Non-cancerous Colorectal Tissues Research Articles

Prevalence of JC Virus in Chinese Patients with Colorectal Cancer

BackgroundJCV is a DNA polyomavirus very well adapted to humans. Although JCV DNA has been detected in colorectal cancers (CRC), the association between JCV and CRC remains controversial. In China, the presence of JCV infection in CRC patients has not been reported. Here, we investigated JCV infection and viral DNA load in Chinese CRC patients and to determine whether the JCV DNA in peripheral blood (PB) can be used as a diagnostic marker for JCV-related CRC.Methodology/Principal FindingsTumor tissues, non-cancerous tumor-adjacent tissues and PB samples were collected from 137 CRC patients. In addition, 80 normal colorectal tissue samples from patients without CRC and PB samples from 100 healthy volunteers were also harvested as controls. JCV DNA was detected by nested PCR and glass slide-based dot blotting. Viral DNA load of positive samples were determined by quantitative real-time PCR. JCV DNA was detected in 40.9% (56/137) of CRC tissues at a viral load of 49.1 to 10.3×104 copies/µg DNA. Thirty-four (24.5%) non-cancerous colorectal tissues (192.9 to 4.4×103 copies/µg DNA) and 25 (18.2%) PB samples (81.3 to 4.9×103 copies/µg DNA) from CRC patients were positive for JCV. Tumor tissues had higher levels of JCV than non-cancerous tissues (P = 0.003) or PB samples (P<0.001). No correlation between the presence of JCV and demographic or medical characteristics was observed. The JCV prevalence in PB samples was significantly associated with the JCV status in tissue samples (P<0.001). Eleven (13.8%) normal colorectal tissues and seven (7.0%) PB samples from healthy donors were positive for JCV.Conclusions/SignificanceJCV infection is frequently present in colorectal tumor tissues of CRC patients. Although the association between JCV presence in PB samples and JCV status in tissue samples was identified in this study, whether PB JCV detection can serve as a marker for JCV status of CRC requires further study.

Candidate microRNA biomarkers in human colorectal cancer: Systematic review profiling studies and experimental validation

Colorectal cancer (CRC) is a major cause of cancer mortality worldwide. There is an urgent need to search for specific and sensitive biomarkers for early diagnosis of CRC. We carried out a comprehensive systematic review of published studies that compared the miRNA expression profiles between CRC tissue and paired neighboring noncancerous colorectal tissue to determine candidate miRNA biomarkers for CRC. A miRNA ranking system that takes the number of comparisons in agreement, total study sizes and direction of differential expression into the consideration was devised and used. One of the most up-regulated miRNAs, miRNA-106a, was consistently reported to be differentially expressed in six studies and the five most down-regulated miRNAs, miR-30a-3p, miR-139, miR-145, miR-125a and miR-133a, were consistently reported to be differentially expressed in four studies. Moreover, we further validated five miRNAs in a clinical setting using qRT-PCR, which demonstrated that miR-106a expression was increased, whereas the expression of miR-30a-3p, miR-145, miR-125a and miR-133a was decreased in the CRC tissues. Therefore, these miRNAs may be the candidates to develop a panel of biomarkers with sufficient sensitivity and specificity for the diagnosis of CRC in a clinical setting.

Tissue expression of Toll-like receptors 2 and 4 in sporadic human colorectal cancer

BackgroundToll-like receptors (TLRs) play an important role in innate immunity by sensing a variety of pathogens and inducing acquired immunity. To test our hypothesis that dysregulation of innate immune responses acts to trigger carcinogenesis, we studied the expression of TLR2 and 4 in sporadic human colorectal cancer tissue.MethodsIn specimens of cancerous and noncancerous colorectal tissue obtained at surgery, mRNA expression levels of TLR2 and 4 were quantified by TaqMan real-time polymerase chain reaction and compared between the two types of tissue. To confirm TLR2 and TLR4 protein expression levels, immunohistochemical analysis was performed using the same samples.ResultsTLR2 mRNA expression was significantly higher in cancerous tissue than in noncancerous tissue, while TLR4 mRNA expression did not differ significantly. Immunohistochemical analysis revealed stronger staining for TLR2 in cancerous mucosal epithelial cells than in noncancerous tissue. Staining for TLR4 in the lamina propria of the mucosa was equally weakly positive in noncancerous tissue and cancerous tissue. This TLR-specific difference in expression suggested that such expression does not only reflect a local inflammatory response to cancer infiltration, i.e., if this was the case, both TLR2 and 4 expression would probably be up-regulated. Our results suggest that TLR2 expression might be involved in sporadic colorectal carcinogenesis, whereas TLR4 is not.

