Early-onset colorectal cancer: A sporadic or inherited disease?

Geographical Variations in Early Onset Colorectal Cancer in the United States between 2001 and 2020

BACKGROUND

Colorectal cancer remains the second leading cause of cancer-related death in the US. As early-onset colorectal cancer (EO-CRC) becomes more prevalent in the US, research attention has shifted towards identifying at-risk populations. Previous studies have highlighted the rising rate of early-onset adenocarcinoma (ADC) and neuroendocrine tumors (NET) in the US. However, data on geographical variations of EO-CRC are scarce. Hence, our study aims to analyze time trends in EO-CRC incidence rates across various US regions and to assess these trends by sex and histopathological subtypes (ADC and NET).

METHODS

We analyze data spanning from 2001 to 2020 from the United States Cancer Statistics (USCS) database, covering nearly 98% of the US population. Using SEER*Stat software version (8.4.2, NCI), we calculated EO-CRC incidence rates among adults aged 20-54 years, adjusting for the age standard 2000 US population. The rates were categorized by sex and US geographical regions into west, midwest, northeast, and south. Time trends, reported as annual percentage change (APC) and average APC (AAPC), were generated via Joinpoint Regression software (v.5.0.2, NCI) utilizing the weighted Bayesian Information Criteria "BIC" method to generate the best-fit trends with a two-sided p-value cutoff at 0.05. The rates were also stratified by histopathology into ADC and NET.

RESULTS

Between 2001 and 2020, a total of 514,875 individuals were diagnosed with early-onset CRC in the US, with 54.78% being men. Incidence rates and trends varied across geographical regions. In the western region (comprising 106,685 patients, 54.85% men), incidence rates significantly increased in both women (AAPC = 1.37, p < 0.001) and men (AAPC = 1.34, p < 0.001). Similarly, in the midwestern region (with 110,380 patients, 55.46% men), there were significant increases in incidence rates among women (AAPC = 1.06, p < 0.001) and men (AAPC = 1.35, p < 0.001). The northeastern region (with 94,758 patients, 54.53% men) also witnessed significant increases in incidence rates for both women (AAPC = 0.71, p < 0.001) and men (AAPC = 0.84, p < 0.001). In contrast, the southern region (with 203,052 patients, 54.48% men) experienced slower increases in incidence rates among both women and men (AAPC = 0.25, p < 0.05 in women; AAPC = 0.66, p < 0.05 in men). When stratified by histopathology, incidence rates for adenocarcinomas (ADC) increased in all regions, most notably in the west (AAPC = 1.45, p < 0.05), and least in the south (AAPC = 0.46, p < 0.05). Conversely, for neuroendocrine tumors (NET), while incidence rates increased similarly across all regions, the pace was notably faster compared to ADC, particularly in the west (AAPC = 3.26, p < 0.05) and slower in the south (AAPC = 2.24, p < 0.05) Discussion: Our analysis of nationwide US data spanning two decades and encompassing over half a million early-onset CRC patients, representing nearly 98% of the US population, highlights significant temporal variation in incidence rates across various geographical regions. The most substantial increases in incidence rates were observed in the west, while the least pronounced changes were noted in the south, affecting both men and women. These trends persisted across the main CRC histopathological subtypes, with NET exhibiting a notably swifter pace of increase compared with ADC. These findings hold important implications for public health strategies and underscore the need for targeted interventions to address the rising burden of early-onset CRC across different regions in the US.

Early-Onset Colorectal Cancer: Are Neuroendocrine Tumors or Adenocarcinomas the Culprit? Analysis of the Largest U.S. Cancer Incidence Database, 2001-2020

(1) Background: While prior data showed an increasing incidence of colorectal cancer (CRC) in young adults, the contribution of adenocarcinoma (ADC) and neuroendocrine tumors (NETs) to this trend is not well studied. Therefore, we conducted a comparative analysis of the incidence rates and time trends of colorectal ADC and NETs in young adults (aged 24-54) using the United States Cancer Statistics (USCS) database. (2) Methods: Age-adjusted CRC incidence rates between 2001 and 2020 were calculated and categorized by sex, histopathology, and stage at diagnosis. Annual percentage change (APC) and average APC (AAPC) were computed via joinpoint regression utilizing weighted Bayesian information criteria to generate the simplest trend. Pairwise comparative analysis of ADC and NETs was conducted using tests of identicalness and parallelism. (3) Results: In this study, 514,875 patients were diagnosed with early-onset-CRC between 2001 and 2020 (54.8% men). While CRC incidence was significantly increased, including both ADC (448,670 patients) and NETs (36,205 patients), a significantly greater increase was seen for NETs (AAPC = 2.65) compared to ADC (AAPC = 0.91), with AAPC difference = 1.73 (p = 0.01) and non-identical non-parallel trends (p-values < 0.001). This was most notable in males (AAPC difference = 1.81, p = 0.03) and for early-stage tumors (AAPC difference = 3.56, p < 0.001). (4) Conclusions: Our study, covering ~98% of the U.S. population provides the first comparative analysis of early-onset CRC histopathological subtypes, showing that the rate of increase of NETs in young adults is much greater than that of ADC. Given that patients with NETs with malignant behavior can experience significant mortality, our findings are importance, highlighting the rapidly increasing NET incidence in young adults and encouraging early screening that can improve outcomes.

Distinct intratumoral microbiome of young-onset and average-onset colorectal cancer

BACKGROUND

The unexplained rise of young-onset CRC (yoCRC, age <50 years) is of concern. Evidence suggests that microbial dysbiosis may be a contributing factor, but the tumor microbial profile of yoCRC in comparison to average-onset CRC (aoCRC, age >60) has not been fully investigated.

METHODS

16S rRNA amplicon sequencing was performed in tumor and paired adjacent non-malignant fresh frozen tissue specimens prospectively collected from 136 yoCRC and 140 aoCRC patients. Phyloseq, microbiomeSeq, metagenomeSeq, and NetComi were utilized for bioinformatics analysis. Statistical tests included Fisher's exact test, ANOVA, PERMANOVA with Bonferroni correction, linear regression, and Wilcoxon test. p-value <0.05 was considered statistically significant.

FINDINGS

yoCRC patients were more likely to have left-sided (72.8 vs. 54.3%), rectal (36.7% vs. 25%), and stage IV (28% vs. 15%) tumors. yoCRC tumors had significantly higher microbial alpha diversity (p = 1.5 × 10-5) and varied beta diversity (R2 = 0.31, p = 0.013) than aoCRC tumors. yoCRC tumors were enriched with Akkermansia and Bacteroides, whereas aoCRC tumors showed greater relative abundances of Bacillus, Staphylococcus, Listeria, Enterococcus, Pseudomonas, Fusobacterium, and Escherichia/Shigella. Akkermansia had a predominantly negative correlation with the microbial communities in yoCRC tumors. yoCRC and aoCRC tumors had distinct microbial profiles associated with tumor location, sidedness, stage, and obesity. Fusobacterium (R2 = -0.23, p = 0.001) and Akkermansia (R2 = 0.05, p = 0.001) abundance correlated with overall survival in yoCRC.

INTERPRETATION

Our study provides a comprehensive understanding of the microbial perturbations in yoCRC tumors. We identify microbial candidates that may highlight a distinct pathogenesis of yoCRC and serve as preventive, diagnostic, and therapeutic targets.

FUNDING

Sondra and Stephen Hardis Chair in Oncology Research (A.A.K.).

Referral challenges for early-onset colorectal cancer: a qualitative study in UK primary care

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC) in adults aged <50 years has increased in several Western nations. National surveys have highlighted significant barriers to accessing timely care for patients with EOCRC, which may be contributing to a late stage of presentation in this population group.

AIM

To explore awareness of the increasing incidence of EOCRC, and to understand the potential barriers or facilitators faced by GPs when referring younger adults to secondary care with features indicative of EOCRC.

DESIGN & SETTING

Qualitative methodology, via virtual semi-structured interviews with 17 GPs in Northern Ireland.

METHOD

Reflective thematic analysis was conducted with reference to Braun and Clarke's framework.

RESULTS

Three main themes were identified among participating GPs: awareness, diagnostic, and referral challenges. Awareness challenges focused on perceptions of EOCRC being solely associated with hereditary cancer syndromes, and colorectal cancer being a condition of older adults. Key diagnostic challenges centred around the commonality of lower gastrointestinal complaints and overlap in EOCRC symptoms with benign conditions. Restrictions in age-based referral guidance and a GP 'guilt complex' surrounding over-referral to secondary care summarised the referral challenges. Young females were perceived as being particularly disadvantaged with regard to delays in diagnosis.

CONCLUSION

This novel research outlines potential reasons for the diagnostic delays seen in patients with EOCRC from a GP perspective, and highlights many of the complicating factors that contribute to the diagnostic process.

Clinical and pathological characteristics of early-onset colorectal cancer in South Korea

Background

Early-onset colorectal cancer (EOCRC) may differ by race and ethnicity, and recently South Korea has witnessed a surge in cases. We aimed to evaluate the clinical and pathological features of patients with EOCRC, and to determine the predictors of overall survival.

Methods

In this retrospective study, EOCRC was defined as CRC diagnosed in patients aged < 50 years, and late-onset CRC was defined as CRC diagnosed in those over 75 years of age. The clinical and pathological characteristics of patients with EOCRC were compared with late-onset CRC. We also used multivariable Cox proportional hazard models to find predictors of overall survival in patients with EOCRC.

Results

The proportion of early-onset CRC was 9.1% of 518 patients with CRC, and the clinical and pathological characteristics were similar between early-onset (n = 47) and late-onset CRC (n = 134). However, EOCRC had a preponderance for distal tumor location (70.2% vs. 50.7%, P = 0.02) and T1-2 stage disease (23.4% vs. 11.2%, P = 0.04), compared with those of late-onset CRC. Using multivariable Cox proportional hazard models, only vascular invasion (hazard ratio = 8.75, 95% confidence interval 1.139‒67.197) was found to be a risk factor for overall survival (P = 0.04) for patients with CRC.

