Oncogenic Role of Connective Tissue Growth Factor Is Associated with Canonical TGF-ß Cascade in Colorectal Cancer.

TGF-ß signaling pathways promote tumour development and control several downstream genes such as CTGF and MMPs. This study aimed to investigate the association between CTGF and MMP-1 mRNA expressions with clinicopathological status and survival rate in colorectal cancer patients. We investigated expression levels of CTGF and MMP-1 genes in paraffin-embedded tumours and adjacent normal tissue blocks (ADJ) by Real Time-PCR. Then, the expression of Smad2 and Smad4 proteins in the TGF-ß canonical pathway was evaluated by immunohistochemistry. Finally, the correlation between CTGF, MMP-1, and the canonical TGF-ß-signalling pathway with the clinicopathological features was investigated. Expression levels of MMP-1and CTGF were higher in tumours compared with adjacent normal tissues. Overexpression levels of MMP-1 and CTGF were associated with lymph node metastasis, distant metastasis, tumour histopathological grading, advanced stage, and poor survival (p < 0.05). Additionally, a significant association between the upregulation of MMP-1 and tumour location was noted. Upregulation of Smad2 and Smad4 proteins were also significantly correlated with lymph node metastasis, distant metastasis, advanced stage, and poor survival (p < 0.0001). This study showed that canonical TGF-ß signalling regulates both CTGF and MMP-1 expression and CRC progression. Moreover, TGF-ß signalling and its downstream genes could be used as novel biomarkers and novel approaches for targeted therapy in CRC.

Insights into the Role of Matrix Metalloproteinases in Precancerous Conditions and in Colorectal Cancer.

Colorectal cancer (CRC) is the third and second cancer for incidence and mortality worldwide, respectively, and is becoming prevalent in developing countries. Most CRCs derive from polyps, especially adenomatous polyps, which can gradually transform into CRC. The family of Matrix Metalloproteinases (MMPs) plays a critical role in the initiation and progression of CRC. Prominent MMPs, including MMP-1, MMP-2, MMP-7, MMP-8, MMP-9, MMP-12, MMP-13, MMP-14, and MMP-21, have been detected in CRC patients, and the expression of most of them correlates with a poor prognosis. Moreover, many studies have explored the inhibition of MMPs and targeted therapy for CRC, but there is not enough information about the role of MMPs in polyp malignancy. In this review, we discuss the role of MMPs in colorectal cancer and its pathogenesis.

APC and AXIN2 Are Promising Biomarker Candidates for the Early Detection of Adenomas and Hyperplastic Polyps.

Aberrant activation of the WNT/CTNNB1 pathway is notorious in colorectal cancer (CRC). Here, we demonstrate that the expression of specific and crucial WNT signaling pathway genes is linked to disease progression in colonic adenomatous (AP) and hyperplastic (HP) polyps in an Iranian patient population. Thus, we highlight potential gene expression profiles as candidate novel biomarkers for the early detection of CRC. From a 12-month study (2016-2017), 44 biopsy samples were collected during colonoscopy from the patients with colorectal polyps and 10 healthy subjects for normalization. Clinical and demographic data were collected in all cases, and mRNA expression of APC, CTNNB1, CDH1, AXIN1, and AXIN2 genes was investigated using real-time polymerase chain reaction (PCR). CTNNB1 and CDH1 expression levels were unaltered in AP and HP subjects, whereas mRNA expression of APC was decreased in AP contrasted with HP subjects, with a significant association between APC downregulation and polyp size. Although AXIN1 showed no changes between AP and HP groups, a significant association between AXIN1 and dysplasia grade was found. Also, significant upregulation of AXIN2 in both AP and HP subjects was detected. In summary, we have shown increased expression of AXIN2 and decreased expression of APC correlating with grade of dysplasia and polyp size. Hence, AXIN2 and APC should be explored as biomarker candidates for early detection of AP and HP polyps in CRC.

Lack of association between VEGF -2578C/A polymorphism and risk of colorectal cancer in an Iranian population.

