Global patterns and trends in colorectal cancer incidence in young adults.

OBJECTIVE: Early-onset colorectal cancer (CRC) is increasing in the USA despite rapid declines in older ages. Similar patterns are reported in Australia and Canada, but a comprehensive global analysis of contemporary data is lacking. DESIGN: We extracted long-term data from Cancer Incidence in Five Continents and supplemental sources to report on worldwide CRC incidence rates and trends by age (20-49 years and ≥50 years) through diagnosis year 2012 or beyond (Australia, Finland, New Zealand, Norway, Sweden, USA). RESULTS: During 2008-2012, age-standardised CRC incidence rates in adults <50 ranged from 3.5 per 100 000 (95% CI 3.2 to 3.9) in India (Chennai) to 12.9 (95% CI 12.6 to 13.3) in Korea. During the most recent decade of available data, incidence in adults <50 was stable in 14 of 36 countries; declined in Austria, Italy and Lithuania; and increased in 19 countries, nine of which had stable or declining trends in older adults (Australia, Canada, Denmark, Germany, New Zealand, Slovenia, Sweden, UK and USA). In Cyprus, Netherlands and Norway, inclines in incidence in young adults were twice as rapid as those in older adults (eg, Norway average annual per cent change (AAPC), 1.9 (95% CI 1.4 to 2.5) vs 0.5 (95% CI 0.3 to 0.7)). Among most high-income countries with long-term data, the uptick in early-onset disease began in the mid-1990s. The steepest increases in young adults were in Korea (AAPC, 4.2 (95% CI 3.4 to 5.0)) and New Zealand (AAPC, 4.0 (95% CI 2.1 to 6.0)). CONCLUSION: CRC incidence increased exclusively in young adults in nine high-income countries spanning three continents, potentially signalling changes in early-life exposures that influence large bowel carcinogenesis.

Barriers to Lynch Syndrome Testing and Preoperative Result Availability in Early-onset Colorectal Cancer: A National Physician Survey Study.

OBJECTIVE: Although widely recommended, Lynch syndrome (LS) testing with tumor microsatellite instability (MSI) and/or immunohistochemistry (IHC) is infrequently performed in early-onset colorectal cancer (CRC), and CRC generally. Reasons are poorly understood. Hence, we conducted a national survey focusing on gastroenterologists, as they are frequently first to diagnose CRC, assessing testing barriers and which specialist is felt responsible for ordering MSI/IHC. Additionally, we assessed factors influencing timing of MSI/IHC ordering; testing on colonoscopy biopsy, opposed to post-operative surgical specimens, assists decisions on preoperative germline genetic testing and extent of colonic resection (ECR). METHODS: A 21-question web-based survey was distributed through an American College of Gastroenterology email listing. RESULTS: In total 509 completed the survey. 442 confirmed gastroenterologists were analyzed. Only 33.4% felt gastroenterologists were responsible for MSI/IHC ordering; pathologists were believed most responsible (38.6%). Cost, unfamiliarity interpreting results and unavailable genetic counseling most commonly prevented routine ordering (33.3%, 29.2%, 24.9%, respectively). In multivariable analysis, non-academic and rural settings were associated with cost and genetic counseling barriers. Only 46.1% felt MSI/IHC should always be performed on colonoscopy biopsy. Guideline familiarity predicted whether respondents felt surgical resection should be delayed until results returned given potential effect on ECR decisions. CONCLUSION: Inconsistencies in who is felt should order MSI/IHC may lead to diffusion of responsibility, preventing consistent testing, including preoperatively. Assuring institutional universal testing protocols are in place, with focus on timing of testing, can optimize care. Strategies addressing cost barriers and genomic service availability in rural and non-academic settings can enhance testing. Greater emphasis on guideline familiarity is required.

Understanding the contribution of family history to colorectal cancer risk and its clinical implications: A state-of-the-science review.