Conclusion

EOCRC had preponderance for distal tumor location and early T-stage disease, compared with late-onset CRC. Considering the increasing incidence of EOCRC, more studies on clinical and pathological characteristics of EOCRC may be warranted.

ANALYSIS OF THE TRACKING INITIATIVES OF COLORECTAL CANCER IN BRAZIL

BACKGROUND

Colorectal cancer (CRC) is an important public health problem, as it represents the world's third most diagnosed neoplasm and the fourth cause of mortality. Its prevention can be divided into primary, secondary, demonstrated by tracking techniques, and tertiary, which consists of cancer diagnosis in symptomatic patients. Despite presenting a high incidence, the mortality rates decreased in the past two decades in developed countries, while the opposite happened in underdeveloped countries. That is attributed to the increase of colorectal cancer tracking programs in developed countries, which allows the precocious diagnosis and treatment of precancerous injuries and CRC. In that manner, the American Cancer Society divides the secondary tracking methods in exams based on feces samples and visual analysis of the colon and rectum, indicating its initiation starting at 45 years old in lower-risk patients.

OBJECTIVE

Verify in an analytical way the actions of colorectal cancer tracking held in Brazil, as to evaluate the necessity of implementation of a national tracking program of CRC.

METHODS

The methodology was based on a descriptive-quantitative secondary study that correlated the incidence of CRC, its morbidity and mortality, and the impact of the precocious tracking programs. It included activities not reported in medical literature through personal contacts with coordinators of regional programs to compare with the existent data in the literature. It was used as a variable for the tracking strategies the exams held, and their respective results.

RESULTS

It described nine programs held in different regions in Brazil, using two screening methods for CRC: a noninvasive method that consists of the research of blood hidden in feces, being the majority through the FIT method, and an invasive method, having the colonoscopy as its representant. These initiatives were effective in the detection of early forms of this disease.

CONCLUSION

Despite the existence of several private tracking programs and the broad divulgation of the importance of the tracking and the early diagnosis of colorectal cancer, it was demonstrated that Brazil lacks a national program that patronizes the tracking methods, which reflects in the major prevalence of late diagnosis in the population.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

Young-onset colorectal cancer

In the past decades the incidence of colorectal cancer (CRC) in people under the age of 50 years has increased, which is referred to as early-onset CRC or young-onset CRC (YO-CRC). YO-CRC is expected to account for 11% of colon cancers and 23% of rectal cancers by 2030. This trend is observed in different parts of the world and in both men and women. In 20% of patients with YO-CRC, a hereditary cancer syndrome is found as the underlying cause; however, in the majority of patients no genetic predisposition is present. Beginning in the 1950s, major changes in lifestyle such as antibiotic use, low physical activity and obesity have affected the gut microbiome and may be an important factor in YO-CRC development. Owing to a lack of screening, patients with YO-CRC are often diagnosed with advanced-stage disease. Long-term treatment-related complications should be taken into account in these younger patients, making the more traditional sequential approaches of drug therapy not always the most appropriate option. To better understand the underlying mechanism and define relationships between environmental factors and YO-CRC development, long-term prospective studies are needed with lifestyle data collected from childhood.

Impact of Institutional Universal Microsatellite-Instability (MSI) Reflex Testing on Molecular Profiling Differences Between Younger and Older Patients with Colorectal Cancer

INTRODUCTION

DNA mismatch repair deficient (dMMR) or microsatellite instability-high (MSI-H) colorectal cancer (CRC) is found in about 15% of early-stage diseases and 5% of metastatic diseases. We reviewed a large, single-institutional database after implementation of universal reflex dMMR/MSI-H testing in CRC to compare profiles of younger (≤50) and older (>50) patients.

PATIENTS AND METHODS

Between 2009 and 2017, all patients diagnosed with CRC at the University of Florida underwent reflex somatic tumor testing for dMMR by immunohistochemistry (MLH1, PMS2, MSH2, MSH6), MSI by PCR, and Next-Generation Sequencing. Statistical analysis was conducted with 2-sample comparison tests and logistic regression models.

RESULTS

There were 375 patients included in the final analysis. Patients were grouped as younger (ages ≤50 years-old; n = 80) or older (>50 years-old; n = 295). Compared to tumors from older patients, tumors from younger patients were less likely to be dMMR/MSI-H (12.5% vs. 21.4%, P = .013) and less likely to have a BRAF mutation (1.5% vs. 16.1%, P = .002). BRAF mutation status was highly associated with MMR status; BRAF-mutated tumors were 29.7 times more likely than BRAF-WT tumors to be dMMR/MSI-H (P = < .001, 95% CI 11.3-78.3).

CONCLUSIONS

Tumors of younger patients were less likely than tumors of older patients to have a dMMR/MSI-H or BRAF mutation. Universal MMR/MSI testing in our dataset identified a relatively large population of older patients with sporadic CRC who were eligible for immunotherapy.

A review of the cost-effectiveness of genetic testing for germline variants in familial cancer

BACKGROUND

Targeted germline testing is recommended for those with or at risk of breast, ovarian, or colorectal cancer. The affordability of genetic sequencing has improved over the past decade, therefore the cost-effectiveness of testing for these cancers is worthy of reassessment.

OBJECTIVE

To systematically review economic evaluations on cost-effectiveness of germline testing in breast, ovarian, or colorectal cancer.

METHODS

A search of PubMed and Embase databases for cost-effectiveness studies on germline testing in breast, ovarian, or colorectal cancer, published between 1999 and May 2022. Synthesis of methodology, cost-effectiveness, and reporting (CHEERS checklist) was performed.

RESULTS

The incremental cost-effectiveness ratios (ICERs; in 2021-adjusted US$) for germline testing versus the standard care option in hereditary breast or ovarian cancer (HBOC) across target settings were as follows: (1) population-wide testing: 344-2.5 million/QALY; (2) women with high-risk: dominant = 78,118/QALY, 8,337-59,708/LYG; (3) existing breast or ovarian cancer: 3,012-72,566/QALY, 39,835/LYG; and (4) metastatic breast cancer: 158,630/QALY. Likewise, ICERs of germline testing for colorectal cancer across settings were: (1) population-wide testing: 132,200/QALY, 1.1 million/LYG; (2) people with high-risk: 32,322-76,750/QALY, dominant = 353/LYG; and (3) patients with existing colorectal cancer: dominant = 54,122/QALY, 98,790-6.3 million/LYG. Key areas of underreporting were the inclusion of a health economic analysis plan (100% of HBOC and colorectal studies), engagement of patients and stakeholders (95.4% of HBOC, 100% of colorectal studies) and measurement of outcomes (18.2% HBOC, 38.9% of colorectal studies).

CONCLUSION

Germline testing for HBOC was likely to be cost-effective across most settings, except when used as a co-dependent technology with the PARP inhibitor, olaparib in metastatic breast cancer. In colorectal cancer studies, testing was cost-effective in those with high-risk, but inconclusive in other settings. Cost-effectiveness was sensitive to the prevalence of tested variants, cost of testing, uptake, and benefits of prophylactic measures. Policy advice on germline testing should emphasize the importance of these factors in their recommendations.

Colorectal cancer-associated SNP rs17042479 is involved in the regulation of NAF1 promoter activity

A novel risk locus at 4q32.2, located between the Nuclear Assembly Factor 1 (NAF1) and Follistatin Like 5 (FSTL5) genes, was associated with increased risk of developing colorectal cancer (CRC), with SNP rs17042479 being the most associated. However, the link between CRC development and the risk locus at 4q32.2 is unknown. We investigated the promoter activity of NAF1 and FSTL5 and analyzed the risk locus at 4q32.2 as gene regulatory region. Our results showed that the activity of the FSTL5 promoter was low compared to the NAF1 promoter. Analyses of the NAF1 promoter in conjunction with the region containing the risk locus at 4q32.2 showed that the region functions as gene regulatory region with repressor activity on NAF1 promoter activity. The SNP rs17042479(G) increased the repressor effect of the region. CRC patients’ biopsies were genotyped for SNP rs17042479(A/G), and NAF1 expression profiles were examined. We found an association between SNP rs17042479(G), cancer stage and tumor location. Additionally, patients with SNP rs17042479(G) showed lower NAF1 expression in comparison to patients with SNP rs17042479(A) in tumor tissue and the NAF1 expression in tumor tissue was lower compared to healthy tissue. The results in the study imply that reduced NAF1 expression in the tumor contribute to a more aggressive phenotype. Furthermore, this study suggests that the SNP rs17042479(G) change the expression of NAF1 and thereby increases the risk of developing CRC.

Colorectal Cancer-Infiltrating Regulatory T Cells: Functional Heterogeneity, Metabolic Adaptation, and Therapeutic Targeting

Colorectal cancer (CRC) is a heterogeneous disease with one of the highest rates of incidence and mortality among cancers worldwide. Understanding the CRC tumor microenvironment (TME) is essential to improve diagnosis and treatment. Within the CRC TME, tumor-infiltrating lymphocytes (TILs) consist of a heterogeneous mixture of adaptive immune cells composed of mainly anti-tumor effector T cells (CD4+ and CD8+ subpopulations), and suppressive regulatory CD4+ T (Treg) cells. The balance between these two populations is critical in anti-tumor immunity. In general, while tumor antigen-specific T cell responses are observed, tumor clearance frequently does not occur. Treg cells are considered to play an important role in tumor immune escape by hampering effective anti-tumor immune responses. Therefore, CRC-tumors with increased numbers of Treg cells have been associated with promoting tumor development, immunotherapy failure, and a poorer prognosis. Enrichment of Treg cells in CRC can have multiple causes including their differentiation, recruitment, and preferential transcriptional and metabolic adaptation to the TME. Targeting tumor-associated Treg cell may be an effective addition to current immunotherapy approaches. Strategies for depleting Treg cells, such as low-dose cyclophosphamide treatment, or targeting one or more checkpoint receptors such as CTLA-4 with PD-1 with monoclonal antibodies, have been explored. These have resulted in activation of anti-tumor immune responses in CRC-patients. Overall, it seems likely that CRC-associated Treg cells play an important role in determining the success of such therapeutic approaches. Here, we review our understanding of the role of Treg cells in CRC, the possible mechanisms that support their homeostasis in the tumor microenvironment, and current approaches for manipulating Treg cells function in cancer.

