Abstract PO-226: Gene expression levels correlation to colon cancer disparities amongst African and Caucasian American men

Author(s):  
Darryl A. Sams ◽  
Dana R. Marshall
2021 ◽  
Vol 22 (16) ◽  
pp. 8485
Author(s):  
Iranzu Gómez de Segura ◽  
Patricia Ahechu ◽  
Javier Gómez-Ambrosi ◽  
Amaia Rodríguez ◽  
Beatriz Ramírez ◽  
...  

Objective: The protein microfibril-associated glycoprotein (MAGP)-1 constitutes a crucial extracellular matrix protein. We aimed to determine its impact on visceral adipose tissue (VAT) remodelling during obesity-associated colon cancer (CC). Methods: Samples obtained from 79 subjects (29 normoponderal (NP) (17 with CC) and 50 patients with obesity (OB) (19 with CC)) were used in the study. Circulating concentrations of MAGP-1 and its gene expression levels (MFAP2) in VAT were analysed. The impact of inflammation-related factors and adipocyte-conditioned media (ACM) on MFAP2 mRNA levels in colon adenocarcinoma HT-29 cells were further analysed. The effects of MAGP-1 in the expression of genes involved in the extracellular matrix (ECM) remodelling and tumorigenesis in HT-29 cells was also explored. Results: Obesity (p < 0.01) and CC (p < 0.001) significantly decreased MFAP2 gene expression levels in VAT whereas an opposite trend in TGFB1 mRNA levels was observed. Increased mRNA levels of MFAP2 after the stimulation of HT-29 cells with lipopolysaccharide (LPS) (p < 0.01) and interleukin (IL)-4 (p < 0.01) together with a downregulation (p < 0.05) after hypoxia mimicked by CoCl2 treatment was observed. MAGP-1 treatment significantly enhanced the mRNA levels of the ECM-remodelling genes collagen type 6 α3 chain (COL6A3) (p < 0.05), decorin (DCN) (p < 0.01), osteopontin (SPP1) (p < 0.05) and TGFB1 (p < 0.05). Furthermore, MAGP-1 significantly reduced (p < 0.05) the gene expression levels of prostaglandin-endoperoxide synthase 2 (COX2/PTGS2), a key gene controlling cell proliferation, growth and adhesion in CC. Interestingly, a significant decrease (p < 0.01) in the mRNA levels of MFAP2 in HT-29 cells preincubated with ACM from volunteers with obesity compared with control media was observed. Conclusion: The decreased levels of MAGP-1 in patients with obesity and CC together with its capacity to modulate key genes involved in ECM remodelling and tumorigenesis suggest MAGP-1 as a link between AT excess and obesity-associated CC development.


2015 ◽  
Vol 33 (3_suppl) ◽  
pp. 653-653
Author(s):  
Bodil E. Engelmann ◽  
Tina Binderup ◽  
Andreas Kjær ◽  
Annika Loft ◽  
Thomas A. Gerds ◽  
...  

653 Background: Positron emission tomography (PET) with the glucose analogue 18F-fluorodeoxyglucose (FDG) is widely used in oncologic imaging. This study examines the molecular mechanism underlying the detection of colon cancer (CC) by FDG-PET. Methods: Pre-operative PET/CT scans and tissue samples from primary CC and surrounding normal mucosa were obtained from 42 patients. FDG uptake was quantified using maximal standardized uptake value (SUVmax). The expression of ki67, glucose transporter 1 (GLUT-1), hexokinase 1 (HK1), hexokinase 2 (HK2), vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1α (HIF1α) and carbonic anhydrase IX (CaIX) mRNA was examined by quantitative real time reverse transcriptase-polymerase chain reaction. Results: All primary tumours showed increased uptake of FDG. The mean SUVmax was 15.0 (range 5.3 – 37.8). No correlation was found between tumour size and SUVmax. Mean gene expression levels of GLUT1, HK2, ki67, HIF1α, VEGF and CaIX, but not HK1, were significantly higher in primary tumours than in surrounding normal colonic mucosa. Linear regressions pairing tumour SUVmax with gene expression levels showed significant correlations between SUVmax and HK2, ki67 and CaIX, respectively. Conclusions: These results confirm FDG PET/CT as a functional imaging method in CC, and that FDG accumulation reflects molecular events related to glycolysis, cell proliferation, hypoxia, but not angiogenesis.


