Agreement Between the Prevalence of Nonalcoholic Fatty Liver Disease Determined by Transient Elastography and Fatty Liver Indices.

Nonalcoholic fatty liver disease (NAFLD) is a global public health problem linked to the rising prevalence of obesity and metabolic disorders.1 Accurate estimates of NAFLD in populations are challenging because the gold standard for detection is liver biopsy, an invasive procedure that precludes its use in research settings.2 NAFLD can also be detected via noninvasive imaging, such as ultrasound, magnetic resonance imaging-determined proton density fat fraction, magnetic resonance spectroscopy, and the controlled attenuation parameter derived via transient elastography (CAP-TE).2 Given the complexities of imaging in population studies, however, many estimates have been based on calculated indices, such as the Fatty Liver Index (FLI)3 and the Hepatic Steatosis Index (HSI).4 Concern has been raised that the indices underestimate the prevalence of NAFLD,5 thus downplaying the scope of the public health challenge. Ability to examine whether these concerns are substantive has been provided by a recent study of the US population. Using data from the study, it was reported that the US prevalence of CAP-TE-determined NAFLD was 47.8%.6 The current analysis used data from the same national study to examine how well the fatty liver indices corresponded to CAP-TE-determined NAFLD. Because most persons with NAFLD reportedly have elevated alanine aminotransferase (ALT) levels,7 the correspondence between elevated ALT and CAP-TE was also examined.

Racial differences in breast cancer outcomes by hepatocyte growth factor pathway expression.

PURPOSE: Black women have a 40% increased risk of breast cancer-related mortality. These outcome disparities may reflect differences in tumor pathways and a lack of targetable therapies for specific subtypes that are more common in Black women. Hepatocyte growth factor (HGF) is a targetable pathway that promotes breast cancer tumorigenesis, is associated with basal-like breast cancer, and is differentially expressed by race. This study assessed whether a 38-gene HGF expression signature is associated with recurrence and survival in Black and non-Black women. METHODS: Study participants included 1957 invasive breast cancer cases from the Carolina Breast Cancer Study. The HGF signature was evaluated in association with recurrence (n = 1251, 171 recurrences), overall, and breast cancer-specific mortality (n = 706, 190/328 breast cancer/overall deaths) using Cox proportional hazard models. RESULTS: Women with HGF-positive tumors had higher recurrence rates [HR 1.88, 95% CI (1.19, 2.98)], breast cancer-specific mortality [HR 1.90, 95% CI (1.26, 2.85)], and overall mortality [HR 1.69; 95% CI (1.17, 2.43)]. Among Black women, HGF positivity was significantly associated with higher 5-year rate of recurrence [HR 1.73; 95% CI (1.01, 2.99)], but this association was not significant in non-Black women [HR 1.68; 95% CI (0.72, 3.90)]. Among Black women, HGF-positive tumors had elevated breast cancer-specific mortality [HR 1.80, 95% CI (1.05, 3.09)], which was not significant in non-Black women [HR 1.52; 95% CI (0.78, 2.99)]. CONCLUSION: This multi-gene HGF signature is a poor-prognosis feature for breast cancer and may identify patients who could benefit from HGF-targeted treatments, an unmet need for Black and triple-negative patients.

Outdoor light at night and risk of liver cancer in the NIH-AARP diet and health study.

PURPOSE: Accumulating evidence suggests that light at night (LAN) disrupts circadian rhythms and may increase risk of liver cancer. However, there is no population-based study that examined LAN and liver cancer risk. Therefore, we aimed to investigate the association between outdoor LAN and liver cancer risk in a prospective cohort. METHODS: Residential outdoor LAN level was measured from satellite imagery in the NIH-AARP Diet and Health Study, a prospective cohort of 451,945 men and women, 50-71 years old. Relative risks (RR) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models that adjusted for known risk factors for liver cancer and neighborhood characteristics. RESULTS: During an average 12.2 years of follow-up, 897 liver cancers, 603 of which were hepatocellular carcinomas (HCC), were diagnosed. Residential outdoor LAN was not associated with risk of liver cancer (RRQ5 vs Q1 = 0.96, 95% CI: 0.77-1.20, p trend = 0.771) or HCC (RRQ5 vs Q1 = 0.82, 95% CI: 0.62-1.07, p trend = 0.425). CONCLUSION: No association between outdoor LAN and risk of liver cancer or HCC may in part be due to limitations in LAN assessment. More studies on the relationship between light intensity, duration, timing, and wavelength and liver cancer are warranted.