Trends in Early-onset vs Late-onset Colorectal Cancer Incidence by Race/Ethnicity in the United States Cancer Statistics Database

BACKGROUND & AIMS

Colorectal cancer (CRC) incidence has decreased overall in the last several decades, but it has increased among younger adults. Prior studies have characterized this phenomenon in the United States (U.S.) using only a small subset of cases. We describe CRC incidence trends using high-quality data from 92% of the U.S. population, with an emphasis on those younger than 50 years.

METHODS

We obtained 2001 to 2016 data from the U.S. Cancer Statistics database and analyzed CRC incidence for all age groups, with a focus on individuals diagnosed at ages 20 to 49 years (early-onset CRC). We compared incidence trends stratified by age, as well as by race/ethnicity, sex, region, anatomic site, and stage at diagnosis.

RESULTS

We observed 191,659 cases of early-onset and 1,097,765 cases of late-onset CRC during the study period. Overall, CRC incidence increased in every age group from 20 to 54 years. Whites were the only racial group with a consistent increase in incidence across all younger ages, with the steepest rise seen after 2012. Hispanics also experienced smaller increases in incidence in most of the younger age groups. Asians/Pacific Islanders and blacks saw no increase in incidence in any age group in 2016, but blacks continued to have the highest incidence of CRC for every age group. Greater increase in early-onset CRC incidence was observed for males, left-sided tumors, and regional and distant disease.

CONCLUSIONS

Early-onset CRC incidence increased overall from 2001 to 2016, but the trends were markedly different for whites, blacks, Asians/Pacific Islanders, and Hispanics. These results may inform future research on the risk factors underlying early-onset CRC.

Do We Underestimate Colorectal Cancer Patients Under 50?

&lt;b&gt; Introduction:&lt;/b&gt; Early-onset colorectal cancer (EOCRC) accounts for approximately 10% of all colorectal cancers (CRCs). EOCRC has a certain hereditary predisposition and distinct clinicopathological and molecular features compared to the traditional average-onset of colorectal cancer (AOCRC). As previous publications have shown, EOCRC has a more advanced TNM stage and a more aggressive tumor histopathology. &lt;/br&gt;&lt;/br&gt; &lt;b&gt; Aim:&lt;/b&gt; In this study, we aimed to evaluate the differences and similarities of EOCRC compared to AOCRC based on clinicopathological characteristics. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Material and methods:&lt;/b&gt; Between January 2010 and December 2020, 394 patients with inclusion criteria who were operated on at the 3rd level health center for colorectal cancer were included in the study. Patients were divided into two groups as EOCRC (50 years and under) and AOCRC. Pearson&apos;s chi-square test was used to compare categorical variables in independent groups. In addition, logistic regression analysis was performed using the Backward method with the variables whose relationship with the age group was evaluated, with P &lt; 0.100. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Results:&lt;/b&gt; Our final analysis included 80 EOCRC cases and 314 controls. When the EOCRC group was compared with the AOCRC group, there was no statistically significant difference between gender, tumor location, T stage of the tumor, and survival (P = 0.190, P = 0.924, P = 0.165, P = 0.574). However, a statistically significant difference in the N stage, degree of differentiation, lymphovascular invasion (LVI) and perineural invasion (PNI) status, and P-values were: P = 0.006, P = 0.029, P = 0.019, and P = 0.003, respectively. &lt;/br&gt;&lt;/br&gt; &lt;b&gt;Conclusion:&lt;/b&gt; EOCRC has more aggressive tumor biology than AOCRC. Our study shows that more advanced N stage, poor differentiation, tumor deposits, LVI, and PNI are seen more frequently in EOCRC.

miR‑31‑5p‑DMD axis as a novel biomarker for predicting the development and prognosis of sporadic early‑onset colorectal cancer

The incidence of colorectal cancer (CRC) is increasing in young adults, but knowledge regarding the molecular features of sporadic early-onset colorectal cancer (SEOCRC) is limited. The objective of the present study was to investigate potential key tumorigenesis-associated genes and their regulatory microRNAs (miRNAs) in SEOCRC. Using miRNA and mRNA expression screening of SEOCRC and sporadic late-onset colorectal cancer (SLOCRC) by next generation sequencing (NGS) and bioinformatics, the SEOCRC-associated miRNAome and transcriptome were analyzed. In SEOCRC miRNA and mRNA expression profiles, the tumorigenesis-associated genes and their regulatory miRNAs were analyzed according to the miRTarBase database, and specific miRNA-mRNA pairs were selected as the candidate biomarkers in SEOCRC, which were further verified in another cohort of SEOCRC and SLOCRC patients' colon cancer and paracancerous tissues using reverse transcription-quantitative PCR and immunohistochemistry. Moreover, the clinical relevance of these paired signatures to clinicopathological features was determined in 80 patients with SEOCRC. The expression of dystrophin (DMD) was downregulated and that of miR-31-5p was upregulated in SEOCRC tissue compared with adjacent peritumoral tissue. While DMD and miR-31-5p were not differentially expressed in SLOCRC tissues compared with that in adjacent peritumoral tissues. The miR-31-5p-DMD axis was identified as the key regulatory axis specific to SEOCRC, and DMD expression was closely associated with TNM stage and lymph node metastasis. Importantly, Kaplan-Meier analysis revealed that patients with low DMD expression had significantly poorer overall survival, cancer specific survival and recurrence free survival compared with those with high expression of DMD. In conclusion, the miR-31-5p-DMD axis may serve as a novel biomarker in predicting the development of SEOCRC, and DMD can be used as a promising biomarker for the prognosis of SEOCRC.

An Insight into miR-1290: An Oncogenic miRNA with Diagnostic Potential

For more than two decades, the view of the roles of non-coding RNAs (ncRNAs) has been radically changing. These RNA molecules that are transcribed from our genome do not have the capacity to encode proteins, but are critical regulators of gene expression at different levels. Our knowledge is constantly enriched by new reports revealing the role of these new molecular players in the development of many pathological conditions, including cancer. One of the ncRNA classes includes short RNA molecules called microRNAs (miRNAs), which are involved in the post-transcriptional control of gene expression affecting various cellular processes. The aberrant expression of miRNAs with oncogenic and tumor-suppressive function is associated with cancer initiation, promotion, malignant transformation, progression and metastasis. Oncogenic miRNAs, also known as oncomirs, mediate the downregulation of tumor-suppressor genes and their expression is upregulated in cancer. Nowadays, miRNAs show promising application in diagnosis, prediction, disease monitoring and therapy response. Our review presents a current view of the oncogenic role of miR-1290 with emphasis on its properties as a cancer biomarker in clinical medicine.

Colorectal Cancer in North-Eastern Iran: a retrospective, comparative study of early-onset and late-onset cases based on data from the Iranian hereditary colorectal cancer registry

BACKGROUND

The incidence rate of colorectal cancer (CRC) is increasing among patients below 50 years of age. The reason for this is unclear, but could have to do with the fact that indicative variables, such as tumour location, gender preference and genetic preponderance have not been followed up in a consistent mann er. The current study was primarily conducted to improve the hereditary CRC screening programme by assessing the demographic and clinicopathological characteristics of early-onset CRC compared to late-onset CRC in northeast Iran.

METHODS

This retrospective study, carried out over a three-year follow-up period (2014-2017), included 562 consecutive CRCs diagnosed in three Mashhad city hospital laboratories in north-eastern Iran. We applied comparative analysis of pathological and hereditary features together with information on the presence of mismatch repair (MMR) gene deficiency with respect to recovery versus mortality. Patients with mutations resulting in absence of the MMR gene MLH1 protein product and normal BRAF status were considered to be at high risk of Lynch syndrome (LS). Analyses using R studio software were performed on early-onset CRC (n = 222) and late-onset CRC (n = 340), corresponding to patients ≤50 years of age and patients > 50 years.

RESULTS

From an age-of-onset point of view, the distribution between the genders differed with females showing a higher proportion of early-onset CRC than men (56% vs. 44%), while the late-onset CRC disparity was less pronounced (48% vs. 52%). The mean age of all participants was 55.6 ± 14.8 years, with 40.3 ± 7.3 years for early-onset CRC and 65.1 ± 9.3 years for late-onset CRC. With respect to anatomical tumour location (distal, rectal and proximal), the frequencies were 61, 28 and 11%, respectively, but the variation did not reach statistical significance. However, there was a dramatic difference with regard to the history of CRC in second-degree relatives between two age categories, with much higher numbers of family-related CRCs in the early-onset group. Expression of the MLH1 and PMS2 genes were significantly different between recovered and deceased, while this finding was not observed with regard to the MSH6 and the MSH2 genes. Mortality was significantly higher in those at high risk of LS.

CONCLUSION

The variation of demographic, pathological and genetic characteristics between early-onset and late-onset CRC emphasizes the need for a well-defined algorithm to identify high-risk patients.

The role of anaerobic bacteria in the development and prevention of colorectal cancer: A review study

Colorectal cancer (CRC) is the third most frequently diagnosed cancer in both males and females in the Unites States. Colonoscopy is considered a safe method for screening this disorder; however, it can be challenging for patients. As research on microbiota, especially anaerobic microbiota, has expanded substantially, new links have been determined between anaerobic bacteria and CRC progression. These associations can be useful in screening CRC in the near future. This review discusses current research investigating the presence of anaerobic bacteria, including Bacteroides fragilis, Peptostreptococcus anaerobius, Clostridium septicum, Porphyromonas gingivalis, Fusobacterium nucleatum, and Parvimonas micra in CRC and presents an overview about their mechanisms of action. We also discuss the current anaerobic probiotics used for the treatment and prevention of CRC.

