Abstract 5056: HPV, HIV and male gender as major risk factors for anal neoplastic transformation in African Americans

Background: Human Papilloma Virus (HPV) is the most common sexually transmitted infectious agent. The incidence HPV-related anal cancers increased among HIV infected people. Aim: To assess risk factors of anal lesions among African Americans in an inner city hospital. Methods: We reviewed medical records of 370 African-Americans with anal lesions at Howard University Hospital from Jan. 2007 to Dec. 2015. Demographic, clinical and pathological data including; HPV, HIV, HCV (hepatitis C virus), diabetes mellitus (DM), hypertension (HTN) and body mass index (BMI) were collected. Statistical analysis was performed using Chi-square and Student's t-test. Results: 276 (75%) patients were male, with median age of 44 years and BMI of 25.8 kg/m2. The frequency of condyloma, high grade dysplasia, squamous cell carcinoma (SCC) and adenocarcinoma was 191 (52%), 26 (7%), 31 (8%) and 8 (2%), respectively. The frequency of HPV, HIV, and HCV was 231 (68%), 147 (43%) and 42 (12%), respectively. HPV and HIV were risk factors for condyloma and dysplasia (P<0.05). Forty two percent of patients had diabetes (DM) and hypertension (HTN). Conclusion: Our results shows that majority of patients with condyloma are male and young with HPV and HIV infection. A clinical utility of HPV as risk factor may be use for prediction of anal lesions.

Citation Format: Hassan Brim, Ali Afsari, Nazli Atefi, Nicole Retland, Muneer Abbas, Tammey Naab, Babak Shokrani, Adeyinka O. Laiyemo, Edward L. Lee, Seyed M. Nouraie, Hassan Ashktorab. HPV, HIV and male gender as major risk factors for anal neoplastic transformation in African Americans [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5056.

Gastrointestinal Lesions in African American Patients With Iron Deficiency Anemia

Background:

Iron deficiency anemia (IDA) is a frequent disorder that is associated with many serious diseases. However, the findings of an evaluation of IDA-associated gastrointestinal disorders are lacking among African American patients.

Aim:

To determine the most prevalent gastrointestinal lesions among African American patients with IDA especially in young men.

Methods:

We reviewed medical records (n = 422) of patients referred for evaluation of IDA from 2008 to 2012. Iron deficiency anemia was diagnosed using clinical laboratory tests. The results of esophagogastroduodenoscopy, colonoscopy, and pathology specimens along with demographic data were abstracted and analyzed using Stata.

Results:

The mean age was 61.9 years, and 50.5% were women. In total, 189 patients (45%) had gross gastrointestinal (GI) bleeding. The most frequent diagnoses were gastritis (40%), benign colonic lesions (13%), esophagitis (9%), gastric ulcer (6%), and duodenitis (6%). GI bleeding was significantly more frequent in men (P = 0.001). Benign and malignant colonic lesions were significantly more present among older patients: 16% vs 6% (P = .005) and 5% vs 0% (P = .008), respectively. Colitis was more prevalent in younger patients (⩽50): 11% vs 2% (P = .001). In patients with gross lower GI bleeding, the top diagnoses were gastritis (25%), benign colon tumors (10%), and duodenitis (6%). Colon cancer was diagnosed among 15 patients, and all these patients were older than 50 years of age.

Conclusions:

Gastritis and colonic lesions are most common associated lesions with IDA among African Americans. So bidirectional endoscopy is required for unrevealing of the cause of IDA in asymptomatic patients.

Targeted exome sequencing reveals distinct pathogenic variants in Iranians with colorectal cancer

PURPOSE

Next Generation Sequencing (NGS) is currently used to establish mutational profiles in many multigene diseases such as colorectal cancer (CRC), which is on the rise in many parts of the developing World including, Iran. Little is known about its genetic hallmarks in these populations.

AIM

To identify variants in 15 CRC-associated genes in patients of Iranian descent.

RESULTS

There were 51 validated variants distributed on 12 genes: 22% MSH3 (n = 11/51), 10% MSH6 (n = 5/51), 8% AMER1 (n = 4/51), 20% APC (n = 10/51), 2% BRAF (n = 1/51), 2% KRAS (n = 1/51), 12% PIK3CA (n = 6/51), 8% TGFβR2A (n = 4/51), 2% SMAD4 (n = 1/51), 4% SOX9 (n = 2/51), 6% TCF7L2 (n = 3/51), and 6% TP53 (n = 3/51). Most known and distinct variants were in mismatch repair genes (MMR, 32%) and APC (20%). Among oncogenes, PIK3CA was the top target (12%).

MATERIALS AND METHODS

CRC specimens from 63 Shirazi patients were used to establish the variant' profile on an Ion Torrent platform by targeted exome sequencing. To rule-out technical artifacts, the variants were validated in 13 of these samples using an Illumina NGS platform. Validated variants were annotated and compared to variants from publically available databases. An in-silico functional analysis was performed. MSI status of the analyzed samples was established.

CONCLUSION

These results illustrate for the first time CRC mutational profile in Iranian patients. MSH3, MSH6, APC and PIK3CA genes seem to play a bigger role in the path to cancer in this population. These findings will potentially lead to informed genetic diagnosis protocol and targeted therapeutic strategies.