Hepatocyte growth factor pathway expression in breast cancer by race and subtype.

BACKGROUND: African American women have the highest risk of breast cancer mortality compared to other racial groups. Differences in tumor characteristics have been implicated as a possible cause; however, the tumor microenvironment may also contribute to this disparity in mortality. Hepatocyte growth factor (HGF) is a stroma-derived marker of the tumor microenvironment that may affect tumor progression differentially by race. OBJECTIVE: To examine whether an HGF gene expression signature is differentially expressed by race and tumor characteristics. METHODS: Invasive breast tumors from 1957 patients were assessed for a 38-gene RNA-based HGF gene expression signature. Participants were black (n = 1033) and non-black (n = 924) women from the population-based Carolina Breast Cancer Study (1993-2013). Generalized linear models were used to estimate the relative frequency differences (RFD) in HGF status by race, clinical, and demographic factors. RESULTS: Thirty-two percent of tumors were positive for the HGF signature. Black women were more likely [42% vs. 21%; RFD = + 19.93% (95% CI 16.00, 23.87)] to have HGF-positive tumors compared to non-black women. Triple-negative patients had a higher frequency of HGF positivity [82% vs. 13% in non-triple-negative; RFD = + 65.85% (95% CI 61.71, 69.98)], and HGF positivity was a defining feature of basal-like subtype [92% vs. 8% in non-basal; RFD = + 81.84% (95% CI 78.84, 84.83)]. HGF positivity was associated with younger age, stage, higher grade, and high genomic risk of recurrence (ROR-PT) score. CONCLUSION: HGF expression is a defining feature of basal-like tumors, and its association with black race and young women suggests it may be a candidate pathway for understanding breast cancer disparities.

A functional role for the cancer disparity-linked genes, CRYßB2 and CRYßB2P1, in the promotion of breast cancer.

BACKGROUND: In the USA, the breast cancer mortality rate is 41% higher for African-American women than non-Hispanic White women. While numerous gene expression studies have classified biological features that vary by race and may contribute to poorer outcomes, few studies have experimentally tested these associations. CRYßB2 gene expression has drawn particular interest because of its association with overall survival and African-American ethnicity in multiple cancers. Several reports indicate that overexpression of the CRYßB2 pseudogene, CRYßB2P1, and not CRYßB2 is linked with race and poor outcome. It remains unclear whether either or both genes are linked to breast cancer outcomes. This study investigates CRYßB2 and CRYßB2P1 expression in human breast cancers and breast cancer cell line models, with the goal of elucidating the mechanistic contribution of CRYßB2 and CRYßB2P1 to racial disparities. METHODS: Custom scripts for CRYßB2 or CRYßB2P1 were generated and used to identify reads that uniquely aligned to either gene. Gene expression according to race and tumor subtype were assessed using all available TCGA breast cancer RNA sequencing alignment samples (n = 1221). In addition, triple-negative breast cancer models engineered to have each gene overexpressed or knocked out were developed and evaluated by in vitro, biochemical, and in vivo assays to identify biological functions. RESULTS: We provide evidence that CRYßB2P1 is expressed at higher levels in breast tumors compared to CRYßB2, but only CRYßB2P1 is significantly increased in African-American tumors relative to White American tumors. We show that independent of CRYßB2, CRYßB2P1 enhances tumorigenesis in vivo via promoting cell proliferation. Our data also reveal that CRYßB2P1 may function as a non-coding RNA to regulate CRYßB2 expression. A key observation is that the combined overexpression of both genes was found to suppress cell growth. CRYßB2 overexpression in triple-negative breast cancers increases invasive cellular behaviors, tumor growth, IL6 production, immune cell chemoattraction, and the expression of metastasis-associated genes. These data underscore that both CRYßB2 and CRYßB2P1 promote tumor growth, but their mechanisms for tumor promotion are likely distinct. CONCLUSIONS: Our findings provide novel data emphasizing the need to distinguish and study the biological effects of both CRYßB2 and CRYßB2P1 as both genes independently promote tumor progression. Our data demonstrate novel molecular mechanisms of two understudied, disparity-linked molecules.