Colorectal cancer patients in a tertiary hospital in Indonesia: Prevalence of the younger population and associated factors

BACKGROUND

An increasing trend in colorectal cancer (CRC) occurring at younger ages has been observed worldwide, even though incidence is declining in the general population. Most currently available guidelines still recommend CRC screening for older populations, despite an alarming rise in early-onset CRC incidence. Risk stratification is necessary to further determine the population most at risk for early-onset CRC. However, epidemiological data on related clinical characteristics and potential risk factors, especially in developing countries, have not been widely reported.

AIM

To investigate the prevalence, demographics, clinicopathologic features, and associated factors of young-onset CRC patients in a tertiary hospital in Indonesia.

METHODS

Patients undergoing colonoscopy examination between 2008 and 2019, yielding a diagnosis of CRC were identified from medical records. The subjects were classified into two groups according to their age at diagnosis, namely early-onset (18-49 years old) and late-onset (≥ 50-years-old). Demographic data, characteristics, and risk factors of both onset age groups were evaluated using the chi-square and Fisher’s exact test.

RESULTS

Among 495 CRC patients confirmed by histopathology, 205 (41.4%) were classified as early-onset and 290 (58.6%) as late-onset. Most subjects in the early-onset CRC group were male (53.7%), with 89.8% displaying adenocarcinoma histopathology. A majority (78%) of the early-onset CRC patients had left-sided tumors, with the rectum (41%) and rectosigmoid (17.6%) being the most common sites. Abdominal pain was the most frequent symptom in the early-onset CRC patients (55.6%), which was significantly higher than that in the late-onset CRC patients (43.8%, P < 0.05). Early-onset CRC cases were more likely to be underweight (34.6% vs 20.0%, P < 0.001) compared to late-onset CRC cases. The proportion of subjects with suspected hereditary nonpolyposis colorectal cancer (HNPCC) was also higher in the early-onset CRC group than in the late-onset age group (9.3% vs 4.1%, P < 0.05). However, no difference was observed in the parental or family histories of CRC cases.

CONCLUSION

Early-onset CRC patients were more likely to have abdominal pain, underweight status, and HNPCC suspicion than late-onset CRC patients.

Regulation of signal transduction pathways in colorectal cancer: implications for therapeutic resistance

Resistance to anti-cancer treatments is a critical and widespread health issue that has brought serious impacts on lives, the economy and public policies. Mounting research has suggested that a selected spectrum of patients with advanced colorectal cancer (CRC) tend to respond poorly to both chemotherapeutic and targeted therapeutic regimens. Drug resistance in tumours can occur in an intrinsic or acquired manner, rendering cancer cells insensitive to the treatment of anti-cancer therapies. Multiple factors have been associated with drug resistance. The most well-established factors are the emergence of cancer stem cell-like properties and overexpression of ABC transporters that mediate drug efflux. Besides, there is emerging evidence that signalling pathways that modulate cell survival and drug metabolism play major roles in the maintenance of multidrug resistance in CRC. This article reviews drug resistance in CRC as a result of alterations in the MAPK, PI3K/PKB, Wnt/β-catenin and Notch pathways.

Advances in Understanding Early-Onset Colorectal Cancer

Since the 1990s, the incidence of early-onset colorectal cancer (at <50 years of age) in the US has increased by more than 50%; similar increases have also been observed internationally. These increases are found particularly among individuals born during and after the 1960s, raising the possibility that the increased rates of early-onset colorectal cancer are attributable to changes in risk-factor patterns throughout successive generations. The reasons for these alarming epidemiologic patterns for early-onset colorectal cancer worldwide are only recently being investigated and major gaps in our knowledge remain. In the current issue of this journal, Arif and colleagues differentiated characteristics and outcomes of early-onset colorectal cancer in patients with the predisposing conditions of inflammatory bowel disease or hereditary genetic syndromes, compared with patients who have sporadic disease. Also, in this issue, Schumacher and colleagues investigated risk factors for early-onset colorectal adenocarcinoma in a nested case-control study among Kaiser Permanente Southern California (KPSC) health plan members. The research presented on characteristics and outcomes points to the importance of sporadic disease in the rise of early-onset colorectal cancer, while the research presented on risk factors points to the importance of obesity as a potential explanatory factor for this rise.See related articles by Arif et al., p. 1785 and by Schumacher et al., p. 1792.

Young-onset colorectal cancer: A review

Despite the general decrease in overall incidence of colorectal cancer since the early 1990s, the incidence of colorectal cancer in patients less than 50 years old has nearly doubled. A systematic review was performed using the PubMed database (2011-2020) and Cochrane Database of Systematic Reviews (2011-2021) to identify studies (published in English) evaluating epidemiologic, clinical, hereditary, and molecular features; as well as evaluation, management, and prognosis of young-onset colorectal cancer patients. Our search yielded a total of 3401 articles, after applying our inclusion criteria. We fully reviewed 94 full-length studies. This systematic review demonstrates the increasing incidence of young-onset colorectal cancer and highlights the importance of being hypervigilant for the differential diagnosis colorectal cancer when evaluating a young adult who presents with gastrointestinal symptoms.

Metabolic Risk Factors Associated with Early-Onset Colorectal Adenocarcinoma: A Case-Control Study at Kaiser Permanente Southern California

BACKGROUND

The incidence of early-onset colorectal cancer (eoCRC) diagnosed among individuals under age 50 has been rising. However, risk factors for eoCRC are unclear. We investigated whether metabolic abnormalities are risk factors for eoCRC adenocarcinoma.

METHODS

Invasive colorectal adenocarcinoma cases diagnosed between ages 15 and 49 from 2008 to 2018 at Kaiser Permanente Southern California (KPSC) were identified. Those with a history of inflammatory bowel disease were excluded. Noncancer controls were selected 5:1 for each case matched by age, sex, and length of membership prior to index date. Data were collected from KSPC's electronic medical records. The exposures of interest included obesity, type II diabetes, hypertension, and dyslipidemia, assessed from ≥1 year prior to eoCRC diagnosis/index date. Conditional logistic regressions were used to evaluate the associations between these metabolic risk factors and risk of eoCRC adenocarcinoma, adjusting for race/ethnicity, smoking, family history, neighborhood socioeconomic status, and health care utilization.

RESULTS

A total of 1,032 cases and 5,128 controls were included. Risk of colorectal adenocarcinoma was significantly associated with obesity [odds ratio (OR) = 1.41; 95% confidence interval (CI), 1.15-1.74], but not diabetes, hypertension or dyslipidemia. In analysis stratified by tumor location, obesity was significantly associated with risk of colon adenocarcinoma OR = 1.56 (1.17-2.07), but its association with rectal adenocarcinoma was less clear OR = 1.19 (0.85-1.68). No significant interaction was detected between obesity and age (≥40 vs. <40), and obesity and sex.

CONCLUSIONS

Obesity was associated with risk for eoCRC adenocarcinoma.

IMPACT

This finding could help inform early-onset colorectal adenocarcinoma screening and prevention recommendations.See related commentary by Hayes, p. xxx.

Low expression of miR-138 inhibit the proliferation, migration and invasion of colorectal cancer and affect patient survival by targeting SIRT1

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers in the world, resulting in about 600,000 deaths every year. It is urgent to explore the molecular mechanism and find new effective therapy. Abnormal molecular expression in cancer is considered as a screening biomarker and therapeutic target for tumors, MicroRNA (miRNA) as one of the important molecules, plays an important role in the regulation of tumorigenesis.

METHODS

In this study, we aimed to elucidate the molecular mechanism by which mir-138 regulates the development and progression of CRC, and to find new molecular targets for the diagnosis and therapy of CRC. We have used qRT-PCR to study the expression of miR-138 and SIRT1 in CRC cells and tissues, CCK8 assay was used to test the proliferation ability of CRC cells, and invasion and migration ability of CRC cells in vitro were studied by Transwell assay.

RESULTS

We found that miR-138 was significantly decreased in CRC tissues and cell lines by qRT-PCR, the level of miR-138 was significantly correlated with lymph node metastasis and distant metastasis, the CRC patients with high miR-138 level whose overall survival and disease-free survival were significantly longer. We also found that the level of SIRT1 in CRC tissues and cell lines is higher, and through Dual-luciferase reporter assay, we found that SIRT1 is a new target of miR-138 in CRC, and SIRT1 knockdown could inhibit CRC proliferation, migration and invasion in vitro.

CONCLUSIONS

Thus, we found that miR-138 could inhibit CRC cell proliferation, migration and invasion by targeting SIRT1 firstly, and that will provide a new idea for the therapy of CRC.

The relationship between gastrointestinal cancers and the microbiota

The contribution of the microbiota to disease progression and treatment efficacy is often neglected when determining who is at the highest risk of developing gastrointestinal cancers or designing treatment strategies for patients. We reviewed the current literature on the effect of the human microbiota on cancer risk, prognosis, and treatment efficacy. We highlight emerging research that seeks to identify microbial signatures as biomarkers for various gastrointestinal cancers, and discuss how we could harness knowledge of the microbiome to detect, prevent, and treat these cancers. Finally, we outline further research needed in the field of gastrointestinal cancers and the microbiota, and describe the efforts required to increase the accuracy and reproducibility of data linking the microbiome to cancer.

Nongenetic Determinants of Risk for Early-Onset Colorectal Cancer

Background

Incidence of early-onset (younger than 50 years of age) colorectal cancer (CRC) is increasing in many countries. Thus, elucidating the role of traditional CRC risk factors in early-onset CRC is a high priority. We sought to determine whether risk factors associated with late-onset CRC were also linked to early-onset CRC and whether association patterns differed by anatomic subsite.

Methods

Using data pooled from 13 population-based studies, we studied 3767 CRC cases and 4049 controls aged younger than 50 years and 23 437 CRC cases and 35 311 controls aged 50 years and older. Using multivariable and multinomial logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to assess the association between risk factors and early-onset CRC and by anatomic subsite.