Adiponectin, Leptin, IGF-1, and Tumor Necrosis Factor Alpha As Potential Serum Biomarkers for Non-Invasive Diagnosis of Colorectal Adenoma in African Americans

The potential role of adiponectin, leptin, IGF-1, and tumor necrosis factor alpha (TNF-α) as biomarkers in colorectal adenoma is not clear. Therefore, we aimed to investigate the blood serum levels of these biomarkers in colorectal adenoma. The case-control study consisted of serum from 180 African American patients with colon adenoma (cases) and 198 healthy African Americans (controls) at Howard University Hospital. We used ELISA for adiponectin, leptin, IGF-1, and TNF-α detection and quantification. Statistical analysis was performed by t-test and multivariate logistic regression. The respective differences in median leptin, adiponectin, IGF-1, and TNF-α levels between control and case groups (13.9 vs. 16.4), (11.3 vs. 46.0), (4.5 vs. 12.9), and (71.4 vs. 130.8) were statistically significant (P < 0.05). In a multivariate model, the odds ratio for adiponectin, TNF-α, and IGF-1 were 2.0 (95% CI = 1.6-2.5; P < 0.001), 1.5 (95% CI = 1.5(1.1-2.0); P = 0.004), and 1.6 (95% CI = 1.3-2.0; P < 0.001), respectively. There was a positive correlation between serum adiponectin and IGF-1 concentrations with age (r = 0.17, P < 0.001 and r = 0.13, P = 0.009), TNF-α, IGF-1, and leptin concentration with body mass index (BMI) (r = 0.44, P < 0.001; r = 0.11, P = 0.03; and r = 0.48, P < 0.001), respectively. Also, there was a negative correlation between adiponectin and leptin concentrations with BMI (r = -0.40, P < 0.001), respectively. These data support the hypothesis that adiponectin, IGF-1, and TNF-α high levels correlate with higher risk of colon adenoma and can thus be used for colorectal adenomas risk assessment.

Distinctive DNA mismatch repair and APC rare variants in African Americans with colorectal neoplasia

PURPOSE

African Americans have a higher incidence and mortality from colorectal cancer. This disparity might be due, in part, to the type of mutations in driver genes. In this study, we examined alterations specific to APC, MSH3, and MSH6 genes using targeted exome sequencing to determine distinctive variants in the course of neoplastic transformation.

EXPERIMENTAL DESIGN

A total of 140 African American colon samples (30 normal, 21 adenomas, 33 advanced adenomas and 56 cancers) were used as our discovery set on an Ion Torrent platform. A 36 samples subset was resequenced on an Illumina platform for variants' validation. Bioinformatics analyses were performed and novel validated variants are reported.

RESULTS

Two novel MSH6 variants were validated and mapped to the MutS-V region near the MSH2 binding site. For MSH3, 4 known variants were validated and were located in exon 10 (3 non-synonymous) and exon 18 (1 synonymous). As for APC, 20 variants were validated with 4 novel variants: 3 stopgain and 1 non-synonymous. These variants mapped prior to and on the Armadillo repeats region, to the 15-amino acid repeat region, and to the 20-amino acid repeats region, respectively.

CONCLUSION

We defined novel variants that target DNA mismatch repair and APC genes in African Americans with colorectal lesions. A greater frequency of variants in genes encoding DNA mismatch repair functions and APC likely plays major roles in colorectal cancer initiation and higher incidence of the disease in African Americans.

Racial Disparity in Gastrointestinal Cancer Risk

Cancer from the gastrointestinal tract and its associated excretory organs will occur in more than 300,000 Americans in 2017, with colorectal cancer responsible for >40% of that burden; there will be more than 150,000 deaths from this group of cancers in the same time period. Disparities among subgroups related to the incidence and mortality of these cancers exist. The epidemiology and risk factors associated with each cancer bear out differences for racial groups in the United States. Esophageal adenocarcinoma is more frequent in non-Hispanic whites, whereas esophageal squamous cell carcinoma with risk factors of tobacco and alcohol is more frequent among blacks. Liver cancer has been most frequent among Asian/Pacific Islanders, chiefly due to hepatitis B vertical transmission, but other racial groups show increasing rates due to hepatitis C and emergence of cirrhosis from non-alcoholic fatty liver disease. Gastric cancer incidence remains highest among Asian/Pacific Islanders likely due to gene-environment interaction. In addition to esophageal squamous cell carcinoma, cancers of the small bowel, pancreas, and colorectum show the highest rates among blacks, where the explanations for the disparity are not as obvious and are likely multifactorial, including socioeconomic and health care access, treatment, and prevention (vaccination and screening) differences, dietary and composition of the gut microbiome, as well as biologic and genetic influences. Cognizance of these disparities in gastrointestinal cancer risk, as well as approaches that apply precision medicine methods to populations with the increased risk, may reduce the observed disparities for digestive cancers.

Clinical and Pathological Risk Factors Associated with Liver Fibrosis and Steatosis in African-Americans with Chronic Hepatitis C

BACKGROUND AND AIM

Several factors involved in the development of liver fibrosis in African-American patients with chronic hepatitis C have not been well studied. We aimed to evaluate some of these risk factors.

METHODS

We reviewed pathology and medical records of 603 African-Americans with chronic hepatitis C virus (HCV) infection at Howard University Hospital from January 2004 to December 2013. Among the clinical and pathological data collected were HIV (human immunodeficiency virus), HCV genotype, hepatitis B virus (HBV), diabetes mellitus (DM), hypertension (HTN), body mass index (BMI), and hepatic steatosis.