TWIST1 Promoter Methylation in Primary Colorectal Carcinoma

TWIST1 gene, a transcription factor that belongs to the family of basic helix-loop-helix proteins, has been related to tumor progression and metastasis in different cancers. The aim of our study was to investigate TWIST1 promoter methylation in patients with primary colorectal carcinoma and determine its correlation with prognostic factors and disease outcome. Seventy-three patients with primary colorectal adenocarcinoma were studied. From each patient two tissue samples were collected: one sample of the tumor and one sample of normal colorectal tissue from an area located 15cm away from the tumor. Samples of colorectal mucosa obtained from 30 individuals without malignant disease were also studied as a control group. All tissues were analyzed through methylation-specific PCR. TWIST1 hypermethylation was detected in colorectal specimens of 46 patients with cancer, but in none of the tissues from the nonmalignant control group (p < 0.001). In cancer patients, TWIST1 hypermethylation was found in 38 of 73 tumor samples as compared with 20 of 73 matched samples of non-cancerous colorectal tissue (P = 0.001). TWIST1 hypermethylation was not correlated with prognostic predictors for the disease outcome, patients' overall survival and disease-free survival rates. We concluded that TWIST1 hypermethylation is present in the colon and rectum of most patients with colorectal carcinoma, suggesting this molecular alteration may be involved in the process of colorectal carcinogenesis.

Genome-Wide Expression Analysis of Middle Eastern Colorectal Cancer Reveals FOXM1 as a Novel Target for Cancer Therapy

To identify genes potentially playing an important role in the progression of colorectal carcinoma (CRC), we screened global gene expression using cDNA expression array on 41 CRC tissue samples and 25 noncancerous colorectal tissue samples. Among the up-regulated genes, forkhead box M1 (FOXM1) has been shown to play a critical role in pathogenesis of various malignancies. Using immunohistochemistry on 448 Saudi CRC samples in tissue microarray format, FoxM1 protein overexpression was seen in 66% of CRC tissues and was significantly associated with poorly differentiated and highly proliferative tumors (P = 0.0200 and 0.0018, respectively). FoxM1 expression was also significantly associated with MMP-9 protein expression (P = 0.0002). In vitro data using CRC cell lines showed that inhibition of FoxM1 by thiostrepton resulted in inhibition of proliferation and induction of apoptosis in a dose-dependent manner. Overexpression of FoxM1 potentiated cell proliferation, cell transformation, and migration/invasion of CRC cells via up-regulation of FoxM1 target genes MMP2 and MMP9 and protected these cells from thiostrepton-mediated antiproliferative effects. Finally, in vivo, overexpression of FoxM1 promoted growth of CRC-cell line xenograft tumors in nude mice. Altogether, our data indicate that FoxM1 signaling contributes to aggressiveness in a subset of CRC and that the FOXM1 gene may serve as a useful molecular biomarker and potential therapeutic target.

Prevalence of human papillomavirus in Chinese patients with colorectal cancer

The prevalence of human papillomavirus (HPV) was determined in Chinese patients with colorectal cancer (CRC). The study also aimed to determine whether the HPV DNA peripheral blood (PB) assay can be used to diagnose HPV-related CRC. Tumour tissue, noncancerous colorectal tissue and whole-blood samples were obtained from 96 patients with CRC. In addition, 32 colorectal tissue samples were harvested from patients without CRC, and 48 whole-blood samples were collected from healthy blood donors. HPV DNA was detected by means of a nested polymerase chain reaction (PCR) using consensus primers, and HPV genotypes were determined by reverse Southern blot and pyrosequencing. HPV DNA was detected in 32 of the 96 patients with CRC, and colorectal tissues from the 32 control patients without CRC were negative for HPV DNA (P < 0.001). Among 48 healthy donors, three had detectable levels of HPV DNA in their PB. Patients with CRC did not have significantly higher levels of HPV DNA than controls. The HPV prevalence in tumour tissues was higher than that in noncancerous colorectal tissues (P < 0.001) or that in PB samples (P < 0.001). No correlation between the presence of HPV and demographic or medical characteristics was observed. HPV 16 was the viral type most frequently detected and was found in 33 (94%) of 35 HPV-positive patients. HPV infection may be a risk factor for CRC. However, detection of HPV DNA in PB does not appear to reflect the HPV status of CRC.