Persons with a family history (FH) of colorectal cancer (CRC) or adenomas that are not due to known hereditary syndromes have an increased risk for CRC. An understanding of these risks, screening recommendations, and screening behaviors can inform strategies for reducing the CRC burden in these families. A comprehensive review of the literature published within the past 10 years has been performed to assess what is known about cancer risk, screening guidelines, adherence and barriers to screening, and effective interventions in persons with an FH of CRC and to identify FH tools used to identify these individuals and inform care. Existing data show that having 1 affected first-degree relative (FDR) increases the CRC risk 2-fold, and the risk increases with multiple affected FDRs and a younger age at diagnosis. There is variability in screening recommendations across consensus guidelines. Screening adherence is <50% and is lower in persons under the age of 50 years. A provider's recommendation, multiple affected relatives, and family encouragement facilitate screening; insufficient collection of FH, low knowledge of guidelines, and poor family communication are important barriers. Effective interventions incorporate strategies for overcoming barriers, but these have not been broadly tested in clinical settings. Four strategies for reducing CRC in persons with familial risk are suggested: 1) improving the collection and utilization of the FH of cancer, 2) establishing a consensus for screening guidelines by FH, 3) enhancing provider-patient knowledge of guidelines and communication about CRC risk, and 4) encouraging survivors to promote screening within their families and partnering with existing screening programs to expand their reach to high-risk groups. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2633-2645. © 2016 American Cancer Society.

New York Citywide Colon Cancer Control Coalition: A public health effort to increase colon cancer screening and address health disparities.

BACKGROUND: Although screening for colorectal cancer (CRC) is a widely accepted concept nationally and screening rates are increasing, there are differences in screening rates between states and within states. METHODS: In an effort to increase screening rates and ensure equal access with respect to race/ethnicity, the New York City Department of Health and Mental Hygiene formed a coalition of stakeholders in 2003, with its primary focus on colonoscopy, to develop and implement strategies across the city to achieve this goal. RESULTS: From a screening colonoscopy rate of only 42% in 2003, these concerted efforts contributed to achieving a screening rate of 62% by 2007 and a screening rate of almost 70% in 2014 with the elimination of racial and ethnic disparities. CONCLUSIONS: This article provides details of how this program was successfully conceived, implemented, and sustained in the large urban population of New York City. The authors hope that by sharing the many elements involved and the lessons learned, they may help other communities to adapt these experiences to their own environments so that CRC screening rates can be maximized. Cancer 2016;122:269-277. © 2015 American Cancer Society.

The intestinal epithelial cell differentiation marker intestinal alkaline phosphatase (ALPi) is selectively induced by histone deacetylase inhibitors (HDACi) in colon cancer cells in a Kruppel-like factor 5 (KLF5)-dependent manner.

The histone deacetylase inhibitor (HDACi) sodium butyrate promotes differentiation of colon cancer cells as evidenced by induced expression and enzyme activity of the differentiation marker intestinal alkaline phosphatase (ALPi). Screening of a panel of 33 colon cancer cell lines identified cell lines sensitive (42%) and resistant (58%) to butyrate induction of ALP activity. This differential sensitivity was similarly evident following treatment with the structurally distinct HDACi, MS-275. Resistant cell lines were significantly enriched for those harboring the CpG island methylator phenotype (p = 0.036, Chi square test), and resistant cell lines harbored methylation of the ALPi promoter, particularly of a CpG site within a critical KLF/Sp regulatory element required for butyrate induction of ALPi promoter activity. However, butyrate induction of an exogenous ALPi promoter-reporter paralleled up-regulation of endogenous ALPi expression across the cell lines, suggesting the presence or absence of a key transcriptional regulator is the major determinant of ALPi induction. Through microarray profiling of sensitive and resistant cell lines, we identified KLF5 to be both basally more highly expressed as well as preferentially induced by butyrate in sensitive cell lines. KLF5 overexpression induced ALPi promoter-reporter activity in resistant cell lines, KLF5 knockdown attenuated butyrate induction of ALPi expression in sensitive lines, and butyrate selectively enhanced KLF5 binding to the ALPi promoter in sensitive cells. These findings demonstrate that butyrate induction of the cell differentiation marker ALPi is mediated through KLF5 and identifies subsets of colon cancer cell lines responsive and refractory to this effect.