Results

Early-onset CRC was associated with not regularly using nonsteroidal anti-inflammatory drugs (OR = 1.43, 95% CI = 1.21 to 1.68), greater red meat intake (OR = 1.10, 95% CI = 1.04 to 1.16), lower educational attainment (OR = 1.10, 95% CI = 1.04 to 1.16), alcohol abstinence (OR = 1.23, 95% CI = 1.08 to 1.39), and heavier alcohol use (OR = 1.25, 95% CI = 1.04 to 1.50). No factors exhibited a greater excess in early-onset compared with late-onset CRC. Evaluating risks by anatomic subsite, we found that lower total fiber intake was linked more strongly to rectal (OR = 1.30, 95% CI = 1.14 to 1.48) than colon cancer (OR = 1.14, 95% CI = 1.02 to 1.27; P = .04).

Conclusion

In this large study, we identified several nongenetic risk factors associated with early-onset CRC, providing a basis for targeted identification of those most at risk, which is imperative in mitigating the rising burden of this disease.

Clinicopathologic Factors Associated with Mismatch Repair Status Among Filipino Patients with Young-Onset Colorectal Cancer

Introduction

Young-onset colorectal cancer is recognized as a distinct disease that may be sporadic or hereditary in nature. Microsatellite instability testing is recommended as a routine procedure in evaluating colorectal cancer specimens, especially in young-onset disease, because of implications in management. Immunohistochemistry of mismatch repair proteins serves as an inexpensive alternative to microsatellite instability testing with the added advantage of monitoring protein expression levels that may suggest underlying genetic or epigenetic alterations. This descriptive study aimed to determine the frequencies of proficient and deficient mismatch repair status among Filipino young-onset colorectal cancer patients, and to investigate their clinicopathologic profile.

Methods

Tumor tissues were prospectively collected from patients from two tertiary hospitals in the Philippines. Patients of age ≤45 years with resected adenocarcinoma of the colon or rectum were recruited.

Results

Seventy-seven out of 124 patients had tumor samples sent for immunohistochemistry. Of these, 61 samples (79%) were found to have proficient status while 16 samples (21%) had deficient status. Mismatch repair protein deficiencies, when present, more commonly involved MSH2 and MSH6 (9%) rather than MLH1 and PMS2 (5%). The deficient group had a mean age of 37.1 years and a female preponderance (56.25%), presenting as locally advanced ascending or descending colon tumors with mucinous histology in half of the population. The mismatch repair proficient group presented as locally advanced rectal and sigmoid tumors but with fewer mucinous adenocarcinomas (26.2%) compared to the deficient group. In both the mismatch repair proficient and deficient patients with family history reports, most did not have any known relative with cancer (75.4% and 68.75%, respectively).

Conclusion

This is the first attempt to perform mismatch repair testing among young-onset colorectal cancer patients in the Philippines and to gather data on their clinicopathologic characteristics. However, the limited sample size precludes conclusive results for the associations of mismatch repair with clinicopathologic features.

Molecular Genetics and the Role of Molecularly Targeted Agents in Metastatic Colorectal Carcinoma

BACKGROUND

Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity in the world. It is the third most common malignancy and fourth leading cancer-related deaths worldwide. In the USA, CRC is the third most commonly diagnosed cancer in both men and women. It is caused by genetic components and potential environmental factors such as consumption of processed meat, red meat, animal fats, low fiber intake, and obesity. Despite the utilization of effective screening modalities and guidelines in the USA, a significant number of patients are diagnosed with advanced, metastatic disease at the time of presentation to the physician. Recent advances in the understanding of molecular medicine with subsequent development and incorporation of newer therapeutic agents into current chemotherapeutic regimens have improved outcomes; however, the management of metastatic CRC remains challenging, particularly for the treating oncologists.

METHODS

We conducted a literature search on CRC mainly related to molecular genetics, targeted biologic agents, and published clinical trials. We also searched and reviewed ongoing clinical trials from Clinicaltrials.gov.

RESULTS AND CONCLUSIONS

Alterations in several oncogenes are associated with CRC, among those RAS, BRAF, and HER2 are of current clinical importance. Chemotherapy drugs, along with vascular endothelial growth factor or epidermal growth factor receptor monoclonal antibodies, are proven to be efficient with manageable toxicity profiles in metastatic CRC. Additional researches on Her-2-directed therapy, BRAF-targeted agents, immunotherapeutic, and newer molecularly targeted agents are needed for further improvement in outcome.

Therapeutic Characteristics, Chemotherapy-Related Toxicities and Survivorship in Colorectal Cancer Patients

Background

Colorectal Cancer (CRC) is a major health problem around the globe. In Morocco, the disease ranks third after breast and lung cancers. This study is the first in Morocco to investigate epidemiological, clinical and therapeutic features while exhaustively describing toxic side-effects to chemotherapy of CRC and studying the 3-years survivorship.

Methods

This is a descriptive and analytical retrospective study of about 290 patients with CRC enrolled during the period of January-December 2013. Statistical analysis was performed to correlate clinicopathological data with chemotherapy toxicity and survivorship in patients, by Chi² test. Overall Survival (OS) rate has been calculated by the Kaplan-Meier method and compared using Log-rank test.

Results

Fifty-five percent had a tumor localized in rectum, and 42,8% in colon. Mean age of these patients at diagnosis was 56,16 ± 14,6. incidence rate of adverse events (grade I to IV) was 85,6%. Diarrhea was the predominant toxicity (4.6%) occurring at a high grade (grade III–IV).

The 3-years OS rate of patients with CRC was 71%. OS decreased by age, and patients with age subgroup between 40 to 59 years had a better OS than the other age subgroups (60 to 79 years and >80 years) with a p-value of 0.0001. Occurence of toxicity (all grades and types) was linked to a higher survival rates compared to the group who had no toxicity noticed (p-value of 0.001).

Conclusion

Our study shows that patients who had a polychemotherapy had a better OS than those who had monotherapy (p-value of 0.002).

Aggressive Colorectal Cancer in the Young

Despite the steady decline in the incidence of colorectal cancer (CRC) and cancer-related mortality in Americans of 50 years and older over the last few decades, there has been a disturbing trend of steadily rising incidence in early-onset colorectal cancer (EOCRC), defined as CRC in those younger than 50 years. With the incidence of EOCRC increasing from 4.8 per 100,000 in 1988 to 8.0 per 100,000 in 2015, and with the decreased rates in those older than 50 years largely attributed to improved screening in the older population, new screening recommendations have recently lowered the age for screening average-risk individuals from 50 to 45. EOCRC has been found to present differently from late-onset CRC, with a higher proportion of patients presenting with left-sided and rectal cancer, more aggressive histological features, and more advanced stage at the time of diagnosis. This article reviews the most recent evidence from population-based studies and institutional series, as well as the newest screening guidelines, and provides an up-to-date summary of our current understanding of EOCRC, from clinical presentation to tumor biology and prognosis, and future directions in treatment and prevention.

Colorectal cancer in younger adults from a Bi-National Colorectal Cancer Audit registry

BACKGROUND

The incidence of colorectal cancer (CRC) in younger adults (<50 years old) is rising worldwide, at a rate of 1% per annum since mid-1980s. The clinical concern is that younger adults may have more advanced disease leading to poorer prognosis compared to their older cohort due to lack of screening. Therefore, the aim of this study is to assess the incidence and short-term outcomes of colorectal cancer in younger adults.

METHODS

This is a retrospective study from a prospectively maintained bi-national database from 2007 to 2018.

RESULTS

There were 1540 younger adults diagnosed with CRC, with a rise from 5.8% in 2007 to 8.4% in 2018. Majority had lower American Society of Anaesthesiologists (ASA) scores (89%), rectal cancers (46.1%) and higher tumour stage (65.4%). As a consequence, they were likely to have higher circumferential resection margin positivity (6%, P = 0.02) and to receive adjuvant chemotherapy (57.1%, P < 0.001) compared to their older cohort. Multivariate analysis showed disadvantaged socioeconomic status (odds ratio (OR) 3.3, 95% confidence interval (CI) 1.37-7.94, P < 0.001) and increasing tumour stage (OR 14.9, 95% CI 1.89-116.9, P < 0.001) were independent predictors for circumferential resection margin positivity whereas being female (OR 0.71, 95% CI 0.53-0.95, P = 0.02), higher ASA score (OR 175.3, 95% CI 26.7-1035.5, P < 0.001), urgent surgery (OR 2.75, 95% CI 1.84-4.11, P < 0.001) and anastomotic leak (OR 5.02, 95% CI 3.32-7.58, P < 0.001) were predictors of inpatient mortality.

CONCLUSION

There is a steady rise in the incidence of colorectal cancer in younger adults. Both physicians and younger adults should be aware of the potential risk of colorectal cancer (CRC) and appropriate investigations performed so not to delay the diagnosis.

Effect of sodium butyrate on HDAC8 mRNA expression in colorectal cancer cell lines and molecular docking study of LHX1 - sodium butyrate interaction

Colorectal cancer (CRC) is the third most common type of cancer and the fourth leading cause of cancer related deaths worldwide. The Histone Deacetylase 8 (HDAC8) gene is a gene with unique features which can be used as a potential target for drug design. The LHX1 transcription factor is an important transcription factor for this gene. The aim of this study was to investigate the effect of sodium butyrate (NaB) as a histone deacetylase inhibitor (HDACi) on the expression of the HDAC8 gene in the colorectal cancer cell line, and the molecular docking of the LHX1 transcription factor with NaB. For this purpose, HCT-116 and HT-29 cell lines were treated with different concentrations of NaB (6.25 mM to 150 mM) at 24, 48 and 72 hours. Subsequently, RNA was extracted from the treated and untreated cells and cDNA was synthesized. Quantitative Real-Time-PCR was done to investigate the mRNA expression of HDAC8. Molecular docking was also performed to investigate the interaction between NaB and LHX1. Based on Real-time-PCR results, the concentration of 150 mM of NaB after 24 hours in HT-29 and HCT-116 cell lines caused a significant reduction in mRNA expression of HDAC8 (P<0.05). After 48 hours of treatment, there was a significant decrease in the mRNA expression of HDAC8 at all concentrations (P<0.05). The docking results showed that LHX1 and NaB interacted best at the lowest energy levels. Our results also showed that NaB bonded strongly to LHX1. In addition, our results demonstrated that NaB bound to the LHX1 transcription factor and inhibited the function of this factor and consequently decreased the transcription from the HDAC8 gene which resulted in cell death. Future studies are needed to assess the likely molecular mechanisms of NaB action on gene expression.

