scholarly journals The gut microbiome and potential implications for early-onset colorectal cancer

2020 ◽  
Vol 9 (3) ◽  
pp. CRC25
Author(s):  
Reetu Mukherji ◽  
Benjamin A Weinberg

Recently, there has been an unexpected trend toward increased incidence of colorectal cancer in younger individuals, particularly distal colon and rectal cancer in those under age 50. There is evidence to suggest that the human gut microbiome may play a role in carcinogenesis. The microbiome is dynamic and varies with age, geography, ethnicity and diet. Certain bacteria such as Fusobacterium nucleatum have been implicated in the development of colorectal and other gastrointestinal cancers. Recent data suggest that bacteria can alter the inflammatory and immune environment, influencing carcinogenesis, lack of treatment response and prognosis. Studies to date focus on older patients. Because the microbiome varies with age, it could be a potential explanation for the rise in early-onset colorectal cancer.

Gut ◽  
2020 ◽  
pp. gutjnl-2020-321661 ◽  
Author(s):  
Hanyu Chen ◽  
Xiaobin Zheng ◽  
Xiaoyu Zong ◽  
Zitong Li ◽  
Na Li ◽  
...  

ObjectiveFactors that lead to metabolic dysregulation are associated with increased risk of early-onset colorectal cancer (CRC diagnosed under age 50). However, the association between metabolic syndrome (MetS) and early-onset CRC remains unexamined.DesignWe conducted a nested case–control study among participants aged 18–64 in the IBM MarketScan Commercial Database (2006–2015). Incident CRC was identified using pathologist-coded International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes, and controls were frequency matched. MetS was defined as presence of ≥3 conditions among obesity, hypertension, hyperlipidaemia and hyperglycaemia/type 2 diabetes, based on ICD-9-CM and use of medications. Multivariable logistic regressions were used to estimate ORs and 95% CIs.ResultsMetS was associated with increased risk of early-onset CRC (n=4673; multivariable adjusted OR 1.25; 95% CI 1.09 to 1.43), similar to CRC diagnosed at age 50–64 (n=14 928; OR 1.21; 95% CI 1.15 to 1.27). Compared with individuals without a metabolic comorbid condition, those with 1, 2 or ≥3 conditions had a 9% (1.09; 95% CI 1.00 to 1.17), 12% (1.12; 95% CI 1.01 to 1.24) and 31% (1.31; 95% CI 1.13 to 1.51) higher risk of early-onset CRC (ptrend <0.001). No associations were observed for one or two metabolic comorbid conditions and CRC diagnosed at age 50–64. These positive associations were driven by proximal (OR per condition 1.14; 95% CI 1.06 to 1.23) and distal colon cancer (OR 1.09; 95% CI 1.00 to 1.18), but not rectal cancer (OR 1.03; 95% CI 0.97 to 1.09).ConclusionsMetabolic dysregulation was associated with increased risk of early-onset CRC, driven by proximal and distal colon cancer, thus at least in part contribute to the rising incidence of early-onset CRC.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. 1571-1571
Author(s):  
Hanyu Chen ◽  
Zitong Li ◽  
Xiaobin Zheng ◽  
Jinhee Hur ◽  
Xiaoyu Zong ◽  
...  