RESULTS

The frequency of DM, HTN, HIV, and HBV was 22, 16, 11, and 4%, respectively. Median BMI was 27.3 kg/m². The frequency of fibrosis stages 0, 1, 2, 3, and 4 was 2, 48, 28, 11, and 11%, respectively. In multivariate logistic regression, we found a significant association between liver fibrosis stage (3-4 vs. 0-2) and HIV infection (OR 2.4, P = 0.026), HTN (OR 3.0, P = 0.001), age (OR 2.6 for every 10 years, P < 0.001), weight (OR 1.1 for every 10 lb increase, P = 0.002), and steatosis grade (OR 1.6, P = 0.002). The frequency of liver steatosis was 73%. In an ordinal logistic regression, significant risk factors for steatosis were female gender (OR 1.5, P = 0.034) and inflammation grade (P = 0.001).

CONCLUSION

This study shows that steatosis is independently associated with fibrosis in African-American patients with HCV infection. Female patients were at higher risk of steatosis.

Abstract 4384: Targeted sequencing reveals distinct and rare pathogenic variants in Caucasians with colorectal cancer

PURPOSE: Next-generation sequencing (NGS) is currently used to establish mutational profiles in many multigene diseases such as colorectal cancer (CRC) which is on the rise in many parts of the developing World including in the Middle East. Little is known about its genetic hallmarks in these populations. AIM: To identify variants in 15 CRC-associated genes in patients of Iranian descent.

METHODS: CRC specimens from 63 patients were used to establish the variants’ profile on an Ion Torrent platform by targeted exome sequencing. To rule out technical artifacts, the variants were validated in 13 of these samples using an Illumina NGS platform. Validated variants were annotated and compared to variants from publically available databases. An in-silico functional analysis was performed. MSI status of the analyzed samples was established. RESULTS: There were 51 validated variants distributed on 12 genes: 22% MSH3 (n=11/51), 10% MSH6 (n=5/51), 8% AMER1 (n=4/51), 20% APC (n=10/51), 2% BRAF (n=1/51), 2% KRAS (n=1/51), 12% PIK3CA (n=6/51), 8% TGFβR2A (n=4/51), 2% SMAD4 (n=1/51), 4% SOX9 (n=2/51), 6% TCF7L2 (n=3/51), and 6% TP53 (n=3/51). Most known and distinct variants were in mismatch repair genes (MMR, 32%) and APC (20%). Among oncogenes, PIK3CA was the top target (12%). MSH3 variants were more frequent and predominantly homozygous in the analyzed population.

CONCLUSION: These results illustrate for the first time CRC mutational profile in Iranian patients. MSH3, MSH6, APC and PIK3CA genes seem to play a bigger role in the path to cancer in this population. This is especially true for MSH3 variants that were very frequent and predominantly homozygous as these will associate with the EMAST phenotype that has prognostic implications. These findings will potentially lead to informed genetic diagnosis protocol and targeted therapeutic strategies.

Citation Format: Pooneh Mokarram, Sudhir Varma, Hamed Azimi, Hasti Olumi, Ali reza Safarpour, Michael Nickerson, Hassan Brim, Hassan Ashktorab. Targeted sequencing reveals distinct and rare pathogenic variants in Caucasians with colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4384. doi:10.1158/1538-7445.AM2017-4384

Abstract 2573: TP73's regulation and expression in human cancer cell lines

TP73 is the homologue of the master tumor suppressor TP53. It is involved in cellular responses to stress and development. The TP73 gene encodes two different proteins, TAp73 and ΔNp73 and maps to a region on chromosome 1p36 that is frequently deleted in neuroblastoma and other tumors, and thought to contain multiple tumor suppressor genes. However, the analysis of p73-knockout mice yielded conflicting results with respect to tumor suppression. World-wide efforts in sequencing the TP73 gene in patient tumor samples have not provided evidence for genetic alterations as a common cause of p73 inactivation in human cancer. The role of TP73 in tumorigenesis has remained elusive to date. In this study, we isolated two stem cell lines from normal young and old human liver tissues and determined TP73 expression in human breast cancer cell lines (MCF7 & MDA321), human hepatocellular carcinoma (HCC) cell lines (HepG2, SNU398, SNU449 & SNU475), neuroblastoma cell lines (IMR32 & SK-N-SH), normal liver stem cell, non-cancerous Li-Fraumeni Syndrome (LFS) skin fibroblasts cells and normal skin fibroblasts. Results show that TAp73 only expresses in cancer cell lines. Moreover, when HepG2 and MDA231 were treated with paclitaxel, a cytoskeletal drug that targets tubulin, TAp73 expression was drastically down-regulated in HepG2 cells and abrogated in MDA231 cells at 1 to 5 µmol/L concentrations. Furthermore, ChIP assay results demonstrated that TP53 and CTCF (a chromosomal networking protein CCCTC binding factor) bind to TP73 promoter and regulate TP73 expression. Our observation may prove significant for the development of future therapeutic and diagnostic applications.

*These authors contributed equally to this work.

Citation Format: Zhixing Yao, David R. Yao, William Yu, Hassan Brim, Hassan Ashktorab, Zaki A. Sherif. TP73's regulation and expression in human cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2573. doi:10.1158/1538-7445.AM2017-2573

Abstract 4578: Does poor prognosis in African Americans with MSI-H colorectal cancer associate with altered immune markers

BACKGROUND: Microsatellite instability high (MSI-H) of sporadic colorectal carcinomas (CRC) is usually associated with improved prognosis and a high density of tumor-infiltrating lymphocytes. However, African Americans with MSI-H have poor prognosis.

