining some recent therapeutic approaches that are ongoing in preclinical and clinical studies. The possibilities that this signaling offers for diagnosis and prognosis of neoplastic diseases, and the concerns of targeting this pathway are also discussed. Expert opinion: Despite the stimulating results obtained in preclinical studies on cancer and other disease models, the clinical experience with Wnt modulators is still in its infancy, and is mainly restricted to anticancer therapy. Even with concerns of the safety of drugs targeting Wnt signaling, the attention of researchers worldwide is increasing to this issue in terms of their therapeutic potential for diseases such as PD, for which no cure exists.

Genetic instability, CpG island methylator phenotype, and proliferative activity are distinct differences between diminutive and small tubular adenoma of the colorectum

It is recommended that small (6-10 mm) lesions be treated with endoscopic resection (ER), whereas diminutive (≤5 mm) lesions are not currently an indication for ER according to the Japanese guidelines. The aim of this study was to evaluate the molecular alterations, and therefore treatment indications, in diminutive versus small tubular adenoma (TA). We prospectively analyzed genetic instability, including microsatellite instability and loss of heterozygosity, methylation status, KRAS/BRAF mutations, and Ki-67 staining in 96 TAs without a villous component. Although no microsatellite instability was identified in either diminutive or small TAs, genetic instability was seen in small TAs (9.1%) but not diminutive TAs (P = .04). In addition, the low-level CpG island methylator phenotype (CIMP-L) was more frequently observed in small TAs (31.8%) than in diminutive TAs (P = .01). Thus, genetic instability and CIMP-L were associated with small TAs, and only CIMP-L was an independent predictive marker for small TAs (odds ratio, 3.29; P = .03). Intriguingly, the Ki-67 proliferative index tended to be higher in small TAs than in diminutive TAs (P = .06) and higher in TAs with CIMP-L than in those without CIMP (P = .08). KRAS mutations were seen in codon 12 in 5.2% of TAs, but no BRAF gene mutations were found. As the molecular events and proliferative activity for the progression may increase from diminutive to small TAs, small TAs should be treated with ER, whereas a "predict, resect, and discard" strategy may be acceptable in most diminutive lesions except flat and depressed-type lesions, in keeping with the current strategy in the West.

MicroRNA Signatures of Colonic Polyps on Screening and Histology

Colorectal cancer and adenoma adjacent to cancer exhibit distinct microRNA (miRNA) alterations in an apparent mucosa-to-adenocarcinoma sequence. The pattern of microRNAs in screen-detected polyps in relation to histologic features and cancer risk has not been investigated. miRNA expression analysis was performed on normal mucosa (NM), hyperplastic polyps (HP), tubular adenomas (TA), tubulovillous adenomas or high-grade dysplasia (TVHG), and serrated polyps [sessile serrated adenoma/polyps (SSA/P) and traditional serrated adenomas (TSA)] in biopsy specimens from 109 patients undergoing screening/surveillance colonoscopy. Generalized linear models were used to identify differentially expressed miRNAs by histologic type and logistic regression to identify miRNA predictors of histopathology. False discovery rate (FDR) was used to control for multiple comparisons. We identified 99 miRNAs differing in at least one of five histopathologic groups (FDR ≤0.05). In a comparison of HPNM versus TVHG, the top most upregulated and downregulated miRNAs in HPNM included miR-145, -143, -107, -194, and -26a (upregulated), and miR-663, -1268, -320b, -1275, and -320b (downregulated; FDR P < 0.05). miR-145 and -619 showed high accuracy to discriminate low- from high-risk polyps without serrated histology (TVHG vs. HPNM + TA; CI, 95.6%), whereas miR-124, -143, and -30a showed high accuracy of separating high-risk polyps (TVHG + TSA) from low-risk polyps (HPNM + TA + SSA/P; CI, 96.0%). For TSAs, miR-125b and -199a were uniquely downregulated relative to HPNMs, and miR-335, -222, and -214 discriminated between non-serrated and serrated histology. Our data support the presence of colorectal cancer-associated miRNA alterations in screen-detected adenomas that may be useful for risk stratification for surveillance interval planning. Cancer Prev Res; 9(12); 942-9. ©2016 AACR.

Protocol Outlines for Parts 1 and 2 of the Prospective Endoscopy III Study for the Early Detection of Colorectal Cancer: Validation of a Concept Based on Blood Biomarkers

BACKGROUND

Programs for population screening of colorectal cancer (CRC) have been implemented in several countries with fecal immunochemical testing (FIT) as the preferred platform. However, the major obstacle for a feces-based testing method is the limited compliance that reduces the clinical sensitivity for detection of participants with non-symptomatic CRC. Therefore, research approaches have been initiated to develop screening concepts based on biomarkers in blood. Preliminary results show that protein, genetic, epigenetic, and metabolomic components may be valuable in blood-based screening concepts, particularly when combinations of the various components appear to lead to significant improvements.