Biliary tract cancer incidence and trends in the United States by demographic group, 1999-2013.

BACKGROUND: Biliary tract cancers (BTCs) are rare but deadly cancers (gallbladder cancer [GBC], intrahepatic cholangiocarcinoma [ICC], extrahepatic cholangiocarcinoma [ECC], and ampulla of Vater cancer [AVC]). A recent US study reported increasing GBC incidence among people younger than 45 years and blacks; however, it did not examine trends for other biliary tract sites. METHODS: This study characterized demographic differences in BTC incidence rates and time trends by anatomic site. Population-based North American Association of Central Cancer Registries data were used to calculate age-adjusted incidence rates, incidence rate ratios (IRRs), and estimated annual percent changes (eAPCs) for 1999-2013 by site and demographic group. For sites with significant differences in eAPC by age group, IRRs were compared by age group. RESULTS: GBC incidence rates declined among women (eAPC, -0.5%/y; P = .01) and all racial/ethnic groups except for non-Hispanic blacks, among whom rates increased (1.8%/y; P < .0001). Although GBC rates increased among 18- to 44-year-olds (eAPC, 1.8%/y; P = .01), they decreased among people 45 years old or older (-0.4%/y; P = .009). Sex (P < .0001) and racial/ethnic differences (P = .003 to .02) in GBC incidence were larger for younger people than older people. During this period, ICC (eAPC, 3.2%/y; P < .0001) and ECC rates (1.8%/y; P = .001) steadily increased across sex and racial/ethnic groups. Although AVC incidence rates increased among younger adults (eAPC, 1.8%/y; P = .03) but not older adults (-0.20%/y; P = .30), sex and racial/ethnic IRRs did not differ by age. CONCLUSIONS: Differential patterns of BTC rates and temporal trends have been identified by anatomic site and demographic groups. These findings highlight the need for large pooling projects to evaluate BTC risk factors by anatomic site.

Postmenopausal breast cancer and oestrogen associations with the IgA-coated and IgA-noncoated faecal microbiota.

BACKGROUND: The diversity and composition of the gut microbiota may affect breast cancer risk by modulating systemic levels of oestrogens and inflammation. The current investigation tested this hypothesis in postmenopausal women by identifying breast cancer associations with an inflammation marker, oestrogen levels, and faecal microbes that were or were not coated with mucosal immunoglobulin A (IgA). METHODS: In this population-based study, we compared 48 postmenopausal breast cancer cases (75% stage 0-1, 88% oestrogen-receptor positive) to 48 contemporaneous, postmenopausal, normal-mammogram, age-matched controls. Microbiota metrics employed 16S rRNA gene amplicon sequencing from IgA-coated and -noncoated faecal microbes. High-performance liquid chromatography/mass spectrometry (HPLC/MS) and radioimmunoassay were used to quantify urine prostaglandin E metabolite (PGE-M), a possible marker of inflammation; urine oestrogens and oestrogen metabolites were quantified by HPLC/MS-MS. RESULTS: Women with pre-treatment breast cancer had non-significantly elevated oestrogen levels; controls' (but not cases') oestrogens were directly correlated with their IgA-negative microbiota alpha diversity (P=0.012). Prostaglandin E metabolite levels were not associated with case status, oestrogen levels, or alpha diversity. Adjusted for oestrogens and other variables, cases had significantly reduced alpha diversity and altered composition of both their IgA-positive and IgA-negative faecal microbiota. Cases' faecal microbial IgA-positive imputed Immune System Diseases metabolic pathway genes were increased; also, cases' IgA-positive and IgA-negative imputed Genetic Information Processing pathway genes were decreased (P⩽0.01). CONCLUSIONS: Compared to controls, breast cancer cases had significant oestrogen-independent associations with the IgA-positive and IgA-negative gut microbiota. These suggest that the gut microbiota may influence breast cancer risk by altered metabolism, oestrogen recycling, and immune pressure.

Prevalence of HPV Infection in Racial-Ethnic Subgroups of Head and Neck Cancer Patients.