AIM: To evaluate whether or not expression of different immune and tumor markers individually or in combination in African American MSI-H CRC associate with the prognosis status.

METHODS: Tissues Microarray (TMA) were prepared by microdissection from FFPE (Formalin Fixed Paraffin Embedded) blocks of 15 MSI-H patients. Immune markers (CD8+, Granzymes, Perforins, CD4+, STAT1, IRF1 and IRF5) and PD-L1 status were analyzed by immunohistochemistry (IHC). Demography and clinical data including TNM, tumor grading (WHO standard), histological type of the tumor, date of diagnosis, date of the last follow-up examination, treatment, comorbidities, metastasis, recurrence, 5-year disease-free survival and death were collected. RESULTS: There were 4 patients with improved prognosis (27%) with relatively high CD4 density (2 with &gt;50% and 2 with 11-50%) regardless of PD-L1 status (3+/1-), stage (II,III), and other immune markers (CD8, CD4, Granzymes, Perforins, IRF1, IRF5 and STAT1). One of the improved prognosis patients with KRAS mutation has elevated expression of all considered immune markers besides CD4. There were 9 patients (6 dead, 3 alive) with poor prognosis, with different immune and tumor markers level (3 were PD-L1+ and 5 have relatively high CD4 count; but with low level of STAT1. There were also 2 patients with expected improved prognosis based on their immune markers level (stage II), however, they died within the 5 year period post-diagnosis, due to their age (98 and 87 years old).

Conclusion: MSI-H Colorectal cancer from African American patients has poor prognosis which may correlate with the nature of tumor-associated immune response. Other factors such as MSH3 defects might cancel the positive prognosis of MSI-H status. Nonetheless, low STAT1 and low CD4 may be indicators of poorer prognosis.

Citation Format: Umamaheshwari Golconda, Lena Sokol, Babak Shokrani, Edward Lee, Donna Hansel, Oluwole Fadare, Sandip Patel, Mehdi Nouraie, Hooman Soleimani, Zaki Sharif, Ali Afsari, Fareed Daremipouran, Hassan Brim, Hassan Ashktorab. Does poor prognosis in African Americans with MSI-H colorectal cancer associate with altered immune markers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4578. doi:10.1158/1538-7445.AM2017-4578

Abstract 5273: Detection of sessile serrated adenomas/polyps in African Americans

Introduction: The majority of colorectal cancers (CRCs) develop through the adenoma-carcinoma sequence, while 15-20% develop via the serrated pathway. Sessile Serrated Adenoma/Polyps (SSA/P) are more difficult to detect during colonoscopy and generally require a shorter time follow-up than other lesions (3 vs. 5 years). These polyps lead to cancer faster than conventional adenomas. In order to better define patients at risk for these lesions, we performed a retrospective study to evaluate clinicopathological features of patients diagnosed with SSA/P.

Methods: We reviewed pathology reports of patients at Howard University Hospital from 2010-2015. We identified 5,900 patients with colorectal lesions, of whom 312 (5.3%) were diagnosed with SSA/P. We analyzed the specific clinical, pathological and demographic features of patients with SSA/P lesions.

Results: We identified 312 cases with SSA/P. The incidence of SSA/P over the 5 years period was 5.3%: 198/312 (63.4%) patients had 2 or more polyps, 54.5% of the SSA/P patients were females, 70.5% of patients were 50-64 years of age and 18% were older than 65. SSA/P lesions’ locations were as follows: rectal: 32.1%; rectosigmoid: 18.6%; sigmoid: 16.8%; Ascending Colon: 13.2 % and Descending Colon: 7.1%. Reasons for colonoscopy were as follows: Screening: 43.6 %; GI bleeding: 15.1%; Abdominal Pain: 13.1%and Change in Bowel Habits: 10.2%.

Conclusion: Our results show that there is a slightly increased predominance of SSA/P occurrence in females. Most SSA/P occurred in patients 50 to 64 years old. This age range is younger in comparison to patients with conventional adenomas. SSA/Ps were predominantly distal (rectal, rectosigmoid, sigmoid) whereas previous literature reports a proximal location. Most patients in our study were diagnosed in screening colonoscopies; however, other patients presented with symptoms such as GI bleeding, abdominal pain, or change in bowel habits.

Citation Format: Nazli Atefi, Sanmet Singh, Babak Shokrani, Edward Lee, Ali Afsari, Mehdi Nouraie, Adeyinka Laiyemo, Joseph Mathews, Carla Williams, Hassan Brim, Hassan Ashktorab. Detection of sessile serrated adenomas/polyps in African Americans [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5273. doi:10.1158/1538-7445.AM2017-5273

A meta-analysis of MSI frequency and race in colorectal cancer

PURPOSE

African Americans (AA) are at a higher risk of colorectal cancer (CRC) and some studies report a higher frequency of microsatellite instability (MSI) in this population while others report lower frequency compared to Caucasians.

AIM

To determine and evaluate the association of race and clinical factors with MSI frequency through meta- analysis.

METHODS

Twenty-two studies out of 15,105 (1997-2015) were evaluated after a search in different literature databases, using keywords “colorectal cancer, microsatellite instability, African Americans, Caucasians and Hispanics”. We used random effect meta-analysis to calculate the MSI frequency in all studies as well as in African American and Caucasian samples. Meta-regression analysis was used to assess the univariate effect of race, gender, age, tumor location and stage on MSI frequency.