OBJECTIVES

The protocol described in this paper focuses on the validation of concepts based on biomarkers in blood in a major population screened by FIT.

METHODS

In Part 1, participants will be identified and included through the Danish CRC Screening Program comprising initial FIT and subsequent colonoscopy to those with a positive result. Blood samples will be collected from 8000 FIT-positive participants, who are offered subsequent colonoscopy. Findings and interventions at colonoscopy together with personal data including co-morbidity will be recorded. Blood samples and data will also be collected from 6000 arbitrarily chosen participants with negative FIT. In Part 2, blood samples and data will be collected from 30,000 FIT-negative participants three times within 4 years. The blood samples will be analyzed using various in-house and commercially available manual and automated analysis platforms.

RESULTS

We anticipate Part 1 to terminate late August 2016 and Part 2 to terminate late September 2022. The results from Parts 1 and 2 will be presented within 12 to 18 months from termination.

CONCLUSIONS

The purpose of this study is to improve the efficacy of identifying participants with neoplastic bowel lesions, to identify false negative participants, to identify participants at risk of interval neoplastic lesions, to improve the compliance in screening sessions, and to establish guidelines for out-patient follow-up of at-risk participants based on combinations of blood-based biomarkers.

Colorectal cancer development and advances in screening

Most colon tumors develop via a multistep process involving a series of histological, morphological, and genetic changes that accumulate over time. This has allowed for screening and detection of early-stage precancerous polyps before they become cancerous in individuals at average risk for colorectal cancer (CRC), which may lead to substantial decreases in the incidence of CRC. Despite the known benefits of early screening, CRC remains the second leading cause of cancer-related deaths in the United States. Hence, it is important for health care providers to have an understanding of the risk factors for CRC and various stages of disease development in order to recommend appropriate screening strategies. This article provides an overview of the histological/molecular changes that characterize the development of CRC. It describes the available CRC screening methods and their advantages and limitations and highlights the stages of CRC development in which each screening method is most effective.

Upper gastrointestinal bleeding risk scores: Who, when and why?

Upper gastrointestinal bleeding (UGIB) remains a significant cause of hospital admission. In order to stratify patients according to the risk of the complications, such as rebleeding or death, and to predict the need of clinical intervention, several risk scores have been proposed and their use consistently recommended by international guidelines. The use of risk scoring systems in early assessment of patients suffering from UGIB may be useful to distinguish high-risks patients, who may need clinical intervention and hospitalization, from low risk patients with a lower chance of developing complications, in which management as outpatients can be considered. Although several scores have been published and validated for predicting different outcomes, the most frequently cited ones are the Rockall score and the Glasgow Blatchford score (GBS). While Rockall score, which incorporates clinical and endoscopic variables, has been validated to predict mortality, the GBS, which is based on clinical and laboratorial parameters, has been studied to predict the need of clinical intervention. Despite the advantages previously reported, their use in clinical decisions is still limited. This review describes the different risk scores used in the UGIB setting, highlights the most important research, explains why and when their use may be helpful, reflects on the problems that remain unresolved and guides future research with practical impact.

Cancer Prevention: Obstacles, Challenges and the Road Ahead

Approaches to reduce the global burden of cancer include two major strategies: screening and early detection and active preventive intervention. The latter is the topic of this Commentary and spans a broad range of activities. The genetic heterogeneity and complexity of advanced cancers strongly support the rationale for early interruption of the carcinogenic process and an enhanced focus on prevention as a priority strategy to reduce the burden of cancer; however, the focus of cancer prevention management should be on individuals at high risk and on primary localized disease in which screening and detection should also play a vital role. The timing and dose of (chemo-)preventive intervention also affects response. The intervention may be ineffective if the target population is very high risk or already presenting with preneoplastic lesions with cellular changes that cannot be reversed. The field needs to move beyond general concepts of carcinogenesis to targeted organ site prevention approaches in patients at high risk, as is currently being done for breast and colorectal cancers. Establishing the benefit of new cancer preventive interventions will take years and possibly decades, depending on the outcome being evaluated. We also propose that comparative effectiveness research designs and the value of information obtained from large-scale prevention studies are necessary in order for preventive interventions to become a routine part of cancer management.