The landscape of HPV infection in racial/ethnic subgroups of head and neck cancer (HNC) patients has not been evaluated carefully. In this study, a meta-analysis examined the prevalence of HPV in HNC patients of African ancestry. Additionally, a pooled analysis of subject-level data was also performed to investigate HPV prevalence and patterns of p16 (CDNK2A) expression amongst different racial groups. Eighteen publications (N = 798 Black HNC patients) were examined in the meta-analysis, and the pooled analysis included 29 datasets comprised of 3,129 HNC patients of diverse racial/ethnic background. The meta-analysis revealed that the prevalence of HPV16 was higher among Blacks with oropharyngeal cancer than Blacks with non-oropharyngeal cancer. However, there was great heterogeneity observed among studies (Q test P<0.0001). In the pooled analysis, after adjusting for each study, year of diagnosis, age, gender and smoking status, the prevalence of HPV16/18 in oropharyngeal cancer patients was highest in Whites (61.1%), followed by 58.0% in Blacks and 25.2% in Asians (P<0.0001). There was no statistically significant difference in HPV16/18 prevalence in non-oropharyngeal cancer by race (P=0.682). With regard to the pattern of HPV16/18 status and p16 expression, White patients had the highest proportion of HPV16/18+/p16+ oropharyngeal cancer (52.3%), while Asians and Blacks had significantly lower proportions (23.0% and 22.6%, respectively) [P <0.0001]. Our findings suggest that the pattern of HPV16/18 status and p16 expression in oropharyngeal cancer appears to differ by race and this may contribute to survival disparities.

Discrimination Experiences and All-Cause and Cardiovascular Mortality: Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: Epidemiologic studies have documented the associations between experiences of discrimination and adverse health outcomes. However, the relationship between discrimination and mortality, and the factors that may moderate this relationship are not well understood. This study examined whether lifetime and everyday discrimination were associated with all-cause and cardiovascular mortality and whether these associations differed by race and ethnicity, gender, and racial and ethnic residential segregation. METHODS: The study included 1633 Black, 1403 Hispanic/Latino, and 2473 White participants aged 45 to 84 years from the Multi-Ethnic Study of Atherosclerosis, enrolled from 2000 to 2002 and followed across 5 exams (2002-2018). Discrimination was measured using the lifetime discrimination (major experiences of unfair treatment) and everyday discrimination (day-to-day experiences of unfair treatment) scales. Racial and ethnic residential segregation was measured using the Gi* statistic. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs, adjusting for sociodemographic characteristics, health behaviors, and clinical risk factors. RESULTS: Each increase in reports of lifetime discrimination was associated with increased all-cause (HR, 1.06 [95% CI, 1.00-1.11]) and cardiovascular (HR, 1.15 [95% CI, 1.04-1.27]) mortality, adjusting for sociodemographic factors, health behaviors, and clinical risk factors. Associations between lifetime discrimination and cardiovascular mortality were observed across all racial and ethnic groups but were strongest and only statistically significant among Black participants (HR, 1.18 [95% CI, 1.02-1.37]). Additionally, in the fully adjusted model, each increase in reports of everyday discrimination was strongly associated with increased cardiovascular mortality (HR, 1.21 [95% CI, 1.03-1.43]). Associations for lifetime and everyday discrimination with all-cause and cardiovascular mortality were not modified by race and ethnicity, gender, or racial and ethnic residential segregation. CONCLUSIONS: These findings suggest that experiences of discrimination are associated with increased all-cause and cardiovascular mortality.

Prediction of nonalcoholic fatty liver disease using anthropometry and body fat measures by sex and race/ethnicity in the United States.

OBJECTIVE: The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing in the United States and is strongly linked to obesity in many, but not all, racial/ethnic groups. It is conceivable that the lack of correspondence is related to differential fat distribution. The study objective was to examine which fat distribution measures best predicted NAFLD by sex within racial/ethnic groups. METHODS: The analysis included 1,404 participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES). Area under the receiver operating characteristic curve (AUC) analyses compared the ability of dual-energy x-ray absorptiometry-measured percentage total fat and abdominal fat with measured BMI, waist circumference, and waist to height ratio to predict ultrasound transient-elastography-assessed NAFLD in each sex and racial/ethnic group. RESULTS: AUC analysis found the best predictors of NAFLD among men were waist circumference and total abdominal fat area (AUC: 84.1%) and the best predictor among women was visceral fat (AUC: 85.2). NAFLD prediction by body fat measures, however, was similar between racial/ethnic groups. CONCLUSIONS: The best predictors of NAFLD, using body fat distribution measures, vary by sex but not by racial/ethnic group.

