Risk factors for developing colorectal cancer in Japanese patients with ulcerative colitis: a retrospective observational study-CAPITAL (Cohort and Practice for IBD total management in Kyoto-Shiga Links) study I

A Systematic Review on the Increasing Incidence of Inflammatory Bowel Disease in Southeast Asia: Looking Beyond the Urbanization Phenomenon

The incidence of inflammatory bowel disease (IBD) has been increasing in Southeast Asia (SEA) in tandem with its economic growth and urbanization over the past 2 decades. Specific characteristics of IBD in SEA are similar to East Asia and the West, such as the declining ratio of ulcerative colitis to Crohn's disease. However, exceptionally low familial aggregation is seen. Smoking is also not a common risk factor in patients with Crohn's disease. The incidence of perianal disease is higher in SEA than in Australia and is comparable to the West. In a multiracial population, such as Singapore and Malaysia, Indians have the highest incidence and prevalence rates, which are likely to be due to important putative mutations. For instance, a higher frequency of the NOD2 predisposing mutation SNP5 and IBD risk allele IGR2198a and IGR2092a were found in Indians. Although differences in the genetic constitution play an important role in the epidemiology and prognosis of IBD in SEA, the emergence of this disease offers a unique opportunity to identify potential exposomes that contribute to its pathogenesis.

Predicting Colorectal Cancer Occurrence in IBD

Patients with colonic inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC), and are therefore enrolled into a surveillance programme aimed at detecting dysplasia or early cancer. Current surveillance programmes are guided by clinical, endoscopic or histological predictors of colitis-associated CRC (CA-CRC). We have seen great progress in our understanding of these predictors of disease progression, and advances in endoscopic technique and management, along with improved medical care, has been mirrored by the falling incidence of CA-CRC over the last 50 years. However, more could be done to improve our molecular understanding of CA-CRC progression and enable better risk stratification for patients with IBD. This review summarises the known risk factors associated with CA-CRC and explores the molecular landscape that has the potential to complement and optimise the existing IBD surveillance programme.

[How Should We Do Different Approach to Treat Inflammatory Bowel Disease by Gender Difference?]

Although not as prominent, there are gender/sex differences in incidence/prevalence, clinical manifestation and disease course, comorbidities, therapeutic response, and patients coping strategy to the disease of inflammatory bowel disease (IBD). In this review, current knowledge about gender-specific differences in IBD would be provided and how to apply this in clinical practice be discussed.

Sex matters: impact on pathogenesis, presentation and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD), as do most chronic inflammatory disorders, displays unique features and confers different risk factors in male and female patients. Importantly, sex-based differences in IBD exist for epidemiological incidence and prevalence among different age groups, with men and women developing distinct clinical symptoms and disparity in severity of disease. In addition, the presentation of comorbidities in IBD displays strong sex differences. Notably, particular issues exclusive to women's health, including pregnancy and childbirth, require specific considerations in female patients with IBD of childbearing age that can have a substantial influence on clinical outcomes. This Review summarizes the latest findings regarding sex-based differences in the epidemiology, clinical course, comorbidities and response to current therapies in patients with IBD. Importantly, the latest basic science discoveries in this area of investigation are evaluated to provide insight into potential mechanisms underlying the influence of sex on disease pathogenesis, as well as to design more personalized and efficacious care, in patients with IBD.

Risk of Colorectal Cancer in Ulcerative Colitis Patients: A Systematic Review and Meta-Analysis

Background

Ulcerative colitis (UC) patients have an increased risk for the development of colorectal cancer (CRC). Our aim was to assess the risk of CRC in UC patients compared with disease extent, disease duration, and geographic variation.

Methods

In this systematic review and meta-analysis, we searched PubMed, scientific meetings, and the bibliographies of identified articles, with English language restrictions for studies published from 1988 to 2018, and assessed the risk of CRC in UC patients. Patients with Crohn's disease, family history of CRC, and colorectal adenomatous polyp (CAP) were excluded from this research. The study was registered with PROSPERO, number CRD42018102213.

Findings

We included 58 studies that included 267566 UC patients. Extensive UC and left-sided UC had a higher risk of CRC than proctitis UC. Geography also played a role in UC-associated CRC development. The time of malignant transformation in Asian UC patients started after 10-20 years of this disease duration. North American UC-associated CRC patients significantly increased in more than 30 years of this disease duration.

