Although there is much evidence that beta-catenin is deregulated in cancer as a result of inactivating mutations in the APC and AXIN tumor-suppressor proteins and gain-of-function mutations in beta-catenin itself, the principal consequences of beta-catenin deregulation in cancer appear to be largely distinct from the effects attributable to inactivation of E-cadherin or alpha-catenin.
Loss of heterozygosity in APC was found in one cancer in adenoma that had no mutation. p53 overexpression was detected in one adenoma and 10 cancerous regions, most of which also exhibited APC alterations.
This approach classified CRC into two major groups consistent with previous classification systems: (1) ∼16 % hypermutated cancers with either microsatellite instability (MSI) due to defective mismatch repair (∼13 %) or ultramutated cancers with DNA polymerase epsilon proofreading mutations (∼3 %); and (2) ∼84 % non-hypermutated, microsatellite stable (MSS) cancers with a high frequency of DNA somatic copy number alterations, which showed common mutations in APC, TP53, KRAS, SMAD4, and PIK3CA.
Our hypothesis, which has received recent experimental support, is that the mechanism that links abnormalities at the gene level (eg, APC mutations) and abnormalities at the tissue level (eg, proliferative shift, dysplasia, carcinoma) from cancer initiation to metastasis is SC overpopulation.
Using NGS, the following mutations were detected: nonsense mutations in four tumor suppressor genes [APCR1114X (molecular argument that the cancer was a primary tumor of colon), TP53 R213X, RB1 E137X and FBWX7 R393X & S282X], mutations in three receptor tyrosine kinases (RET A919V of high transforming activity, EGFR E114K and FLT3 L601I) well known as oncogenes.
During the course of screening the 5' half of exon 15 of the APC gene for germline and somatic mutations in two groups of patients, those with the inherited cancer prone syndrome adenomatous polyposis coli (APC) or with sporadic colorectal cancer, we have identified a number of intragenic changes that are not associated with the disease phenotype.
Our results suggest that 5qLOH, APC mutations and ras mutations are present at early stages, whereas p53 inactivation is associated with progression of malignancy in a large proportion of cases.
When the analysis was restricted to our 'super-controls', healthy individuals with no family history for cancer, also rs1799977:A>G (MLH1 I219V) was associated with an increased risk in both colon and rectum patients with an odds ratio of 1.28 (CI=1.02-1.60) and 1.34 (CI=1.05-1.72), respectively (under the dominant model); while 2 SNPs, rs1800932:A>G (MSH6 P92P) and rs459552:T>A (APCD1822V) seemed to confer a protective effect.
Here, we present the creation of a stable cell line system that constitutively expresses our dual-reporter vector harboring two cancer initiating nonsense mutations in the adenomatous polyposis coli (APC) gene.
High frequency microsatellite instability and low-frequency microsatellite instability and apparently stable cancers were different in terms of tumour localisation (p=0.015), frequency of APC mutations (p=0.012), occurrence of Crohn's-like/lymphoid reaction (p=0.0353) and morphological evidence of origin from an adenoma (p=0.0338).
Regarding the relationship between COX-2 and cancer related proteins, we found that COX-2 expression is positively associated with APC (p = 0.006), and P53 (p = 0.026), supporting a cross link between these proteins in gastric carcinogenesis.
In addition, recent data on APC gene mutations challenges the existing paradigm for colon cancer carcinogenesis and precursor lesions, which may in turn have clinical implications for cancer prevention.
RUNX3 showed protein silencing in cancer and normal mucosa, compared to inflammatory peritumoural infiltrate in almost all cases, showing a non-lymphocytic predominant pattern and being correlated with epigenetic silencing.Our results show aberrant promoter's methylation in APC, CDH1, CDKN2A, MLH1 and RUNX3 associated with GC, as well as a non-lymphocytic predominant infiltrate with high expression of RUNX3.
To determine the incidence of copy number variants in cancer predisposition genes from families in the Wessex region, we have analysed the hMLH1 and hMSH2 genes in patients with hereditary nonpolyposis colorectal cancer (HNPCC), BRCA1 and BRCA2 in families with hereditary breast/ovarian cancer (BRCA) and APC in patients with familial adenomatous polyposis coli (FAP).
Familial adenomatous polyposis (FAP) is a cancer predisposition syndrome driven by germline loss-of-function of the APC gene and phenotypically manifests with intestinal polyposis and a variety of extra-intestinal bone and soft tissue tumors.
These results indicate that VHL gene mutations are related to the carcinogenesis of the clear-cell type of primary renal cell carcinomas, whereas alteration of the APC gene is not involved in the pathogenesis of this cancer.
The germline transmission of a mutation in the adenomatous polyposis coli (APC) gene leads to cancer of the gastro-intestinal tract upon somatic inactivation of the remaining allele in familial adenomatous polyposis (FAP) patients.
Mitochondrial targeting of adenomatous polyposis coli protein is stimulated by truncating cancer mutations: regulation of Bcl-2 and implications for cell survival.
Most colorectal cancers have mutations of the adenomatous polyposis coli (APC) gene or the beta-catenin gene that stabilize beta-catenin and activate beta-catenin target genes, leading ultimately to cancer.