RESULTS

The overall MSI frequency among CRCs was 17% (95%CI: 15%-19%, I²=91%). In studies with available race data, The MSI rate among AAs, Hispanics and Caucasians were 12%, 12% and 14% respectively and was not significantly different. Sub-group analysis of studies with racial information indicates MSI OR of 0.78 for AAs compared to Caucasians.

CONCLUSION

CRCs demonstrate an overall MSI frequency of 17%. MSI frequency differences between AAs and Caucasians were not pronounced, suggesting that other factors contribute to the racial disparity. The methodological approaches and biological sources of the variation seen in MSI frequency between different studies need to be further investigated.

IL1B-CGTC haplotype is associated with colorectal cancer in admixed individuals with increased African ancestry

Single-nucleotide polymorphisms (SNPs) in cytokine genes can affect gene expression and thereby modulate inflammation and carcinogenesis. However, the data on the association between SNPs in the interleukin 1 beta gene (IL1B) and colorectal cancer (CRC) are conflicting. We found an association between a 4-SNP haplotype block of the IL1B (-3737C/-1464G/-511T/-31C) and CRC risk, and this association was exclusively observed in individuals with a higher proportion of African ancestry, such as individuals from the Coastal Colombian region (odds ratio, OR 2.06; 95% CI 1.31–3.25; p < 0.01). Moreover, a significant interaction between this CRC risk haplotype and local African ancestry dosage was identified in locus 2q14 (p = 0.03). We conclude that Colombian individuals with high African ancestry proportions at locus 2q14 harbour more IL1B-CGTC copies and are consequently at an increased risk of CRC. This haplotype has been previously found to increase the IL1B promoter activity and is the most frequent haplotype in African Americans. Despite of limitations in the number of samples and the lack of functional analysis to examine the effect of these haplotypes on CRC cell lines, our results suggest that inflammation and ethnicity play a major role in the modulation of CRC risk.

Fecal Bacteria Act as Novel Biomarkers for Noninvasive Diagnosis of Colorectal Cancer

Purpose: Gut microbiota have been implicated in the development of colorectal cancer. We evaluated the utility of fecal bacterial marker candidates identified by our metagenome sequencing analysis for colorectal cancer diagnosis.Experimental Design: Subjects (total 439; 203 colorectal cancer and 236 healthy subjects) from two independent Asian cohorts were included. Probe-based duplex quantitative PCR (qPCR) assays were established for the quantification of bacterial marker candidates.Results: Candidates identified by metagenome sequencing, including Fusobacterium nucleatum (Fn), Bacteroides clarus (Bc), Roseburia intestinalis (Ri), Clostridium hathewayi (Ch), and one undefined species (labeled as m7), were examined in fecal samples of 203 colorectal cancer patients and 236 healthy controls by duplex-qPCR. Strong positive correlations were demonstrated between the quantification of each candidate by our qPCR assays and metagenomics approach (r = 0.801-0.934, all P < 0.0001). Fn was significantly more abundant in colorectal cancer than controls (P < 0.0001), with AUROC of 0.868 (P < 0.0001). At the best cut-off value maximizing sum of sensitivity and specificity, Fn discriminated colorectal cancer from controls with a sensitivity of 77.7%, and specificity of 79.5% in cohort I. A simple linear combination of four bacteria (Fn + Ch + m7-Bc) showed an improved diagnostic ability compared with Fn alone (AUROC = 0.886, P < 0.0001) in cohort I. These findings were further confirmed in an independent cohort II. In particular, improved diagnostic performances of Fn alone (sensitivity 92.8%, specificity 79.8%) and four bacteria (sensitivity 92.8%, specificity 81.5%) were achieved in combination with fecal immunochemical testing for the detection of colorectal cancer.Conclusions: Stool-based colorectal cancer-associated bacteria can serve as novel noninvasive diagnostic biomarkers for colorectal cancer. Clin Cancer Res; 23(8); 2061-70. ©2016 AACR.

Colorectal Cancer in Young African Americans: Is It Time to Revisit Guidelines and Prevention?

BACKGROUND & AIMS

Previous studies have suggested an increase in the incidence of colorectal cancer (CRC) in young adults (younger than 50 years). Among older people, African Americans have disproportionally higher CRC incidence and mortality. We assessed whether this CRC disparity also applies to CRC diagnosed among young people.

METHODS

Using the Surveillance, Epidemiology, and End Results cancer registries, a population-based cancer registry covering 25.6 % of the United States' African American population, we identified patients diagnosed with CRC between the years of 2000-2012. The age-adjusted rates for non-Hispanic whites (NHW), African Americans, and Asian-Pacific Islanders (API) were calculated for the age categories 20-24, 25-29, 30-34, 35-39, and 40-44.

RESULTS

CRC age-adjusted incidence is increasing among all three racial groups and was higher for African Americans compared to NHW and API across all years 2000-2012 (P < 0.001). Stage IV CRC was higher in African Americans compared with NHW, while there was higher stage III CRC in API compared with NHWs.

CONCLUSION

CRC incidence is increasing among the young in all racial groups under study. This increase in frequency of CRC is true among young African American adults who display highly advanced tumors in comparison with other races. While the present attention to screening seems to have decreased CRC prevalence in individuals older than 50, special attention needs to be addressed to young African American adults as well, to counter the observed trend, as they have the highest incidence of CRC among young population groups by race/ethnicity.