2013 ◽  
Vol 31 (4_suppl) ◽  
pp. 397-397
Author(s):  
John P. Shen ◽  
Devon Marcus McGee ◽  
Andrew M. Lowy ◽  
Paul Timothy Fanta

397 Background: Appendix cancer is rare, which precludes its study in randomized trials. As such, no evidence-based guidelines currently exist regarding the optimum systemic therapy for this disease entity. Typically, these patients are treated with regimens for colorectal carcinoma. Previous studies have shown high intra-tumoral mRNA levels of EGFR were significantly associated with response to irinotecan based chemotherapy, and that mucinous colorectal cancer overexpresses markers of resistance to 5-FU and oxaliplatin. We examined pharmacogenomics markers for appendiceal cancer and colon cancer to understand underlying similarities and differences between these tumor types. Methods: Intratumoral gene expression levels were assessed from paraffin-embedded tissue samples, using laser capture microdissection and quantitative real-time PCR from 69 colorectal and 34 appendiceal adenocarcinomas. A retrospective chart review was performed to correlate gene expression with overall survival. KRAS and BRAF mutational analyses and gene expression levels of ERCC1, TS, and EGFR were correlated with overall survival. Results: Appendiceal tumors had significantly higher expression of EGFR, (2.66 vs 1.4, p<.0001). No BRAF V600E mutations were found in the appendiceal tumors, incidence was 8.97% of the colon patients. UPDATE: In appendix cancer, KRAS mutations were noted in 65.5% of patients, there were no BRAF mutations. Median ERCC1, TS, EGFR, and VEGFR2A expression was 1.4, 1.21, 1.57, 2.19 respectively. Patients with metastatic appendiceal cancer had a significantly longer median OS than metastatic colon patients, (113 mo vs 43.9 mo, p = .0154). For appendiceal cancer patients, there was no significant correlation between any of the biomarkers and OS, although the sample size was underpowered for such an analysis. Conclusions: Metastatic appendiceal cancer patients have significantly better outcomes than metastatic colon cancer patients. Molecular analyses reveal significant differences between these tumor types. Further molecular study of appendiceal cancer is needed, as this study and others suggest fundamental differences in biology from colon cancer.


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 4040-4040 ◽  
Author(s):  
Y. Ning ◽  
G. Lurje ◽  
K. Danenberg ◽  
J. Cooc ◽  
D. Yang ◽  
...  

4040 Background: Tumor recurrence after curative resection is still a major problem in the management of adjuvant colon cancer, with recurrence rate approximately 30–40%. Identifying molecular markers for tumor recurrence is critical for successfully selecting patients who are more likely to benefit from adjuvant chemotherapy. Our group previously showed that angiogenesis gene polymorphisms (VEGF and IL-8) may associated with tumor recurrence in adjuvant colon cancer (Lurje Ann Oncol, 2008). Here we tested the hypothesis whether gene expression levels of angiogenesis pathway (COX-2, EGFR, VEGF, VEGFR1, VEGFR2 and IL-8) could also predict the risk of tumor recurrence in stage II and III colon cancer patients treated with adjuvant chemotherapy. Methods: Tissue samples from 140 adjuvant colon cancer patients (69 females and 71 males with a median age of 59 years; range=28–86) were available for gene expression assays. These tissue samples were obtained at the University of Southern California/Norris Comprehensive Cancer Center (USC/NCCC) and LAC+USC medical center between 1999 and 2006. Sixty-three patients had stage II and 77 had stage III colon cancer. The median follow-up was 5.4 years (range=2.0–16.8). 51 of 140 patients (36.4%) developed tumor recurrence with a 5-year probability of 0.28 ± 0.06 for stage II and 0.40 ± 0.06 for stage III colon cancer patients. mRNA was extracted from laser-capture-microdissected tumor tissue. After cDNA was prepared by reverse transcription, quantitation of the candidate genes and an internal reference gene (ß-actin) was performed using a fluorescence-based real-time detection method (TaqMan). Results: We found VEGF and VEGFR1 gene expression levels independently significantly associated with time to tumor recurrence in adjuvant colon cancer patients. Patients with lower VEGF gene expression and lower VEGFR1 gene expression levels had significantly longer time to tumor recurrence compared to those with higher VEGF and higher VEGFR1 gene expression levels (p<0.05, log-rank test). Conclusions: VEGF and VEGFR1 gene expression levels may predict tumor recurrence risk in adjuvant colon cancer patients. Our exploratory data warrant future confirmatory trial. [Table: see text]


2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e22042-e22042
Author(s):  
N. Virk ◽  
D. Yang ◽  
H. J. Lenz ◽  
A. B. El-Khoueiry ◽  
K. D. Danenberg ◽  
...  