DcR3 and survivin are highly expressed in colorectal carcinoma and closely correlated to its clinicopathologic parameters

To investigate the expression of death decoy receptor 3 (DcR3) and survivin in colorectal carcinoma. Tumor and normal tissues were taken from a total of 100 colorectal carcinoma patients during surgery, and the expression of DcR3 and survivin was examined by immunohistochemistry, Western blotting, and reverse transcription-polymerase chain reaction (RT-PCR) analyses. RT-PCR showed that the expression levels of DcR3 mRNA (0.846+/-0.242, P<0.01) and survivin mRNA (0.7835+/-0.2392, P<0.01) in colorectal cancer tissues were significantly higher than those in adjacent normal tissues. Western blotting showed that the expression levels of DcR3 protein (0.795+/-0.261, P<0.01) and survivin protein (0.6765+/-0.1351, P<0.01) in tumor tissues were significantly higher than those in non-cancer tissues. The immunohistochemical streptavidin-peroxidase (SP) method showed that the positive expression rates of DcR3 and survivin were 67.0% and 58.0% in colorectal cancer tissues, and 18.0% and 3.0% in non-cancerous colorectal tissues (P<0.05), respectively. The positive correlations of DcR3 (P<0.01) and survivin (P<0.01) to the differentiation of colorectal carcinoma cells, lymph node metastasis, and pathological stage were observed. The expression of DcR3 and survivin was found to be positively correlated to clinicopathologic parameters of colorectal carcinoma. The overexpressed DcR3 and survivin in colorectal cancer may contribute to the development of the cancer. The monitoring of these two proteins may be useful for the diagnosis, differentiation, metastasis, and determination of stages of colorectal carcinoma.

MDR1 T-129C Polymorphism can be Predictive of Differentiation, and Thereby Prognosis of Colorectal Adenocarcinomas in Japanese

The expression level of MDR1 mRNA was evaluated in colorectal adenocarcinomas and adjacent noncancerous colorectal tissues obtained from 21 Japanese patients. It was lower in the former than in the latter (p=0.012), suggesting its down-regulation as a consequence of malignant transformation of colorectal tissues, possibly with the suppression of differentiation. Relatively lower expression was suggested in moderately-differentiated colorectal adenocarcinomas than well-differentiated ones, but there was no statistical difference (p=0.111). MDR1 mRNA up-regulation was found in a colorectal adenocarcinoma cell line, HCT-15, after treatment with two typical differentiating agents, sodium butyrate and all-trans retinoic acid, suggesting its involvement in the cellular events, resulting in differentiation without malignant transformation. MDR1 T-129C, but not G2677A,T and C3435T, was associated with the lower expression of MDR1 mRNA both in colorectal adenocarcinomas (p=0.040) and adjacent noncancerous colorectal tissues (p=0.023), possibly being an useful invasive marker predicting poorly-differentiated colorectal adenocarcinomas and thereby the poor prognosis of the patients, especially when no extra biopsy samples will be obtained. Further investigations with relatively large number of patients should be undertaken to confirm these preliminary results.

Clinical Significance of Human Kallikrein Gene 6 Messenger RNA Expression in Colorectal Cancer

Human kallikrein gene 6 (KLK6) is a member of the human kallikrein gene family, and recent studies have found that many kallikreins have altered expression patterns in various malignancies. The purpose of the current study was to quantify the expression of KLK6 in malignant and benign colorectal tissues and to statistically analyze whether KLK6 expression levels correlate with clinicopathologic variables and prognosis in patients with colorectal cancer. Paired colorectal tissue samples from cancerous and corresponding noncancerous tissues were obtained from 63 patients with colorectal cancer who underwent surgical resection. Quantitative analyses of KLK6 mRNA expression were done using real-time quantitative reverse transcription-PCR. KLK6 mRNA overexpression in cancerous tissues compared with normal counterparts was observed in 57 of 63 (90%) patients. The mean expression level of KLK6 mRNA in cancerous tissues was significantly higher than that in noncancerous tissues (P < 0.0001). Elevated KLK6 expression was significantly correlated with serosal invasion (P < 0.05), liver metastasis (P < 0.05), and advanced Duke's stage (P < 0.01). Furthermore, patients with high KLK6 expression had a significantly poorer actuarial overall survival than patients with low KLK6 expression (5-year overall survival rates: 54% and 73%, respectively, P < 0.05). The results of this study indicated that KLK6 mRNA expression was significantly higher in cancerous than in noncancerous colorectal tissues, and high expression of KLK6 mRNA correlated with serosal invasion, liver metastasis, advanced Duke's stage, and a poor prognosis for patients with colorectal cancer.