AIM: Here, we evaluated the VEGF gene -2578C/A polymorphism as a potential susceptibility factor in colorectal cancer (CRC) occurrence amongst Iranian CRC patients. BACKGROUND: Vascular endothelial growth factor (VEGF) is a key regulatory factor in angiogenesis which plays essential roles in the development of malignancy in colorectal cancer (CRC), as the third most prevalent cancer worldwide. METHODS: VEGF -2578C/A polymorphism was evaluated in 200 CRC patients and 200 healthy control subjects via restriction fragment length polymorphism analysis. RESULTS: The frequencies of CC, AC and AA genotypes among CRC patients were 22.5%, 51% and 26.5%, respectively, with their respective genotype frequencies at 16%, 54% and 30% in control cohorts (P=0.247). The A allele frequency among the case group was 52% and for control group, it was 57%. C allele frequency in case and control groups was 48% and 43%, respectively (p=0.156). No significant association was observed (p=0.990) between this polymorphism and CRC stage. CONCLUSION: Our findings provide limited support for the hypothesis that the -2578C/A VEGF are associated with increased risk of colorectal cancer in Iranian colorectal cancer patients and suggest instead that meta data studies, which have previously relied upon populations definitions such as 'Asian', should more specifically take into account country of origin when associating prognostic value to a given genotype.

The Differential DNA Hypermethylation Patterns of microRNA-137 and microRNA-342 Locus in Early Colorectal Lesions and Tumours.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, representing 13% of all cancers. The role of epigenetics in cancer diagnosis and prognosis is well established. MicroRNAs in particular influence numerous cancer associated processes including apoptosis, proliferation, differentiation, cell-cycle controls, migration/invasion and metabolism. MiRNAs-137 and 342 are exon- and intron-embedded, respectively, acting as tumour-suppressive microRNA via hypermethylation events. Levels of miRNAs 137 and 342 have been investigated here as potential prognostic markers for colorectal cancer patients. The methylation status of miRNA-137 and miRNA-342 was evaluated using methylation-specific (MSP) polymerase chain reaction (PCR) on freshly frozen tissue derived from 51 polyps, 8 tumours and 14 normal colon mucosa specimens. Methylation status of miRNA-137 and miRNA-342 was significantly higher in tumour lesions compared to normal adjacent mucosa. Surprisingly, the methylation frequency of miR-342 (76.3%) among colorectal cancer patients was significantly higher compared to miR-137 (18.6%). Furthermore, normal tissues, adjacent to the lesions (N-Cs), displayed no observable methylation for miRNA-137, whereas 27.2% of these N-Cs showed miRNA-342 hypermethylation. MiRNA-137 hypermethylation was significantly higher in male patients and miR-342 hypermethylation correlated with patient age. Methylation status of miRNA-137 and miRNA-342 has both diagnostic and prognostic value in CRC prediction and prevention.

The Application of Gene Expression Profiling in Predictions of Occult Lymph Node Metastasis in Colorectal Cancer Patients.

A key factor in determining the likely outcome for a patient with colorectal cancer is whether or not the tumour has metastasised to the lymph nodes-information which is also important in assessing any possibilities of lymph node resection so as to improve survival. In this review we perform a wide-range assessment of literature relating to recent developments in gene expression profiling (GEP) of the primary tumour, to determine their utility in assessing node status. A set of characteristic genes seems to be involved in the prediction of lymph node metastasis (LNM) in colorectal patients. Hence, GEP is applicable in personalised/individualised/tailored therapies and provides insights into developing novel therapeutic targets. Not only is GEP useful in prediction of LNM, but it also allows classification based on differences such as sample size, target gene expression, and examination method.

GJA4/Connexin 37 Mutations Correlate with Secondary Lymphedema Following Surgery in Breast Cancer Patients.

Lymphedema is a condition resulting from mutations in various genes essential for lymphatic development and function, which leads to obstruction of the lymphatic system. Secondary lymphedema is a progressive and incurable condition, most often manifesting after surgery for breast cancer. Although its causation appears complex, various lines of evidence indicate that genetic predisposition may play a role. Previous studies show that mutations in connexin 47 are associated with secondary lymphedema. We have tested the hypothesis that connexin 37 gene mutations in humans are associated with secondary lymphedema following breast cancer surgery. A total of 2211 breast cancer patients were screened and tested for reference single nucleotide polymorphisms (SNPs) of the GJA4 gene (gap junction protein alpha 4 gene). The results presented in this paper indicate that two SNPs in the 3' UTR (the three prime untranslated region) of the GJA4 gene are associated with an increased risk of secondary lymphedema in patients undergoing breast cancer treatment. Our results provide evidence of a novel genetic biomarker for assessing the predisposition to secondary lymphedema in human breast cancer patients. Testing for the condition-associated alleles described here could assist and inform treatment and post-operative care plans of breast cancer patients, with potentially positive outcomes for the management of disease progression.