e22042 Background: Recent efforts have expanded our understanding of the molecular pathogenesis of UGI cancers and how oncogenes and tumor suppressor genes play a role in both carcinogenic and metastatic processes. These markers may serve as prognostic and/or predictive factors for recurrence following resection and resistance to radiotherapy and chemotherapy. Gene expression levels of thymidylate synthase (TS), thymidylate phosphorylase (TP), epidermal growth factor receptor (EGFR) and excision repair cross complementing (ERCC-1) have been shown to be associated with outcomes in lung, gastric and colon cancer. We evaluated TS, ERCC-1, EGFR and TP gene expression levels in patients with UGI cancers. Methods: This was a retrospective study of 80 pts with UGI cancers evaluated at USC who underwent molecular profiling. The primary objective was to determine a correlation between TS, TP, ERCC1 and EGFR and correlate with clinical outcome. Characteristics of these 80 pts: (16 females, 64 males ); median age 61 years (range 34–85); tumor types evaluated - 32 (40%) esophageal, 24(30%) gastric, 24(30%) GE junction; stages- 53 % IV, 21% III, 12% II, 2% I were evaluated for intratumoral gene expression of TS, TP, ERCC-1, & EGFR by real time quantitative PCR using Taqman technology from microdisected paraffin-embedded tumor sections. Results: High TS expression was associated with shorter OS (12.8 months vs. 23.7 months p=0.036). A significant correlation was found between TP & ERCC-1 (p=0.0078, r=0.37); TP & TS (p=0.0128, r=0.35); TP & EGFR (p=0.0065, r=0.39); TS & ERCC-1 (p=0.0004, r=0.39); ERCC-1 & EGFR (p=0.025, r=0.30). No statistically significant relationship was found between TS & EGFR (p=0.06,r=0.25). There was no correlation of ERCC-1, TP, & EGFR with OS that reached statistical significance. Conclusions: TS mRNA levels were shown to be associated with OS in UGI tumors, consistent with data reported in colon cancer. TS gene expression was significantly associated with expression levels of ERCC-1. In addition, ERCC1 was associated with EGFR. These data show for the first time that molecular pathways of cytotoxic agents are linked to the EGFR pathway suggesting that sensitivity to fluoropyrimidines, oxaliplatin, and EGFR inhibitors may be associated. No significant financial relationships to disclose.


Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 854
Author(s):  
Yishu Wang ◽  
Lingyun Xu ◽  
Dongmei Ai

DNA methylation is an important regulator of gene expression that can influence tumor heterogeneity and shows weak and varying expression levels among different genes. Gastric cancer (GC) is a highly heterogeneous cancer of the digestive system with a high mortality rate worldwide. The heterogeneous subtypes of GC lead to different prognoses. In this study, we explored the relationships between DNA methylation and gene expression levels by introducing a sparse low-rank regression model based on a GC dataset with 375 tumor samples and 32 normal samples from The Cancer Genome Atlas database. Differences in the DNA methylation levels and sites were found to be associated with differences in the expressed genes related to GC development. Overall, 29 methylation-driven genes were found to be related to the GC subtypes, and in the prognostic model, we explored five prognoses related to the methylation sites. Finally, based on a low-rank matrix, seven subgroups were identified with different methylation statuses. These specific classifications based on DNA methylation levels may help to account for heterogeneity and aid in personalized treatments.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Weitong Cui ◽  
Huaru Xue ◽  
Lei Wei ◽  
Jinghua Jin ◽  
Xuewen Tian ◽  
...  

Abstract Background RNA sequencing (RNA-Seq) has been widely applied in oncology for monitoring transcriptome changes. However, the emerging problem that high variation of gene expression levels caused by tumor heterogeneity may affect the reproducibility of differential expression (DE) results has rarely been studied. Here, we investigated the reproducibility of DE results for any given number of biological replicates between 3 and 24 and explored why a great many differentially expressed genes (DEGs) were not reproducible. Results Our findings demonstrate that poor reproducibility of DE results exists not only for small sample sizes, but also for relatively large sample sizes. Quite a few of the DEGs detected are specific to the samples in use, rather than genuinely differentially expressed under different conditions. Poor reproducibility of DE results is mainly caused by high variation of gene expression levels for the same gene in different samples. Even though biological variation may account for much of the high variation of gene expression levels, the effect of outlier count data also needs to be treated seriously, as outlier data severely interfere with DE analysis. Conclusions High heterogeneity exists not only in tumor tissue samples of each cancer type studied, but also in normal samples. High heterogeneity leads to poor reproducibility of DEGs, undermining generalization of differential expression results. Therefore, it is necessary to use large sample sizes (at least 10 if possible) in RNA-Seq experimental designs to reduce the impact of biological variability and DE results should be interpreted cautiously unless soundly validated.


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