Genomics of Colorectal Cancer in African Americans

Genome-wide studies are increasingly becoming a must, especially for complex diseases such as cancer where multiple genes and diverse molecular mechanisms are known to be involved in genes' function alteration. In this review, we report our latest genomic and epigenomic findings in African-American colorectal cancer patients. This population suffers a higher burden of the disease and most investigators in this field are looking for the underlying genetic and epigenetic targets that might be responsible for this disparity. We here report genome-wide copy number variations, single nucleotide mutations and DNA methylation findings that might be specific to this population.

Reduced Representation Bisulfite Sequencing Determination of Distinctive DNA Hypermethylated Genes in the Progression to Colon Cancer in African Americans

Background and Aims. Many studies have focused on the determination of methylated targets in colorectal cancer. However, few analyzed the progressive methylation in the sequence from normal to adenoma and ultimately to malignant tumors. This is of utmost importance especially in populations such as African Americans who generally display aggressive tumors at diagnosis and for whom markers of early neoplasia are needed. We aimed to determine methylated targets in the path to colon cancer in African American patients using Reduced Representation Bisulfite Sequencing (RRBS). Methods. Genomic DNA was isolated from fresh frozen tissues of patients with different colon lesions: normal, a tubular adenoma, a tubulovillous adenoma, and five cancers. RRBS was performed on these DNA samples to identify hypermethylation. Alignment, mapping, and confirmed CpG methylation analyses were performed. Preferential hypermethylated pathways were determined using Ingenuity Pathway Analysis (IPA). Results. We identified hypermethylated CpG sites in the following genes: L3MBTL1, NKX6-2, PREX1, TRAF7, PRDM14, and NEFM with the number of CpG sites being 14, 17, 10, 16, 6, and 6, respectively, after pairwise analysis of normal versus adenoma, adenoma versus cancer, and normal versus cancer. IPA mapped the above-mentioned hypermethylated genes to the Wnt/β-catenin, PI3k/AKT, VEGF, and JAK/STAT3 signaling pathways. Conclusion. This work provides insight into novel differential CpGs hypermethylation sites in colorectal carcinogenesis. Functional analysis of the novel gene targets is needed to confirm their roles in their associated carcinogenic pathways.

Can optical diagnosis of small colon polyps be accurate? Comparing standard scope without narrow banding to high definition scope with narrow banding

AIM: To study the accuracy of using high definition (HD) scope with narrow band imaging (NBI) vs standard white light colonoscope without NBI (ST), to predict the histology of the colon polyps, particularly those < 1 cm.

METHODS: A total of 147 African Americans patients who were referred to Howard University Hospital for screening or, diagnostic or follow up colonoscopy, during a 12-mo period in 2012 were prospectively recruited. Some patients had multiple polyps and total number of polyps was 179. Their colonoscopies were performed by 3 experienced endoscopists who determined the size and stated whether the polyps being removed were hyperplastic or adenomatous polyps using standard colonoscopes or high definition colonoscopes with NBI. The histopathologic diagnosis was reported by pathologists as part of routine care.

RESULTS: Of participants in the study, 55 (37%) were male and median (interquartile range) of age was 56 (19-80). Demographic, clinical characteristics, past medical history of patients, and the data obtained by two instruments were not significantly different and two methods detected similar number of polyps. In ST scope 89% of polyps were < 1 cm vs 87% in HD scope (P = 0.7). The ST scope had a positive predictive value (PPV) and positive likelihood ratio (PLR) of 86% and 4.0 for adenoma compared to 74% and 2.6 for HD scope. There was a trend of higher sensitivity for HD scope (68%) compare to ST scope (53%) with almost the same specificity. The ST scope had a PPV and PLR of 38% and 1.8 for hyperplastic polyp (HPP) compared to 42% and 2.2 for HD scope. The sensitivity and specificity of two instruments for HPP diagnosis were similar.

CONCLUSION: Our results indicated that HD scope was more sensitive in diagnosis of adenoma than ST scope. Clinical diagnosis of HPP with either scope is less accurate compared to adenoma. Colonoscopy diagnosis is not yet fully matched with pathologic diagnosis of colon polyp. However with the advancement of both imaging and training, it may be possible to increase the sensitivity and specificity of the scopes and hence save money for eliminating time and the cost of Immunohistochemistry/pathology.

Increased MACC1 levels in tissues and blood identify colon adenoma patients at high risk

Background

Colorectal cancer is a preventable disease if caught at early stages. This disease is highly aggressive and has a higher incidence in African Americans. Several biomarkers and mutations of aggressive tumor behavior have been defined such as metastasis-associated in colon cancer 1 (MACC1) that was associated with metastasis in colorectal cancer patients. Here, we aim to assess colon tissue MACC1 protein and circulating MACC1 transcripts in colon preneoplastic and neoplastic African American patients.

Methods

Patients’ tissue samples (n = 143) have been arranged on three tissue microarrays for normal (n = 26), adenoma (n = 68) and cancer (n = 49) samples. Immunohistochemistry was used to detect MACC1 expression. Blood samples (n = 93) from normal (n = 45), hyperplastic (n = 15) and tubular adenoma (n = 33) patients were used to assess MACC1 transcripts using qRT-PCR. Distribution of continuous variables was tested between different diagnoses with Kruskal–Wallis test. Categorical variables were tested by Chi square test. We assessed the prognostic ability of IHC staining by calculating area under receiver operating characteristics curve (ROC) for adenoma and cancer separately. Differences between groups in terms of MACC1 transcript levels in plasma were calculated by using non-parametric (exact) Wilcoxon-Mann–Whitney tests. We performed all calculations with SPSS, version 21.