Increased screening colonoscopy rates and reduced racial disparities in the New York Citywide campaign: an urban model.

OBJECTIVES: In 2003, in response to low colonoscopy screening rates and significant sociodemographic disparities in colonoscopy screening in New York City (NYC), the NYC Department of Health and Mental Hygiene, together with the Citywide Colon Cancer Control Coalition, launched a multifaceted campaign to increase screening. We evaluated colonoscopy trends among adult New Yorkers aged 50 years and older between 2003 and 2007, the first five years of this campaign. METHODS: Data were analyzed from the NYC Community Health Survey, an annual, population-based surveillance of New Yorkers. Annual prevalence estimates of adults who reported a timely colonoscopy, one within the past 10 years, were calculated. Multivariate models were used to analyze changes over time in associations between colonoscopy screening and sociodemographic characteristics. RESULTS: Overall, from 2003 to 2007 the proportion of New Yorkers aged 50 years and older who reported timely colonoscopy screening increased from 41.7% to 61.7%. Racial/ethnic and sex disparities observed in 2003 were eliminated by 2007: prevalence of timely colonoscopy was similar among non-Hispanic whites, non-Hispanic blacks, Hispanics, men, and women. However, Asians, the uninsured, and those with lower education and income continued to lag in receipt of timely colonoscopies. CONCLUSIONS: The increased screening colonoscopy rate and reduction of racial/ethnic disparities observed in NYC suggest that multifaceted, coordinated urban campaigns can improve low utilization of clinical preventive health services and reduce public-health disparities.

Deciphering the colon cancer genes--report of the InSiGHT-Human Variome Project Workshop, UNESCO, Paris 2010.

The Human Variome Project (HVP) has established a pilot program with the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) to compile all inherited variation affecting colon cancer susceptibility genes. An HVP-InSiGHT Workshop was held on May 10, 2010, prior to the HVP Integration and Implementation Meeting at UNESCO in Paris, to review the progress of this pilot program. A wide range of topics were covered, including issues relating to genotype-phenotype data submission to the InSiGHT Colon Cancer Gene Variant Databases (chromium.liacs.nl/LOVD2/colon_cancer/home.php). The meeting also canvassed the recent exciting developments in models to evaluate the pathogenicity of unclassified variants using in silico data, tumor pathology information, and functional assays, and made further plans for the future progress and sustainability of the pilot program.

Developing a quality screening colonoscopy referral system in primary care practice: a report from the national colorectal cancer roundtable.

The use of colonoscopy in colorectal cancer (CRC) screening has increased substantially in recent years. Media messages and changes in insurance reimbursement, as well as new screening guidelines from the American Cancer Society and the US Preventive Services Task Force, have contributed to this increase. Primary care providers (PCPs) are frequently responsible for making the recommendation and referral for screening. The process of successfully referring a patient for screening colonoscopy can be cumbersome and requires a coordinated effort between the PCP and the endoscopist. In recognition of the potential complexity of this process, the National Colorectal Cancer Roundtable has issued a report to describe the components of a quality screening colonoscopy referral system in primary care practice. The elements of a quality program include an optimal scheduling and referral system, the appropriate patient preparation information, consistent reporting and follow-up systems, and a detailed approach to dealing with special situations.

An A13 repeat within the 3'-untranslated region of epidermal growth factor receptor (EGFR) is frequently mutated in microsatellite instability colon cancers and is associated with increased EGFR expression.