1571 Background: The etiology and contributors to the rising incidence of early-onset colorectal cancer (CRC diagnosed under age 50), driven largely by distal and rectal cancer, remain largely unknown. Metabolic syndrome is associated with higher risk of CRC diagnosed at older ages; however, its association with early-onset CRC remains unclear. Methods: We conducted a nested case-control study among participants aged 18-50 years with ≥2 years of enrollment and prescription drug coverage in the IBM MarketScan Commercial Databases (2006-2015). Incident CRC cases were identified using ICD-9-CM diagnosis codes. Controls without any cancer were identified using frequency matching on age, sex, geographical region, and duration of insurance enrollment. Metabolic syndrome was defined using either ICD-9-CM diagnosis codes or the presence of at least 3 of the following: obesity, hypertension, hyperlipidemia, and hyperglycemia/type 2 diabetes. In addition to ICD-9-CM codes, hypertension, hyperlipidemia, and hyperglycemia/type 2 diabetes were also defined based on regular use of medications. Multivariable logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: A total of 4,673 early-onset CRC and 40,832 controls were included. Metabolic syndrome was associated with increased risk of early-onset CRC (OR: 1.33, 95% CI 1.16-1.52), after adjusting for a range of potential confounders. The number of metabolic comorbid conditions was positively associated with risk of early-onset CRC in a dose-response fashion. Compared to individuals without any conditions, individuals with 1, 2, ≥3 metabolic conditions had a 13% (OR: 1.13, CI 1.04-1.22), 18% (OR: 1.18, CI 1.07-1.31), and 40% (OR: 1.40, CI 1.22-1.61) higher risk of early-onset CRC (Ptrend<0.001), respectively. These associations were driven by proximal (OR for ≥2 vs 0 metabolic comorbid conditions: 1.40, CI 1.15-1.69) and distal colon cancer, OR ≥2 vs 0: 1.25, CI 1.03-1.53), but not rectal cancer (OR≥2 vs 0: 1.07, CI 0.92-1.24). Conclusions: Metabolic syndrome and metabolic comorbid conditions were associated with increased risk of early-onset CRC, largely driven by proximal and distal colon cancer. Metabolic dysregulations may contribute to the rising incidence of early-onset CRC.


Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3829
Author(s):  
Alan Aitchison ◽  
Christopher Hakkaart ◽  
Robert C. Day ◽  
Helen R. Morrin ◽  
Frank A. Frizelle ◽  
...  

While overall colorectal cancer (CRC) cases have been declining worldwide there has been an increase in the incidence of the disease among patients under 50 years of age. Mutation of the APC gene is a common early event in CRC but is reported at lower rates in early-onset colorectal cancer (EOCRC) than in older patients. Here we investigate the APC mutation status of a cohort of EOCRC patients in New Zealand using a novel sequencing approach targeting regions of the gene encompassing the vast majority of known APC mutations. Using this strategy we find a higher rate (72%) of APC mutation than previously reported in EOCRC with mutations being spread throughout the gene rather than clustered in hotspots as seen with sporadic mutations in older patients. The rate of mutations falling within hotspots was similar to those previously seen in EOCRC and as such our study has implications for sequencing strategies for EOCRC patients. Overall there were low rates of both loss of heterozygosity and microsatellite instability whereas a relatively high rate (40%) of APC promoter methylation was found, possibly reflecting increasing exposure of young people to pro-oncogenic lifestyle factors.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mark Loftus ◽  
Sayf Al-Deen Hassouneh ◽  
Shibu Yooseph

Abstract Background Colorectal cancer is a leading cause of cancer-related deaths worldwide. The human gut microbiome has become an active area of research for understanding the initiation, progression, and treatment of colorectal cancer. Despite multiple studies having found significant alterations in the carriage of specific bacteria within the gut microbiome of colorectal cancer patients, no single bacterium has been unequivocally connected to all cases. Whether alterations in species carriages are the cause or outcome of cancer formation is still unclear, but what is clear is that focus should be placed on understanding changes to the bacterial community structure within the cancer-associated gut microbiome. Results By applying a novel set of analyses on 252 previously published whole-genome shotgun sequenced fecal samples from healthy and late-stage colorectal cancer subjects, we identify taxonomic, functional, and structural changes within the cancer-associated human gut microbiome. Bacterial association networks constructed from these data exhibited widespread differences in the underlying bacterial community structure between healthy and colorectal cancer associated gut microbiomes. Within the cancer-associated ecosystem, bacterial species were found to form associations with other species that are taxonomically and functionally dissimilar to themselves, as well as form modules functionally geared towards potential changes in the tumor-associated ecosystem. Bacterial community profiling of these samples revealed a significant increase in species diversity within the cancer-associated gut microbiome, and an elevated relative abundance of species classified as originating from the oral microbiome including, but not limited to, Fusobacterium nucleatum, Peptostreptococcus stomatis, Gemella morbillorum, and Parvimonas micra. Differential abundance analyses of community functional capabilities revealed an elevation in functions linked to virulence factors and peptide degradation, and a reduction in functions involved in amino-acid biosynthesis within the colorectal cancer gut microbiome. Conclusions We utilize whole-genome shotgun sequenced fecal samples provided from a large cohort of late-stage colorectal cancer and healthy subjects to identify a number of potentially important taxonomic, functional, and structural alterations occurring within the colorectal cancer associated gut microbiome. Our analyses indicate that the cancer-associated ecosystem influences bacterial partner selection in the native microbiota, and we highlight specific oral bacteria and their associations as potentially relevant towards aiding tumor progression.