Early-onset colorectal cancer: A distinct entity with unique genetic features

The aim of the present study was to elucidate the genetic features of early-onset colorectal cancer (CRC), particularly the genetic mutations that may be regarded as prognostic and/or predictive markers in CRC and other malignancies. In total, 40 patients with non-polyposis CRC aged 35 or younger were selected. The formalin-fixed, paraffin-embedded tumors acquired were subjected to mismatch repair (MMR) protein immunochemical staining and gene analysis with next-generation sequencing (44 exons, 17 genes; Ion Torrent Sequencing Platform). A total of 11 (27.5%) tumors presented with MMR protein deficiency (dMMR) and 26 (65%) tumors harbored one or more genetic mutations, including K-RAS proto-oncogene (35%), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA; 20%), B-Raf proto-oncogene (5%), erb-b2 receptor tyrosine kinase 2 (5%), discoidin domain receptor tyrosine kinase 2 (5%), N-RAS proto-oncogene (2.5%), KIT proto-oncogene (2.5%), TSC complex subunit 1 (2.5%), DNA methyltransferase 3 alpha (2.5%) and ABL proto-oncogene 1 (2.5%). Of the dMMR tumors, 81.8% (9/11) of cases presented with mutations in the tested genes, while only 58.6% (17/29) of the MMR-proficient (pMMR) tumors presented with these (P=0.158). PI3KCA was frequently mutated in dMMR tumors compared to pMMR tumors (P=0.025). In a subgroup with a family history of CRC, the dMMR status (P<0.001) and PIK3CA genetic mutation status (P=0.01) were more frequently observed compared to the other two groups (with a family history of other cancer types or no malignancy). Almost all patients who had relatives with CRC presented with both dMMR and other genetic mutations, while this was not observed in the patients who had relatives with other types of carcinoma. Certain genetic mutations that are rarely reported in CRC were only identified in those patients with a family history of carcinoma. In conclusion, non-polyposis CRC in young adults presents as a distinct entity with a unique set of genetic features. However, investigation of more cases in further studies is required to verify the present results.

Early-onset colorectal cancer: initial clues and current views

Over the past several decades, the incidence of early-onset colorectal cancer (EOCRC; in patients <50 years old) has increased at an alarming rate. Although robust and scientifically rigorous epidemiological studies have sifted out environmental elements linked to EOCRC, our knowledge of the causes and mechanisms of this disease is far from complete. Here, we highlight potential risk factors and putative mechanisms that drive EOCRC and suggest likely areas for fruitful research. In addition, we identify inconsistencies in the evidence implicating a strong effect of increased adiposity and suggest that certain behaviours (such as diet and stress) might place nonobese and otherwise healthy people at risk of this disease. Key risk factors are reviewed, including the global westernization of diets (usually involving a high intake of red and processed meats, high-fructose corn syrup and unhealthy cooking methods), stress, antibiotics, synthetic food dyes, monosodium glutamate, titanium dioxide, and physical inactivity and/or sedentary behaviour. The gut microbiota is probably at the crossroads of these risk factors and EOCRC. The time course of the disease and the fact that relevant exposures probably occur in childhood raise important methodological issues that are also discussed.

Pro-inflammatory TNF-α and IFN-γ Promote Tumor Growth and Metastasis via Induction of MACC1

Colorectal cancer (CRC) is one of the most common malignancies worldwide. Early stage CRC patients have a good prognosis. If distant metastasis occurs, the 5-year survival drops below 10%. Despite treatment success over the last decades, treatment options for metastatic disease are still limited. Therefore, novel targets are needed to foster therapy of advanced stage CRC patients and hinder progression of early stage patients into metastasis. A novel target is the crucial oncogene Metastasis-Associated in Colon Cancer 1 (MACC1) involved in molecular pathogenesis of CRC metastasis. MACC1 induces cell proliferation and motility, supports cellular survival and rewires metabolism resulting in increased metastasis in vivo. MACC1 is a prognostic biomarker not only for CRC but for more than 20 solid cancer entities. Inflammation plays a pivotal role in tumorigenesis, tumor progression and metastasis. For CRC, inflammatory bowel disease and ulcerative colitis are important inflammation associated risk factors. Certain cytokines, such as TNF-α and IFN-γ, are key factors in determining the contribution of the inflammatory process to CRC. Knowledge of the connection between inflammation and MACC1 driven tumors remains unclear. Gene expression analysis of CRC cells after cytokine stimulation was analyzed by qRT-PCR and Western blot. Cellular motility was assessed by Boyden chamber assays. MACC1 promoter activity after stimulation with pro-inflammatory cytokines was measured using promoter-luciferase constructs. To investigate signal transduction from receptor to effector molecules, blocking experiments using neutralizing antibodies and knockdown experiments were performed. Following TNF-α stimulation, MACC1 and c-Jun expression were significantly increased at the mRNA and protein level. Knockdown of c-Jun reduced MACC1 inducibility following TNF-α stimulation. TNF-α promoted MACC1-induced cell migration that was reverted following MACC1 knockdown. Moreover, MACC1 and c-Jun expression were downregulated by blocking TNFR1, but not TNFR2. Knock down of the NF-κB subunit, p65, reduced basal MACC1 and c-Jun mRNA expression levels. Adalimumab, a clinically approved monoclonal anti-TNF-α antibody, hindered MACC1 induction. The present study highlights that TNF-α regulates the induction of MACC1 via the NF-κB subunit p65 and the transcription factor c-Jun in CRC cells. This finding unravels a novel signaling pathway upstream of MACC1 and provides a potential therapeutic target for the treatment of CRC patients with an associated inflammation.

Molecular Analyses of Left- and Right-Sided Tumors in Adolescents and Young Adults with Colorectal Cancer

BACKGROUND

The incidence of colorectal cancer (CRC), particularly left-sided tumors (LT), in adolescents and young adults (AYA) is rising. Epigenetic events appear to play an important role in tumorigenesis and cancer progression, especially in younger patients. We compared molecular features of LT to right-sided tumors (RT) in AYA.

MATERIALS AND METHODS

A total of 246 LT and 56 RT were identified in a cohort of 612 AYA with primary CRC. Tumors were examined by next-generation sequencing (NGS), protein expression, and gene amplification. Tumor mutational burden (TMB) and microsatellite instability (MSI) were determined based on NGS data.

RESULTS

RT showed higher mutation rates compared with LT in several genes including BRAF (10.3% vs. 2.8%), KRAS (64.1% vs. 45.5%), PIK3CA (27% vs. 11.2%), and RNF43 (24.2% vs. 2.9%). Notably, additional mutations in distinct genes involved in histone modification and chromatin remodeling, as well as genes associated with DNA repair and cancer-predisposing syndromes, were characteristic of RT; most frequently KMT2D (27.8% vs. 3.4%), ARID1A (53.3% vs. 21.4%), MSH6 (11.1% vs. 2.3%), MLH1 (10.5% vs. 2.3%), MSH2 (10.5% vs. 1.2%), POLE (5.9% vs. 0.6%), PTEN (10.8% vs. 2.3%), and BRCA1 (5.4% vs. 0.6%). MSI was seen in 20.8% of RT versus 4.8% of LT. RT had a higher frequency of TMB-high regardless of MSI status.

CONCLUSION

Molecular profiling of AYA CRC revealed different molecular characteristics in RT versus LT. Epigenetic mechanisms and alteration in DNA repair genes warrant further investigation and may be a promising treatment target for CRC in AYA.

IMPLICATIONS FOR PRACTICE

Colorectal cancer (CRC) in adolescents and young adults (AYA) comprises a distinct entity with different clinicopathologic features and prognosis compared with older patients. Molecular profiling of right- and left-sided tumors in AYA is needed to gain novel insight into CRC biology and to tailor targeted treatment in this age group. This study found that right- and left-sided CRC show distinct molecular features in AYA, overall and in subgroups based on microsatellite instability status. Alterations in DNA double-strand break repair and homologous recombination repair, as well as epigenetic mechanisms, appear to play a critical role. The present molecular profiling data may support the development of personalized treatment strategies in the AYA population.

Examining factors underlying geographic disparities in early-onset colorectal cancer survival among men in the United States

Background: Despite overall incidence reduction in colorectal cancer (CRC) the past 32 years, unexplained incidence and mortality rates have increased significantly in younger adults ages 20-49. To improve understanding of sex-specific differences among this population, we aimed to determine the variance in early-onset CRC (EOCRC) survival among US men diagnosed with CRC before age 50, while considering individual- and county-level CRC outcome determinants. Methods: Hotspots (i.e., counties with high EOCRC mortality rates) were derived from Centers for Disease Control and Prevention data from 1999-2017, and linked to SEER data for men aged 15-49 years with CRC. Cox proportional hazards models were used to compare CRC-specific survival probability and hazard in hotspots versus non-significant counties. A generalized R2 was used to estimate the total variance in EOCRC survival explained by clinicodemographic and county-level determinants. Results: We identified 232 hotspot counties for EOCRC-214 (92%) of which were in the South. In hotspots, 1,009 men were diagnosed with EOCRC and 31,438 in non-significant counties. After adjusting for age, race, tumor stage and grade, surgery, chemotherapy, radiation therapy, and marital status, men residing in hotspot counties had higher hazard of CRC-specific death (HR 1.24, 95% CI, 1.12-1.36). Individual/county-level factors explained nearly 35% of the variation in survival, and adult smoking served as the strongest county-level determinant of EOCRC survival. Conclusion: Distinct geographic patterns of EOCRC were predominantly located in the southern US. Survival after EOCRC diagnosis was significantly worse among men residing in hotspot counties.