Conclusion

In a systematic review of the literature, we found that disease extent, disease duration, and geography were strong, independent risk factors in UC-associated CRC development.

Whole Exome Sequencing of Ulcerative Colitis-associated Colorectal Cancer Based on Novel Somatic Mutations Identified in Chinese Patients

BACKGROUND

Carcinogenesis is a severe consequence of chronic ulcerative colitis. We investigated the somatic mutations and pathway alterations in ulcerative colitis-associated colorectal cancer (CRC) in Chinese patients compared with sporadic CRCs to reveal potential therapeutic targets in ulcerative colitis-associated CRC.

METHODS

Whole exome sequencing was performed on archival tumor tissues and paired adjacent nondysplastic mucosa from 10 ulcerative colitis-associated CRC patients at a high risk of carcinogenesis. Genomic alteration profiles from 223 primary CRCs from The Cancer Genome Atlas served as sporadic CRC controls. A meta-analysis was performed to investigate differences in major genetic mutations between ulcerative colitis-associated and Crohn's disease-associated CRCs.

RESULTS

We identified 44 nonsilent recurrent somatic mutations via whole exome sequencing, including 25 deleterious mutations involved in apoptosis and the PI3K-Akt pathway (COL6A3, FN1), autophagy (ULK1), cell adhesion (PODXL, PTPRT, ZFHX4), and epigenetic regulation (ARID1A, NCOR2, KMT2D, NCOA6, MECP2, SUPT6H). In total, 11 of the 25 mutated genes significantly differed between ulcerative colitis-associated CRC and sporadic CRC (APC, APOB, MECP2, NCOR2, NTRK2, PODXL, RABGAP1, SIK3, SUPT6H, ULK1, USP48). Somatic TP53 mutations occurred in 33% of ulcerative colitis-associated CRCs. Subsequent meta-analysis revealed distinct mutation profiles for Crohn's disease- and ulcerative colitis-associated CRCs. Mutations involving the NF-kB pathway and epigenetic regulation were more common in ulcerative colitis-associated CRCs than in sporadic CRCs.

CONCLUSION

Distinct genomic alteration profiles of deleterious somatic mutations were found in ulcerative colitis-associated and sporadic CRCs. Mutations of epigenetic regulators, such as KMT2D and NCOA6, were common, suggesting an epigenetic pathomechanism for colitis-associated carcinoma in Chinese patients.

Osteopontin Deficiency Suppresses Intestinal Tumor Development in Apc-Deficient Min Mice

Osteopontin (OPN) is a secreted phosphoglycoprotein, and is a transcriptional target of aberrant Wnt signaling. OPN is upregulated in human colon cancers, and is suggested to enhance cancer progression. In this study, the effect of deficiency of OPN on intestinal tumor development in Apc-deficient Min mice was investigated. At 16 weeks of age, the number of small intestinal polyps in Min/OPN(+/−) and Min/OPN(−/−) mice was lower than that of Min/OPN(+/+) mice. Colorectal tumor incidences and multiplicities in Min/OPN(+/−) and Min/OPN(−/−) mice were significantly lower than those in Min/OPN(+/+) mice, being 48% and 0.6 ± 0.8, 50% and 0.8 ± 0.9 vs. 80% and 1.6 ± 1.7, respectively. OPN expression in colorectal tumors was strongly upregulated in Min/OPN(+/+) compared to adjacent non-tumor parts, but was decreased in Min/OPN(+/−) and not detected in Min/OPN(−/−). Targets of OPN, matrix metalloproteinases (MMPs)-3, -9, and -13 were lowered by OPN deficiency. Macrophage marker F4/80 in colorectal tumors was also lowered by OPN deficiency. MMP-9 expression was observed in tumor cells and tumor-infiltrating neutrophils. These results indicate that induction of OPN by aberrant Wnt signaling could enhance colorectal tumor development in part by upregulation of MMP-3, -9, and -13 and infiltration of macrophage and neutrophils. Suppression of OPN expression could contribute to tumor prevention, but complete deficiency of OPN may cause some adverse effects.