Association of VEGF genotype with mRNA level in colorectal adenocarcinomas

The mRNA expression of vascular endothelial growth factor (VEGF) was evaluated in colorectal adenocarcinomas and adjacent noncancerous colorectal tissues in 18 Japanese patients. The expression was confirmed to be up-regulated in the colorectal adenocarcinomas, when compared with the noncancerous tissues. Twelve genotypes of VEGF: six positions in the promoter region, two in the 5′UTR, and four in the 3′UTR, and their association with the expression of VEGF mRNA were evaluated. While G-1877A, T-1455C, G-1154A, C702T, and G1612A were not detected, C-2578A, T-1498C, G-1190A, C-634G, C-7T, C936T, and C1451T were found at allele frequencies of 4/36, 15/36, 15/36, 20/36, 8/36, 6/36, and 6/36, respectively, suggesting that C-2578A, G-1154A, and G1612A were associated with a decreased risk for colorectal adenocarcinoma. T-1498C (G-1190A) and C-7T were found to be associated with higher levels of VEGF mRNA, and may be a risk factor for the development of liver metastasis and/or prognosis of colorectal adenocarcinoma.

Alterations in the signal-transducing molecules of T cells and NK cells in colorectal tumor-infiltrating, gut mucosal and peripheral lymphocytes: correlation with the stage of the disease.

T cells from mice bearing an experimental colon carcinoma, and from patients with colorectal and renal carcinomas, have atypical T-cell receptors (TCR). In the present study, further characterization of modulations in CD3- and CD16-associated zeta chain in peripheral blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) from colorectal carcinomas was performed. Relative to PBL, the percentage of natural killer (NK) cells among fresh TIL was reduced, while a higher proportion of T cells expressing HLA-DR was found. As previously reported, we found significantly reduced levels of the CD3- and CD16-associated zeta chain in TIL and, to a lesser extent, also in patients' PBL. Levels of zeta chain in T and NK cells from non-cancerous colorectal tissue from patients were lower than in PBL but higher than in TIL, with a direct relationship between levels of this signal-transducing molecule and the distance from the tumor. In addition, zeta levels correlated with the Dukes' stage of the disease, since PBL from patients with lymph-node involvement or distant organ metastases (Dukes' stages C and D) had significantly less CD3 zeta than patients with localized disease (stages A and B). Patients' T cells also had decreased levels of cell-surface and cytoplasmic CD3 epsilon. We also observed reduced levels of the TCR accessory molecules CD4 and CD8, mainly on TIL but to a lesser extent also on patients' PBL. Biochemical analysis of anti-CD3 epsilon-immunoprecipitated TCR complexes demonstrated that the CD3 complex was not associated with the zeta chain, either on TIL or on PBL or on lymphocytes from non-cancerous colon tissue, suggesting a defect in the assembly of the TCR complex. Following several days of in vitro culture with recombinant interleukin-2 and phytohemagglutinin, anti-CD3 or anti-CD2 monoclonal antibodies (MAbs), levels of CD3 zeta chain as well as of cell surface CD3 epsilon were normalized. Our findings suggest an abnormal expression as well as assembly of several different signal-transducing molecules of T cells and NK cells, which correlate with the stage of the disease in patients with colorectal carcinomas.

Serum and tissue trace elements in colorectal cancer.

Serum copper, zinc, and Cu/Zn ratio were measured using atomic absorption spectrophotometry in 30 patients with colorectal cancer and compared with 30 healthy control subjects. In the patients with colorectal cancer, the tissue copper and zinc levels were also measured in paired histologically normal and malignant colorectal tissue samples obtained at surgery. The mean serum copper levels were higher in patients with colorectal cancer (165.99 vs. 98.84 micrograms/dl) (P < 0.001). The mean serum zinc levels were lowered only in advanced (Dukes stages C and D) colorectal cancer compared to controls (89.94 vs. 115.08 mu/dl) (P < 0.001). However, the Cu/Zn ratio progressively increased with the advancing stage of malignancy (1.86 vs. 0.86) (P < 0.001). The cancerous colorectal tissue showed a higher concentration of both copper (2.78 vs. 1.79 micrograms/g) (P < 0.001) and zinc (27.16 vs. 18.98 micrograms/g) (P < 0.01) compared to non-cancerous colorectal tissue. The exact mechanism responsible for the alterations in trace element levels in patients with colorectal cancer is largely unclear and requires further evaluation. However, the serum copper level and the Cu/Zn ratio are of value in estimating the extent of the carcinoma as well as in determining the prognosis of these patients.