Reusing a prepaid health plan's fecal immunochemical tests for microbiome associations with colorectal adenoma.

An altered colonic microbiota probably increases colorectal adenoma (CRA) and cancer (CRC) risk, but large, unbiased fecal collections are needed to examine the relationship of gut microbiota diversity and composition to colorectal carcinogenesis. This study assessed whether fecal immunochemical tests (FITs) from CRA/CRC screening may fulfill this requirement. Using FIT, self-collected by members of Kaiser Permanente Hawaii (KPH), as well as interspersed quality control (QC) specimens, DNA was extracted and amplified to generate 16S rRNA microbiome profiles rarified at 10,000 reads. CRA/CRC were diagnosed by colonoscopy and histopathology. Covariates were from electronic KPH records. Of 921 participants' FIT devices, 538 (58%) yielded at least 10,000 rRNA reads and 1016 species-level variants mapped to 46 genera. Of the 538 evaluable participants, 63 (11.7%) were FIT-negative per protocol, and they were considered negative for CRA/CRC. Of the 475 FIT + participants, colonoscopy and pathologic review revealed that 8 (1.7%) had CRC, 71 (14.9%) had high-risk CRA, 107 (22.5%) had low-risk CRA, and 289 (60.8%) did not have CRA/CRC. Men were 2.27-fold [95% confidence interval (CI) 1.32-3.91] more likely than women to be FIT+ . Men also had 1.96-fold (CI 1.24-3.07) higher odds of low-risk CRA, with similar trends for high-risk CRA and CRC. CRA/CRC were not associated with overweight, obesity, diabetes, or antibiotic prescriptions in this study. QC analysis across 24 batches of FIT devices revealed QC outliers in four batches. With or without exclusion of the four QC-outlier batches, as well as lenient (1000-read) rarefaction, CRA/CRC had no consistent, statistically significant associations with fecal microbiome alpha diversity, beta diversity or genera relative abundance. CRA/CRC had expected associations with male sex but not with microbiome metrics. Fecal microbiome profiling using DNA extracted from at-home collected, re-used FIT devices is feasible, albeit with substantial challenges. Using FITs for prospective microbiome studies of CRA/CRC risk should consider the impact of the current findings on statistical power and requisite sample sizes.

Sweetened beverage consumption and risk of liver cancer by diabetes status: A pooled analysis.

BACKGROUND: Consumption of sweetened beverages has been linked to several risk factors for liver cancer including diabetes. Studies investigating the role of sweetened beverage consumption and liver cancer, however, are limited. As persons with diabetes are advised against consumption of sugar, the objective of this study was to examine the role of sweetened beverage consumption and liver cancer risk by diabetes status. METHODS: Data from two U.S. cohorts: the NIH-AARP Diet and Health Study, and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial were harmonized and pooled. Hazard ratios and 95%CI were estimated using Cox proportional hazard models stratified by median follow-up time. RESULTS: Among persons without diabetes, there were no statistical evidence of associations between liver cancer and consumption of sweetened beverages overall, sugar sweetened beverages (SSB), or artificially sweetened beverages (ASB). Sugar sweetened (SS) soda consumption, however, was associated with liver cancer in the first follow-up interval (HR:1.18. 95%CI: 1.03, 1.35). In contrast, among persons with diabetes, there were significant associations between liver cancer and consumption of sweetened beverages overall (HR: 1.12, 95%CI 1.01, 1.24), ASBs (HR: 1.13, 95% CI: 1.02, 1.25), soda overall (HR: 1.13, 95% CI: 1.00, 1.26) and artificially sweetened (AS) soda (HR: 1.13, 95% CI: 1.01, 1.27) in the first follow-up interval. CONCLUSIONS: Increased soda consumption may be associated with risk of liver cancer. The results suggest that decreasing consumption of SS soda by persons without diabetes, and AS soda by persons with diabetes, could be associated with reduced liver cancer risk.

Mammographic breast density and its association with urinary estrogens and the fecal microbiota in postmenopausal women.