DNA methylation markers for oral pre-cancer progression: A critical review

Although oral cancers are generally preceded by a well-established pre-cancerous stage, there is a lack of well-defined clinical and morphological criteria to detect and signal progression from pre-cancer to malignant tumours. We conducted a critical review to summarize the evidence regarding aberrant DNA methylation patterns as a potential diagnostic biomarker predicting progression. We identified all relevant human studies published in English prior to 30th April 2015 that examined DNA methylation (%) in oral pre-cancer by searching PubMed, Web-of-Science and Embase databases using combined key-searches. Twenty-one studies (18-cross-sectional; 3-longitudinal) were eligible for inclusion in the review, with sample sizes ranging from 4 to 156 affected cases. Eligible studies examined promoter region hyper-methylation of tumour suppressor genes in pathways including cell-cycle-control (n=15), DNA-repair (n=7), cell-cycle-signalling (n=4) and apoptosis (n=3). Hyper-methylated loci reported in three or more studies included p16, p14, MGMT and DAPK. Two longitudinal studies reported greater p16 hyper-methylation in pre-cancerous lesions transformed to malignancy compared to lesions that regressed (57-63.6% versus 8-32.1%; p<0.01). The one study that explored epigenome-wide methylation patterns reported three novel hyper-methylated loci (TRHDE; ZNF454; KCNAB3). The majority of reviewed studies were small, cross-sectional studies with poorly defined control groups and lacking validation. Whilst limitations in sample size and study design preclude definitive conclusions, current evidence suggests a potential utility of DNA methylation patterns as a diagnostic biomarker for oral pre-cancer progression. Robust studies such as large epigenome-wide methylation explorations of oral pre-cancer with longitudinal tracking are needed to validate the currently reported signals and identify new risk-loci and the biological pathways of disease progression.

Increased risk of colorectal polyps in patients with non-alcoholic fatty liver disease undergoing liver transplant evaluation

BACKGROUND

Screening colonoscopy is a standard part of the liver transplant (LT) evaluation process. We aimed to evaluate the yield of screening colonoscopy and determine whether non-alcoholic fatty liver disease (NAFLD) was associated with an increased risk of colorectal neoplasia.

METHODS

We retrospectively assessed all patients who completed LT evaluation at our center between 1/2008-12/2012. Patients <50 years old and those without records of screening colonoscopy, or with greater than average colon cancer risk were excluded.

RESULTS

A total of 1,102 patients were evaluated, 591 met inclusion criteria and were analyzed. The mean age was 60 years, 67% were male, 12% had NAFLD and 88% had other forms of chronic liver disease. Overall, 42% of patients had a polyp found on colonoscopy: 23% with adenomas, 14% with hyperplastic polyps and with 1% inflammatory polyps. In the final multivariable model controlling for age, NAFLD [odds ratio (OR) 2.41, P=0.001] and a history of significant alcohol use (OR 1.69, P=0.004) were predictive of finding a polyp on colonoscopy. In addition, NAFLD (OR 1.95, P=0.02), significant alcohol use (OR 1.70, P=0.01) and CTP class C (OR 0.57, P=0.02) were associated with adenoma, controlling for age.

CONCLUSIONS

Screening colonoscopy in patients awaiting LT yields a high rate of polyp (43%) and adenoma (22%) detection, perhaps preventing the accelerated progression to carcinoma that can occur in immunosuppressed post-LT patients. Patients with NAFLD may be at a ~2 fold higher risk of adenomas and should be carefully evaluated prior to LT.

The ARMC5 gene shows extensive genetic variance in primary macronodular adrenocortical hyperplasia

OBJECTIVE

Primary macronodular adrenal hyperplasia (PMAH) is a rare type of Cushing's syndrome (CS) that results in increased cortisol production and bilateral enlargement of the adrenal glands. Recent work showed that the disease may be caused by germline and somatic mutations in the ARMC5 gene, a likely tumor suppressor gene (TSG). We investigated 20 different adrenal nodules from one patient with PMAH for ARMC5 somatic sequence changes.

DESIGN

All of the nodules were obtained from a single patient who underwent bilateral adrenalectomy. DNA was extracted by standard protocol and the ARMC5 sequence was determined by the Sanger method.

RESULTS

Sixteen of 20 adrenocortical nodules harbored, in addition to what appeared to be the germline mutation, a second somatic variant. The p.Trp476* sequence change was present in all 20 nodules, as well as in normal tissue from the adrenal capsule, identifying it as the germline defect; each of the 16 other variants were found in different nodules: six were frame shift, four were missense, three were nonsense, and one was a splice site variation. Allelic losses were confirmed in two of the nodules.