Colorectal cancers (CRC) with microsatellite instability (MSI) have clinical, pathologic, genetic, and epigenetic features distinct from microsatellite-stable CRC. Examination of epidermal growth factor receptor (EGFR) mRNA and protein expression levels in a panel of colon cancer cell lines identified strong expression of EGFR in multiple cell lines with MSI. Although no relationship between EGFR overexpression and the length of a CA dinucleotide repeat in intron 1 was observed, a variant A13/A14 repeat sequence within the 3'-untranslated region (3'-UTR) of the EGFR gene was identified, which was mutated by either mononucleotide or dinucleotide adenosine deletions in 64% of MSI cell lines and 69% of MSI colon tumors. Using a Tet-Off system, we show that this mutation increases EGFR mRNA stability in colon cancer cells, providing a mechanistic basis for EGFR overexpression in MSI colon cancer cell lines. To determine whether this mutation is a driver or a bystander event in MSI colon cancer, we examined the effect of pharmacologic and molecular inhibition of EGFR in EGFR 3'-UTR mutant MSI cell lines. Cell lines with an EGFR 3'-UTR mutation and that were wild-type (WT) for downstream signaling mediators in the Ras/BRAF and PIK3CA/PTEN pathways were sensitive to EGFR inhibition, whereas those harboring mutations in these signaling mediators were not. Furthermore, in cell lines WT for downstream signaling mediators, those with EGFR 3'-UTR mutations were more sensitive to EGFR inhibition than EGFR 3'-UTR WT cells, suggesting that this mutation provides a growth advantage to this subset of MSI colon tumors.

A del T poly T (8) mutation in the 3' untranslated region (UTR) of the CDK2-AP1 gene is functionally significant causing decreased mRNA stability resulting in decreased CDK2-AP1 expression in human microsatellite unstable (MSI) colorectal cancer (CRC).

BACKGROUND: We have previously published results indicating that decreased expression of CDK2-AP1 in MSI human colorectal cancer is associated with deletion mutations in the poly (T) 8 repeat sequence within the 3'-UTR of the CDK2-AP1 gene. In this study, we test the hypothesis that the del T mutation results in decreased CDK2-AP1 expression by causing reduced mRNA stability. METHODS: We introduced wild-type and mutant 3'-UTR sequences fused to a green fluorescent protein (GFP) gene separately into human CRC cell lines and quantified the expression of the GFP gene. Native CDK2-AP1 mRNA stability was measured in human CRC cell lines, using an actinomycin D assay and the mRNA structure folding software mfold 3.2. RESULTS: Mutant GFP-3'-UTR samples demonstrated significantly reduced GFP expression compared with wild-type GFP-3'-UTR as measured by both FACS and real-time PCR. Both the actinomycin D assay and mfold software demonstrated significantly reduced mRNA stability for the del T poly (T) 8 transcript compared with the wild type. CONCLUSIONS: In summary, these novel results support our hypotheses that the del T poly (T) 8 observed in the 3'-UTR of the CDK2-AP1 gene in human MSI CRC is functionally significant and results in decreased CDK2-AP1 expression. The results also indicate the mechanism of this decreased expression is caused at least in part by decreased mRNA stability.

Erlotinib, an effective epidermal growth factor receptor tyrosine kinase inhibitor, induces p27KIP1 up-regulation and nuclear translocation in association with cell growth inhibition and G1/S phase arrest in human non-small-cell lung cancer cell lines.

Erlotinib, a small-molecule epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has been shown to have potent antitumor effects against human non-small-cell lung cancer (NSCLC) cell growth; however, the mechanism of such an effect is not elucidated. Here, we demonstrate that erlotinib-induced cell growth inhibition in EGFR high-expressing human H322 NSCLC cells was accompanied by G1/S phase arrest, which was largely caused by a decrease in expression of G1/S-related cyclins, suppression of activities of cyclin-dependent kinase (CDK) 2 and CDK4, induction of CDK inhibitor p27(KIP1), and retinoblastoma hypophosphorylation. To further understand the role of p27(KIP1) in G1/S arrest and cell growth inhibition by erlotinib, we determined its effect on the expression of p27(KIP1) at transcriptional and posttranscriptional levels. Studies using real-time reverse transcription-polymerase chain reaction analysis and p27 promoter-driven luciferase reporter showed that erlotinib treatment resulted in the promotion of p27 gene transcription. In addition, erlotinib treatment led to an increase in p27(KIP1) half-life by inhibiting p27(KIP1) phosphorylation at Thr187 and by down-regulating Skp2 expression. Furthermore, immunofluorescence staining and cell fractionation showed that erlotinib treatment led to p27(KIP1) translocation to the nucleus. Knockdown of p27(KIP1) expression with p27(KIP1) small interfering RNA significantly abrogated erlotinib-induced G1 phase arrest and cell growth inhibition, suggesting that induction of p27(KIP1) is required for G1 arrest and cell growth inhibition by erlotinib. It is noteworthy that we found that G1 arrest and p27(KIP1) up-regulation by erlotinib occurred in the tested sensitive cell lines but to a lesser extent in the resistant cell lines. Taken together, these results suggest that erlotinib inhibits human NSCLC cell growth predominantly by inducing p27(KIP1) expression and by suppressing cell-cycle events involved in the G1/S transition.