2020 ◽  
Vol 158 (6) ◽  
pp. S-496
Author(s):  
Arif A. Arif ◽  
Daljeet Chahal ◽  
Caroline Speers ◽  
Mary A. De Vera ◽  
Sharlene Gill ◽  
...  

Author(s):  
Jeong Eun Kim ◽  
Jaeyong Choi ◽  
Chang-Ohk Sung ◽  
Yong Sang Hong ◽  
Sun Young Kim ◽  
...  

AbstractThe global incidence of early-onset colorectal cancer (EO-CRC) is rapidly rising. However, the reason for this rise in incidence as well as the genomic characteristics of EO-CRC remain largely unknown. We performed whole-exome sequencing in 47 cases of EO-CRC and targeted deep sequencing in 833 cases of CRC. Mutational profiles of EO-CRC were compared with previously published large-scale studies. EO-CRC and The Cancer Genome Atlas (TCGA) data were further investigated according to copy number profiles and mutation timing. We classified colorectal cancer into three subgroups: the hypermutated group consisted of mutations in POLE and mismatch repair genes; the whole-genome doubling group had early functional loss of TP53 that led to whole-genome doubling and focal oncogene amplification; the genome-stable group had mutations in APC and KRAS, similar to conventional colon cancer. Among non-hypermutated samples, whole-genome doubling was more prevalent in early-onset than in late-onset disease (54% vs 38%, Fisher’s exact P = 0.04). More than half of non-hypermutated EO-CRC cases involved early TP53 mutation and whole-genome doubling, which led to notable differences in mutation frequencies between age groups. Alternative carcinogenesis involving genomic instability via loss of TP53 may be related to the rise in EO-CRC.


Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3857
Author(s):  
Pilar Mur ◽  
Nuria Bonifaci ◽  
Anna Díez-Villanueva ◽  
Elisabet Munté ◽  
Maria Henar Alonso ◽  
...  

A large proportion of familial and/or early-onset cancer patients do not carry pathogenic variants in known cancer predisposing genes. We aimed to assess the contribution of previously validated low-risk colorectal cancer (CRC) alleles to familial/early-onset CRC (fCRC) and to serrated polyposis. We estimated the association of CRC with a 92-variant-based weighted polygenic risk score (wPRS) using 417 fCRC patients, 80 serrated polyposis patients, 1077 hospital-based incident CRC patients, and 1642 controls. The mean wPRS was significantly higher in fCRC than in controls or sporadic CRC patients. fCRC patients in the highest (20th) wPRS quantile were at four-fold greater CRC risk than those in the middle quantile (10th). Compared to low-wPRS fCRC, a higher number of high-wPRS fCRC patients had developed multiple primary CRCs, had CRC family history, and were diagnosed at age ≥50. No association with wPRS was observed for serrated polyposis. In conclusion, a relevant proportion of mismatch repair (MMR)-proficient fCRC cases might be explained by the accumulation of low-risk CRC alleles. Validation in independent cohorts and development of predictive models that include polygenic risk score (PRS) data and other CRC predisposing factors will determine the implementation of PRS into genetic testing and counselling in familial and early-onset CRC.


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