Prevalence of clinically actionable disease variants in exceptionally long-lived families

Background

Phenotypic expression of pathogenic variants in individuals with no family history of inherited disorders remains unclear.

Methods

We evaluated the prevalence of pathogenic variants in 25 genes associated with Mendelian-inherited disorders in 3015 participants from 485 families in the Long Life Family Study (LLFS). Boot-strapping and Fisher’s exact test were used to determine whether allele frequencies in LLFS were significantly different from the allele frequencies reported in publicly available genomic databases.

Results

The proportions of pathogenic autosomal dominant mutation carriers in BRCA1 and SDHC in LLFS study participants were similar to those reported in publicly available genomic databases (0.03% vs. 0.0008%, p = 1 for BRCA1, and 0.08% vs. 0.003%, p = 0.05 for SDHC). The frequency of carriers of pathogenic autosomal recessive variants in CPT2, ACADM, SUMF1, WRN, ATM, and ACADVL were also similar in LLFS as compared to those reported in genomic databases. The lack of clinical disease among LLFS participants with well-established pathogenic variants in BRCA1 and SDHC suggests that penetrance of pathogenic variants may be different in long lived families.

Conclusion

Further research is needed to better understand the penetrance of pathogenic variants before expanding large scale genomic testing to asymptomatic individuals.

Demographic trends in the incidence of young-onset colorectal cancer: a population-based study

Background

Evidence is emerging that the incidence of colorectal cancer is increasing in young adults, but the descriptive epidemiology required to better understand these trends is currently lacking.

Methods

A population‐based cohort study was carried out including all adults aged 20–49 years diagnosed with colorectal cancer in England between 1974 and 2015. Data were extracted from the National Cancer Registration and Analysis Service database using ICD‐9/10 codes for colorectal cancer. Temporal trends in age‐specific incidence rates according to sex, anatomical subsite, index of multiple deprivation quintile and geographical region were analysed using Joinpoint regression.

Results

A total of 56 134 new diagnoses of colorectal cancer were analysed. The most sustained increase in incidence rate was in the group aged 20–29 years, which was mainly driven by a rise in distal tumours. The magnitude of incident rate increases was similar in both sexes and across Index of Multiple Deprivation quintiles, although the most pronounced increases in incidence occurred in the southern regions of England.

Conclusion

Colorectal cancer should no longer be considered a disease of older people. Changes in incidence rates should be used to inform future screening policy, preventative strategies and research agendas, as well as increasing public understanding that younger people need to be aware of the symptoms of colorectal cancer.

Age and Lymph Node Positivity in Patients With Colon and Rectal Cancer in the US Military Health System

BACKGROUND

Young age may be associated with an increased risk of lymph node involvement at diagnosis of colorectal cancer. Accessibility to care, which is related to cancer detection, tumor stage, and therefore lymph node positivity, may vary by age and thus influence research results.

OBJECTIVE

The purpose of this study was to investigate whether young patients had an increased risk of lymph node-positive colon and rectal cancers in the Department of Defense Military Health System, which provides universal health care to its beneficiaries.

DESIGN

This was a retrospective, cross-sectional study.

SETTINGS

Patients were identified from the US Department of Defense Automated Central Tumor Registry.

PATIENTS

Included patients were diagnosed with histologically confirmed primary stage I to III colon and rectal adenocarcinomas between 1989 and 2013, had surgery and ≥1 lymph node examined, and did not receive preoperative radiotherapy. Logistic regression was used to examine the relationships between age at diagnosis (18-49, 50-59, 60-69, and ≥70 y) and lymph node positivity overall and stratified by tumor T stage and number of lymph nodes examined.

MAIN OUTCOME MEASURES

Lymph node positivity of colon and rectal cancers was measured.

RESULTS

The youngest patients (aged 18-49 y) were more likely to have lymph node-positive colon and rectal cancers compared with those who were aged ≥70 years after adjustment for potential confounders (OR = 2.04 and 95% CI, 1.63-2.56 for colon cancer; OR = 1.73 and 95% CI, 1.11-2.70 for rectal cancer). A similar tendency was shown in most colon and rectal cancer subgroups stratified by tumor T stage and number of lymph nodes examined.

LIMITATIONS

This study was limited by its small sample size for certain subgroup analyses. No information on comorbidities, BMI, or other indicators of health status was available.

CONCLUSIONS

In a universal healthcare system, young age was associated with increased lymph node positivity of colon and rectal cancers, suggesting that factors other than access to care may play a role in this association. See Video Abstract at http://links.lww.com/DCR/B90. EDAD Y POSITIVIDAD DE GANGLIOS LINFÁTICOS EN PACIENTES CON CÁNCER DEL COLON Y EL RECTO EN EL SISTEMA DE SALUD MILITAR DE EE UU: La edad temprana puede estar asociada con un mayor riesgo de compromiso de los ganglios linfáticos en el momento del diagnóstico de cáncer colorrectal. La accesibilidad a la atención medica, que está relacionada con la detección del cáncer, el estadio del tumor y, por lo tanto, la positividad de los ganglios linfáticos, puede variar según la edad y, por lo tanto, influir en los resultados de la investigación.Investigar si los pacientes jóvenes tenían un mayor riesgo de cáncer del colon y el recto con ganglios linfáticos positivos en el Sistema de Salud Militar del Departamento de Defensa, que brinda atención médica universal a sus beneficiarios.Estudio transversal retrospectivo.Se identificaron pacientes del Registro Automático Central de Tumores del Departamento de Defensa de los Estados Unidos.Fueron diagnosticados con adenocarcinomas del colon y el recto en estadio I-III confirmados histológicamente entre 1989-2013, se les realizó una cirugía y se examinaron ≥ 1 ganglio linfático, y no recibieron radioterapia preoperatoria. La regresión logística se utilizó para examinar las relaciones entre la edad al momento del diagnóstico (18-49, 50-59, 60-69 y ≥70 años) y la positividad de los ganglios linfáticos en general y fue estratificada por el estadio T tumoral y el número de ganglios linfáticos examinados.Positividad de ganglios linfáticos de cáncer del colon y el recto.Los pacientes más jóvenes (18-49 años) tenían más probabilidades de tener cáncer del colon y el recto con ganglios linfáticos positivos en comparación con aquellos que tenían 70 años o más después del ajuste por posibles factores de confusión (odds ratio: 2.04, intervalo de confianza del 95%: 1.63 -2.56 para el cáncer de colon; odds ratio: 1.73, intervalo de confianza del 95%: 1.11-2.70 para el cáncer de recto). Se mostró una tendencia similar en la mayoría de los subgrupos de cáncer del colon y el recto estratificados por el estadio T tumoral y el número de ganglios linfáticos examinados.Tamaño de muestra pequeño para ciertos análisis de subgrupos. No hay información sobre comorbilidades, índice de masa corporal u otros indicadores del estado de salud.En un sistema de salud universal, la edad joven se asoció con un aumento de la positividad de los ganglios linfáticos del cáncer del colon y el recto, lo que sugiere que otros factores además del acceso a la atención medica pueden desempeñar un papel en esta asociación. Consulte Video Resumen en http://links.lww.com/DCR/B90.

Young-onset colorectal cancer in the North East of Scotland: survival, clinico-pathological features and genetics

Background

Colorectal cancer (CRC) in patients aged under 55 years is on the rise, constituting approximately 10% of cases. Our aim was to determine the survival and clinico-pathological details of young-onset CRC (yCRC), as well as audit the referral rate to genetic services and thus establish the incidence of inherited cancer syndromes.

Methods

A retrospective case note review was conducted for patients aged under 55 years who were diagnosed with CRC between 2005 and 2015 in the North East of Scotland. Cases were identified by pathology records and data was obtained from patient notes. Analysis was performed using SPSS version 25 (IBM, New York, USA) to produce Kaplan-Meier survival estimates, descriptive statistics and markers predictive for genetic referral.

Results

Data from 345 patients (age range 22–54 years) were identified. The one year, five year and overall survival rates were found to be 89, 63 and 55%, respectively. Most patients (61%) presented with advanced disease. Of 201 patients that met criteria for genetic referral, only 93 (46%) were referred to genetic services. Microsatellite instability (MSI) was identified in 14% of those referred.

Conclusion

Survival in yCRC was found to be better than that in later onset disease, despite higher rates of advanced disease. Patients were under-referred to genetic services, where a significant proportion were found to be MSI positive and investigated for Lynch syndrome.

Population-based analysis of outcomes with early-age colorectal cancer

BACKGROUND

The aim was to evaluate differences in stage, treatment and prognosis in patients aged less than 50 years with colorectal cancer compared with older age groups.

METHODS

This population-based study included all patients diagnosed with colorectal cancer in Sweden, 2010-2015. Disease stage, treatment, 5-year disease-free survival (DFS) and relative survival were analysed in relation to age groups: less than 50, 50-74 and at least 75 years.

RESULTS

Of 34 434 patients included, 24·1, 19·7 and 14·0 per cent of patients aged less than 50, 50-74 and at least 75 years respectively were diagnosed with stage IV disease (P < 0·001). Adverse histopathological features were more common in young patients. Among patients aged less than 50 years, adjuvant chemotherapy was given to 18·9, 42·0 and 93·9 per cent of those with stage I, III and III disease respectively, compared with 0·7, 4·4 and 29·6 per cent of those aged 75 years or older (P < 0·001). Stage-adjusted DFS at 5 years for patients under 50 years old was 0·96, 0·90 and 0·77 in stage I, II and III respectively. Corresponding proportions were 0·88, 0·82 and 0·68 among patients aged 50-74 years, and 0·69, 0·62 and 0·49 for those aged 75 years or older. Relative survival was better for young patients only among those with stage III disease.