CONCLUSION

This is the most genetic variance of the ARMC5 gene ever described in a single patient with PMAH: each of 16 adrenocortical nodules had a second new, 'private,' and--in most cases--completely inactivating ARMC5 defect, in addition to the germline mutation. The data support the notion that ARMC5 is a TSG that needs a second, somatic hit, to mediate tumorigenesis leading to polyclonal nodularity; however, the driver of this extensive genetic variance of the second ARMC5 allele in adrenocortical tissue in the context of a germline defect and PMAH remains a mystery.

Serrated neoplasia-role in colorectal carcinogenesis and clinical implications

Colorectal cancer (CRC) is considered a heterogeneous disease, both regarding pathogenesis and clinical behaviour. Four decades ago, the adenoma-carcinoma pathway was presented as the main pathway towards CRC, a conclusion that was largely based on evidence from observational morphological studies. This concept was later substantiated at the genomic level. Over the past decade, evidence has been generated for alternative routes in which CRC might develop, in particular the serrated neoplasia pathway. Providing indisputable evidence for the neoplastic potential of serrated polyps has been difficult. Reasons include the absence of reliable longitudinal observations on individual serrated lesions that progress to cancer, a shortage of available animal models for serrated lesions and challenging culture conditions when generating organoids of serrated lesions for in vitro studies. However, a growing body of circumstantial evidence has been accumulated, which indicates that ≥15% of CRCs might arise through the serrated neoplasia pathway. An even larger amount of post-colonoscopy colorectal carcinomas (carcinomas occurring within the surveillance interval after a complete colonoscopy) have been suggested to originate from serrated polyps. The aim of this Review is to assess the current status of the serrated neoplasia pathway in CRC and highlight clinical implications.

Proceedings of the second international molecular pathological epidemiology (MPE) meeting

Disease classification system increasingly incorporates information on pathogenic mechanisms to predict clinical outcomes and response to therapy and intervention. Technological advancements to interrogate omics (genomics, epigenomics, transcriptomics, proteomics, metabolomics, metagenomics, interactomics, etc.) provide widely open opportunities in population-based research. Molecular pathological epidemiology (MPE) represents integrative science of molecular pathology and epidemiology. This unified paradigm requires multidisciplinary collaboration between pathology, epidemiology, biostatistics, bioinformatics, and computational biology. Integration of these fields enables better understanding of etiologic heterogeneity, disease continuum, causal inference, and the impact of environment, diet, lifestyle, host factors (including genetics and immunity), and their interactions on disease evolution. Hence, the Second International MPE Meeting was held in Boston in December 2014, with aims to: (1) develop conceptual and practical frameworks; (2) cultivate and expand opportunities; (3) address challenges; and (4) initiate the effort of specifying guidelines for MPE. The meeting mainly consisted of presentations of method developments and recent data in various malignant neoplasms and tumors (breast, prostate, ovarian and colorectal cancers, renal cell carcinoma, lymphoma, and leukemia), followed by open discussion sessions on challenges and future plans. In particular, we recognized need for efforts to further develop statistical methodologies. This meeting provided an unprecedented opportunity for interdisciplinary collaboration, consistent with the purposes of the Big Data to Knowledge, Genetic Associations and Mechanisms in Oncology, and Precision Medicine Initiative of the US National Institute of Health. The MPE meeting series can help advance transdisciplinary population science and optimize training and education systems for twenty-first century medicine and public health.

The evolving role of nonsteroidal anti-inflammatory drugs in colon cancer prevention: a cause for optimism

Colorectal cancer (CRC) is a serious yet preventable disease. The low acceptance and cost of colonoscopy as a screening method or CRC make chemoprevention an important option. Nonsteroidal anti-inflammatory drugs (NSAIDs), not currently recommended for CRC prevention, have the potential to evolve into the agents of choice for this indication. Here, we discuss the promise and challenge of NSAIDs for this chemopreventive application.Multiple epidemiologic studies, randomized clinical trials (RCTs) of sporadic colorectal polyp recurrence, RCTs in patients with hereditary colorectal cancer syndromes, and pooled analyses of cardiovascular-prevention RCTs linked to cancer outcomes have firmly established the ability of conventional NSAIDs to prevent CRC. NSAIDs, however, are seriously limited by their toxicity,which can become cumulative with their long-term administration for chemoprevention, whereas drug interactions in vulnerable elderly patients compound their safety. Newer, chemically modified NSAIDs offer the hope of enhanced efficacy and safety.Recent work also indicates that targeting earlier stages of colorectal carcinogenesis, such as the lower complexity aberrant crypt foci, is a promising approach that may only require relatively short use of chemopreventive agents. Drug combination approaches exemplified by sulindac plus difluoromethylornithine appear very efficacious. Identification of those at risk or most likely to benefit from a given intervention using predictive biomarkers may usher in personalized chemoprevention. Agents that offer simultaneous chemoprevention of diseases in addition to CRC, e.g., cardiovascular and/or neurodegenerative diseases,may have a much greater potential for a broad clinical application.