Results

In patient tissues, there was a statistically significant difference in MACC1 expression in normal vs. adenoma samples (p = 0.004) and normal vs. cancer samples (p < 0.001). There was however no major difference in MACC1 expression between adenoma vs. cancer cases or tubular adenomas vs tubulovillous adenomas. The area under the curve for both normal vs. adenoma and normal vs. cancer cases were 70 and 67 %, respectively. MACC1 expression was not correlated to age, gender or anatomical sample location. In patient plasma, MACC1 transcripts in adenoma patients were significantly higher than in plasma from normal patients (p = 0.014). However, the difference between normal and hyperplastic plasma MACC1 transcripts was not statistically significant.

Conclusion

Metastasis-associated in colon cancer 1 is expressed at early stages of colorectal oncogenesis within the affected colonic tissue in this patient cohort. The plasma transcripts can be used to stratify African American patients at risk for potential malignant colonic lesions.

Abstract 3130: Adiponectin, Leptin, IGF1 and TNFα serum biomarker as noninvasive diagnosis of colon adenoma

Background and Aim: The potential role of Adiponectin, Leptin, IGF1 and TNFα as biomarker in colon adenoma has not been studied. Therefore, we investigated the blood serum levels of these biomarkers in colorectal adenoma.

Method: The case-control study consisted of 198 African American patients with colon adenoma (cases) and 198 healthy individuals (controls) at Howard University Hospital. We used Elisa for biomarkers detection. Statistical analysis was performed by t-test and multivariate logistic regression.

Results: The differences in median leptin, Adiponectin, IGF1 and TNFα levels between control and case groups (6.7 vs.16.4), (11.3 vs.46.0), (4.5 vs.12.9) and (71.4 vs. 130.8) were statistically significant (p&lt;0.05), respectively. In a multivariate model, the odds ratio (ORs) for Adiponectin, TNFα and IGF1 were 2.0 (95% CI = 1.6-2.5; P≤0.001), 1.5 (95% CI = 1.5- 2.0; P 0.004) and 1.6 (95% CI = 1.3-2.0; P≤ 0.001), respectively. There were positive correlations between serum Adiponectin and IGF1 concentrations with age (r = 0.17, P≤ 0.001 and r = 0.13, P = 0.009), also between TNFα, IGF1 and Leptin concentration with Body Mass Index (BMI) (r = 0.44, P≤ 0.001 and r = 0.11, P = 0.03; r = 0.48, P≤0.001), respectively. There was a negative correlation between Adiponectin concentration and BMI (r = -0.40, P≤0.001), respectively.

Conclusion: These data support the hypothesis that serum Adiponectin, IGF1 and TNFα are risk biomarkers for noninvasive detection of colorectal adenomas.

Citation Format: Hassan Ashktorab, Akbar Soleimani, Alexandra Nichols, Komal Sodhi, Lakshmi Kannan, Laiyemo Adeyinka, Mehdi Nouraie, Hassan Brim. Adiponectin, Leptin, IGF1 and TNFα serum biomarker as noninvasive diagnosis of colon adenoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3130.

Abstract 5013: A meta-analysis of MSI frequency and race in colorectal cancer

BACKGROUND: African Americans(AA) are at a higher risk of colorectal cancer (CRC) and some studies report a higher frequency of microsatellite instability (MSI) in their tumors while others report lower frequency compared to Caucasians.

AIM: To determine and evaluate the association of race and clinical factors with MSI rate through meta- analysis.

METHODS: Twenty-two studies out of 15105 (1997-2015) were evaluated after a search in different literature databases, using keywords “colorectal cancer, microsatellite instability”. We used random effect meta-analysis to calculate the MSI frequency in all studies as well as in African American and Caucasian samples. Meta-regression analysis was used to assess the univariate effect of race, gender, age, tumor location and stage on MSI rate.

RESULTS: The overall MSI frequency among CRCs was 17% (95%CI: 15%-19%, I2 = 91%). The MSI rate among racial groups were 12%, 12% and 14% in AAs, Hispanics and Caucasians respectively and was not significantly different. Sub-group analysis of studies with racial information indicates MSI OR (95% CI) of 0.78 (0.58-1.06) for AAs compared to Caucasians.

CONCLUSION: CRCs demonstrate an MSI frequency of 17%. MSI frequency differences between AAs and Caucasians were not pronounced, suggesting other factors contribute to the racial disparity. There is a large variation in MSI rate between different studies. Methodology approaches and biological sources of this variation should be investigated.

Citation Format: Hassan Ashktorab, Sadhna Ahuja, Lakshmi Kannan, Xavier Llor, Nathan Ellis, Rosa M. Xicola, Adeyinka O. Laiyemo, John M. Carethers, Hassan Brim, Mehdi Nouraie. A meta-analysis of MSI frequency and race in colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5013.

Abstract 4488: Targeted sequencing revealed distinctive and pathogenic mutations in African Americans with colorectal cancer

Background & Aim: We recently analyzed 12 pairs of African American CRC tumors and their matched normal tissue using whole exome sequencing and established a panel of novel mutations that are potentially useful for the detection of CRC in this population. In this study, we examined APC, MSH3, and MSH6 mutations using targeted exome sequencing (TES) to determine distinctive mutations frequencies and their chronology in the neoplastic transformation.