A novel mutation detection approach of hMLH1 and hMSH2 genes for screening of colorectal cancer.

BACKGROUND: Recently, Denaturing High-Performance Liquid Chromatography (DHPLC) has been widely used for mutation detection hMLH1 and hMSH2 genes due to reduced cost of analysis, accuracy, and high sample throughput. Unfortunately, one major drawback in screening the hMLH1 and hMSH2 genes with any analysis technique involves sample preparation. Additionally, there are limitations to this technique which include: (1) amplicons for hMLH1 and hMSH2 exons cannot be generated under the same PCR thermal cycler condition due to differences in the annealing temperatures of the traditional primer sets which drastically increases sample preparation time; (2) due to minimal changes in the DHPLC chromatogram when compared to the corresponding wild-type amplicon, there is a possibility to not detect a homozygous mutation; and (3) lack of specialized mutation analysis software for automated screening of the hMLH1 and hMSH2 genes with the Transgenomic Wave system. METHODS: To overcome these limitations, the hMLH1 and hMSH2 condition-oriented-PCR primer-embedded-reactor (COPPER) plate was developed to reduce the sample preparation time and technological skill required for analysis, as well as standardize a mutation screening technique for hMLH1 and hMSH2 analysis using the Transgenomic Wave system for research and clinical genetics investigations. In this study, we validated the COPPER plate for simultaneous amplification of the exons of the hMLH1 and hMSH2 genes coupled to DHPLC detection for colorectal cancer (CRC) patients. RESULTS AND CONCLUSIONS: Our results suggest that the COPPER plate DHPLC approach is a simple, cost effective, accurate, universal, and reproducible technology for screening hMLH1 and hMSH2 genes which are associated with human CRC. We also believe that the COPPER plate DHPLC approach is amenable for characterization of other germline alterations in clinical genetics and pharmacogenetics.

Modulation of CDK2-AP1 (p12(DOC-1)) expression in human colorectal cancer.

We have previously demonstrated an association between microsatellite instability and decreased CDK2-AP1 (p12(DOC-1)) expression in human colorectal cancer (CRC) cell lines. In those same studies, induction of CDK2-AP1 expression promoted both cell cycle arrest and apoptosis. The goals of our present study were to better understand the mechanisms leading to reduced CDK2-AP1 expression in microsatellite unstable (MSI) CRC and to study further the effect of CDK2-AP1 modulation on cell proliferation and apoptosis utilizing RNA interference (RNAi) techniques. We used direct sequencing to screen for mutations of the poly (T)8 microsatellite-like region in the 3' end of the CDK2-AP1 gene in 24 CRC cell lines. We then utilized an in vitro human mismatch repair (MMR) recombinant system to assess for correction of the mutation and changes in CDK2-AP1 expression secondary to hMLH1 transfection. We also investigated the effect of CDK2-AP1 modulation in four settings: (1) native CDK2-AP1 absence, (2) endogenous CDK2-AP1 expression, (3) RNAi-induced CDK2-AP1 inhibition and (4) induced CDK2-AP1 over expression. The mutation - del T poly (T)8 - at the 3' end of the CDK2-AP1 gene was found in 3/12 (25%) of MSI CRC cell lines, but in none of the microsatellite stable samples (0/12). Interestingly, when wild-type MMR protein - MLH1 - was induced in an in vitro human recombinant system, the del T poly (T)8 mutation was reversed and CDK2-AP1 expression increased. RNAi-mediated CDK2-AP1 inhibition was associated with decreased apoptosis and increased cell proliferation in CDK2-AP1-non deficient CRC cell lines. We conclude that mutations in the microsatellite-like sequence of the CDK2-AP1 gene in MSI CRC are associated with decreased CDK2-AP1 expression. In addition, modulation of CDK2-AP1 expression in human CRC alters cell proliferation and apoptosis.