Serrated polyps and their alternative pathway to the colorectal cancer: a systematic review

Colorectal cancer (CRC) is the third most frequently diagnosed cancer in the world. For a long time, only one pathway of colorectal carcinogenesis was known. In recent years, a new “alternative” pathway through serrated adenoma was described. Recent meta-analysis estimated these cancers as about 10% to 30% of all CRCs. Serrated polyps are the second most popular groups of polyps (after conventional adenomas) found during colonoscopy. Serrated polyps of the colon are clinically and molecularly diverse changes that have common feature as crypt luminal morphology characterized by glandular serration. Evidence suggests that subtypes of serrated polyps, particularly TSA and SSA/P, can lead to adenocarcinoma through the serrated pathway. Moreover, the data indicate that the SSA/P are the precursors of colorectal carcinoma by MSI and may be subject to rapid progression to malignancy. An important step to reduce the incidence of CRC initiated by the serrated pathway is to improve the detection of serrated polyps and to ensure their complete removal during endoscopy. Understanding of the so-called serrated carcinogenesis pathway is an important step forward in expanding possibilities in the prevention of CRC.

The molecular pathogenesis of colorectal cancer and its potential application to colorectal cancer screening

INTRODUCTION

Advances in our understanding of the molecular genetics and epigenetics of colorectal cancer have led to novel insights into the pathogenesis of this common cancer. These advances have revealed that there are molecular subtypes of colon polyps and colon cancer and that these molecular subclasses have unique and discrete clinical and pathological features. Although the molecular characterization of these subgroups of colorectal polyps and cancer is only partially understood at this time, it does appear likely that classifying colon polyps and cancers based on their genomic instability and/or epigenomic instability status will eventually be useful for informing approaches for the prevention and early detection of colon polyps and colorectal cancer.

CONCLUSIONS

In this review, we will discuss our current understanding of the molecular pathogenesis of the polyp to cancer sequence and the potential to use this information to direct screening and prevention programs.

Incident urothelial cancer in the Malmö Diet and Cancer Study: cohort characteristics and further validation of ezrin as a prognostic biomarker

BACKGROUND

Reduced membranous expression of the cytoskeleton-associated protein ezrin has previously been demonstrated to correlate with poor prognosis in urothelial bladder cancer in several independent studies. The present study provides a first description of clinicopathological characteristics of incident urothelial cancers, not only located to the bladder, in the prospective, population-based cohort study Malmö Diet and Cancer. In addition, the prognostic value of ezrin expression is validated in primary tumours, and the longitudinal expression of ezrin examined in a subset of primary and recurrent tumours (n=28).

METHODS

Among a total number of 355 incident tumours registered up until Dec 31 2010, 335 were located to the bladder. Immunohistochemical expression of cytoplasmic and membranous ezrin was evaluated in tissue microarrays with primary tumours from 272 cases and recurrent tumours from 28 cases. A combined score of the minimum, mean and maximum fraction and percentage of staining was calculated. Classification regression tree analysis was applied for selection of prognostic cutoff. Kaplan-Meier analysis, log rank test, univariable and multivariable Cox regression proportional hazards' modeling were used to evaluate the impact of ezrin expression on 5-year overall survival (OS).

RESULTS

Ezrin expression could be evaluated in 263/272 primary and all 28 recurrent tumours. Membranous but not cytoplasmic ezrin was significantly reduced in recurrent compared to primary tumours (p < 0.001). Low cytoplasmic and membranous ezrin expression were associated with more advanced T-stage (p = 0.004, p < 0.001) and high-grade tumours (p = 0.025, p < 0.001), but not with age, sex, tumour location or smoking status. Both low cytoplasmic and membranous ezrin staining were associated with a significantly reduced 5-year OS (HR = 1.65; 95% CI 1.06-2.57 and HR = 2.51, 95% CI 1.52-4.17), but only low membranous ezrin remained prognostic after adjustment for age, sex, stage, grade and smoking status (HR = 1.69, 95% CI 1.00-2.85).

CONCLUSIONS

This study provides a first description of the clinicopathological characteristics of 355 incident urothelial cancers in the Malmö Diet and Cancer Study up until 2010. In addition, the value of ezrin expression as a prognostic biomarker is further consolidated in this type of cancer.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_189.