CONCLUSION

Patients younger than 50 years with colorectal cancer had a poorer stage at diagnosis and received more intensive oncological treatment. DFS was better than that among older patients in early-stage disease.

Identification of key genes involved in the development and progression of early-onset colorectal cancer by co-expression network analysis

A number of studies have revealed that there is an increasing incidence of early-onset colorectal cancer (CRC) in young adults (before the age of 50 years) and a progressive decline in CRC among older patients, after the age of 50 years (late-onset CRC). However, the etiology of early-onset CRC is not fully understood. The aim of the present study was to identify key genes associated with the development of early-onset CRC through weighted gene co-expression network analysis (WGCNA). The GSE39582 dataset was downloaded from the Gene Expression Omnibus database, and the data profiles of tissues from patients diagnosed before the age of 50 years were selected. The top 10,000 genes with the highest variability were used to construct the WGCNA. Hub genes were identified from the modules associated with clinical traits using gene significance >0.2 and module membership >0.8 as the cut-off criteria. Gene Ontology and pathway analyses were subsequently performed on the hub genes and a protein-protein interaction network (PPI) was constructed. The diagnostic value of module hub genes with a degree score >5 in the PPI network was verified in samples from patients with CRC diagnosed before the age of 50 years obtained from The Cancer Genome Atlas. Eight co-expressed gene modules were identified in the WGCNA and two modules (blue and turquoise) were associated with the tumor-node-metastasis stage. A total of 140 module hub genes were identified and found to be enriched in 'mitochondrial large ribosomal subunit', 'structural constituent of ribosome', 'poly (A) RNA binding', 'collagen binding', 'protein ubiquitination' and 'ribosome pathway'. Twenty-six module hub genes were found to have a degree score >5 in the PPI network, seven of which [secreted protein acidic and cysteine rich (SPARC), decorin (DCN), fibrillin 1 (FBN1), WW domain containing transcription regulator 1 (WWTR1), transgelin (TAGLN), DEAD-box helicase 28 (DDX28) and cold shock domain containing C2 (CSDC2)], had good prognostic values for patients with early-onset CRC, but not late-onset CRC. Therefore, SPARC, DCN, FBN1, WWTR1, TAGLN, DDX28 and CSDC2 may contribute to the development of early-onset CRC and may serve as potential diagnostic biomarkers.

Outcomes of Patients with Early Onset Colorectal Cancer Treated in a UK Specialist Cancer Center

The incidence of early onset colorectal cancer (EOCRC) is rapidly increasing, but there remains paucity of outcome data for young CRC patients. We reviewed the characteristics and outcomes of 241 adults, age <50, who were diagnosed with EOCRC between January 2009 and December 2014. Median age was 42, 56% were male, and 7% had hereditary etiology. Seventy percent had left-sided primaries. At diagnosis, 11%, 50%, and 39% had stage II, III, and IV CRC. Of the patients with stage II and III CRC who underwent curative surgery, 60% and 88% had adjuvant chemotherapy, with 5-year relapse free survival of 82% and 74% respectively. Of the 123 patients with metastatic (m) EOCRC, 93%, 63%, 33%, and 12% had 1st, 2nd, 3rd, and 4th line systemic anticancer therapy (SACT) respectively. For first line SACT, 99% had doublet chemotherapy, with bevacizumab or an anti-EGFR antibody in 57%. Median overall survival (mOS) of mEOCRC patients was 20.1 months (95% C.I: 15.9–23.2). Younger age and signet cells were associated with shorter mOS, whereas more lines of SACT and curative metastasectomy with longer mOS. Metastatic EOCRC patients had poorer outcomes than expected, despite optimal multimodality treatment. This suggests an aggressive disease biology that warrants further research and therapy development.

Therapeutic Opportunities in Colorectal Cancer: Focus on Melatonin Antioncogenic Action

Colorectal cancer (CRC) influences individual health worldwide with high morbidity and mortality. Melatonin, which shows multiple physiological functions (e.g., circadian rhythm, immune modulation, and antioncogenic action), can be present in almost all organisms and found in various tissues including gastrointestinal tract. Notably, melatonin disruption is closely associated with the elevation of CRC incidence, indicating that melatonin is effective in suppressing CRC development and progression. Mechanistically, melatonin favors in activating apoptosis and colon cancer immunity, while reducing proliferation, autophagy, metastasis, and angiogenesis, thereby exerting its anticarcinogenic effects. This review highlights that melatonin can be an adjuvant therapy and be beneficial in treating patients suffering from CRC.

Comprehensive characterization of RAS mutations in colon and rectal cancers in old and young patients

Colorectal cancer (CRC) is increasingly appreciated as a heterogeneous disease, with factors such as microsatellite instability (MSI), cancer subsite within the colon versus rectum, and age of diagnosis associated with specific disease course and therapeutic response. Activating oncogenic mutations in KRAS and NRAS are common in CRC, driving tumor progression and influencing efficacy of both cytotoxic and targeted therapies. The RAS mutational spectrum differs substantially between tumors arising from distinct tissues. Structure-function analysis of relatively common somatic RAS mutations in G12, Q61, and other codons is characterized by differing potency and modes of action. Here we show the mutational profile of KRAS, NRAS, and the less common HRAS in 13,336 CRC tumors, comparing the frequency of specific mutations based on age of diagnosis, MSI status, and colon versus rectum subsite. We identify mutation hotspots, and unexpected differences in mutation spectrum, based on these clinical parameters.

Activating oncogenic mutations in KRAS and NRAS are common in colorectal cancer, which is a heterogenous disease. Here, the authors show that the RAS mutation spectrum is markedly different between colon and rectal cancer, and also different based on age of diagnosis and microsatellite instability.

Lack of APC somatic mutation is associated with early-onset colorectal cancer in African Americans

African Americans (AAs) have higher incidence and mortality rates of colorectal cancer (CRC) compared with other US populations. They present with more right-sided, microsatellite stable disease and are diagnosed at earlier ages compared with non-Hispanic Whites (NHWs). To gain insight into these trends, we conducted exome sequencing (n = 45), copy number (n = 33) and methylation analysis (n = 11) of microsatellite stable AA CRCs. Results were compared with data from The Cancer Genome Atlas (TCGA). Two of the 45 tumors contained POLE mutations. In the remaining 43 tumors, only 27 (63%) contained loss-of-function mutations in APC compared with 80% of TCGA NHW CRCs. APC-mutation-negative CRCs were associated with an earlier onset of CRC (P = 0.01). They were also associated with lower overall mutation burden, fewer copy number variants and a DNA methylation signature that was distinct from the CpG island methylator phenotype characterized in microsatellite unstable disease. Three of the APC-mutation-negative CRCs had loss-of-function mutations in BCL9L. Mutations in driver genes identified by TCGA exome analysis were less frequent in AA CRC cases than TCGA NHWs. Genes that regulate the WNT signaling pathway, including SOX9, GATA6, TET1, GLIS1 and FAT1, were differentially hypermethylated in APC-mutation-negative CRCs, suggesting a novel mechanism for cancer development in these tumors. In summary, we have identified a subtype of CRC that is associated with younger age of diagnosis, lack of APC mutation, microsatellite and chromosome stability, lower mutation burden and distinctive methylation changes.

Rising Incidence of Colorectal Cancer in Patients Younger than Age 50 in Hawai'i

Colorectal cancer is the third most common cancer in the United States in both men and women, and the second leading cause of cancer-related deaths. Whereas the overall incidence of colon and rectal cancer has been decreasing over the past two decades, due in large part to improved colorectal screening and surveillance of patients who are at risk, incidence rates of colorectal cancer in young adults ages 20 to 50 have actually been increasing. Recently, the American Cancer Society updated their guidelines with recommendations that everyone, not just African Americans or those with a strong family history of colon cancer, should begin colorectal screening at age 45 rather than age 50. However, the United States Multi-Society Task Force on Colorectal Cancer, which is comprised of the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy, felt that there is still insufficient evidence to support early screening in the absence of known risk factors. Previous authors have examined the epidemiology and natural history of early onset colorectal cancer but none of these studies are specific to the state of Hawai'i, which has a unique ethnic profile. The purpose of this article is to review the most recently reported incidence rate and demographics of early onset colorectal cancer in Hawai'i and to discuss our own experience with colon cancer in patients younger than age 50. If we can determine specific characteristics of young patients with early onset colorectal cancer in Hawai'i, we can better identify those patients who would benefit most from earlier screening.

Global Increasing Incidence of Young-Onset Colorectal Cancer Across 5 Continents: A Joinpoint Regression Analysis of 1,922,167 Cases

BACKGROUND

Colorectal cancer incidence among young adults in the United States is on the rise, but whether this phenomenon is present in other parts of the world is not well documented. This study aims to explore the temporal change of incidence rates for colorectal cancer in various countries across the globe.

METHODS

We extracted colorectal cancer incidence and population data from 1988 to 2007 based on data from the International Agency for Research on Cancer and compared incidence between age groups. Twelve representative jurisdictions from five continents were selected. Young-onset colorectal cancer cases were defined as those ages <50 years. Joinpoint regression was used to measure the trends of colorectal cancer incidence and to estimate the annual percent change (APC).

RESULTS

The APC for those ages <50 years was noted to be increasing at a faster rate as compared with those ages ≥50 years in many regions, including Australia (+1.10% vs. -0.35%), Brazil (+9.20% vs. +5.72%), Canada (+2.60% vs. -0.91%), China-Hong Kong (+1.82% vs. -0.10%), China-Shanghai (+1.13% vs. -2.68%), Japan (+2.63% vs. +0.90%), the United Kingdom (+3.33% vs. +0.77%), and the United States (+1.98% vs. -2.88%). These trends were largely driven by rectal cancer, except in Brazil and the United Kingdom.

CONCLUSIONS

Increasing incidence of young-onset colorectal cancer was noted in many regions across the globe.

IMPACT

Further studies focusing on young-onset colorectal cancer, particularly with regard to risk factors and establishing the optimal age of screening, are warranted.