Materials & Methods: A total of 140 colon samples: (30 normal, 21 adenomas, 33 advanced adenomas & 56 tumors collected from African Americans were used as our discovery set on an Ion Torrent platform. A subset of 36 samples were used as validation set on an Illumina platform. Bioinformatic analysis was performed on both sets of data. Common mutations were considered validated.

Results: Two novel MSH6 mutations were validated. Four known mutations in MSH3 were validated and were located in nonsynonymous (exon 10) and 1synonomous mutation (exon 18). As for the APC, 20 mutations were validated include 4 novel mutations. The novel mutations were 3 stopgain and 1 nonsynonymous located at the EB1 binding site, in the mutational cluster region (MCR), and at the 15 Amino Acid repeat.

Conclusion: We here defined novel mutations that target DNA MMR and APC genes in African Americans with colorectal lesions. Greater frequency of mutations in cells defective for DNA repair and APC genes is an advantage in cell growth and genetic instability and relevant to the initiating events of colon tumorigenesis.

Citation Format: Hassan Ashktorab, Hamed Azimi, Mike Nickerson, Sara Bass, Joseph Boland, Meredith Yeager, Sudhir Varma, Mohamed Daremipouran, Zaki Sherif, Shima Ghavimi, Babak Shokrani, Edward Lee, Adeyinka Laiyemo, Hassan Brim. Targeted sequencing revealed distinctive and pathogenic mutations in African Americans with colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4488.

Genetic Polymorphisms of TLR4 and MICA are Associated with Severity of Trachoma Disease in Tanzania

Aim

To examine the association of TLR4 Asp299Gly and MICA exon 5 microsatellites polymorphisms with severity of trachoma in a sub-Saharan East Africa population of Tanzanian villagers.

Methods

The samples were genotyped for MICA exon 5 microsatellites and the TLR4 299 A/G polymorphism by Restriction Fragment Length Polymorphism (RFLP), and GeneScan^®, respectively. The association of TLR4 Asp299Gly and MICA exon 5 microsatellites with inflammatory trachoma (TI) and trichiasis (TI) were examined.

Results

The results showed an association between TLR4 and MICA polymorphisms and trachoma disease severity, as well as with protection. TLR4 an allele was significantly associated with inflammatory trachoma (p=0.0410), while the G allele (p=0.0410) was associated with protection.

Conclusion

TLR4 and MICA may modulate the risk of severity to trachoma disease by modulating the immune response to Ct. In addition; the increased frequency of MICA-A9 heterozygote in controls may suggest a positive selection of these alleles in adaptation to environments where Ct is endemic.

Global Epidemiology of Nonalcoholic Fatty Liver Disease and Perspectives on US Minority Populations

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a clinical syndrome predicted to be the next global epidemic affecting millions of people worldwide. The natural course of this disease including its subtype, non-alcoholic steatohepatitis (NASH), is not clearly defined especially in the African-American segment of the US population.

AIMS

To conduct a review of the global epidemiology of NAFLD with emphasis on US minority populations.

METHODS

A thorough search of evidence-based literature was conducted using the Pubmed database and commercial web sources such as Medscape and Google Scholar.

RESULTS

NAFLD and its subtype NASH are becoming the principal cause of chronic liver disease across the world. In the US, Hispanics are the most disproportionately affected ethnic group with hepatic steatosis, and elevated aminotransferase levels, whereas African-Americans are the least affected. Genetic disparities involved in lipid metabolism seem to be the leading explanation for the lowest incidence and prevalence of both NAFLD and NASH in African-Americans.

CONCLUSIONS

The unprecedented rise in the prevalence of NAFLD globally requires an initiation of population cohort studies with long-term follow-up to determine the incidence and natural history of NAFLD and its underrepresentation in African-Americans. Future studies should also focus on the delineation of the interplay between genetic and environmental factors that trigger the development of NAFLD and NASH.

Targeted Exome Sequencing Outcome Variations of Colorectal Tumors within and across Two Sequencing Platforms

BACKGROUND AND AIM

Next generation sequencing (NGS) has quickly the tool of choice for genome and exome data generation. The multitude of sequencing platforms as well as the variabilities within each platform need to be assessed. In this paper we used two platforms (ION TORRENT AND ILLUMINA) to assess single nucleotides variants in colorectal cancer (CRC) specimens.

METHODS

CRC specimens (n = 13) collected from 6 CRC (cancer and matched normal) patients were used to establish the mutational profile using ION TORRENT AND ILLUMINA sequencing platforms. We analyzed a set of samples from Formalin Fixed Paraffin Embedded and FF (FF) samples on both platforms to assess the effect of sample nature (FFPE vs. FF) on sequencing outcome and to evaluate the similarity/differences of SNVs across the two platforms. In addition, duplicates of FF samples were sequenced on each platform to assess variability within platform.

RESULTS

The comparison of FF replicates to each other gave a concordance of 77% (± 15.3%) in Ion Torrent and 70% (± 3.7%) in Illumina. FFPE vs. FF replicates gave a concordance of 40% (± 32%) in Ion Torrent and 49% (± 19%) in Illumina. For the cross platform concordance were FFPE compared to FF (Average of 75% (± 9.8%) for FFPE samples and 67% (± 32%) for FF and 70% (± 26.8%) overall average).

CONCLUSION

Our data show a significant variability within and across platforms. Also the number of detected variants depend on the nature of the specimen; FF vs. FFPE. Validation of NGS discovered mutations is a must to rule-out false positive mutants. This validation might either be performed through a second NGS platform or through Sanger sequencing.