Deleted in oral cancer-1 expression upregulates proapoptosis elements in microsatellite-unstable human colorectal cancer.

BACKGROUND: We previously reported differential expression of the growth suppressor, deleted in oral cancer-1 (DOC-1), in microsatellite-unstable (MSI+) versus microsatellite-stable colorectal cancer (CRC) cell lines. MSI+ CRC cell lines demonstrated decreased DOC-1 expression and decreased apoptosis. Transfection of wild-type DOC-1 into an MSI+ cell line (SW48) resulted in increased apoptosis. We undertook our current experiment to identify specific elements modulated by DOC-1 expression that result in increased apoptosis. METHODS: SW48 is an MSI+ CRC cell line that does not constitutively express DOC-1. SW48 was suspended in culture medium and incubated to 60% confluence. Half the plates were transfected with cytomegalovirus (CMV)-DOC-1. At 30 hours, RNA and protein were isolated with Trizol. Complementary DNA microarray was performed to compare SW48(CMV-DOC-1) with SW48, which lacks DOC-1. Signal intensity was analyzed by GenePix Pro 3.0 software. Expression ratios / 1.5 were considered significant. Poor-quality spots were flagged and excluded from analysis. Real-time polymerase chain reaction was performed to determine DOC-1 levels in both cell lines. RESULTS: Successful transfection of DOC-1 was confirmed by real-time polymerase chain reaction and by Western blot. Microarray revealed significant differential expression of DOC-1, as expected. Increased DOC-1 expression in SW48(CMV-DOC-1) was associated with significantly increased expression of proapoptosis components of the caspase cascade (CASP7, CASP9) and bcl2/bax pathway (BNIP3, BNIP3L, BID). CONCLUSIONS: DOC-1 expression promotes apoptosis by upregulation of specific elements of the caspase cascade and bcl2/bax pathways. DOC-1 therefore deserves further study as a candidate for the therapeutic modulation of apoptosis in MSI+ CRC.

Differential expression of DOC-1 in microsatellite-unstable human colorectal cancer.

The precise genetic mechanism of malignant transformation in DNA mismatch repair deficient, microsatellite-unstable colorectal cancer (CRC) has yet to be elucidated. We employed cDNA microarray to identify patterns of gene expression among CRC cell lines and to compare directly lines with and without microsatellite instability. This study was undertaken to test the hypothesis that microsatellite-unstable CRC cell lines demonstrate specific patterns of gene expression that differ significantly from those observed among microsatellite-stable CRC. Multiple differential expression patterns were identified. Genes demonstrating differential expression included deleted-in-oral-cancer-1 (DOC-1), a highly conserved growth suppressor. DOC-1 expression correlated with microsatellite status, with significantly decreased expression in microsatellite-unstable cell lines and constitutive expression in microsatellite-stable cell lines. We also observed alterations in the biologic behavior of p12(DOC-1)-deficient cell lines, with increased S phase and decreased apoptosis compared to microsatellite-stable (DOC-1+) cell lines. Transfection of p12(DOC-1) into SW48, which lacks p12(DOC-1) expression, resulted in cell cycle and apoptosis profiles similar to other p12(DOC-1)+ cell lines. These results support the hypothesis that microsatellite-unstable CRC is characterized by novel patterns of gene expression different from those associated with microsatellite-stable CRC, and demonstrate that p12(DOC-1) has tumor suppressor potential in colon epithelial cells.