BACKGROUND: Breast density, as estimated by mammography, is a strong risk factor for breast cancer in pre- and postmenopausal women, but the determinants of breast density have not yet been established. The aim of this study was to assess if urinary estrogens or gut microbiota alterations are associated with mammographic density in postmenopausal women. METHODS: Among 54 cancer-free, postmenopausal controls in the Breast and Colon Health study, we classified low- versus high-density women with Breast Imaging Reporting and Data System (BI-RADS, 5th edition) mammographic screening data, then assessed associations with urinary estrogens and estrogen metabolites (determined by liquid chromatography/tandem mass spectrometry), and fecal microbiota alpha and beta diversity (using Illumina sequencing of 16S rRNA amplicons). RESULTS: Multiple logistic regression revealed no significant association between breast density and fecal microbiota metrics (PD_tree P-value = 0.82; un-weighted and weighted UniFrac P = 0.92 and 0.83, respectively, both by MiRKAT). In contrast, total urinary estrogens (and all 15 estrogens/estrogen metabolites) were strongly and inversely associated with breast density (P = 0.01) after adjustment for age and body mass index. CONCLUSION: Mammographic density was not associated with the gut microbiota, but it was inversely associated with urinary estrogen levels. IMPACT: The finding of an inverse association between urinary estrogens and breast density in cancer-free women adds to the growing breast cancer literature on understanding the relationship between endogenous estrogens and mammographic density.

Investigation of the association between the fecal microbiota and breast cancer in postmenopausal women: a population-based case-control pilot study.

We investigated whether the gut microbiota differed in 48 postmenopausal breast cancer case patients, pretreatment, vs 48 control patients. Microbiota profiles in fecal DNA were determined by Illumina sequencing and taxonomy of 16S rRNA genes. Estrogens were quantified in urine. Case-control comparisons employed linear and unconditional logistic regression of microbiota α-diversity (PD_whole tree) and UniFrac analysis of ß-diversity, with two-sided statistical tests. Total estrogens correlated with α-diversity in control patients (Spearman Rho = 0.37, P = .009) but not case patients (Spearman Rho = 0.04, P = .77). Compared with control patients, case patients had statistically significantly altered microbiota composition (ß-diversity, P = .006) and lower α-diversity (P = .004). Adjusted for estrogens and other covariates, odds ratio of cancer was 0.50 (95% confidence interval = 0.30 to 0.85) per α-diversity tertile. Differences in specific taxa were not statistically significant when adjusted for multiple comparisons. This pilot study shows that postmenopausal women with breast cancer have altered composition and estrogen-independent low diversity of their gut microbiota. Whether these affect breast cancer risk and prognosis is unknown.

Modulation of the intestinal microbiota alters colitis-associated colorectal cancer susceptibility.

It is well established that the intestinal microbiota plays a key role in the pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC) collectively referred to as inflammatory bowel disease (IBD). Epidemiological studies have provided strong evidence that IBD patients bear increased risk for the development of colorectal cancer (CRC). However, the impact of the microbiota on the development of colitis-associated cancer (CAC) remains largely unknown. In this study, we established a new model of CAC using azoxymethane (AOM)-exposed, conventionalized-Il10(-/-) mice and have explored the contribution of the host intestinal microbiota and MyD88 signaling to the development of CAC. We show that 8/13 (62%) of AOM-Il10(-/-) mice developed colon tumors compared to only 3/15 (20%) of AOM- wild-type (WT) mice. Conventionalized AOM-Il10(-/-) mice developed spontaneous colitis and colorectal carcinomas while AOM-WT mice were colitis-free and developed only rare adenomas. Importantly, tumor multiplicity directly correlated with the presence of colitis. Il10(-/-) mice mono-associated with the mildly colitogenic bacterium Bacteroides vulgatus displayed significantly reduced colitis and colorectal tumor multiplicity compared to Il10(-/-) mice. Germ-free AOM-treated Il10(-/-) mice showed normal colon histology and were devoid of tumors. Il10(-/-); Myd88(-/-) mice treated with AOM displayed reduced expression of Il12p40 and Tnfalpha mRNA and showed no signs of tumor development. We present the first direct demonstration that manipulation of the intestinal microbiota alters the development of CAC. The TLR/MyD88 pathway is essential for microbiota-induced development of CAC. Unlike findings obtained using the AOM/DSS model, we demonstrate that the severity of chronic colitis directly correlates to colorectal tumor development and that bacterial-induced inflammation drives progression from adenoma to invasive carcinoma.